David Vizard's PowerTec 10 EP 45 Crank Journal Polish = + 20 HP?
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- čas přidán 22. 08. 2024
- In this, Episode 45 part 1, DV looks into crank prep moves that can help increase the high end output of your motor. some can be done at home to boot. Also he looks into design features that you need to know about if you are buying a crank - especially if it is a low buck stroker crank. And, last on the list, is the fabled 20 hp increase supposedly delivered by micro crank polishing. So does it - or is that just ad hype?
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David is a good person. I called him up one day, looking to buy springs and bob weights for my Mini distributor (since I had 2 editions of how to midify your Modi) and David refused to sell me anything because the industry couldn't wind the same spring twice and end up with the same spring constant.
We talked over the engine specs, which cam I used, the head changes, the use of the engine, and then he had me write down the necessary static advance, vacuum advance, and the bob weight advance curve that would avoid the knock zone, and get the thing to run well.
I took that information to my local Mini wrench, he looked at it all, said "hmm that's an interesting curve, do you mind if I take a copy?" and built up my distributor accordingly.
It worked very nicely, but the one thing that stuck with me was that David refused to sell me something that he knew wasn't going to work properly. That's a sign of integrity.
Thank you David.
Andrei, thank you very much for your kind words. DV
I listen 2 some of his talks & all the little bit xtras he talks about makes up 4 some fabulous HP Gains .
My take is this man's career and love is being passed on in these video's. I have only watched 20mn dabbling briefly. Many folks like instant type power gains. The short I watched are for patient meticulous mechanic types or engineer minded. Indexing any system is not for everyone. I have dabbled many yrs at work with amazing results or problem solving issue's. All engines are relevant across the industry. 1 or 2 thoughts here......seasoning before machining, not building charge during and seasoning after. Any part really like cams. Not doing so is one of the reasons rebuilds don't always last long. Earthly realignment we can say. I dabble in science/physics related subjects decades. Physics isn't everyone's favorite class. The coolest bad ass subject matter on earth imo, better fuel mileage ect
David, I found that one "unique" counter weight profile you formed with a body & fender grinder to be most interesting! You possess the ability to manage to be able to find hidden H/P & Torque in practically any moving piece both inside & outside of an internal combustion engine. I would have racked my brain in trying to figure out how to "lathe out" a radiused counter weight profile @ an affordable price. Meanwhile ole professor Vizard Picks up a $25.00 body & fender air tool plus a couple/three grinding discs & then transforms a $600.00 crankshaft into a $2,500.00 engineering marvel! You are a MAJOR ASSET to our brotherhood of hotrodders, performance enthusiasts & machinists for sure!!!
Bob, - you just made my day - Thanks
DV
if you have a old school laith it's not that hard to make a HSS tool bit shaped by a mill or powered hand tools in the reverse pattern of what your looking for and it's faster than grinding for 3+hours plus balancing can be done somewhat without drilling. look up keth farnered or tublican or booth/abome. as for me i hung around old grumpy guys that if you're responsible and respectful they might tell there secrets or not if thay don't ever like you lol 😂and a cnc 3-plain or more can do it to as my high school experience was educating me to be a mechanist ( and had 1 to 2 years left to pass the testing to get hired. i was planning on that pay for parts of my mechanical engineering degree and helping forward my manufacturing understanding and help my hobby's at home 😉) ( and i was and still kinda hoping that i could get hired as a power/test/or safety crash automotive engineer but that didn't happen and in 2022 is getting more far fetched to achieve and now ended up fixing plant equipment and cars ) but that didn't work out as i had my mom ( honestly at points in my childhood sucked at be there and a mom as this wasn't the first time she left/ilresponsibility ) bonce for some guy @ 17y but luck was kind enough to have my deploma it just was a lot harder to get and a bad ish job by 18/19y
You forgot more than most will ever know. I built my first small block around your book over 20 years ago.
Thanks again
I think I memorized it...lol
I have just about every book he ever made worth every penny and I'm looking forward to going to his school
I am a believer in Scat cranks and rods , great price as well!
Scat are reliable import cranks
I have found listening to David's calming voice about topics of Interest has become quite therapeutic during my ride home from a stressful day of work
Majority of crank manufacturers are now nitrating or using coatings to make the surfaces smoothers then even a high polish. Dry film bearings, or nickle coated cranks give a microscopic smooth finish. Oil shedding abilities also take credit for some of the HP gain. Plus stronger cranks from additional coatings.
I suspect the Germans were trying to get anything they could to splash upon the piston bottoms of that "Rocket Fueled" F-1 motor in that era.....Heat rejection at any costs! Scat makes a great product....as they always sourced the final machining and finish right here in the USA. It's just a shame that our steel suppliers haven't been utilized for raw materials.....The way things are going....I predict some changes are coming.
I was curious on the profile being that way myself. I figure they had a reason with the amount of tech in those engines.
Trump 2024 is coming ....
i thought the same thing, possibly able to save some weight aswell, less oil.
Thanks David. I ground cranks for a decade at Dick Moritz and Midwestern motor rebuilders in Tulsa in the 80s and your 20hp title caught my eye.. I was happy to hear you call it BS. Love your stuff. I own most of your books and did everything you taught me in my 406 build down to port & polishing the oil pump. Yes I run a 9000 series scat. Weisco flat tops MLS cometic. 027 gaskets and have a .037 quench.. it runs like a raped ape. Love it. Thanks.
Oh. It's 10.89/1 and runs fine on 93 octane with 220 flotek cnc ported heads that flow 315cfm.. also read your book on carbs and have a older HP950 (830cfm) that runs perfect using that book on 4150s you wrote sure helped. That and having dual afr wideband gages helps.
Mr. Gamora sir, Glad to be of help and thanks for taking the time to tell us all the results you achieved.
DCV
When you said some manufacturer claimed 20 hp I immediately said bull! If you would have said otherwise I would have felt dumb. I greatly respect your knowledge on engine building. Second to none!
This guy is a true master at his game, he has more than likely forgot more than most know, thanks David
Thank you. I'm learning.
I ran out of words to congratulate me. Just thank for sharing your knowledge 🙏
Thanks for taking time to make these videos and sharing your knowledge 👍👍👍
As usual, really appreciate the tech! It's kind of amazing, with so many high quality and affordable cranks available right off the shelf these days, and for more applications than ever too, I think crankshaft design often gets taken for granted and overlooked anymore. I'm partial to Molnar stuff, but there's so many good options available today.
There's a pretty cool example of Scat cranks in the big block Ford community - a lady named Erica Ortiz raced a steel body Thunderbird Pro Mod in the old Fun Ford Weekend series in the 2000s if anyone remembers the Pro 5.0 days, got down to 6.80s@200s in the 1/4 with a big block Ford.
The engine was a production 4-bolt main 429 Super Cobra Jet block(generally thought to be a little 'stronger' than a stock 2-bolt main block, and a little 'weaker'[with production BBF blocks it's really about cap walk/chatter] than a 2-bolt block with 4-bolt main conversion caps, which are splayed instead of parallel and use larger bolts), bored/stroked to 498", budget Ford Motorsports SCJ aluminum heads, with a pair of 76mm turbos. Oh yea, and a *CAST* Scat crank! This car was making around 1700-1800HP crank on the high-6 second passes(2700lbs), and doing so with a production BBF block, a Scat cast crank, and budget aluminum heads. Engine was built by Al Moody who some may have heard of, very impressive combo! These builders that are out there producing big power with production blocks always catch my attention more than any other.
There's video of a 6.8x pass here on YT too, if you search 'Erica Ortiz thunderbird', maroon '90s T-bird slammed on giant tires
Sometimes life gets in the way of watching your videos in a timely manner
Thank you for sharing you wisdom on the topic and looking forward to viewing part two of this series .From western Canada where 3verythings out of balance !
Thank you for all that knowledge that you freely share. I've followed you for years, from the book days. Now hearing the written words come to voice, means so much more to me. Knowledge is power. Thanks again.
David, I've started watching your videos, AND LEARNING(!) from them at the suggestion of Richard Holdener in his videos. I love how you have no fear of dispelling various falsehoods that are rampant in this hobby. Don't ever stop doing that! I've also bought your head porting book, if only to learn the proper methods to have someone do if i should find need of such a service. I just love learning the proper way of doing things. Thank you, David!
Thanks David for this informative video. My thought when I saw the title was if it takes 20 HP to turn the crank you've done something horribly wrong in the assembly of the engine. Maybe they were running undersized bearings on a standard crank so that when they polished .010 off the crank they were able to make those "20 HP gains". LOL 😂
Ive polished cranks. It take a surprising amount of effort to remove .001" (not that youd want to) never mind .010". perhaps if youve under cut a crank and dont have a nitride it goes much faster but hopefully for you that's not the case because you want crank pins to be precise. You're more likely to gain 20hp from changing the oil levels.
@@danieldimitri6133 I ground cranks for a decade myself and .010 must be a typo.. we had a old 50s machine that we had to use to grind long caterpillar and big 8" oil rig journals with it and it was a little sloppy on the heavy oil rig cranks and tended to leave a out of rount by .0005 and the tolerance was .001 so I had to polish the Out of round out and when I was done you couldn't find any out of round but it took me a hour of meticulous polishing to accomish a mirror finish with no waves and no taper and no out of round.. .010 would look like shit or take forever and to mic it at the end perfectly with no ooo or taper would be impossible even for a seasoned grinder..
Gooday Daniel ,You got that right ! I can polish a std/std crank with 2000 grit & I use a .001" undersize bearing . Never work without serious heat build or knock. I've used A Van Norman 111 crank grinder (1943 yr, Model) set up to take the cranks between centres that worked perfect to .0000" no fooling ! No taper or runout that I could detect ! Just out of curiosity how was the machine that you used set up ie.. in chucks/between centres ? & if it is between centres I want to know where u are located. Thank You James T. Burke & Gooday
Thanks for your analysis, I really appreciate your comments.
Sidenote On a personal level it’s been an honour and a privilege talking with you David and I want to thank you for taking the time, it really means a lot too be talking with you a legend and iconic name in the car world! i have been a fun of your for some years now and have a few of your books as well and boy you’re books have helped me , till next time you’re friend from Canada
You are very welcome sir.
Hers a story of a broken crankshaft. I was working for a shop that rebuilt and R&R’d engines. I left that job because the owner was the biggest crook I’ve ever met, but right before I left we had a gentleman come in to the shop. As he drove his dodge van onto the lot the racket is was making caught everyone’s attention. It was such a strange sound coming from that engine that none of us who heard it could diagnose what was wrong. My mechanics went straight into trying to figure out what the problem was, with none of their efforts working to fix the engine. So we ok the job on and after pulling the engine it was taken to the rear down area. When one of the guys pulled the pan, and started pulling the crank out he came into the parts room where I worked and got me along with the other guys to go look at what he found. The crankshaft was broke into two pieces right under the center main bearing. In the 318, the center bearing is the thrust bearing and that bearing has flanges on its sides to keep the crank running in line with the rest of the rotating mass. The crank had broken at an angle, and the front half drove the back half when one of the cylinders at the front of the engine fired, and then the back half drove the front half when one of the rear cylinders fired. It was the damndest thing I’ve ever seen!
Thank you DV👍
Specter ran 415 miles per hour at Bonneville with a Turbo charged 482 in³ Cadillac 472 with a stock Block, a stock Cast crank and ported stock heads This is a record for a stock production engine block and crank! Maybe even a record for ported mass produced stock heads. I.e. not even hemis! Although I think the 2017 and up Viper V10 might be able to outdo it! They said that the maximum RPM they hit during this several mile run was 5000 RPM, Does that imply that; the stock block can live under incredible torque And more development of this engine probably Should be done? All of the 472 and 500 cadillacs had very high nickel blocks and heads, they also all had 5" bore spacing with thick cylinder walls! Your opinion on bothering to build a turbocharged Cadillac 472 or 500 is very interesting to me! Thank you sir, respectfully, Kurt Osborne PS. there are no factory forged cranks or after market cranks for this engine, although the potential for a very large stroker is there ! Here in maui they are the only old big blocks you can basically get very cheap or for free! I have 3 of them.
Kurt, a very interesting post here. Can you expand on it - I, as well as others, would like to know more.
thanks
DV
@@marvingvx1 1973 and earlier '76 CC' combustion chamber heads are superior! STOCK FLOW numbers with stock 2.0 "&1.625 valves at 28"H2O are =
..100.......200..........300.............400..........500...........600...........700... Other than the stock Cam, valve Springs and intake the 6.75" armaloy rods & stock rocker stands
83/73..134/107...180/141...215/164...248/181...263/191...277/206. Limit the engine to + -- 5000 rpm! (HEI distributors from "76" on fit all years!) "77" was Feul Inj.
( No clear answers on whether ARP rod bolts will increase the RPM limit for the bottom end! (***472= 5200rpm Because of the piston speed difference for the shorter stroke**? But it has a heavier piston!?>
I'm thankful for anything you have to say, you're a frickin genius on SBCs!
John.
thanks for the compliment but I think genius may be somewhat of an overstatement!
DV
@@marvingvx1 ok, let me rephrase, your engineering knowledge, ability and attention to detail mark you as being one of the best. I'm interested in what you say. The previous was a quick phrase which said about the same thing to me anyway.
You keep teaching and I will always take notes!
@@marvingvx1Polishing journals wouldn’t make sense for power gain because the crank and all the other metal parts are riding on oil not metal to metal
Great information again David
Thank You very much. You are very kind to share your knowledge of years experience. Thanks again David Always be safe in your travels and Take Care
Mr. Critter - much appreciated sentiments sir. Thank you.
DV
I remember way back i when i was a kid i use to hang around a shop in my home town that a fellow had a monza that he had done pretty well with . I remember the Pete saying he pickup up horse power on his engine going to a smaller main bearing size. . i think he said he spun it to 10k or a bit more . Thanks for the videos
David is fantastic. Can we do without that creepy music?
David is passing on information you'll never get from anyone on the internet. But, you complain about background music?
Ģ
@@olderthanyoucali8512 .
Stop
what you non tribal? great music david dont change a thing
I appreciate the approach of cost/benefit being the deciding factor, when most answers to performance is "Throw more money at it."
Just had a Scat stock stroke small block chevy forged crank balanced and the machinist commented that it was a very nice crank.
Three other possible issues with short rod to stroke ratios -
The piston acc'n around TDC is higher which puts additional stress on the connecting rod, etc.
The higher velocities due to ^^^^ can help or hinder the gas flows during overlap.
The secondary imbalances are worse, which can lead to high levels of vibration.
I keep telling people that it's the side thrust from the piston, and not the actual combustion pressures, that causes cylinder walk and failure - the higher pressures increase the side force from the piston - simple vector forces - but the actual pressure is equal on all sided of the bore so no imbalance causing movement.
This can lead to issue #4 - head gasket sealing problems and split cylinders if the bores aren't supported adaquately.
Hey David. I have purchased and studied lots of your books and watched and rewatched your videos for some time and would actually really enjoy to have you autograph a book to hang in my house. I hope this is possible to make happen!
Colby, Yes go to our web site get the address there sand mail it to Marvin.
Put a note in the pages saying how you would like it dedicated plus $5 for the return shipping.
DV
🔔😎👍
WOW, just WOW.
I've often wondered about the Ford 302 counterweights vs the 5.0 crankshaft.
🤔🤔😎
Good to know about fancy polish jobs
DV just want to say thanks again
On a running engine the crank has a hydraulic film of oil that doesn't compress so the friction reduction would be between the oil and the surface of the crank ,not the crank touching the bearing surfaces like many amateurs think happens. It only touches during startup which is where more wear occurs than anything. I don't see 20hp reduction from micro polishing either maybe less wear on startup is possible
I remember accumulators for oil pressure prior to cranking.
Awesome video David and
🙋♂️🇬🇧
Sharing your work and like everyone I see when you release a new video.
Might be worth mentioning that it is probably a good idea to polish the journals in the right direction. It is somewhat contested but the argument is that you get microscopic burrs in the direction of polishing that if angled the wrong way (in relation to crank rotation) might cause problem with bearing life.
Guess they think of bearing micro-cavitation due to oil film turbulence. However for there to be much turbulence in the oil film (which causes friction and heating) to begin with the clearance is most likely too large anyways. If done in the engines direction of rotation or not, polishing by belt or wheel is not recommended, but better than nothing if the surface finish is unknown. Tho a mirror finish or not is not the best indication for surface finish. An actually flat/true surface with a dull-looking finish is far superior to a (relatively) "bumpy/uneven" one that is shiny like a mirror (polishing a turd, is still a turd).
Also usually (proper, mind you) crank polishing is a process isotropic in nature where there is no particular order to the direction of the abrasive action or to the final mirror-finish. First step is the "Isotropic Super-Finishing", or "Chemically Accelerated Surface Finishing" as it actually is called in a vibrating tumbling ceramic media, then in step two the parts are "Burnished" aka the peaks of the surface are smeared into the valleys by vibration tumbling in ball-bearings giving the mirror finish. Both steps have random directions (everywhere) of the "abrasive" and "smearing" actions respectively.
Watching from panama Central America. Thanks Mr Vizard!
I know you likely have already filmed the part-2 crank balancing video, though I hope you discuss reasoning / rationale behind selecting specific balance factors beyond 50% (specifically when 51-54% may or may not be advantageous).
Thank you again, David! @10:00. Rod/Stroke ratio is B/A, not A/B as you said. But you knew that!
Well David I got my answers , it can be done with a backwards spinning starter but it’s just for the test stand endless you want a five speed reverse lol but that can still be overcome with some ingenuity. Comp cams said I’m the first person to ever ask for this style of cam and that they would have too retool and r n d and for them to even think of it would be thirty grand , I almost feel like grinding my own billet cam from scratch. Either way I’m making it happen, also have plans for a five cycle motor build using a dodge la block stay toned for that one . As always much love your friend in Canada
Fantastic feature, you may also want to talk about low pressure oil drillings, we did it at TWR race engines for Menards Nascar engines back in 2003, the cranks were made by Chambon in France who also made the F1 cranks for Ferrari. Happy to share info if its unknown.
Thank you David. That was some of the most informative information I've ever heard about Crankshaft technology
Excelant video need to see more.
Enjoy your videos, like to see you do some Audi engines like the 1.8 5 valve per cylinder version
and the 24 valve per cylinder version of the VR6 engine !
Sounds like fun. The VW 1.8T 20V was probably the most common 5V engine seen in the USA. I had an MKIV Jetta and it was fun.
Just seen a tuner on CZcams take a bone stalk 2003 MK4 golf.. Is 1.8t Motor is bone stock from valve cover to Oil Pan.. All he installed was a big Turbo.. And ID 2000 injectors.... And a downpipe... Trying to see what they could get for horsepower and torque out of a 220000 mile bone stalk not well took in care of motor.. The motor Had been beat pretty bad before they started tuning.. Right now they're not done tuning or squeezing power yet.... They made 566 horsepower and over 500' pounds of torque.. Stock rod stock motor top to bottom... One thing he has done is made sure the Is torque don't kick in early and snap the rods... But that's impressive
@@shawnlibby675 The 1.8T lasted a long time if you changed the oil more often than the manual said. Following the manual schedule and using Castrol 5w40 Syntec or something lesser was the early end of many B5/B5.5 Passats in the USA.
@@skylinefever You are correct Very correct.. My 05GLI factory oil Pan on a 1.8 Turbo 6 speed 4.7 qt ... Depending on how you drive I Usually try to get it out around the 2000 mile mark.. I also overfill the oil a little bit... I've had the car for over 8 years.. Still on a stock K03S Turbo.. I Have pounded on this car a lot... Still don't puff one puff of smoke and don't burn any oil burn any oil but the Turbo Still performs OK but I think it needs a new one lol... The only thing notorious on this car I've had a problem with is the motor mounts transmission mount and a arms... But other than that these motors are tough keep the oil changed And keep The Timing belt changed accordingly... It's also one of the only motives in the world that will run in idle turned over backwards lol.. And I run 502 approved mobile one fully advanced synthetic 0/40 w.. The car is on an APR tune also and a 3" downdown pipe 007fogebov..02m6 spd edl fwd
I love that Creepy ? Music.
Thanks David been a 1/4 mile racer for 40 years. The parts nowadays are far and away better than anything we could buy at any reasonable price . Someone telling me that are making 400-450hp from a 302 ford,driving it everyday with automatic trans. Stock gears and power brakes..that's just BS...There is just to much internet..BS
YOUR honesty and knowledge come shining through all of your videos
The know how are priceless and should be required viewing for all the young racers . Thanks again
Mr. Slick Sir, 450 is doable but you had better know what is needed to achieve it. But I see your point here - I have tested several 450 claimed hp engines that did not break the 400 mark.
DV
@@marvingvx1 400 rear wheel horsepower is nothing to sneeze at but the new super cars are using tech. Today that was reserved for formula 1 engines of yesterday. Thank you for the reply...Don
Omg...at the 9:30 mark i was reminded of The Great Piston Pin Offset Swaparoooo Controversy 😲😛
Thank you DV and Co.
Most Pontiac guys step up to a Crower Billet.
A Winnberg.
Moldex.
Kellog forged.
A few use Scat.
Eagle is the Original Replacement crank for Pontiac V8 but has a not so good reputation and Factory Pontiac cranks are way stronger.
Just can't get enough love every minute
Pontiac 455 engines 1970-1976 use Lightning drilled Rod Journals also stock the only out of all Pontiac V8 engines displacement ever made.
I can testify they are Super Strong the Nodular Cast iron crank.
Many have pushed to 1000 Hp Roots Super Charged. Twin Turbo to 1600 Hp. Massive crank compared to most but it's near Bullet Proof.
I ran a Scat 9000 series Import finished in the USA Years back. Best $199.00 crankshaft fir a SBC 350. It never broke or failed.
"It can be done at home"
Before you get someone to balance it right...
I'd be too embarrassed to take something to a machinist that would look like I'd already tinkered with it.
I dunno about other countries, but in Australia if you do something yourself then take it to a tradesperson for further work they'll either laugh in your face or won't touch it to save their own arse in case something happens.
Gooday David , there is a difference that Norton & other crank grinding abrasive companies recommend for different materials . The # on the side of a crank grinding wheel tells U the specifications & it tells quite a story in itself. There is a few a that require different grinding wheels , however I never here U say anything about cross drilling the main journals for a full 360 degrees of oil supply to the rods . I like chrome crankshafts & other types of surface hardening as well , like on older GMC trucks & some Vette engine etc... Nitriding I think . Also something else I think U should know . Most factories (before say C.N.C.) grinding crankshafts (Ford ,Chev, Dodge) did all their cranks between centres . I can take one crank after another & grind the mains & there all the same on O.D. & never having to adjust the machine after the first one is done & they r on the money ! So David please tell me why (all the reground cranks in this part of the world are done in crankshaft grinding machines held in chucks & therefore ruining the balance of the crank & the crankshaft grinding machine as well ) I can't get an old crank refurbished without getting a crude facsimile & an out of balance crank back for my money . P.S. I've heard of a 283 in a taxi that reached 1,000,00 miles or close that was rebuilt with some knowledge of what the hell is going on . I've built winning stock car engines & all I want to start with was a std/std crank a 2000 grit hand polish & a sbc set up with William Tyler Jenkins book on his recommendations for sbc's cooling in the block & heads. I don't like to brag , but o'well , here goes. I was asked buy a good friend to build a sbc 305 (YUK PUK) for their car . I said I would be glad to & I was told not to cheat building it . I didn't cheat I used all the stock parts ! Well we had three first's in three races & in the last race , they put him in the back of the pack (dirty ,rotten ,little you get the pic )WWEELLL guess what he still came in first & we where the only car from our province in those races . Cause that's the way we do it . They called cheat again & their series folded . I'm I BAD ? AKA MOTOR MOUSE Thank You & Gooday James T. Burke
James - a good read here. You raise so many relevant points that I would like to mention but video length is already a concern. Maybe we should talk about a part 3 for this mini series. I could well use some guidance here.
DV
Gooday David , I would be honoured to contribute any information from my limited knowledge to you . I will provide you with a little info about rebuilt engines for cars ,trucks , bikes , boats & small propeller planes . I have watched various videos on you tube proving to me that their work is done incorrectly & replied to their videos saying so. My replies were met with humour / disrespect & down right stupidity in their ignorance . You see I was using a crank grinding machine the incorrect way at first (the way I was taught) & could not meet specifications & then I learned the proper way & they were " perfect " meeting all the specifications with no runout to .0000" I consider myself lucky to have learned from a person that was in the Ford Plant during the second world war (with the war effort) & seen how the crankshafts were held in the crank grinding machines . The Van Norman 111 crank grinder was the oldest & best machine I have used . I believed it was a 1943 Model . You see the problem is our armed forces use these pieces of crap in everything from boats/cars/jeeps/trucks to helicopters . I've heard of several of our choppers having to make a forced landing & the ones that don't shake themselves apart & boats losing an engine 60 miles from shore . The worst part about knowing the difference is that no one regrinds crankshafts properly around here & you have to buy new to get what you pay for . I bought the V.N. 111 when my employer passed on & I lost it in a fire started buy a person welding for someone else a few years back . Now I've given up building engines . I do somethings different when I do valve jobs , that seem to work better than most . From the land of the fabled schooner " Bluenose" by a person who has magic hands ! The only way these people(doing them incorrectly) get any work at all must be out of ignorant people needing their done in a last ditch desperate attempt to get their engines rebuilt fast. It does not need to be proper , just fast & cheaper than new . Well in the long run you might as well buy new cause it won't be cheaper in the long haul & you don't know where or when their work (CRAP) is going to let go ( CAPUT)! I would be more than honoured to contribute & it kind of flatters me to think I could contribute to someone I think is as smart as you . Thank You James T. Burke From the land of one of the finest schooners everbuilt on Earth ! N.S. , Canada Gooday & God Bless@@marvingvx1 G
Gooday David , whenever you might want to talk about crankshafts & things let me know. I would like to pass onto you & others like yourself any pertinent info about crankshafts . One thing I have found is a complete screw job on anyone needing a crankshaft reground clear across the market . I found out from a person who with the war effort (Second World war) toured the Ford engine plants & seen how all their crankshafts were being machined . Just to make a point ; all their cranks were being machined between centers & used a dog on both ends . You see I originally was taught to regrind cranks in -between 2 chucks & could not meet the specs for the cranks . Then I see on U-Tube people doing them incorrectly for boats, small planes etc... I was able to achieve .0000" runout no problem on all journals . I used this man's machine Van Norman 111 to do it precisely like the factories did them . That man passed on & I bought his equipment . Then a welder burnt up the place & my machines ruined. It was no accident & I sued & won a decision never replacing what had been lost. These stupid bastards are ruining the machines their using & their products are a piss poor example of what real machinist do . The machine I had the pleasure of using was the very oldest & "THE VERY BEST" You Say Expose IT I just did. I guess were all lemmings & have to except what we get from these people. @@marvingvx1
Mr Vizard thank you for all this information
I enjoyed the Engineering Data input from You David Thdnks.
Great information as always. Thank you for sharing your knowledge!
Very awsome info!
I have a scat rotating in a turbo build for 7-8 yrs no issues. I've had problems with the build but I know the bottom end is solid.
As always David. Great info
Yeah I've had people tell me that scat cranks and rods were junk so I was going to stay away from that stuff and do a crawler but if the things you showed on these cranks to do for my circle track racing in a street stock that we're not pushing over 600 650 horse price wise compared to the others I'm going to give it a try I really like your little explanation on these cranks
Rick, Make sure you use a good crank damper!
DV
great information!
DV, thank you for lots of info and insight. Much appreciated!
I understood center counter weight cranks would reduce crank flex and main bearing issues at higher rpm (7500+) Since a drag race engine is only run for
TBL - yes! DV
My scat crank still holding up in my 383 build with a 250 shot of nos.. Video a bit on the basic side.. But glad your getting the secrets out 😆
Love your work sir.
Thanks David, great video👍
Thank you
Good info to have, thanks David.
Good stuff David. Care to do any consulting for an underfunded national touring stock car racing team? We can't pay much, if anything, but we have fun and can feed you pretty well. I guess you could call us a geriatric racing team, but we finished, I think, 6th is driver's points last year. Keep the good stuff coming buddy.
thank you , and love you david vizard ! ! !
DV is a gem!
Good Video 👍
First scat crank I bought was 40 years ago - knife edged VW crank - I think from Brazil ..
David, can you get your Ed to run a spellcheck before he prints the credits and headings , he is 95% of the way there - but there are a few missed vowels and adjectives spelt like they sound.. lol, I'm not being picky but english was my strong suit in school (I was terrible at maths) and I just can't leave it lie.. 🤓Keep up the great work though, you are getting more confident in front of the camera and your presentation just gets better and the subject matter just cant get more interesting. (can't wait for the 421 build too, have ordered a Chevrolet 400 block as I was planning something similar beforehand, but wouldn't you know it - supply chain is out until April)
Chuck, As it happens none of use are good at spelling. We are good innovators and engineers though. Not really an excuse but my (our) defence here is that someone who can only spell a word one way lacks imagination!!!
But just for you - we will really try harder in future!!!
DV
Great video Mr. Vizard! What are your thoughts on crank surface prep to shed oil (I polished the casting finish to a smooth finish) and rod side clearances-I've seen pictures of massive rod side clearances (nascar engine) you could measure with a tape measure instead of feeler gauges. Thank you. Please minimize/stop the music when Mr. Vizard is speaking.
Irritating music.
I am no expert, but I've been around a couple Nascar long blocks. I think the idea behind the big end side clearance is to encourage both the big end and the wrist pin end to "float" thereby reducing friction. Those Nascar boys do wild things to pick up tenths of a horsepower.
Looking forward to the coating episode, can you please also making an episodo about piston rings, materials, coatings, finishings, piston ring groeve, tips about the finishing of these groeves and rings contact surfaces.
Remy, I am currently putting together a ring episode.
DV
@@marvingvx1 that will be awesome Mr. Vizard
I’m sure oil pressure and viscosity has as much, if not more effect than the polish o the crank
Mr. Hoonatic, Yes it does - maybe I should show some oil tests along the way here soon.
DV
Thanks David!
Well done! Thank you.
Knowledge is power.
The hole in the rod throws of a crankshaft is for strength. . .but more importantly it's for *stiffness* Hollow section tubular materials will always be stiffer than solid section given the same material composition. It doesn't make sense to our brains at first, but the science of it proves this to be correct.
Lets see, does that mean that if I put a solid bar inside a tube I can bend it easier?
Well from an engineering standpoint that is not exactly true. A 3" solid bar is stiffer than a 3" bar with a hole in it. This is true for bending and torsion. That being said the center adds very little to the values.
@@bcbloc02 A 3" solid bar will have higher initial stiffness, but far lower ability to resist permanent plastic deformation than the hollow section. Also weight savings.
@@bcbloc02 My tubing bender bends roll bar tubing no problem but has a hell of a time trying to bend a solid bar even at smaller diameter. I don't under stand the science of it only the reality of it. Would it be stronger if the bar was many tubes like a lamination of tubes?
@@midgetrace No a solid bar will be stiffer and stronger than a laminated bar, that is unless the deformation is so great that it starts to crack then strength goes down rapidly. I suspect in the case of the crank deal the hole has more to do with improving crank life by reducing weight and thus the cyclic rotational forces than any increase in strength as material gone always reduces strength.
Thanks for video!
Hey David, saw the title for this video, and had to watch it. Despite your tenure as a respected automotive journalist and engine builder, I was trying to imagine how the hell someone would have had 20 horsepower worth of friction at the crankshaft journals on a V8 engine, without making enough heat to start burning pieces blue
Yes, I understand that it does take horsepower to shear the oil as it tries to stick to a pair of sliding pieces, this will create heat, and take power.
But 20 horsepower? I would be shocked to find that there would be that kind of power loss.
An interesting test would be to put a dummy shaft in the block of an engine, just a straight piece of shaft with no oil holes or throws...
Run an oil pump to provide pressure, and measure how much force it takes to spin that shaft at different RPM levels
This would, of course, not take into account the connecting rod journals, but would isolate the mains by themselves. It would be a quick and easy way - for a guy who had the resources -(pro stock, nascar, etc) to determine what the bearings consume for power in a dynamic situation
I expect that people who compete at those levels probably have measured this and know.
But, truck drivers who tinker with the occasional hot rod engine, like myself, have to rely on CZcams
😆
David Vizard is a top R&D mechanical engineer, not a journalist.
Mr. Carfarmer sir - I totally agree - 20 hp's worth of friction would burn stuff left, right and center.
DV
Good job kids.
✌🇺🇸✌🤠
Scat crankshafts were sold to LLC last year, owned by same company that bought AFR
Cassandra (great name by the way!) yes I was told that Scat had been sold. It was about time for Tom to retire.
DV
Well I feel even better about my scat stoker kit now
O bougth 2 books (how to build horsepowet and one for head hork)it had the best and clear explanation of the engine science ! This man os a legend! I am from Brasil 🇧🇷 and here we work alot on the six online gm that is similar tô holden 6… do you have any book about the SIXES?
have a question say you have a crank case volumed and you machined casting off everything possible say a blue print specification on a rotating bottom end LS/SBC/SBF. does crank case pumping gases/air. volumetric effiecenticy matter for the like's of a ls standard say 7000 to 7500 rpm vs and last gen SBC... and i wonder when a vacuum pump becomes a must or when you get to a limit when you should really have one
Now on a small block chevy, we have been running a 4.155 bore with a 3.25 stroke crank, using a 6.125 in rod. The ratio is above 1.8. Is this hurting performance at all?
I would say since that is a high rpm type deal.. you are in a ideal situation!
I believe you meant to say fifteen hundred watts not 15,000 thousand. Good work and thanks for your continu
Great tech. Thanks look forward to more developments.
This channel is dead for now, find his other channel here: www.youtube.com/@DavidVizard
How would more air be drawn into the cylinder if the piston is not moving and in he same position longer? With a longer stroke the piston will be moving down farther and longer allowing more air to be pulled in. Can you explain how I’m incorrect?
I have always thought that If all is well and there is oil pressure, then the crank bearings will not be in contact with the journals, therefore what could polishing acheive?
You mentioned crankcase vacuum and it's affect on windage. I was wondering if you could speak about vacuum pumps and PVC help or hindrance on street-strip engines? Thanks for an informative episode, once again !
Jeff - can do - look for this down the road.
DV
Scat offers good quality and value on stock type replacement cranks for SBC.
Michael - my thoughts exactly!
DV
If you are saying "Ain't" then you are hanging out with me too much! Lol
Does it mention what alloy the crank is made of?
6:45 I thought that was called "Compression height." Maybe pin height and compression height are used interchangeably? I always always told this number was the center of the piston pin bore to the piston crown.
22:35 Thanks. This might explain why I saw counterweights on boxer cranks, heard someone say it was better, and now I think I see the point. I always thought boxers were neat because you could easily do away with counterweights. Also, some inline fours depended on counterbalance shafts, and a boxer would never need them. It is one reason why when the Evo 8/9 and WRX STI were on sale in the USA, I wanted the WRX STI. I suppose since those rally cars are on boost, beefing up a crank is more valuable than shaving off a little weight.
23:03 When using a stroker crank to build a Jeep 4.0 to 4.7 stroker, some people like to buy the old fully counterweighted crank from the early Jeep 4.2/258 if they run boost.
Yes Skyline, I do tend to use these two terms interchangeably.
DV
@@marvingvx1 Thanks.
at 18-19 rpm the oil shear is the biggest problem. not boundry layer.