Selecting the right camshaft- Matching your cam to your compression ratio - PART 1

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  • čas přidán 10. 03. 2023
  • This video highlights what can happen if you choose a camshaft that is too big for your engine, and why it is important to select the right combination of parts.
    The test subject in this video is a 406 Pontiac from previous videos but this applies to all engines.
    We have increased static compression from 9.1:1 to 9.88:1
    The Crower 60916 camshaft has been advanced 4 degrees to increase cylinder pressure and improve low end torque.
    It is manufactured with 4 degrees of advance ground into it, to achieve the 108CL it was installed 4 degrees of advance. It is now installed at 104 which is on the 8 degree advance mark.
    We will find out how much of a difference this makes on March 18 when we Dyno this engine again.
  • Auta a dopravní prostředky

Komentáře • 158

  • @duanedahl8856
    @duanedahl8856 Před rokem +6

    It's worth mentioning that your altitude where you live is also very important! I use the Wallace racing calculator and it has this included.
    And the cam timing number you need are the "off the seat" duration number and not the "at .050" number to select the most proper camshaft for the application.
    I live at 3400 above sea level, and I'm using Aluminum cylinder heads, so an 11.8 to one static compression is what I need to get 170 psi with the parts I have!...good to see professional builders sharing this priceless info!

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks for your valued information and comments Duane

  • @robertwest3093
    @robertwest3093 Před rokem +5

    Us car guys need more real world videos like this! Thank you for sharing.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks for your kind words Robert, it motivates me to keep making videos.
      Allan Gold

  • @HunterNapier
    @HunterNapier Před 2 měsíci +1

    Thank you for including the story about getting it wrong. I have been fighting with my FE 390 rebuild with a new cam, but all stock for almost 8 months. I have tried everything, advancing cam, smaller carb, different tuning, etc. All stock motor except a cam I have now finally come to realize, is WAY too big for the compression ratio (Probably mid to high 8's, I have 120 flat in all cylinders on compression test).
    It just is nice to see that not everyone gets it right 100% of the time even pros, and really helps fix the hole in my pride over getting it wrong. Along with the tech info, I think I feel confident enough to get back out there and get it fixed.

    • @goldsgarage8236
      @goldsgarage8236  Před 2 měsíci

      Good information hunter, thanks for commenting. Experience is expensive! AG

  • @4speed3pedals
    @4speed3pedals Před rokem +4

    Many videos talk about dynamic compression ratio and this is the first video I have watched that gives a good understanding of what it actually is without going on a search for a video on the topic. Many books also leave you in limbo. Thanks for posting this video as it makes understanding a camshaft a little less complex for most to be successful with their build.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks Stovebolt, I am glad it was helpful. Comments like yours have inspired me to take a deeper dive into this subject and I will be making another video on the subject soon, possibly today. Watch for it. Allan Gold

    • @chrisburnsed6349
      @chrisburnsed6349 Před 8 měsíci

      It’s always in limbo because every engine is different. Their is no “set” numbers . That’s why all components need to be carefully chosen so they work together properly.

  • @GrandPitoVic
    @GrandPitoVic Před rokem +3

    I really enjoy this channel. Alot of really good info you really don't hear anywhere else. Thank you for letting us follow along. When I clicked on the thumbnail I thought this channel had been around a while. Your very comfortable in front of the camera. Or so it seems lol. Thank you sir.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks for your kind words Hugh. It motivates me to keep digging!
      Please keep watching and commenting!
      Allan Gold

  • @lcee6592
    @lcee6592 Před rokem +2

    Fantastic information!! Amazing the difference small changes make in engine power. I’m a life long Pontiac man and love how those old Indians make great torque!

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +2

      Thanks L, they are a beautiful piece of history and fun to work on. Thanks for watching Gold's Garage. AG

  • @Leo9ine
    @Leo9ine Před rokem +10

    This is great! I was surprised to see you had 700 subscribers, I was expecting 100x that number. People will discover these videos soon enough. Thanks for sharing the knowledge

    • @dissapointingsoup4893
      @dissapointingsoup4893 Před rokem +1

      same here! totally clicked on this thinking it was a shop with a decent following. theyll get there!

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +2

      Thanks for your nice comments Leo. It encourages me to keep digging. I have a lot of content in the pipeline so please watch for it. Thanks again!

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks for your comment soup!

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +2

      Thanks for your kind words Leo. You are encouraging me to keep building engines and making videos. More to come.

    • @richardgdinwiddie5104
      @richardgdinwiddie5104 Před rokem

      Nicely done ,very informative

  • @alexvendrig9205
    @alexvendrig9205 Před rokem +2

    Interesting-really like the preplanning advice-

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Thanks Alex, always appreciate your input. Are you coming to the dyno test next Saturday?

  • @johnz8210
    @johnz8210 Před rokem +2

    That was fantastic, thanks for the video.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Thanks for your kind words John, lots of content to come. AG

  • @krnt13
    @krnt13 Před 2 měsíci

    I was lucky that I ended with 175psi of static compression when rebuilding my first engine with only guessing by picking parts around.
    But now that I'm rebuilding my second engine I want to take more time and measure things correctly and do the correct planning, videos like this are a gold mine of knowledge and encourage critical thinking before making decisions, thanks!

  • @Andrew-xf3wb
    @Andrew-xf3wb Před rokem +2

    cant wait for part 2. thank you.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks Andrew, we are excited to see the results also.

  • @johnzuggster375
    @johnzuggster375 Před 2 měsíci

    Pure Gold, thank you brother, your much appreciated!

  • @bobbyoshomebuilt2544
    @bobbyoshomebuilt2544 Před rokem +1

    Oh do I like this topic! Off to work but I'll return with my experiences with on this topic soon.

  • @edsmachine93
    @edsmachine93 Před rokem +2

    Very good Tech.
    I have been talking about this same subject for years.
    Have to get the cylinder pressure up.
    Do that the Horsepower and Torque comes up.
    Taking advantage of your Low and Midlift flow numbers.
    Good topic.
    I just subscribed to your channel.
    Take care, Ed.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +2

      Thanks Ed. Your comments are inspiring more thoughts on the subject and so I am thinking of a follow up video about how the OEM's managed this in the early muscle cars. They were pretty smart. Watch for it.
      Allan Gold

    • @edsmachine93
      @edsmachine93 Před rokem

      ​@@goldsgarage8236Thanks Allan, I'll be watching for your video.
      Great topic.
      Thanks again, Ed.

  • @kevinmanning4880
    @kevinmanning4880 Před rokem +2

    Valuable information! Thank you so much for doing this video! I'm planning on putting together an aftermarket top end on a Pontiac 428.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +2

      Thanks Kevin, glad it was helpful.

    • @heshtesh
      @heshtesh Před rokem +1

      I'm trying to pry a 69 428 from a friend for a 72 Gran Prix, still has the original factory headers.

    • @kevinmanning4880
      @kevinmanning4880 Před rokem +3

      @@heshtesh you can always use a 400 block and get a 428 aftermarket crankshaft that fits in a 400 block and Chevy big block connecting rods, all balanced from Butler, all you need to do it block machining and put it together.

    • @heshtesh
      @heshtesh Před rokem +1

      @@kevinmanning4880 Appreciate the info but i've already got a big dollar sbc pump gas stroker for the street and what you suggest will only start another bad habit lol! Read a funny comment the other day from a Pontiac owner " nowhere else can one spend so much money to get so little power as with a Pontiac" lol I could feel for the guy. No I think i'll try to keep it simple this time around.

    • @kevinmanning4880
      @kevinmanning4880 Před rokem +1

      @@heshtesh you haven't been associated with the correct kind of people. Have you heard of Big Chief? He beat everything in no preps, with a '70 GTO, I mean everything. There's a Canadian driving his 1965 GTO to drag week, he pulls a 9.77. Pulls a trailer behind the Goat from Dragstrip to Dragstrip.

  • @remybrouwer8700
    @remybrouwer8700 Před rokem +1

    Great way of present things

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Thanks for your kind words Remy, I encourages me to make more videos.
      Allan Gold

  • @jimclarke1108
    @jimclarke1108 Před 11 měsíci +1

    Very interesting and helpful, deletes a lot of guess work and saves💲

    • @goldsgarage8236
      @goldsgarage8236  Před 11 měsíci

      Thanks Jim, exactly what I am trying to do so your comment reinforces that I am on a good path. Ag

  • @gordocarbo
    @gordocarbo Před 3 měsíci +1

    Good stuff!!
    Know what readers need esp younger ones?
    Comprehensive vids that give basic explanations/characterisitcs of intake and exhaust valve opening and closing points, what the mean, changes, etc.
    You know that choosing 2 different brands of say a 280 hft cam can behave differently. Especially when increasing cyl compression its so crucial toget it right...so you dont have a ping monster nor a soggy dog.
    Think we all would appreciate it
    DV touches on some of it but the hour plus vids its easy to get lost.

    • @goldsgarage8236
      @goldsgarage8236  Před 3 měsíci +1

      Thanks Gord, i have other videos on this subject. More to come. AG

  • @John-zo4wu
    @John-zo4wu Před 11 měsíci +1

    Very informative video, thanks! I have a 327 with the CompCam version of the GM 3896929 300HP cam. My cranking pressure is 160, it runs smooth as a smelt!

    • @goldsgarage8236
      @goldsgarage8236  Před 11 měsíci +1

      Sounds like a very nice street engine John, Thanks for your input. AG

    • @mikewillett5076
      @mikewillett5076 Před 3 měsíci +1

      Just curious, do you know pretty accurately what your static compression is?

    • @John-zo4wu
      @John-zo4wu Před 3 měsíci +1

      @@mikewillett5076 It was 160psi last I checked.

  • @CK-mf6du
    @CK-mf6du Před 10 měsíci +1

    The past 3 motors I put together I did this, shooting for 7.75 to 8 to 1 dynamic with iron heads. They run excellent, so much better than tossing something together with low compression. The combo doesn't work right without doing this. Nice to see similar experiences. Valve lift is also important based on what your heads flow. And obviously what powerband you want the engine to have. Pointless to have a cam that makes power up to 7500 rpm in a stock 454 big block. If it's built for it that's different.

    • @goldsgarage8236
      @goldsgarage8236  Před 10 měsíci +1

      Thanks CK, all good points, thanks for your input. AG

  • @jaygooch1190
    @jaygooch1190 Před 8 měsíci +1

    I have had great success in the past running really high compression (12.5 to 1) in a 355 chevrolet and relatively short duration (242/246] at .050 on a 108 LSA. Dart iron eagle 215 heads and rpm airgap intake. Mid 6.60s in the eighth in a 3200lb car.

    • @goldsgarage8236
      @goldsgarage8236  Před 8 měsíci

      Mid 6.60's is pretty fast. That would be low 10's in the quarter. I had a chance to drive a 6.60 drag car a few years ago. It was pretty exciting. AG

    • @bartbarnett2811
      @bartbarnett2811 Před 6 měsíci

      What is the intake centerline angle

  • @shanman41
    @shanman41 Před rokem +1

    Great video! I am in the process of designing a building a 496 for my 70 Chevelle. The block is at the machine shop now and I have went all Eagle forged lower end with main studs. Little much but I want the option of putting it on the bottle in the future. This is just street motor with a 10.2:1 CR with a .025 compressed head gasket. I haven't nailed down what cam I am going to be running but your video is great! I am sure I will watch in a couple more times :) Looking forward to part 2.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Thanks for your input shanman. I apologize that I just noticed it now. AG

  • @Haffschlappe
    @Haffschlappe Před 3 měsíci +1

    I use an NOS Edelbrock perforiert Plus 2102 cam in My smallblock L48 engine with 9.7:1 compression that works nicely

  • @larryw5429
    @larryw5429 Před rokem +9

    I run forged flat tops with small valve reliefs, 64 cc vortec heads and 15 thou shim gasket and it runs fantastic.. The amount of torque over the old 882 open chamber heads is crazy! Now I worry about the 700r4 trans lol!

  • @joe-hp4nk
    @joe-hp4nk Před rokem +8

    A tight LSA will trap more compression, something in the range of 106 - 108. Also I use .015 steel shim gaskets with cast iron heads.

    • @itseithergonnaworkoritaint7852
      @itseithergonnaworkoritaint7852 Před rokem +6

      Yes and David Vizard has some great videos on his yt channel about LSA too, he also has formulas on how to calculate LSA as well. He pounds the table about LSA that these cam manufacturers are making the LSA way to wide leaving 60 to 80 HP and Torque on the table.
      But here's the deal with DV's claims, his findings are solid for WOT max power but not necessarily for average power, cruising or fuel economy if that is something one is looking for? Tight LSA cams have more overlap that isn't necessarily part throttle friendly and the bigger the dur @ .050" the worse. So keep this in mind before choosing the extra top end power you'll have by sacrificing some part throttle power.

    • @joe-hp4nk
      @joe-hp4nk Před rokem +2

      @@itseithergonnaworkoritaint7852 I run a 107 LSA in my 355 and the mid range is awesome. But I agree, if you want cruising and mild, stick with stock LSA.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +9

      You are both making some good points. The ideal LSA depends on engine displacement and cylinder head flow, (port size, valve size etc.) The bigger the displacement on the same heads the tighter it can be. Cam companies typically limit LSA because of the adverse effect on vacuum, drivability at low speed etc. I build street engines not race engines so the priority is mid range torque, throttle response and drivability. On the dyno average torque and horsepower is more important than peak. Thank you both for your input.

    • @nashvilleoutlaw
      @nashvilleoutlaw Před rokem +1

      ​@@goldsgarage8236 what would you say psi or dynamic compression should be for 87 octane? Absolutely everything I've found only talks about "pump gas" I assume 93 and I understand it depends on heads, chamber design, eliminating hot spots in the cambers, quinch and so on. It would be nice to know a general range. Currently building a 383 fun/daily driver. Afr 195 enforcer heads, compression in 9.3 to 9.5 range, 0.040 quinch. I haven't cc'ed the heads yet so just an educated guess with 18cc dish pistons. I've found 1 article in all of google that was an 87 build that I did the math on the parts used and should have been about 7.56 dynamic compression around 151psi or so. Any ideas?

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +4

      Thanks Nashville.
      I think you should be ok with 87 octane and 151 PSI compression pressure. Even so, unless cost is a big issue, why not just use 91 anyway so you don't have to worry about it? Hope this helps. AG

  • @stevenbarnett2169
    @stevenbarnett2169 Před 5 měsíci +1

    I always check for run out on a new crankshaft. Many have been sent back as they were bent.

  • @johncalhoun8011
    @johncalhoun8011 Před rokem +1

    Very thorough...

    • @goldsgarage8236
      @goldsgarage8236  Před 11 měsíci +1

      Thanks John, glad you are enjoying my videos. AG

  • @chrisburnsed6349
    @chrisburnsed6349 Před 8 měsíci +1

    Even more important is making sure the cam lift isn’t way more than the heads can flow at peak lift of the cam. That will harm power even more than compression. Your heads have a peak flow number at a certain lift. Beyond that valve lift it has a negative effect on flow which hurts power. So a bigger cam isn’t always better. I believe this should be figured out before determining your optimal compression

  • @robr5786
    @robr5786 Před rokem +2

    I've read on a Pontiac forum that Crower 60916 does not come from the factory with 4 degrees advance ground into it,that they need to be degreed to get to a 108-109,and they need to be advanced 4degrees to get to 108-109

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +2

      Thanks for your comment Rob, Initially I had to advance it 4 degrees to get to 108 centerline. This time I advanced it 4 more degrees to get to 104 centerline. The crank sprocket it now installed on the 8A keyway.

  • @davidreed6070
    @davidreed6070 Před 11 měsíci +1

    You can't forget the LSA that is very important.what is happening to start the intake stroke,a lot of people miss that.

    • @goldsgarage8236
      @goldsgarage8236  Před 11 měsíci +1

      Good point and yes it is important. I should have addressed that in the video as well. I will try to fit that discussion into a future video. Thanks. AG

  • @julianjennings4638
    @julianjennings4638 Před rokem +1

    David Visard. Tested. Wisdom by experience.

  • @subzero18851
    @subzero18851 Před 3 měsíci +1

    Great video! One comment I have regarding intake closing point is that depending on the cam manufacturer they may list the actual valve closing event or the tappet closing event.
    The calculators dont specify which one to use. Comp is the only cam manufacturer that I know of that lists actual "valve" timing events, others list "tappet" timing, and others don't even specify which one they are listing. Do you have any insight on this?

  • @Engineer_GM_Ford_Chrysler

    Love your video! Question, I have a stock factory 1996 chevy 5.7 vortec engine. I would like to change the pistons and add flat top pistons. I also want to run the LT4 Hotcam. I am trying to do this on a budget and keep it streetable. What do you recommend in maximum static compression for the Lt4 Hotcam. I will be using 1.6 roller rockers. Also will run headers with dual 2.5" pipes. The top of the engine will be ported vortec heads with machine work and springs and hardware to match cam. Also the intake will be factory with the spider injection upgraded to the improved system with injectors for each cylinder, rather than the poppets. Also the injectors will be 36lbs. Oh, also high flow performance fuel pump. I want to put this engine together right. I don't mind running 91 oct premium gas. Transmission will be whatever stall converter to maximize launching and sither 4:11 or 4:56. Gears. The truck is just a fun weekend ride to cruise around and hit the strip occasionally.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks Richard. With this cam and steel heads i still think you should stay under 10:1 to be safe. The Summit CR calculator works ok. With that info I suggest you google the Wallace Dynamic CR calculator and determine your cranking pressure. Again, I suggest 180psi max. Hope this helps. AG

    • @Engineer_GM_Ford_Chrysler
      @Engineer_GM_Ford_Chrysler Před rokem

      @@goldsgarage8236 what camshaft would you recommend in this setup I have , except bumping the compression to 10:5 to 11 to 1? And still have "decent" street manners, run on 91 premium fuel and no more than 3600 stall? Using the vortec heads I mentioned? I guess what I'm after is at least getting into the 400-450 plus ft-lbs torque territory. I don't mind having that "Chop" in the cam when idling. Like I mentioned in my earlier post, my truck is a fun truck for cruising around and occasional strip action. Its definitely not a work truck and it will rarely see the highway, except when traveling to the strip an hour away from home. I know there will be a handful of cams to choose, but just from your experience, what do you think?

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      I will do my best. The vehicle and how you are planning to drive it is important. Since you are using gears, (high ratio numerically) and a converter and you want to race it a bigger cam is warranted. Is it an S10 or full size truck?
      Also a bigger cam will allow you to use more static compression so aim for the high side of 180PSI. Something in the 280-285 degrees of advertised duration, 230-240 @.050". This cam will have a late IV closing point, 66-70 ABDC. As for lift, I am thinking about .550" max with the 1.6 rockers. If you know the flow numbers from your Vortex heads, that should be taken into consideration. Some heads actually have reduced flow at higher lift.
      You will need to machine your Vortex heads to accommodate this lift and there is a max so that is a factor also. Check this out thoroughly to avoid coil bind or valve guide to retainer interference.
      If you don't mind the chop, a shorter LSA, probably about 108 would be ideal.
      Most factory cams are 110 which is a bit of a compromise, you don't want any wider LSA.
      Richard, that is my input for what its worth. You can also call the cam company for their suggestion and get other opinions.
      Thanks for the question. AG

  • @nobleeffort2.4
    @nobleeffort2.4 Před 9 měsíci +1

    Question on using a dynamic compression calculator. Should I be using total duration figures, or duration @.050? Im working on coming up with a good static compression and camshaft combination for 93 octane.

    • @goldsgarage8236
      @goldsgarage8236  Před 9 měsíci +2

      Good question Noble. Always use advertised duration, not duration @.050" AG

  • @camaro1972ah
    @camaro1972ah Před 3 měsíci

    hi , great Vidoe watched with keen interest. trying to work if my cam is "good" for the street. So much info online its hard to work out.Ive a bbc 427 with a cam thats 230/236@50 on a 114 lsa. I did a dynamic compression test and hit an average of 160 psi plus. Is that decent for the street? For low end grunt and snappy throttle? My Intake valve closes quite late relative to other street cams ( mine closes 45 abdc , a comp cams 262xe closes 35 abdc.Is this a big difference. Any advice appreciated before I replace camshaft!!

    • @goldsgarage8236
      @goldsgarage8236  Před 3 měsíci

      Thanks for the question Camaro. I think you are using the @.050" numbers for IVCP to calculate your dynamic compression. You should be using the @.006" or the advertised duration numbers. Nothing is being compressed until the valve is completely closed. The cam spec's are ok but i don't know enough about the application, static CR, gearing, weight of the car etc. Recalculate your DCR and let me know. Hope this helps. AG

    • @camaro1972ah
      @camaro1972ah Před 3 měsíci

      Hi apolgies for the confusion , yes numbers are all at 50.I meant to write cranking compression not dynamic - as your video here is all about cranking compression pressure. So Im cranking avg 160psi - Im a bit concerned current cam too big for street use , but does they psi indicate its ok? wanting lots of low rpm torque acceleration etc , not so much high HP high rpm use. @@goldsgarage8236

  • @fortyshooter1
    @fortyshooter1 Před rokem

    All I have is the Intake Closing point at .050 lift cam specs. The calculators I see use the .006 lifter specs. Is there a conversion factor for this or call Lunati for those specs?

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Thanks for the question. I think you should call. Some cams lift off the seat much quicker than others so I don't think there is any conversion factor. It's interesting that some flat tappet cams lift the valve off the seat quicker than roller cams.

    • @evcass69
      @evcass69 Před rokem

      The lobe ramp rate will control the delta between advertised IVC & 0.050 IVC. Using AIVC for DCR is best. Maybe you can get the AIVC from the vendor that ground the cam?

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks evcass69, I always use advertised intake valve closing specs for my dynamic compression ratio calculations with good results.

  • @magnusdanielsson2749
    @magnusdanielsson2749 Před rokem +2

    I got a bit of problem with my build in that the quench distance is too large.
    So I need to take the block back and get it ”zero decked”.
    The cr is a very healthy 12.4:1 so the quench is probably needed..

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks Magnus, I would suggest you re-calculate your CR after to deck the block.

    • @magnusdanielsson2749
      @magnusdanielsson2749 Před rokem +1

      @@goldsgarage8236 Yeah I think Ill have to modify the combustion chamber in that case so the CR doesnt get too high.
      My main thing Im wondering about atm is the issue with quench distance. Only reason to deck the block would be to get the quench tighter but Im not sure if its worth it.
      On one hand I have pistons with a shallow dish in them and only a 11mm band/ring going around the piston that could act on the quench.
      On the other hand I seem to be in the distance that one should never be (0.055-0.06") according to most opinion.
      The head gasket I have will compress to 0.043-0.049" and since my pistons are around 0.011 below the deck it gives that large quench distance.
      A "zero decking" seem like it could be good but I cant really tell if it is worth it.
      I guess another possible solution is to taper the chamber quench pad slightly in the hopes of relieving some of the potential for the non-optimal quench distance making it knock sensitive.
      On-going research =)

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +2

      Magnus, I agree, minimizing quench is definitely good to do but it is expensive because it requires decking the block. It does allow more compression without detonation, however decking the block increases compression so it is kind of a double edged sword. I am building 2 400SBC's right now. One is .005" deck and the other block is untouched. I need 75cc heads to get the compression manageable in the decked block. Watch for them on the test stand and dyno.

    • @magnusdanielsson2749
      @magnusdanielsson2749 Před rokem

      @@goldsgarage8236 yeah. And its hard to take back a decked block to how it was 😄
      My brother suggested Id draw up the gasket in cad and have it cur out in copper. But Im not sure how it would seal up the water in the long run. Common practice on race engines not so sure on street engines.
      Another benefit with that approach is I can reduce the crevice volume compared to the stock gasket wich have a 95mm hole compared to the 92.5mm bore on the engine.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Magnus. You can buy thicker head gaskets to reduce the compression but it kind of defeats the purpose of decking the block. Better to take it out of the heads or pistons if you can.

  • @ragingbull3406
    @ragingbull3406 Před rokem

    Can anyone answer why some calculators ask for the intake closing +15 degrees? United Engine Machine in particular. Wallace Racing Calculator doesn't ask but their calculations match my "actual" cranking pressure.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks Ragingbull340, I am getting good results with the Wallace calculator and advertised specs.

    • @ragingbull3406
      @ragingbull3406 Před rokem

      @@goldsgarage8236 Thanks for replying. I've decided to only use the Wallace calculator. One question. When figuring cranking compression, should I use "advertised" intake closing and not .050? Thanks again.

  • @kevinfinney7541
    @kevinfinney7541 Před rokem +1

    What flowmaster muffler is that ? Sounds great.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Sorry Kevin, what video are you referring to in your question? AG

  • @evcass69
    @evcass69 Před rokem

    My builder in 2019 scared me that I'd need to use E85 only in my daily 418 LS3. I've been using 92/93 octane with 11.9 SCR, 8.9 DCR, 220 cranking psi. Peak tq is only with 20* advance, though oem heads.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Thanks evcass69, it would be interesting to know if you could make as much torque with less CR and more advance. I have never seen 220 PSI in a street motor.

    • @evcass69
      @evcass69 Před rokem

      @@goldsgarage8236 I wonder also.

  • @1996slamster
    @1996slamster Před rokem

    I’m going to assume 160 to 180 is a target for premium pump fuel? What cylinder pressure would one want for running 87 octane fuel?

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks Ron. This is an interesting subject and I am planning to do some more research on it for a future video. To answer your question I referred to the 1968 Chevrolet manual. A 307 200HP engine (base engine that would require only "regular gas") had a cranking pressure of 150PSI. As always, other factors such as timing advance, spark plug heat range, fuel air ratio, driving style etc. could influence this as well.
      I hope this helps and watch for more info in this subject.

    • @1996slamster
      @1996slamster Před rokem

      It’s a very interesting subject! Unfortunately octane and it’s function is a very misunderstood subject. In my opinion, octane and a proper timing curve are the two most important parts of a properly functioning engine no matter the usage from racing to towing the race car. Looking forward to more of your videos.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks again Ron. This discussion inspired my next video. Would you believe that a 12.5:1 CR L88 427 has the same cranking pressure as the 307? I will explain why and how. Look for it soon.

  • @VGHCX
    @VGHCX Před 23 dny

    Help me understand please. If I have an engine with a rocker arm ratio of 1.5 and a valve spring with an open pressure of 300lbs. Does this mean the pounds of pressure needed at the cam would be 450lbs Since there is NO mechanical advantage upon opening the valve?

    • @goldsgarage8236
      @goldsgarage8236  Před 23 dny

      You are correct. Take moments about the pivot point. X x 1=300 x 1.5, therefore X=450. So the greater your rocker arm ratio, the more force you are putting between the valve lifter and cam. Hope this helps. AG

    • @VGHCX
      @VGHCX Před 23 dny

      @@goldsgarage8236 Thx for the response. Now, assuming I replaced the 1.5 for 1.6 ration rockers and I adjust the geometry to achieve the same amount of lift. Would the pounds of pressure at the cam degrease or increase? I think the pressure would be 480lbs, thus an increase.

    • @goldsgarage8236
      @goldsgarage8236  Před 23 dny

      If you replace the 1.5 with 1.6 rockers, you will have 480 lb. force (not pressure) on the cam and lifter. AG

    • @VGHCX
      @VGHCX Před 22 dny

      @@goldsgarage8236 Good catch. I mixed the terminology. This clearly proves why the OHC engines can outrev the OHV rivals. The emence pressure on the cam from the high pressure valve springs means a larger mass is needed for durability. Thus limiting RPM. I wish there were a way to bridge this gap. Would it be nice to have the best of both worlds.

  • @JARRETT7121
    @JARRETT7121 Před rokem

    Rhoads hydraulic lifters will also trap compression and you want to run with a deck clearance no less or more than .035

  • @scotthultin7769
    @scotthultin7769 Před rokem +1

    .967 I .928 E and the Henry show is 14.5to 1 what it mean to work so well is with my head 540 oil into lifters wouldn't bleed down I lose hundred thousand lift
    You might say that's dumb
    But it's straight 50 oil in it. there I had a lift from my camshaft
    I'd run 9.06 et at 148 mph in the 1/4
    With 50 weight oil in it it would run a 8.67 et at 167 mph

  • @realazliving
    @realazliving Před rokem +1

    One comment is that with that 0.065 head gasket you had no quench action. That's not great for efficiency or power. With the 0.025 the quench is probably great as long as the piston isn't way down the bore. It's too tight if it's zero decked and you might touch the head. Probably 0.035-0.045 is a good place to be. Quench is gasket thickness plus how far down the bore the piston is at tdc.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks for your comment Robert, and sorry that I just noticed it. You are correct about the .065" gasket. My mistake for not measuring it on the first build. I agree .035"-.045" is ideal and the higher the compression, the more important it is. AG

  • @331GTnvan
    @331GTnvan Před 6 měsíci

    How does this change with adding boost?

    • @goldsgarage8236
      @goldsgarage8236  Před 6 měsíci

      Thanks for the question. I am sorry, i don't have any experience with boost. Maybe another viewer can weigh in on this question. AG

  • @jessesyfie7244
    @jessesyfie7244 Před rokem

    Your 160/180psi is probably a good number for pump gas, 87 octane? I have a 400SB with about 170/180 psi runs on 87 just fine. But my question is going to 91 octane how much more psi can I go? 200/210psi? I don't like leaving power on the table.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Thanks Jesse, i am planning to discuss this issue in my follow up video. Thanks for supporting my channel. AG

    • @jessesyfie7244
      @jessesyfie7244 Před rokem

      @@goldsgarage8236 yes and yes. Can't wait to watch it.

  • @amiabledave50
    @amiabledave50 Před rokem

    We all get that one should know static and dynamic compression ratios of their engine. But you fell flat when matching a cam to a compression ratio. Or maybe that was in part 2 which I can't find.

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Thanks for the input. You are correct, the follow up video thumbnail is Quadrajet tuning. I think March 26. I describe the changes and results. I hope you are able t find it. AG

  • @racerd9669
    @racerd9669 Před rokem

    The major problem is none of the cam grinders advertise the actual degs ATDC when the intake touches the seat. .006 is not good enough.

  • @marknowakowski6590
    @marknowakowski6590 Před rokem

    I wound eventually like to increase my TQ n HP on my stock 95 gen 2 5.7 LT1 engine a few hundred ponies more to the rear wheels without blowing her up hmmmmmmmm what to do ?????

    • @goldsgarage8236
      @goldsgarage8236  Před rokem

      Thanks Mark, Please keep watching my channel and hopefully you will find some of the info you are looking for. i have a 400SBC build coming up next. AG

  • @johncalhoun8011
    @johncalhoun8011 Před rokem

    I am very serious about you Building a 350 Chevy Engine for me.

  • @larryw5429
    @larryw5429 Před rokem +1

    Compression adds power everywhere in power curve! What people need to decide is what kind of fuel to run and what kind of octane they want to use! If they want to run 87 octane 9 to 1 is all I would push with todays crap 87 octane!

    • @goldsgarage8236
      @goldsgarage8236  Před rokem +1

      Thanks Larry, I agree. The dynamic compression should also be calculated as the cam can bleed off some of the cranking pressure.

  • @bartbarnett2811
    @bartbarnett2811 Před 6 měsíci

    😂 me dieing inside because I have 250 psi and I run 93 with two stroke racing oil pistons are.003 out of the hole and a .035 with fire ring gasket. 230 24 something 107 or 106 intake centerline and 114 lsa .54 lift 6in forged rods. steel crank. bracket racing keath black flat tops 7cc valve releaf she pulls hard to 7000k 😂 and has managed to break everything behind the flywheel it all started with the damn 454 clutch snap that b**** into a million bits. Twisted a drive shaft in half then snap the pinion gear shaft after it was all said and done with chromoly everything in the rear end I cracked the f****** housing now I have a little Dana 80 and i have put the project on hold because it eat all the hp but I put so much effort in making it fit i don't want to take it out so I'm thinking she will be a mud truck now but I have 3.55 gears and just kinda lost interest in it

  • @jamesward5493
    @jamesward5493 Před 6 měsíci

    Why not just use 10 to 1 compression.

  • @rogergrandify
    @rogergrandify Před 8 měsíci

    how about getting to the point

  • @Scubasteve22
    @Scubasteve22 Před 2 měsíci

    That cam is weak in the knees on the lift side of things....You wanna build some cyl pressure, put that cam on a 108 LSA instead of taking a 112 then advancing it 8 dgrees....Save the 112 lsa crap for large bbc...or LS. A tighter LSA will kick the pants off that 112 dual pattern, any day of the week.. If vacuum is all your concerned about, then don't be disappointed when the dyno falls short...jmtc

  • @wavefchan6766
    @wavefchan6766 Před rokem

    Sorry 9.5 compression is still to low. If you're a real man you should at lease run 10.5 even on a street motor