EPISODE 103 Tuning Classic Car with Vacuum Gauge, Plug Reading, Jetting Autorestomod
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- čas přidán 12. 02. 2013
- Home page: www.autorestomod.com
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This week we use a vacuum gauge to fine tune our 1965 Mustang hardtop, how to read your plugs to know if the carburetor you are running is too lean or too rich. We also show what the exhaust should sound like at the tail pipes and how to use the spark plug wire removal test to find dead cylinders. We also give tips on how to test your car so that your changes will compare well with past test.
Thanks for watching!
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THANKS !
This Vacuum Gauge tuning ,solved all my idling, stalling and misfiring problems !
My 64 Fairlane 260ci engine with Holley carb. was running on 15inHg. tuned all to 20inHg and all problems solved.
The Fairlane pulls incredible now, gas-milage has extreme improved and idles very happy.
you tunned your engine
but what your engine problem was?
Thanks for the video. I been working on my 1974 dodge van and your tips helped me to get it running a bit smoother.
Great comprehensive video for someone that is just learning older style carb and distributor tuning.
Good point. That is where the drive comes in. You may need to back off of the timing a bit. We may hit that one in a future episode Mike! We appreciate you bringing it up!
Thanks for the kind words Pavel! We're planning to delve into the Fox bodies '79-'93 Mustangs very soon. We can only imagine the trials you must face doing an American car in the Czech Republic...
Great video on setting up a carburetor with a vacuum gauge . I on my way to get one now . 👍🏼👍🏼
Glad you guys put this get there. Subscribed because l learned much to use on my new old 66 Impala I just got for my 64th Bday. Great content n well done.
I would kill who ever gave me a piece of shit Chevy!!!
Stumbled on your video. Thanks for posting the very useful info. I plan to try these tips on my big block 70 Chevelle .It’s a carbon footprint nightmare. My wife hates to ride in it because we always smell like fuel after going for a ride
Thank you! Learned a lot off this video and was fun to watch
Hi guys, I've already seen all your episodes. It's one of the best channels on youtube. Lot to learn :) and I can use many of your tips on my 1984 Ford Capri 2,3l V6. Greetings from Prague, Czech Republic and keep on doing those great videos. Thanks, Pavel
This is hands down the best video on how to use a vacuum gauge I have found on CZcams! Thanks for the great video, going to apply it to my Motorcraft 2150 on a 79 CJ7 I bought recently. I am new to carbs and this is a huge help. Gotta say though, while the information is terrific... Mr.Fords makeup did it for me.
G M czcams.com/video/JDPwY0LbRVY/video.html
Very comprehensive and well explained, thanks. Subscribed!
Just a couple of regular guys, and that is why I watch, no paid professionals following a scripted routine, NORMAL guys youd find in their garage in Anytown USA working on classic cars.
When the car is running badly after all the things we've shown you that is a good indication. If it is running rich (black smoke from the tailpipe) that is also a good time to go in and work on the carb.
This is absolutely amazing.
Yes, these things will work on any carbureted engine.
Usually it will be around 1 to 1.5 turns of the idle mixture screws. You might also check for vacuum leaks around the carburetor base. If you are still having problems contact us on our web site and we'll see what we can do.
This video had some valuable information, thanks.
Its pretty amazing what a vacuum gauge can tell you with an old car, or any car for that matter.
Running air/fuel ratio gages on my XKE, helps to tune the 3 SU HD8 carbs for power
Depends on what you are tuning. Unplugged it can help you set the initial timing. plugged in you can set idle mixture and check the vacuum drop under acceleration.
Sounds good! Vinnie will be happy to know that we have another 3rd Gen Camaro/Firebird owner!
Great video guys, thanks. I learned a lot, and it'll come in handy for me down the road. If I ever get down to SC I'm bringing beer.
If your pump is maintaining the recommended pressure for the carburetor (Edelbrock says no more than 6.5 psi at the carburetor). First look to vacuum on the distributor, if the ported vacuum is not hooked up get that working and make sure that the vacuum can on your distributor is the correct one for your application. From there if the problem persist look to your metering set up.
Thanks for the great video. You are awesome!
Y’all explain this better then anyone else
best place is the vacuum tree on the intake. That is a "neutral" vacuum source (pulling form the total vacuum of the intake). If there is no tree, find a single port plug that will fit that threaded opening and use it to establish the vacuum.
Just learning so much from this channel! Hi again, I just did my first vacuum tune on my 71 Lincoln Mark III (its got the Motorcraft 4300 on it). Upon starting the car fires right up and idles smooth until I tap the gas to begin driving and the choke opens then it idles rough. Sitting at the stop sign at the end of my street I can feel the whole car shaking. After 10 minutes of driving sitting at a stop sign/red light, no more rough idle. Made sure the car was warm, setup the vacuum gauge and its at 20.5/21 inches of vacuum at factory idle mixture screw settings and even with the screws all the way in or all the way out I'm at the same measurement with no change but needle dances more than what the good tune you showed in the video. I do however notice my fuel pressure gauge is bouncing from 6 to 7psi at any idle mixture screw setting. Something other than the carb is the issue?
hey guys thanks for the video. I enjoyed it. I just started tuning my carb with a vacuum gauge and this video helped a lot. I was able to raise my vacuum from 14hg and idling like crap to 21hg with a beautiful smooth idle. I have a question about the timing adjustment with the vacuum gauge. 1) are you still using manifold constant vacuum? 2) did you unhook the vacuum advance?
i am new to tuning and building. i have EVERYTHING you recommend. just no knowledge of what im looking for other then a smoother sound. thanks for the info. good video
edit: after watching this and a few other videos i went out and hooked up my vacuum gauge and was at 5. i twisted the distributor as far as i could and brought it up to 17, i think im off a tooth, but i also have a large (not some hog ass race cam though) cam, a comp 268xfi. so 17 may be as much as she wants but it definitely sounds WAY BETTER also readjusted the idle screws on my oversized demon 750 and it does not smell nearly as rich. thanks man great video
Go look at our timing video too: czcams.com/video/Qz_cYOe2B20/video.html
True. The larger the cam the worse your vacuum signal. But even in those instances a Vacuum gauge can still help you out with figuring out what power valve to run. Note that we like vacuum advance for street engines or mild performance engines. If it is so radical that the signal is below 10 inches of vacuum no matter what you do then you are going to have to apply a whole new set of rules.
Hey guys, I have a 71' F100 w/302 and it idles in the 18-20 range. Though it flutters continually between that range and occasionally slightly smooths out, but not completely, for a few seconds and then back to the flutter...Any ideas what's causing this condition?
Try using the vacuum gage rolling in high gear @ 40 mph adjust the timing to the highest setting after you have done what you did. The movement that you make by turning the distributor will be ever so slight a 1/64 at a time. You can only do this with a tiny hammer, I like to use one that I made from a 3/4 inch brass bar stock an inch and a half long. You just let the weight of the hammer touch the vacuum chamber while the hold down bolt is snug but not tight. Vans are easy because you don't need to stop and get out. It does not matter if the engine is computer controlled or not because what you are doing is increasing the range of advance. Every engine is different because of machining and the condition of the timing chain. You get the best performance and mpg by setting the timing this way. Sometimes you have to back it off a bit because of a slight ping but that depends on the fuel you're burning and how fast the curve on the distributor advance is. This is what I learned running a chassis dyno back in the day but you can do it on the street too it just takes a little more time. The video was entertaining and you got everything right but you have to know how critical a tiny tap to the rotation of the the distributor really is it could mean a couple of miles per gallon and I'm not kidding have fun and keep on doing the videos good job!
We'd recommend getting into some howto videos. Check out Miller Welders and see what they have. Eastwood also offers how-to videos on welding. Best thing to do is to get the basic knowledge and start out on sheet metal (salvage yard stuff is great if you have a You-Pull-It yard around, fenders are usually less than $40. Cheaper than sheet steel.
Cool video. I've been learning a lot lately.
Don't know about these old classics but most vehicles have a plastic grommet on the firewall to where you can run wires or vacuum hoses into the cabin that way completely bypassing the possibility of the hood crimping the vacuum hose. So what if you have to use 10 or more feet of vacuum hose the readings will be the same no matter the length. Great video on the importance of good vacuum and base idle!
Good point DJ.
Drill and weather strip with some seam sealer, instant custom hole in the firewall
Thank you guys so much!! I wish I knew where u guys have ur shop at to personally shake ur hand!! Great teachers.. I'm just a troubled 25 year old trying to revive my dream cars!! I have the 87 Trans am 5.0 and a 88 firebird 5.7 which both need alot of work so ull hear from me more...
I'm looking forward to using this on my Fairlane. It's been sitting for a while so I could work on my other projects. The car never ran right after I replaced the points last year and continues to overheat.
+KayakTN on my 1969 El Camino I was having slight overheating issues for awhile and found out that my timing was a little off which had the spark detonating a little late and partially dry firing in the cylinder causing the cylinder wall to be higher in temp increasing my coolant temp by about 20 degrees! Hope you get your girl on the road cruising soon!
Can you time a motor with a vacuum gauge? My motor seems happier at a higher base timing (The engine bay sticker say 10 degrees and I've got it running nicely at 13-14 BTDC) Could that be due to the age of my motor or the carb mounting gaskets are in need of replacing?
Thanks for the information… I was born in 83 so I know more about fuel injection but I recently bought a 72 F100 because I’ve wanted a bump side since I was a teenager. I’m soaking up this information like a sponge…😄
One of the best shows on u-tube. RIP POPS
Thanks for the kind words! Miss my dad just about every day. Find myself sounding like him with the kids...too funny.
I have a question i have a 1965 mustang 6 cylinders with an engine 200ci i got the engine rebuilt and everything but it souns like its going to turn off and the engine shakes alot what can be wrong with it
Depends Barry, most of the suspension will work. power brake boosters won't. spindles will. Brakes are the same. No sheet metal any where on the car will bolt up. You might use the floor pans BUT there will be heavy mods. Check Autokrafters, they have a Maverick catalog that will show what is available.
Just finished doing this with my Chevy Vega. A bit easier as there is only one idle screw on the 2BBL, but it runs great. Thanks!
I wish you would showed what you have the gauge hooked up to and what lines are dissconnected and what vaccume lines are connected can you just hook up the gauge to the brake booster port on carb and cap off advanced timing good info but still can't pay attention to it because not enough info on how to hook up the gauge and to what
I have no idea what to hook this shit up to. Been looking everywhere. Makes me feel stupid cause i guess its just assumed you should know where they go.
Hook it up to the pcv vacuum going into carb
I have the same issue with my vacuum advance hitting the radiator hose. How did you reposition the distributor to avoid this?
Low vaccum, then do you close the idle mixture screw in more to restrict air?
Do I use the same procedures if I have an incline 6 engine.
Can I disconnect the distributor advance hose that plugs into the carburetor and attach a vacuum gauge hose in that carburetor spot or should I place the vacuum gauge hose somewhere else in the carburetor or intake manifold. I have a 200 inline 6 engine
66' coupe
We'd check the wiring to make sure that the firing order is correct. Go to our web page and contact us and we can send you an image of the firing order to help you out.
There should be a vacuum tree on the intake. Use one of the smaller vacuum ports to test from.
thanks, this is the answer I have been looking for!
Good video 👍
Just a quick question on a Olds 455 4v 380hp Rochester quadra jet engine what should the vacuum be at idle ?
Really depends on the overlap in the cam. I'd look for around 17-20 in stock configuration.
Your videos are a great help
Thanks for the kind words!
You might check for vacuum leaks. If a Holley won't change vacuum and doesn't start to stumble with the mixture screws in, it may be a vacuum issue. Get that worked out and then start tuning.
hey autorestomod, i have a 1965 ford mustang coupe 302 with a 1986 302, 3 speed trans that is automatic. the question is that the block has smog parts on it and has original 2 barrel intake and carb setup. can you pleas help? suggestions?
I have a 67 Mustang 390 dual 4 barrels it runs off of the back carburetor it has a electric choke on the front carburetor shouldn't it have the electric choke on the back carburetor since that's the one that it's running off of until you kick it down and get the front four-barrel carb working?
Do I need to buy a fuel regulator for this set up?? It has two pumps manual on the engine and electric in the tank
Love the video but please show where you attach the vacuum hose! especially the vacuum advance section. I can't tell if you have the hose attached to the actual vacuum advance or not? Also, do you adjust the fuel/air idle screws first then the vacuum advance? Thanks!
Find manifold vacuum. We didn't show where we ported the gauge because Ford even moved the vacuum port. Most small block Fords have a vacuum tree on the back of the intake. To tune in the idle screws you'll need to go to manifold vacuum.
I have a Chevrolet 454 V8 on a P30 chassis. What is your opinion on these 'fuel injected' aftermarket systems for vehicles like mine. David 🐈
What part of the carburator do you need to attach a hose or screw in. Mine is a 1 barrel carburator
Absolutely superb sir .
Thanks!
YES! I like it. Doing it right, great job
Thanks for the kind words.
Bring back Gramps!!! He's the man!! I mean you guys rock too with the solid info and stuff, but bring him back!!!
Sadly, pops passed away last year in November. I miss him every day.
AutoRestoMod Muscle Car Resto and Modifications my respects for the loss.... thanks for making your show. I have learned a great deal for them.
I need to learn how to weld! Need your tutoring please and thank you! Both my cars need body work. Quarter panels and floors need to be redone, living in Chicago Illinois suck because of the snow and salt.
Great vídeo! Let me ask you, is it possible install a carburator quite larger than required to the motor and adjust perfectly? I have a Ford V8 302 and I'm trying to adjust a Holley 4160 600 cfm on it, but till now I'm facing some issues to adjust it
Did you get it figured out?
Hi Dan, not yet! Due to Covid here in Brazil I'm waiting some time to go back and try adjust again
Hey I'm restoring a 1970 Ford Maverick would it be fair for me to assume that most parts used on the mustang can to used on the Maverick
Hey guys! One more helpfull video ! thanks! and if i understood well after the idle mixture screws have been set up i can rotate a bit the distributor to look for the maximum vacuum ?
Yes. But there that can create a detonation issue so you will need to be careful doing that. If you get a hard-hot start condition you will need to back the distributor off just a bit.
Yes. But there that can create a detonation issue so you will need to be careful doing that. If you get a hard-hot start condition you will need to back the distributor off just a bit.
AutoRestoMod Ok i get it, slightly and slowly ! ^^
I have holly 4bbl carb 600cfm on a 289 and have got it to 18 on the vac gauge (no air filter) I can turn the driver side idle mixture screw all the way out and nothing really happens, turning it in will bog the engine down, but the other one is more touchy, I can turn it in & out about 1 1/2 to 2 turns and I get rpm changes, also the rear float bowl always pours fuel out when I unscrew the sight hole, the front one is just rite. Am I in need of a good carb cleaning and should I mess with the timing and see if I get more vacuum? Any tips are appreciated. Thanks
Hello same, i turn idole mixture but nothing change I have only 10...
Great video!learned a lot! So, question for you guys. Have a 65 TBird, 390 CI diagnosed with bad carb. Replaced with a Holley 600. Engine idle is a little rough, with a little flat spot accelerating. Also, hard to start after running to normal temp. Runs well otherwise. Any thoughts? Love your channel. Wish you were near cause I’d definitely come see you for a tune up (which it had less than a hundred miles ago…by a professional 😊)
Thanks and keep up the excellent videos
Thanks very helpful
Hi guys got a huge question!!! I got a 87 Trans am I been working on and can't seem to make it run right hope u guys can help!!! Ok I replaced the carburetor (e4me) q-jet electric one to a edelbrock 1406 because the old one was giving me nightmares! and I also changed the computer controlled distributor to a hei set up so I think I timed it right and all but now it runs rough and floods when I floor it. Now it eats gas like a fat lady at a buffet! Also electric pump still connected in the tank
It sounds like the new carburetor is running too "fat" if it is flooding. You'll most likely have to play with the metering rods. We recommend checking into some tuning guides for the Edelbrock. Also, make sure that you check your set up with the vacuum gauge. youo should have between 15 and 20 inches of vacuum at idle. Private Message us if you have any more questions.
How would I know if my carburetor needs to be rebuild
Hello guys i have 95 FIREBIRD with a sbc (355) w/ th-350 im having problems carb or pump problem not sure!! Under a heavy load im hearing popping noise around 3000-3500 rpms running lean im guessing, to get to higher rpm i have to ease of the pedals but she stilll crawls up to higher rpms. (edelbrock 750 totally rebuilt and holley blue ) i need some help..
i have a 231-2v v6 buick engine and rochester dualjet 210 carb how and what vaccuum port can i hook this up and mount it so i always know how the engine is
You'll want to find a vacuum port on the intake for best results.
great car
I use a vacuum gauge because my timing pointer isn't the correct one but anyways I can get nice high vacuum reading. I shut it off and start in it and my starter labors so I have to back it off and any reason for this. 82 c10 305, lunati cam with 218 duration, edelbrock 1406, new distributor.
mustache guy looks like Freddie Mercury's brother
he looks portuguese
Learned alot, thanks.
Great Video .ole Man At the beginning reminds me of my Neighbor. Lol
That was my dad, he passed in 2016. He was a rip!
Hi Who you connect the vacuum gauge ? i have 1405 edelbrock 600cfm in manifold port or distributor port ,thx (sorry for my poor english i m French :-) )
Connect to the Intake vacuum port
Hey guys I'm having a really annoying misfire/poor idle issue with my 68 L6, wondering if you could help. My vacuum gauge, attached to manifold, reads about 17 at parked idle it drops well below 15 in drive. Timing is set to about 12. A/F mixture screw seems to do nothing on carb. New vacuum hoses, new distributor, cap, and rotor (also switched from dual diaphragm to single), New autolite 1100 carb, new vacuum hoses and entire new engine (old one had bad low end knocking). STILL no matter what I seem to adjust or switch out, I have that hiccup misfire sound, poor idle, and really, really poor gas mileage. I'm lost here. My multimeter numbers jumps around when looking at idle too, its anywhere between 300-560 rpms.
Dakota, Jeff is noodling on this and will respond in an e-mail.
Did Vinnie put you up to this? LOL He actually has a multiple carb set up on a 350 in his Gen 3 Camaro. We'll look into it for sure.
Do you connect the vacuum gauge to the carburetor or the intake manifold to perform the diagnostics you showed?
Intake manifold.
was wondering if i can buy a vacuum gauge to put on my dash that would do the same job to also tune the car, i'm currently restoring a 1986 buick regal limited but want to learn to tune it myself
Sure! Summit Racing sells all manner of gauges.
sweet thank you
Hello I have a 4150 Holley and eldelbrock intake on a 289 as in the video, manual gear, 800rpm. I test vaccum on the manifold, on booster line, it is the same low value 10inHg I tried adjusting idle mixture but nothing changed. Gaskets are still soft I don't see a leak. I know the engine is tired but it is very low and affect brake booster. I had a 289 stock with 2100 2 bbl and vaccum was stable at 16. Can you give me a piece of advice, engine tired or carb issue?
Which 4150 do you have? If you have a 600 cfm, I might look to timing issues. Id recommend advancing the timing a bit and see if the idle comes up. Contact me directly if that does not help. jford@autorestomod.com
Sweet, thanks guys. Yeah, Vinnie mentioned it once or twice. He was real insisting about it, now that I think about it...
On my distributor I had to go past 12 and at about 15 mil
Along there’s another line on the crank shaft that where I got the said vac what is that line and can I leave it there
Yes. Remember, we're not worried about position of the distributor unless it is too far over one way or another. And that is about how it looks..
When u plugged the gauge hose into the carby,was the intake manifold hose left plugged or unplugged?
Always plug any open vacuum ports otherwise your readings will be off.
AutoRestoMod Ok..thanks for the quick reply too...love the channel.
No worries mate, We like us some Monaros!
Hay Jeff. I'm all the way in the UK and now we have an NPD warehouse here, do you know if they do many parts for the 68 Fairlane at all as this would be a huge help. Love the show fellas
Wow I didn't know that. NPD as of this time doesn't do parts for the Fairlane, You'd need to source your parts from places like Autokrafters or Dearborn Classics.
What are the basic settings for the air and fuel screws on an early two barrel carb. when initially starting engine prior to using the vacuum gage?
That can depend on the carburetor. Holleys, Autolites, Motorcraft, and even Edelbrocks usually call for 1.5 to 2 turns out from the idle mixture screw needle bottoming softly into the seat.
(1/2) Thank you for replying. :-) It is on a Packard 120. Im not anywhere near it, its a friends car, I did the head gasket, the carb is new but they played
(2/2) with it till its all out of wack. I believe it is a Carter wdo 4785.
Gordon Woolfrey Gordon,
We'd try starting off with setting the idle screws to 1.5 turns and moving out (or in) and see if the idle clears up any. I'd really recommend trying to find a manual on the WD0 carb too. Check float levels also and make sure that they didn't muck around too much with the timing. Contact Jeff at jford@autorestomod.com for further help on this if these things aren't working.
I have a 1979 f150 7.5 whit motorcraft Holley carburetor (4180) just want to know what size of power valve this come whit originally
Unsure, I would look at calling Mike's carburetor
Phone: 888 689-9758
These guys know their chit
hi, could you help me how to connect the vacuum wire ford 460 lincoln in 1970-71?
It will need to go to a port on the carburetor. If it is a stock carb, it is usually on the base plate.
I know a sc tag when I see one 👍
I wish you would do an autolite 4100 air fuel mixture video
We have an Autolite 4100 on our '72 F100. It's kinda piggy right now so that might make a great video!
I have a 66 Mustang with an Autolite 4100 that I just can't get right - not much on youtube where someone does a live setup of one of these.
I will say that the 4100 is VERY picky about airflow and vacuum leaks.
Hi! I have a '81 V8 302 Mustang. I've followed the procedure step by step, but when I adjust idle mixture, can't make the vacuum go upper than 15inHg. Is it possible that I'm going wrong with something? Or the car is going wrong?
+JohnnyWalker430 Some of the late '70s and early '80s Ford V8s ran a lower vacuum signal. We had a 351 Windsor that ran 12 inches of vacuum at idle. Signal was so low we had to put an auxiliary vacuum can to run the cruise control. If everything else seems ok, that might be "where it is."
Remember that altitude above sea level affects the numbers you're gonna see. 15" of vacuum in Leadville, CO would be really good. Even at low altitudes, a high performance rumpety rump cam will result in a lower absolute vacuum number. Bottom line: 18" to 22" are typical for a healthy, stock V8 at sea level.
so when tuning with a vacuum gauge what do you do first the timing or the carb, also i tried this before watching the video heard it from my dad readings were between 15 to 17 they fluctuated between 3 inches of vac wasnt steady do you know what it means auto resto mod
Phil, sorry this took so long, we just found the e-mail notification request in our spam folder. We'd set the timing at base then tune the carb. Muck around from there. remember, hard hot starting means the timing is too high. A fluctuation in the vacuum signal could mean a vacuum leak somewhere or a cam with overlap. It could also indicate an engine with some miles where the valves are not sealing well. Clear up any vacuum leaks on the intake and carb base and then move forward.
it had a bad carb gasket the vaccuum reading is at 20 inches that was the highest i could get runs real good now, doesnt kick back when starting. its on a 72 dodge dart318 so i think its good now. the problem id use to have was when it was running id do a test drive get on the gas pretty good then itd start idling real bad at the red light. what does it mean when you csn run a 4 barrel carb with one idle mixture screw completely out that makes no difference
phil holbrook First see if it makes any difference with it all the way in. If the idle changes (gets rougher) Adjust out as per our instructions. If the idle doesn't change you have one of two things going on: Idle too high (you are no longer on the idle circuit). Or you may have debris in the idle circuit. Your idle should be down around 600-800 RPM to start tuning.
I have a 1956 Oldsmobile with a 324. Where do I hook the hose to??? I don’t see any place to put it. I’m lost. Does anyone know out there ???
It looks like on the 324 the only viable port is the one on the carburetor that controls the distributor. You could tee into a test like to pull vacuum, but I'm not sure how accurate the reading would be from that port.
I really liked your episode showing how to set your timing with a vacuum gauge. Everyone seems to generally agree that you should disconnect your vacuum advance when setting your initial timing. I can understand doing this when you're running off ported vacuum, but I don't understand why you would disconnect your vacuum advance to set your timing with a vacuum gauge if you are running manifold vacuum because the initial timing shouldn't be a factor since it will dramatically change as soon as you reconnect the vacuum advance. Am I missing something?
Thanks for the kind words Roy. It is done to set initial timing, to get a base timing signal.