Stop unplugging your vacuum advance on distributors

You can gain so much daily driver efficiency by running vacuum advance, it’s free…it’s there use it

Пікірлер: 145

  • @edberry78
    @edberry787 ай бұрын

    The more videos you do on this (and related subjects), the better. I think you did a carb set-up video a while back too. That was fantastic.

  • @adamrodenberg1557
    @adamrodenberg15577 ай бұрын

    A dialed in vacuum advance will also allow the engine to run cooler... I recently bought an old '72 Chevy truck and the temperature gauge would get up to about 212-215 degrees then shut down starving for fuel because of vapor lock, even while going down the interstate with lots of air going through the grill. I replaced the entire cooling system first (new radiator, water pump, thermostat, fan clutch) and it still got too hot. Then I tried every trick to try to avoid the vapor lock (blocked off heat riser passages to intake, added a carb spacer, added a fuel return line coming off of an inline fuel filter just before the carb, insulated the fuel lines) and it still got too hot. Then I even "re-calibrated" the fan clutch (by adjusting the little thermostat clock spring on the front of it) to pull more air through the radiator, which it did, now you can hear the fan roaring with RPM, and it still would get too hot. When it would shut down and I'd have to pull over, when I popped the hood the amount of heat coming out would make me step back... Then I did a little research and decided to check my vacuum advance and the only changes I made was to switch it from a ported vacuum source to a manifold vacuum source, turned the adjustment screw one and a half turns to maximize advance and that is what finally fixed it... Now my temperature gauge stays around 160-170 degrees, even crawling in traffic on a hot summer day in the southeast, and my vapor lock issues are gone... Gas mileage got much better too... If you think about it when the ignition timing is late, the fuel is burning all the way down the bore to BDC and heating up the whole cylinder bore which heats up more coolant, then it's still burning on its' way through the exhaust manifold which dumps excessive heat under the hood... Another interesting thing I remember noticing about vacuum advance was one time when checking the timing on my Charger, I forgot to re-connect the vacuum advance hose and when I went down the interstate, I had to keep my foot in the throttle like almost halfway, almost opening the secondaries on the carb just to stay at 65 MPH. And my gas mileage got so horrible I started looking around for a fuel leak and that's when I found the vacuum hose that I forgot to reconnect. Once I reconnected the vacuum hose and got back on the interstate, I could cruise at 65 MPH with the throttle just barely cracked open off of idle and gas mileage was back to normal... Great videos!!!

  • @coolestchannel4413
    @coolestchannel44137 ай бұрын

    He's right...guys those engineers back in the day knew something 😂

  • @MoparDen
    @MoparDen6 ай бұрын

    Your content is always refreshing! I lenjoy and benefit from the enthusiasm that is very motivating and keeps one focused on the important things to maintain and enjoy our Mopars!

  • @cudaman-yq7pq
    @cudaman-yq7pq7 ай бұрын

    So many of the old distributors had mechanical advance slots that were too long for emissions. Remove the advance plate and shorten the slots with weld, that way you can run a lot more initial advance and keep the total mechanical advance at reasonable levels.

  • @doughelmle6575

    @doughelmle6575

    7 ай бұрын

    I did that but with a FBO plate that has different length slots on a disc so you can get ,in my case , 18 initial and 36 total mechanical advance . I also use manifold vacuum advance to help idle and cruise.

  • @doughelmle6575

    @doughelmle6575

    7 ай бұрын

    74 cuda ,360 with 4.30 gear .

  • @Romanm1957
    @Romanm19577 ай бұрын

    Can't wait to see your video on proper carb vacuum adjustment! I know your cars run good because I can literally hear them when you are testing and tuning, I live in your tract just North of you!

  • @1776_Garage
    @1776_Garage7 ай бұрын

    First time listening to you and learned a lot. You're very knowledgeable.

  • @westcoastdodge
    @westcoastdodge7 ай бұрын

    ​Chris this is some good info,thanks for sharing👍

  • @TheNightmaro79
    @TheNightmaro797 ай бұрын

    More of this Chris! Love these vids man! If you can do more vids on how to set up carbs with big cams low vacuum that would be great haha! Thanks 🤜🤛😎

  • @brianjoy3407
    @brianjoy34077 ай бұрын

    Dude! Ive been away from the channel for a bit...came back and there's no wall directly next to the porta garage. Sweet! You got a new place with ROOM! Love the vac advance discussion and to get that mileage out of that many cubes....you're hitting it on the head! Glad to be back!

  • @Dartman440
    @Dartman4407 ай бұрын

    Yeay! Finally someone that explain this so other can understand! Exellent! Done the same on my Roadrunner with 500 stroker. Manifold vacum, 42 degrees. 👌

  • @vegasrobocop288
    @vegasrobocop2887 ай бұрын

    Good Video Chris.Hitting’em with the facts.

  • @Pontiac73
    @Pontiac737 ай бұрын

    Chris, you are absolutely right. I have a 1973 Trans Am, the motor is BBC 440 ci. The cam is hydraulic roller 229/235 - 109, 9,9:1 compression, 750 Demon BT carb. The driveline is Tremec 5- speed, 0,64 overdrive and 3,73 rear gear. T/A runs 18 mpg on the highway. Initial advance is 8 deg, idle 31 ( 8 + 23 vacuum ). Cruising 53 deg ( 8 + 23 + 22 centrifucal ) Wot 30 deg because i have a Procharger supercharger. Before the Procharger wot advance was 38 deg. Car runs perfect and fuel economy is incredible low. Btw, i live in Finland and internet and youtube is great invention because without that i'll never heard genius guys like Chris.

  • @nicolelongneckergallery
    @nicolelongneckergallery7 ай бұрын

    great video, Birdsong. Spot on good advice.

  • @Sam-yk6mz
    @Sam-yk6mz24 күн бұрын

    I have a 493 stroker motor . Running a msd vacum advance . Was told to take it off.

  • @jasonmushersee
    @jasonmushersee7 ай бұрын

    new piston rings makes tons of vacuum also when i rebuilt my mustang 302 quickly discovered new timing chain kit & valve adjustment was huge in getting a smooth idle had a dwell meter hooked up before/after the rebuild idles so smooth now

  • @glengabruch4664
    @glengabruch46645 ай бұрын

    Thanks for the wisdom. 👍 I run a 400 based 512 stroker with Trick Flow 240 heads and a hydraulic roller cam with 254 duration @.050 with 618 lift, all backed by an A833 4 speed manual in my 1968 Barracuda fastback. Time to get out the old vacuum guage!

  • @Ghostcotton
    @Ghostcotton7 ай бұрын

    Wise advise my dude. Definitely use those ear balls . Just like tuning a guitar or any other musical instruments that needs to be tuned by ear, you’ll hear when everything is in rhythm and operating proper. Glad your posting more. Good shit brother.

  • @vuch9208
    @vuch92087 ай бұрын

    I love Patina! Nice chevy in the background! I've got a '68 Impala SS convertible with a 350 grocery getter out of a camaro with headers, 4 barrel Holley and power glide tranny. She's fun.

  • @DougsterWolverineGarage
    @DougsterWolverineGarage7 ай бұрын

    Thanks Chris! Im looking for a cast iron factory dual point distributor with vacuum advance for my 413. It will be getting a Weiland tunnel ram!

  • @TheMunstersGarage
    @TheMunstersGarage7 ай бұрын

    Tall John did the timing on my coronet at duct tape. It’s been a blast driving and it runs great

  • @mrmoss149
    @mrmoss1497 ай бұрын

    Thank you so much Chris; my son is in the process of converting to a carb setup & he won't listen to me as to how to set it up- he will get it from you. Happy holidays to the baby & baby momma ( baby daddy too). Thanks again

  • @Mr.mopar71
    @Mr.mopar717 ай бұрын

    Thank you! I had arguments about why there's 3 timing setting. 1 at idle 2 vacuum advance 3 mechanical advance. All of them have a purpose.

  • @CHIPNDEATH
    @CHIPNDEATH7 ай бұрын

    thanks for the Advice,, I gonna try it on my 305 ,1980 chevy

  • @b.s.adventures9421
    @b.s.adventures94217 ай бұрын

    I had an old grey beard teach me how to time off of vacuum back in the 90s. I’m sure he’s gone now, but I remember what he taught me. I’m curious about the ported vs non ported vacuum debate. Would love to see your take on the subject.

  • @ricksshop

    @ricksshop

    7 ай бұрын

    I'll usually try straight vacuum first, but if the engine kicks back while cranking hot, or spits and burps at idle, then I'll switch to ported. Mopars seem to like straight vacuum, Fords seem to like ported.

  • @codyhollinger6531
    @codyhollinger65316 ай бұрын

    You are right. I changed it to manifold vacuum cleaner idol. Runs so much betterers. Thanks Chris.

  • @rod426
    @rod4267 ай бұрын

    Good knowledge Chris!😂😂😊

  • @scottsmith6846
    @scottsmith68467 ай бұрын

    Hey Chris thank you for the video information and I'm going to keep this in my Gmail that way when a time comes for me to get a vehicle running and get one then I always have the valuable information thank you so much Chris

  • @petecrabtree6734
    @petecrabtree67347 ай бұрын

    🦅🇺🇸💪😎👍 thank you for teaching me some I had no idea about. Thank you thank you can't wait for the carb turning

  • @user-ud3iw2il3g
    @user-ud3iw2il3g7 ай бұрын

    Yo, Chris, can't wait for your vid on the Daytona Nascar Charger's vacuum advance!!

  • @viking7256
    @viking72567 ай бұрын

    I always set the initial idle timing with the vacuum advance disabled. Then re-enable the vacuum. The idle advance will step up but retard the timing when you open the throttle. This normally prevents "pinking".

  • @brendangeraghty8865
    @brendangeraghty88657 ай бұрын

    This needed to be said, badly. Please paint patina! Such a great colour!

  • @steventangney1367
    @steventangney13677 ай бұрын

    Totaly agree with you on vacuum advance

  • @thatguywithdt6110
    @thatguywithdt61107 ай бұрын

    18-19mpg on the highway with 400/727/2.94 b-body. And yes, it's on manifold vacuum.

  • @shaunclifton5281

    @shaunclifton5281

    7 ай бұрын

    What's the build on your 400 ? I have an early 230-1 truck block 400 that I am trying to decide which stroker version to build. It's definitely getting the ceramic coating throughout and Trick Flows.

  • @thatguywithdt6110

    @thatguywithdt6110

    7 ай бұрын

    Oh I bet it's stock for the most part. Just a single plane intake and 750 carb. Could have a cam? Would make a good stroker. Heres a video of it. kzread.info/dash/bejne/mYOVm8uxY8_Wgps.htmlsi=rGjTJ9BDxBFZvTPu

  • @farmhand6524
    @farmhand65247 ай бұрын

    Great tip saved it💯

  • @cromBumny
    @cromBumny7 ай бұрын

    Id be interested to know if you think a rear sump pan setup gives mopars some extra life

  • @richvandervoort2950
    @richvandervoort29507 ай бұрын

    Can you control the timing digitally using the MSD distributor, a manifold pressure sensor and a programmable controller? A throttle angle sensor would probably help as well.

  • @doughelmle6575
    @doughelmle65757 ай бұрын

    I run a FBO slotted plate and manifold vacuum advance now. 18 initial ,36 total.

  • @XenaFordPrincess
    @XenaFordPrincess7 ай бұрын

    Very well said!

  • @2008aspangler
    @2008aspangler7 ай бұрын

    I’m gonna go home and try this, I’ve always ran vacuum advance but on the ported spot, I’m gonna try it on manifold vacuum and see if it makes it mores betters

  • @NewEngland462
    @NewEngland4622 ай бұрын

    Light springs and total timing coming in at 1800 rpms is all u need. A stock dizzy timing wont come in until 5500 or almost never. At say rpm cruise of 1800-2500 or so with a stock dizzy. Mechanical timing is probably 15-20 or so. Vac can kicks in. 30-35. This on a sbf. 34-36 dgrs total mechanical advance is what they normally like

  • @thelocalangler
    @thelocalangler7 ай бұрын

    great video and topic Chris, so if i understand your instructions on the constant vacuum, the engine requires constant direct vacuum from the intake manifold and other stuff like the heater controls and other accessories use like a secondary vacuum source? this is the exact issue i am having with my umm er.... bronco 400m 2bbl. i don't know how the vacuum works and effects on the vehicle. the more i try to figure it out from the manual the worst it gets.

  • @DodgeDart383
    @DodgeDart3835 ай бұрын

    I have watched this and other videos you do multiple times, I'm new to this, I have a 69 dart gt 383 with 727 and 3.23 gears, Have no idea about what kind of cam it has. 1411 Edelbrock carb. I recently recurved my distributor, lighter springs advance comes in at 1200rpm all in by 2300 ish. distributor has black bushing so allows for 18-19* total mechanical advance, the vac canister was not working so changed that and new one is tested, it works. currently I have my timing set at 18* initial without vac, gives me 33* with vac attached, total timing all in with vac attached is at 52-53* I'm afraid of having too much advance on the top because of ping or detonation possibility and I can't limit the distributor further (no bushings to have less play) so based on keeping my max at 52 or lower the only thing I can do is screw the vac adjustment to stiffer to limit total advance. So my vac canister at lowest setting has max advance of about 0-19* I currently have it screwed in 2 turns and have it at 15* max the vac will advance. If I crew in more the stiffer the spring the less advance it will allow at idle when hooked on and plugged into manifold. I'm thinking of limiting the vac to give me max play of about 12* instead of where it is with 2 full turns now at 15*. Here is my dilemma, would love to hear your thoughts... should I keep the vac advance on loosest setting and lower my initial to make sure I don't go far beyond 52* all in at 2300 rpm with vac attached? or should I screw the vac canister adjuster to stiffer, limit it to only advance say 10* max play and put my initial without vac attached to say 22*. I don't know if my question is making sense. I guess what I mean is, I have the lightest springs in the dizzy with the largest bushing to limit total advance and to let the advance come in sooner. There is no more adjustability left in the dizzy mine is a ready to run distributor, so I think the only other adjustable thing left is the vac canister. Set higher initial and limit the vac canister total allowed advance? or set lower initial timing and allow more advance through the looser vac advance port. I will end up with the same advance at idle and at highway either way you slice it but I guess what happens in between say at part throttle or takeoff the numbers will be different. but at all in and at initial with everything attached I will have the same advance degrees so which avenue is better? How much total play should the vacuum advance have in it, is there an explanation for that. Any of your thoughts, suggestions are appreciated. I want to get the timing diled in proper before I start changing jets and rods on the carb to smooth out any fuel delivery issues once timing is tuned and set where it needs to be.

  • @KevinRoadrageGarage
    @KevinRoadrageGarage7 ай бұрын

    Out of 20 videos I've watched over the last few days. 17 said ported and 3 said manifold.

  • @MH-rb7lp
    @MH-rb7lp7 ай бұрын

    Never mind I got it now... LOL its been a long time since I tried to tune a carb but I get what you are saying (had to think about it).

  • @terrycole9427
    @terrycole94277 ай бұрын

    I'm a old school hot rodder that's the way we tuned them by ear balls way back in the day

  • @corelsland5205
    @corelsland52057 ай бұрын

    You won't believe how happy i am . It drives me nuts it's almost the importend thing follow-up the carb. 👍

  • @roadrunnervsgodzilla2048
    @roadrunnervsgodzilla20487 ай бұрын

    Congrats you've just joined the ported vs manifold debate on KZread. Have you tried A progression distributor. I would be interested in your thoughts on them.

  • @Robert-nk1mw
    @Robert-nk1mw7 ай бұрын

    MSD does make a pro billet for big block mopars with a vacuum canister, its on the ready to run line.

  • @junkerup

    @junkerup

    7 ай бұрын

    That’s hei though

  • @Robert-nk1mw

    @Robert-nk1mw

    7 ай бұрын

    @junkerup since I'm not overly familiar with the MSD distributor what's the difference? I have had an old chevy with the HEI type distributor with the coil in the cap, this srill need the external coil? Not arguing just trying to learn because I've not had the experience you do with this stuff

  • @christophersanders5007
    @christophersanders50077 ай бұрын

    I have timed an engine many times in the past with a vacuum gauge. Not because it made the engine run mo-better, but because I did not degree the cam in...I just slapped it in, and lined up the timing chain marks. I wish I could get classic car insurance for my 4X4 Chevy square body crew cab. Classic insurance companies will not insure a 4-wheel drive truck, and since Nevada changed the classic car registration laws I am screwed on that.

  • @doughelmle6575
    @doughelmle65757 ай бұрын

    What kind of carb work do you think, would be needed {adjustable air bleeds ,boosters} on a small block 408 with trick flow heads,238/246 comp roller,for the street. #3500 LBS cuda,391-4.30 gear,727 ,2800 stall.

  • @mk-xg2kt
    @mk-xg2kt7 ай бұрын

    100% on manifold vacuum. if I remember correctly, all internal combustion engines want maximum cylinder pressure at a certain number of degrees after tdc for peak efficiency .can't remember if the degree number was 14.15.16 or 17(piston position). regardless of rpm. and the same fuel burns differently depending on the fuel mixture. a guy grimsrud have explained this well. but it's a lot of work to get the carburetor and ignition set up right. usually need different weights, springs, ifr, jet, airbleed, powervalve and powervalve restriktor.

  • @after5auto133
    @after5auto1337 ай бұрын

    Is that Freiburgers red duster I see in the background?

  • @mr.b2107
    @mr.b21077 ай бұрын

    Yup, makes good sense to me.

  • @paulkoski8759
    @paulkoski87597 ай бұрын

    I like these videos should have a Tech Time Tuesday food for thought

  • @paulkoski8759

    @paulkoski8759

    7 ай бұрын

    Triple T lol

  • @paulkoski8759

    @paulkoski8759

    7 ай бұрын

    Or TIT Tune in Tuesday

  • @travisbeavers1203
    @travisbeavers12037 ай бұрын

    What about carburetored and boosted applications

  • @Sam-yk6mz
    @Sam-yk6mz24 күн бұрын

    Vacuum goes to carb or manifold ?

  • @farmhand6524
    @farmhand65247 ай бұрын

    Will wipers work then? Be watching...

  • @notthunderr4069
    @notthunderr40697 ай бұрын

    I think you are confusing folks, dont set the intial at 45. 34 at idle with vacuum unplugged. Then plug back in for the extra 20. Can be scary to see 45 but fine. Also dont trust the balancer mark, mine is off by 12 degrees. 550hp 440 six pack daily driven, runs fine with no VA, just lumpier and low mpgs. 4 speed close ratio and 355 will mask the issue. Agree with you and plug the vacuum line in at the bottom of the manifold at the brake booster inlet.

  • @Rallykylen
    @Rallykylen7 ай бұрын

    Hey man what is the deal about the yellow charger that was in your garage all the time before ? Think i can see it in the background.. Can’t find a video of it 🤔

  • @russluther1246
    @russluther12465 ай бұрын

    Loving your, channel. But i think you might be off a little bit. Your duel quad tunnel ram charger is getting it great mileage from the very tall 2.93 gears. My 69 charger 383, was getting close to 20 with the 2.72 stock gearing. Now it has 3.56, gears, and a 512, stroker. It gets around 14 at 60 mph if im not playing to hard. Thats with ported vacuum. But i will try what you are saying, to see if it improves.

  • @lordsauto
    @lordsauto5 ай бұрын

    Does that go for lower compression engines? Also we talking manifold vacuum on vac advance? Chevy 350

  • @ZIPCORD
    @ZIPCORD7 ай бұрын

    Wow, confusion abounds. 1. There are two types of vacuum. Ported vacuum that by design does not pull any vacuum at idle. This is where most every factory vacuum advance system connects. Slightly off idle Ported vacuum will become effective. There is also Manifold vacuum which provides maximum vacuum at idle. After coming off idle both vacuums operate r-e-l-a-t-i-v-e-l-y the same. 2. What he is advising is using Manifold vacuum over (conventional/factory) Ported vacuum or in the cases where there are those who use no vacuum advance at all, they should have it. It will increase the idle RPM with the added advance and the carburetor can be adjusted downward. 3. How he is achieving his numbers. Most cars are using the Ported (not effective at idle) vacuum. For the sake of this discussion let's say the vacuum advance has 13 degrees of advance at maximum vacuum. Moving the vacuum advance hose from Ported vacuum to Manifold vacuum will increase the advance at idle that 13 degrees. That is where he is setting his 45 degrees. Under full throttle the vacuum advance becomes ineffective due to insufficient vacuum. Thus his total under full throttle timing is whatever his total timing (initial + mechanical) and mathematically equates in this case to 32 degrees. How much is initial and how much is mechanical I don't know. Frankly I'm confused because It would seem that the timing should be set at the RPM where full mechanical come in (not at idle) and then knowing it will be 45 degrees at light load with the Manifold vacuum advance (assuming 13 degrees there). But not knowing initial timing and the range of the mechanical timing makes the calculation difficult. I say that because if he had 20 degrees of mechanical timing (none in at idle) and 12 degrees of initial timing (32 degrees total) then he is really close to 65 degrees at light throttle assuming the engine RPM is where the full mechanical comes in and as someone already said that is very high. I hope he can give greater clarification. 4. Here is where this has become one of the great You Tube debates. SOME engines you can do what he has done and they respond well. Others don't. The bad experience is pinging. Likely the cause is either a lot of initial advance (with limited mechanical advance to hit the target number) and/or a vacuum advance that doesn't drop the advance far enough/fast enough. Then the advance is too high for the load upon the engine. Using the Ported vacuum is safer in that regard because there is no high vacuum advance that needs to back down coming off idle. Some engines can get away with Manifold vacuum but others can't . And there is a whole lot more involved regarding initial advance, the range and response of centrifugal advance and the range and sensitivity of the vacuum advance. So, while I completely agree that running vacuum advance is important I can't agree that in every case running Manifold vacuum is always appropriate. Modern cars have knock sensors and the computer adjust the timing to the best condition. With a non-computer system it is a trial and error guessing game and even then not always ideal timing is achieved.

  • @edvisme
    @edvisme7 ай бұрын

    Question. The carburetors you are using are the vacuum or mechanical secondary?

  • @proracing9025
    @proracing90257 ай бұрын

    I am running a 493 stroker in 74 Cuda. 4 speed . What should I be setting timing at ?

  • @jovanda8364
    @jovanda83647 ай бұрын

    Your dog s like come on let s go do some burn out s

  • @andy347495
    @andy3474955 ай бұрын

    im fairly inexperienced, and I need some clarification, I think. I understand what you are saying about having more advance when at part throttle. from the little I think I know, I don't understand why you want manifold vacuum instead of ported. from what I understand, manifold vacuum drops as you give it throttle and ported vacuum increases. with what you are saying, it seems like ported would be advantageous because the timing is being advanced as soon as the throttle is moved. what am I missing? why is that not the case?

  • @dodgedude_3608
    @dodgedude_36087 ай бұрын

    Does this make a difference in automatic vs manual cars? I've never ran a vacuum advance in my manual stuff and haven't had any tunability or drivability issues.

  • @cowtown_dad
    @cowtown_dad7 ай бұрын

    How about EFI and Hyperspark ignition no vacuum advance(similar to MSD), should I connect a vacuum gauge?

  • @toddsdodgegarage8967
    @toddsdodgegarage89677 ай бұрын

    Howdy. im not understanding even though you did a great job explaining, how do you set 45 degrees of timing at idle then how does the motor pull it back to 32 at wide open? I get setting the carb to the highest amount of mercury possible but the timing thing has me confused. Thanks.

  • @christcarscountry6870

    @christcarscountry6870

    2 ай бұрын

    At wide open throttle, your vacuum decreases because the engine is ingesting air rapidly through a large opening (slammed open throttle blades), so when your engine is effectively an "open circuit" letting air in and out rapidly, it loses vacuum. Lower vacuum means less signal at the vacuum pod at the distributor, so it reduces timing. at part throttle cruising, the engine is at low cylinder pressure, steady state rpm, and a small opening (cracked open throttle blades), so it retains vacuum, sends more signal to the vacuum pod, and increases timing. Your mechanical advance that is built into the distributor increases with rpm, your vacuum advance in your vacuum pod DECREASES with engine load. And your engine load is low at idle, low at highway cruising, but high when accelerating, therefore, your timing is high at idle, high at highway cruising, but low(er) when accelerating. Mechanical adds timing with RPM, vacuum takes away timing with load. So you have your base timing (Say 22*, for instance), and your mechanical advance (Say 35* at, say, 2200 rpm and above). That is your linear, unchanging timing curve, which will always rise and fall steadily between idle and 2200 rpm, and will remain the same above 2200 rpm. Your vacuum advance is auxiliary to that fixed curve, adding and taking away in set circumstances. So at idle, when you would be at 22* in this example, you decide to hook up your vacuum advance. Let's say your vacuum advance is tuned to add a maximum of 12* of timing. So now, you would be at say 34* at idle, since idling is a low load circumstance, the vacuum pod is adding maximum timing. Then you accelerate, so vacuum drops and your timing drops down to just your linear, mechanical curve (starting at 22* and increasing linearly with rpm until 35*). But now, you're on the highway and you're going the speed that you want, so you back off the throttle. Now you're cruising on the highway at say 2700 rpm. Since you're above 2200rpm, your mechanical advance is in full swing, so you're at 35*, right? Well, not necessarily. Because now your engine is making peak vacuum, because the engine isn't under load, it's just maintaining it's current state, so now your vacuum advance kicks in and adds that 12* extra timing. So you cruise at 47* of total, maximum timing. Then, any time you whack the throttle open, air rushes into the engine, engine load spikes, the rpm is constantly changing, as is the airflow and power production, so the engine isn't retaining vacuum. Low vacuum? No more vacuum advance. Now you're right back down to 35* of linear, mechanically controlled timing. Perfect for making WOT power. Let off the gas, vacuum spikes, more timing, right back to cruising with glorious fuel mileage and smooth engine operation. All there is to do is edit those numbers for where your base timing is set, how much your mechanical advance adds and at which rpm, how much your vacuum advance adds, and you can figure out how much timing you have in a set circumstance. And to figure out how to tune it all, Birdsong has another excellent video on that. My numbers were picked at random, but reflect how one would choose to tune a street engine with a somewhat exciting cam, and get good results at any rpm.

  • @JJ-zo5wv
    @JJ-zo5wv7 ай бұрын

    Sweetness info

  • @nextalcupfan
    @nextalcupfan7 ай бұрын

    what do you do if you hook up the vacuum advance and at part throttle the engine starts pinging its brains out? 8 deg base timing, i think 12 deg of mechanical advance, engine pulls 19in of vacuum at idle and about 1deg of advance per in of vacuum. (about 20 total) ive tried straight manifold, ported, and no vacuum advance at all. at no vacuum advance i think my total timing is only 26 degrees.... but if i give her any more it just pings at light throttle (idling it sounds great) I only get about 12mpg and it overheats on the highway even with a 100% new cooling system and several block flushes. 1963 Pontiac Bonneville 389, engine is 100% bone stock Induction is a Fitech GoEFI4 fuel injection conversion fuel is premium 91 with no ethanol

  • @jcnewbee8124
    @jcnewbee81247 ай бұрын

    Ya lots of youtubers try to explain this issue but this was much more betters....I would like to know at what point did you decide that fuel mileage was important?...lol.

  • @junkerup

    @junkerup

    7 ай бұрын

    Fuel mpg equal’s efficient running engine with HP

  • @LunaTic-fy9ve
    @LunaTic-fy9ve7 ай бұрын

    When is Smurf getting his blue colors back?

  • @sergiod5362
    @sergiod5362Ай бұрын

    My engine vacuum is highest at 19 but it makes my idle hit almost 1,200 with the curb idle screw all the way out. And no vacuum leaks. Is there a way to drop the idle more without dropping the timing?

  • @mrromantimothy
    @mrromantimothy6 ай бұрын

    Allow me to tell what would happen if you left that vacuum advance line unplugged and kept driving like an average Joe cold air on a warm engine you would eventually burn a penny size hole through one of your pistons , but before that you would have a lot of detonation which would probably overheat your coolling system, so you buy and throw parts at it trying to fix it with the hole finally completed that piston will start dumping fuel into your crankcase diluting your oil while running on 7 cylinders, running late for work so you try to start it and hear a boom under the hood and find your oil cap blown off and your oil pan and valve covers will start leaking from everywhere what was the fuel diluting your oil and finally reaching the right proportions of oxygen to be ignited by the spark plug, so you'll eventually get it running and drive it to your mechanics, and he might just try to restart it and a boom all over again, and all that was caused by a vacuum leak usually at the back of the intake manifold, always inspect your vacuum lines, and replace them,

  • @dantheman8781
    @dantheman87817 ай бұрын

    What does it say underneath the black tape on your hat?

  • @dogdoc1
    @dogdoc13 ай бұрын

    So, can I simply switch to vacuum from mechanical by placing a hose from the distributor to the carburetor?

  • @roodgeregeld
    @roodgeregeld7 ай бұрын

    My smallblock has a stock distributor... No vac...

  • @KuRo88
    @KuRo887 ай бұрын

    Some previous owner of my car blocked off the vaccum advance connector on my carb... Is there any other way I can get vaccum without disturbing something else?

  • @michaw1674
    @michaw16747 ай бұрын

    Programmable 6al2 MSD box with map sensor and locked out pro billet distributor gives you the same thing and more control with cranking retard extra. I actually use exactly 45 degrees full advance like you on my tunnel ram setup.

  • @kevinhamling1963
    @kevinhamling19637 ай бұрын

    A perfect mostbetterer video. ✌️ Peace.

  • @theodoredugranrut8201
    @theodoredugranrut82017 ай бұрын

    Central California watching

  • @wackowacko8931
    @wackowacko89317 ай бұрын

    Manifold vacuum advance canisters and ported vacuum advance canisters are different. Manifold vacuum is highest at idle, while ported vacuum is highest at part throttle/high gear - so those vacuum advance canisters are necessarily different. If you plug a ported vacuum canister into a manifold vacuum source, you will have a wicked part throttle knock. If you back off the timing enough to get rid of the part throttle knock, the engine will become very lazy. If you plug a manifold vacuum advance canister into a ported vacuum source, the engine will require more initial timing to run even reasonably well. Ported vacuum canisters are usually a lot larger than manifold vacuum canisters, and usually have a thermal vacuum switch in between the ported source and the vacuum advance canister. Ported vacuum sources will go midway into the side of the carburetor barrel, and manifold vacuum sources will be located underneath the throttle butterflies or right into the intake manifold at some point. Ported vacuum sources didn't become common until after 1973, so if you had a stock 1977-ish pickup (for example) that ran pretty bad;y or couldn't get out of it's own way, it is/was because of an incorrectly set up ported vacuum advance system.

  • @egodeathplease
    @egodeathplease7 ай бұрын

    You need the vacuum canister that you can adjust with an Allen key. I usually don't end up using the vacuum advance because I'll get part throttle ping or stumble. I usually end up running a short curve with alot of initial timing.

  • @junkerup

    @junkerup

    7 ай бұрын

    Yup, I should do a more in depth tunning later on the subject

  • @egodeathplease

    @egodeathplease

    7 ай бұрын

    @@junkerup I do run it just like that if it will work though. I usually just get my flippers tuned up as best I can with what's handy though.🤣

  • @ferrygraafland1452

    @ferrygraafland1452

    7 ай бұрын

    Same for me. On a stock block i can get it perfect. Right now...on a 416 stroker small block with lots of duration ...ping and stumble.

  • @cj428man
    @cj428man7 ай бұрын

    So what would your recommendation for one of the old Mopar 509 cams with 5" of vacuum at idle. I would love to hook up my vacuum advance.

  • @junkerup

    @junkerup

    7 ай бұрын

    I had a 509 in a 440 and it idled at 13”

  • @cj428man

    @cj428man

    7 ай бұрын

    @@junkerup interesting.

  • @cj428man

    @cj428man

    7 ай бұрын

    @junkerup I have no idea if this is true, but I do live at about 6,700 feet of elevation. I have been told that the higher elevation you will have lower vacuum... 🤷‍♂️ But that could bullshit

  • @louisbeaver87
    @louisbeaver877 ай бұрын

    That's why you need to get a hei distributor for your Mopar

  • @Foxies1972
    @Foxies19727 ай бұрын

    Ok so completely different engine and smaller it’s a holden 3.3 ltr ( small compared to yours) same theory?

  • @raykaufman7156
    @raykaufman71567 ай бұрын

    I'm assuming you aren't trying to start them at 45deg advance? That's gotta be hard on even a Mopar starter...

  • @junkerup

    @junkerup

    7 ай бұрын

    No

  • @moparedtn
    @moparedtn7 ай бұрын

    On anything approaching a stock engine, I'll stick with what the original engineers at Chrysler specified, thanks.

  • @cudaruss7825
    @cudaruss78257 ай бұрын

    Hey from Detroit

  • @DougsterWolverineGarage

    @DougsterWolverineGarage

    7 ай бұрын

    Hey hey From west Michigan!

  • @g.o.b.2558

    @g.o.b.2558

    7 ай бұрын

    Hello from New Mexico 👍

  • @ken7808

    @ken7808

    7 ай бұрын

    Hello from Maine!

  • @dickjohnson1158
    @dickjohnson11587 ай бұрын

    It’s there for a reason right ?

  • @maximuswedgie5149
    @maximuswedgie51497 ай бұрын

    I’m confused. Was told when I purchased my FBO distributor and rev limiter, they told me 16 degrees initial at idle. 40 degrees?

  • @junkerup

    @junkerup

    7 ай бұрын

    There’s a lot into tuning I just was talking about vacuum, but yes I run 40-45 at idle in my cars

  • @maxpower479

    @maxpower479

    7 ай бұрын

    16 degrees without vacuum advance connected...then you reconnect it. Chris means 45 with vacuum connected

  • @maximuswedgie5149

    @maximuswedgie5149

    7 ай бұрын

    @@maxpower479 ah, copy that. Thanks

  • @maximuswedgie5149

    @maximuswedgie5149

    7 ай бұрын

    @@junkerup thanks for the reply, I will definitely look into that👍👍

  • @equestrianalways6132
    @equestrianalways61327 ай бұрын

    Wish I was your neighbor lol

  • @rwg68z76
    @rwg68z767 ай бұрын

    I was told not to use vacuum advance on ready run distributors.

  • @BFTEgodswarrio5939
    @BFTEgodswarrio59397 ай бұрын

    Ok Chris ear balls really i heard yall people in las V smokin some serious 💩

  • @dickkapp336
    @dickkapp3367 ай бұрын

    What about an LS valve train in the MOPAR heads ????

  • @Sam-yk6mz
    @Sam-yk6mz24 күн бұрын

    And I have my timing at 15 .

  • @bradleymadosh911
    @bradleymadosh9117 ай бұрын

    Use your earballs😂

  • @MH-rb7lp
    @MH-rb7lp7 ай бұрын

    Not arguing here but it seems to me if I tried to advance the timing to 45 deg at idle it would not be very happy. I am missing something here... Do a video showing exactly how you are doing this please. Again, not at all arguing, I agree you need a vacuum advance but it seems counter intuitive.

  • @junkerup

    @junkerup

    7 ай бұрын

    Every engine is different, crank timing into it until vacuum drop that’s ur magic number

  • @stpstudios

    @stpstudios

    7 ай бұрын

    Plug the vac advanced to a "timed" port on your carb (doesn't open till the throttle blades open) it help with hot starting & gives max advanced at cruise, but drops off under load & goes to 0 advanced at WOT.

  • @6gunsand6strings

    @6gunsand6strings

    5 ай бұрын

    Use manifold vacuum not timed

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