Vacuum Tuning & Recently Advanced Vacuum Advance Fallacies

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by W. Winget » Thu Jan 05, 2017 10:42 am

Neat animation of gauges here, click and scroll down:

http://www.therangerstation.com/Magazin ... mLeaks.htmV/R W WInget

You will see them like this:
Image
BURNT VALVE: Needle drops regularly by several points at idle speed.


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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by artificer » Thu Jan 05, 2017 11:37 am

Thanks for that. It's informative & also helpful in getting this 'educational' thread back on track, thus not totally railroaded, by the usual naysayers.

Unfortunately these guys keep telling all they are the sole custodians of Jeep knowledge, drowning out, to the detriment of other's, actual experience being shared.
Their methods might be compared to those used by a certain recent candidate who lost as a result of referring to a major part of the constituency as "a basket of deplorables”....

We have a number of G503 folk, 3 or 4 so far besides the originator of this thread, who tried to share their success, only to be drowned out & berated. That is not fair or right, because there is no method of addressing this berating, without sliding down a slippery slope.

This thread actually started to address/counter someone unidentified's INCORRECT statement regarding vacuum tuning.
That statement was totally wrong BUT as usual with anything vacuum related, progressed where a few others wanted to take it...in the wrong direction & down the drain.
John on the initial post wrote:Tuning by vacuum gauge is not wise when the jeep does not come with vacuum advance built into the ignition.
NOT TRUE. Can anyone tell us how &/or why vacuum advance makes any difference to a vacuum gauge reading @ idle speed?
Had the ignition had vacuum advance, you could thus aim for the highest vacuum reading at idle as a good rule of thumb for setting ignition timing.
WRONG....Setting the ignition timing correctly, no matter what method used, has absolutely nothing to do with any distributor advance, mechanical [not doing anything @ idle] or vacuum [blocked off as Hinckley & I said].
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
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Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by foxy » Thu Jan 05, 2017 12:44 pm

W. Winget wrote:Neat animation
Image
BURNT VALVE: Needle drops regularly by several points at idle speed.
Call me a naysayer but am getting sick about these stupid animations that are totally wrong and misleading. What we need is a video with a real VG on a real engine showing each real fault. For example, the animation "BURNT VALVE" is pure fiction!!! If it is an outlet valve that is burnt but not yet severelly leaking the VG will not tell, but an inlet valve will show as hell.
Broken valve springs will NOT show on a VG unless the engine is reved up untill the valve start to fly, Air leak's on a manifold from an idling engine does not show on a VG. Even a bad non sparking spark plug does not really show but is limited to a tiny little needle sweep, A leaky head gasket does not show on the VG unless the engine start to run rough and blow white smoke or loose 2 cylinders..don't even get the VG you will know! To tight valve tappet clearance does not show...Bottom line, the VG show's nothing that isn't obvious by ear or eye...why do we need it for then one might ask? That said there are a few thing's where a VG is really good at like diagnosing a blocked exhaust pipe, Wrongly installed camshaft drive which can't be heard or seen. Finding air leak's in the fuel system & pressure testing a fuel pump is easy with a VG around. Tuning a carburator idle mixture screw with a VG is possible if there are no emission rules to follow, and still unless deaf you can do it by ear as well. Tuning advance with a VG is pure gueswork, you can find highest RPM (also by ear) but then it is too far advanced, how much you have to retard to get near the specified 5° is a "wet finger sientology" or one has to practise with a strobe light. All that nonsence about road testing for pinging and other effect's from a wrongly adjusted timing is 1 : unprofessional and 2 : much more time consuming than hooking up the strobe light. The lack of timing marks is also a drug reason, simply remove the tappet cover and put cylinder 1 or 4 on the rock and you just found TDC. Make a mark on the V-pulley and timing drive cover and you have your timing marks for ever. (turning back to 5° can be done acuratelly with a protractor). Not trying to rain on Artificer's parade, but fact's anyone with a jeep and VG can confirm or prove wrong..

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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by artificer » Thu Jan 05, 2017 2:21 pm

John wrote:6. There are a couple/few G503 vacuum gauge deniers/skeptics/naysayers who throw barbs & rocks whenever the word 'vacuum' is mentioned & that is not likely to change. That is certainly true! 11 totally negative posts by one guy
Luc wrote:Call me a naysayer but am getting sick [it is very easy to unsubscribe. We don't want anyone getting sick, do we.] about these stupid animations that are totally wrong and misleading....Not trying to rain on Artificer's parade, but fact's anyone with a jeep and VG can confirm or prove wrong.
No parade....helping others who have an open mind or @ least trying to do so, before again being rudely interrupted by the same couple of guys trying to close those minds.

Why is it necessary to personally berate others, as has been done on this & any other vacuum related thread?

Was it 5 G503 folk on this particular thread? Folk who readily told others they use the gauge successfully, for what they want it to do. Will we hear from them again?

Unfortunately this same old personality has re-appeared meaning quite valuable machining etc. stuff he can & did contribute [& was praised from this quarter] takes a sideline to vindictive, nastiness & throwing stones.
Luc wrote:I have copied and paste this and many other similar contributions from the past that might be handy one time.
What kind of threat is this?

Things are pretty bad when one needs to consider unsubscribing from their own thread!
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TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by Warren Duchesne » Thu Jan 05, 2017 6:04 pm

I will say that finding TRUE top dead center is not just when the number one piston is at highest point . There is quite a few degrees of crankshaft rotation that the piston stays at top dead center . This is especially true with a engine with a long connecting rod as found in the 134 jeep engine . To find TDC a piston stop or dial indicator can be used . I would assume the factory mark and pointer are accurate. When making your own marks on the front pulley it is not just when the piston is at the top . Warren Duchesne

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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by Tony W » Thu Jan 05, 2017 6:29 pm

Been BANNED again yet foxy.??
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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by foxy » Thu Jan 05, 2017 10:11 pm

Warren Duchesne wrote:I will say that finding TRUE top dead center is not just when the number one piston is at highest point . There is quite a few degrees of crankshaft rotation that the piston stays at top dead center . This is especially true with a engine with a long connecting rod as found in the 134 jeep engine . To find TDC a piston stop or dial indicator can be used . I would assume the factory mark and pointer are accurate. When making your own marks on the front pulley it is not just when the piston is at the top . Warren Duchesne
Warren, When piston 1 & 4 is at highest point the crank is at TRUE TDC without any doubth.
Let's say the TC mark is away from the window when the pistons are at Highest point...well than the flywheel marks are not correct...if you know what I mean?
When the crank rotate away from that point the piston will decend, but a STD dial gauge will not be acurate enough to measure.
Also, The head needs to come off to put a dial gauge on the piston head.
That's why I suggest to use the camshaft, this is by far the most acurate way to find TDC without pulling anything.
Am not playing games, Anyone with a jeep that has the flywheel marks present can check it out.
He will find that the TC mark is EXACT in the middle of the window when the valves are on the rock.
This is more than acurate enough for putting timing marks on the V-pulley in order to use a strobe light or to be able to statically time the engine for a first start up.
People understanding this will now know that it is good practise to check the camshaft timing that way, after replacing the timing chain.

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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by foxy » Thu Jan 05, 2017 10:17 pm

artificer wrote:
Why is it necessary to personally berate others, as has been done on this & any other vacuum related thread?
Am very sorry you take it like that John. As far as am concerned we are talking/discussing a technical subject. There are no insults or negative post's from my side. I do have another opinion than you have. I don't know if this is wrong? Are there any rules am violating?

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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by jeepfinger » Thu Jan 05, 2017 10:30 pm

Tony W wrote:Been BANNED again yet foxy.??
What is it with you lot!! Tony I think that you have got a bit of heat stroke :lol: Explain why should he be banned? Are you jealous our something?

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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by Warren Duchesne » Fri Jan 06, 2017 5:09 am

When the piston is at its highest point the crank is not at true top dead center , it's somewhere close . Like I said before, the crankshaft can move several degrees while the piston stays still . This is called piston dwell time . I am not saying that you couldn't get close enough to put a reasonably accurate mark but I just wanted to point out that the method you describe will not be 100% accurate . Looking at valve movement to determine true TDC would be even less accurate . Warren Duchesne
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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by Joe Gopan » Fri Jan 06, 2017 5:21 am

Amazing how all the Jeeps made since the 40's ever stood a chance with all other mechanics. Am guessing that while this argument has been going on that dozens of Jeep owners around the world have simply set their timing with their lights and their Jeeps are now on their merry way.
I have a small quantity of NOS 40's period simple timing lights that are ideal for use on the Jeeps and CCKW's with timing windows. Will post a pic to show that all timing lights were not created equal. Same for Vacuum gages, the GI issue with all the adaptor fittings are more adaptable for those engines without a wiper hose, and can be readily used to check fuel pumps. My favorite Vacuum Gauge is a pre 1920 model I have used since the 50's, it was removed from an old time La France Fire engine, the needle is well dampened and more reliable than the cheap Harbor Freight versions. Snap-On sells a Vacuum Gauge Kit with adaptor fittings that is similar to the GI Issue of the 40's-70's Motor Pools.
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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by Joe Gopan » Fri Jan 06, 2017 5:22 am

Warren is referring to what is also known as the "Rock" position.
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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by foxy » Fri Jan 06, 2017 5:44 am

Warren Duchesne wrote:When the piston is at its highest point the crank is not at true top dead center , it's somewhere close . Like I said before, the crankshaft can move several degrees while the piston stays still . This is called piston dwell time . I am not saying that you couldn't get close enough to put a reasonably accurate mark but I just wanted to point out that the method you describe will not be 100% accurate . Looking at valve movement to determine true TDC would be even less accurate . Warren Duchesne
I have never said to use a dial gauge on top of the piston to determine TDC. I said that TC mark on the flywheel is right in the middle of the window when the valves are on the rock. And that is more than accurate enough for ignition timing purposes. But I do agree with you that it is not a 100% accurate way to put the crank at TDC, even the flywheel marks and window setup are not 100% accurate. But close enough. Frankly, I was not aware this phenomen is called "dwell time" and glad you mentioned. To ad to my statement, the dist chain must be in good shape and if one want it really accurate he has to turn the crank that the inlet is fully closed (tappet no play and not tight, and then turn the oposite side untill the outlet valve is fully closed and devide that in half. Use mark's on the V-pulley.

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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by dinof » Fri Jan 06, 2017 6:05 am

I can hardly wait until the talk about compensating for the time it takes the electricity to go to the plugs are considered. :)
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Re: Vacuum Tuning & Recently Advanced Vacuum Advance Fallaci

Post by Warren Duchesne » Fri Jan 06, 2017 6:32 am

It is really splitting hairs but everyone is talking about the perfect tune . I would not take the time to find TRUE top dead center on one of these engines myself but watching the piston or valve by eye can lead to being several degrees from true TDC . Warren Duchesne


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