Vacuum Advance doesnt work correctly!

144-250 cid Inline Six Performance
KrautComet
Posts: 14
Joined: Thu Apr 14, 2016 12:57 pm
Location: Osnabrück/Germany(north)

Vacuum Advance doesnt work correctly!

Post by KrautComet »

So this is my first thread in this forum except my introduction!
For everyone who hasnt seen it yet, my name is Erik and i am from Germany. If my English isnt correct sometimes please excuse me. :)

I bought my comet some month ago and before it wasnt moved on fuel for over 5 years but on lpg.
The whole fuel system wasnt existing except the carb which wasnt running anymore. I fixed every problem except the vacuum advance.
If i set the ignition on 10 deg. at idle and speed up the motor it gets earlier by 10 to 20 degrees, just like it should. The point is when i hold that high speed the ignition falls back on 10 deg.!
I overhauled my Holley 1909 already but i wasnt sure if the spark control valve was the right one because it looked differet from the old one.
I used this kit:
http://www.ebay.de/itm/251057570861
Do you know what the issue could be?
I will take some pictures today, so you can see the difference of the valves.

Lip Ripper
Posts: 1870
Joined: Wed Jun 06, 2012 6:47 am
Location: Lake Placid, Florida

Re: Vacuum Advance doesnt work correctly!

Post by Lip Ripper »

It sound's like the mechanical advance in the distributor is frozen. And are you using manifold vacuum or ported vacuum for your advance? The Ford's are designed to use ported vacuum. In other words, no vacuum advance at idle. It should be hooked to the vacuum port on the side of the Holley above the throttle plate.

Stacey

After writing this I looked at your ebay link. I am not familiar with 6 popper's so I may be wrong.
66 Cyclone GT; 245/60R15's on 15x8's and 215/70R15's on 15x7 Magnum's.
There's nothing like the sound of a pushrod V8 singing at the top of her lung's.

Comechero65
Posts: 1870
Joined: Wed Mar 12, 2014 10:37 pm
Location: Santa Clara, Ca

Re: Vacuum Advance doesnt work correctly!

Post by Comechero65 »

Early falcon and comet 6 cyl engines used a carb that provided a sort or vacuum advance to the dist by incorperating a special vacuum contol mechanism as a part of the carb. If your carb doen;t have that feature you won't have any timing advance. Sounds like yours does and is trying to work but is failing and timing falls back off after initial acceleration.
Consequently you are limited to only a few carbs that have that feature. And that part has to work right to maintain correct timing at all engine speeds. The dist in those engines (called Load-a-matic) don't have any mechanical advance only vacuum advance. After 66 the dist did have a mechanical advance so switching to a later dist will get you mechanical advance and no longer be restricted to just a few choice of carbs.
Ron
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KrautComet
Posts: 14
Joined: Thu Apr 14, 2016 12:57 pm
Location: Osnabrück/Germany(north)

Re: Vacuum Advance doesnt work correctly!

Post by KrautComet »

The mechanical advance was my first thought too but when i took a close look at the dist i couldnt find it and so i looked it up on the internet.
I found out that there is that Load-o-matic system but there wasnt an exact picture how it works with my carb, so i already thought about a totally other dist too.
But which ones can i use? There are almost no other comets in Germany and when id search for a dist. which works for comets after 65 id find nothing. :D
So can i search for dists which are offered for falcons and mustangs after 65 too? (170,200 cui engines)

EDIT: If i cant find a dist in Germany ill offer here but what is a smog equippment? My dictionary doesnt know it.
http://www.macsautoparts.com/ford_falco ... comet.html
or this?
http://www.macsautoparts.com/ford_falco ... ntego.html

comethead
Posts: 5692
Joined: Sun Nov 09, 2003 7:44 pm
Location: Palmdale, CA

Re: Vacuum Advance doesnt work correctly!

Post by comethead »

Some 60s cars came equipped with systems that attempted to clean up the dirty exhaust emissions cars were putting out (dirty exhaust = smog) Some smog systems were air pumps and other systems adjusted timing I believe.
Anyhow if your engine doesn't have a "smog" air pump get a distributer that's not for a smog engine.

Mercury and Ford shared engines in the 60s. So a Mustang/Falcon 6 is like a Comet 6. Shop for Mustang engine parts and it will make things MUCH easier.

Good luck!

Joe
1965 Caliente HT- 289/4 speed
1964 Falcon HT- track car- 302/4 speed
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KrautComet
Posts: 14
Joined: Thu Apr 14, 2016 12:57 pm
Location: Osnabrück/Germany(north)

Re: Vacuum Advance doesnt work correctly!

Post by KrautComet »

Good evening,
i searched for mustang parts and i found a shop in germany!
I hope i get one with mechandical adv. now! At least i searched for 68 Mustang with 200 cui motor, so i should be the right one.
I will let you know if it works.
My next question would be if there is a trick to remove the old dist. Is there more than the screw whith the plate which holds it?
When i tried it some days ago it was still stuck after removing that screw but maybe i didnt do it strong enough.

lavron
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Re: Vacuum Advance doesnt work correctly!

Post by lavron »

KrautComet wrote:My next question would be if there is a trick to remove the old dist. Is there more than the screw whith the plate which holds it?
That is all that holds it in, it should pop right out when you remove the bolt and hold down plate.

See Ya,
Mike
Mike's build thread
viewtopic.php?f=9&t=13058
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popscomet
Posts: 9687
Joined: Sat Jan 01, 2011 11:19 pm
Location: Jacksonville, Arkansas

Re: Vacuum Advance doesnt work correctly!

Post by popscomet »

Sometimes you have to work it ,,back and forth ,,I have had to take a small chunk of wood or a hammer handle and PECK on it ,,but do be careful ! :shock: ,put the wood where the vacumn adv screws on to the dist,not out on the end of the adv,,,peck lightly and try to work it,,(I have one froze up in a 302 v8 right now,,,I'd like to bump the timing up just a tad,but it runs so well I don't sweat it.....if and when you get it out,clean all mating surfaces up and I always smear a tad of anti-seize on the dist and besure you put a good coat of it on the gear,,,good luck,...I saw your comet the other night,it's a keeper for sure,that sun visor sets it off to me ,cause OL POP like's stuff that is different.pop
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pop/glenda

KrautComet
Posts: 14
Joined: Thu Apr 14, 2016 12:57 pm
Location: Osnabrück/Germany(north)

Re: Vacuum Advance doesnt work correctly!

Post by KrautComet »

Hey Guys,
the dist. arrived yesterday and today i tried to swap it. More or less everything went wrong because now i have a car without an ignition system.
The old one was hard to pull out but finally it came out with the oil pump drive unit. Its the little rod wich was stuck in the hexagon socket of the dist..
When i took a closer look i saw that someone must have stuck those two together in a wrong position with a lot of force. So now it is unuseable anymore, otherwise i risk that the oil pump stops pumping when the loose rod just turns in the socket.
The new one doesnt fit at all. The hexagon socket and the bearing (seat?) are to wide, even i ordered a dist for a 66 Mustang motor.
My problem is to find out which is the right dist. for me now. Next monday ill try my luck and i hope the guy which runs the shop helps me by measuring every dist. that will possibly fit and compare that whith my old one.

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KrautComet
Posts: 14
Joined: Thu Apr 14, 2016 12:57 pm
Location: Osnabrück/Germany(north)

Re: Vacuum Advance doesnt work correctly!

Post by KrautComet »

Good evening,
id like to give you an update about my dist. project.
I called Macs Autoparts today and asked for a dist. with mech advance and a 1/4 inch hex hole on the bottom.
They told me there is not such a part, the 6 cil. distributors all have a 5/16 hole on the bottom and not a 1/4.
That means that i have to order to orininal one and find the problem with the load-o-matic on the carb.
The other option would be to use the "wrong" dist. and make the pilot hole bigger. Also i would have to make a custom oil pump drive shaft with a 5/16 and 1/4 inch diameter on each end.
But to be honest, i wouldnt be happy to drill in my engine so probably i will go with the first option.

Adams
Posts: 136
Joined: Mon Aug 03, 2015 1:01 am

Re: Vacuum Advance doesnt work correctly!

Post by Adams »

Just out of curiosity, If the timing advances, then falls off, did you check the vacuum can on the distributor to see if it is leaking down?

popscomet
Posts: 9687
Joined: Sat Jan 01, 2011 11:19 pm
Location: Jacksonville, Arkansas

Re: Vacuum Advance doesnt work correctly!

Post by popscomet »

To check the vacumn adv,,I always put a small rubber line on the adv and suck on the hose and watch the breaker plate (cap removed),it should adv ,when it does,then put your tongue over the end and trap your own vacumn,the breaker plate should stay adv,if it goes back,most likely the vac adv is bad... or it does not advance not at all..that's POP's way !!....make sure when hooked to the carb and with motor running it's not running in full advanced all the time..cause then you have nothing in reserve...pop
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pop/glenda

KrautComet
Posts: 14
Joined: Thu Apr 14, 2016 12:57 pm
Location: Osnabrück/Germany(north)

Re: Vacuum Advance doesnt work correctly!

Post by KrautComet »

Thanks for your answer, i didnt check the vac. can yet!
I really dont know how i forgot to check it! I did that now and noticed that it is broken, so i hope it was the problem.
The "good" thing is that i noticed the worn oil pump drive shaft and the damaged dist. because i wanted to change the distributor.
Now i have to wait until my parts flew over the pond..
I will give you and update soon!

Comechero65
Posts: 1870
Joined: Wed Mar 12, 2014 10:37 pm
Location: Santa Clara, Ca

Re: Vacuum Advance doesnt work correctly!

Post by Comechero65 »

What you have discovered is the early 6's used a 1/4" distributor driveshaft and around 66 or later(not sure when) ford switched to a 5/16" shaft. Don't know if they make an adapter shaft with 1/4" one end and 5/16" at the other end. If not you might have to find someone to make you a shaft. Or maybe it's possible to use an oil pump from a later engine that already has the 5/16" drive then the later 5/16" shaft would work. Then you can keep the later dist which has a mechanical advance. and in doing so you don't need to keep the early carb with the special vac advance control output. Then your choices in carbs becomes less limiting. Welcome to the world of 6's. v8's don't have as many of these issues.

As mentioned by Pops the vac advance can leak and the timing will fall back after advancing. Replacing the vac advance diaphragm would be the only choice. Don't know if the later distributor has a vac advance or is strictly mechanical advance. It's nice to have both but at least having the mechanical advance is better than nothing.
Ron
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KrautComet
Posts: 14
Joined: Thu Apr 14, 2016 12:57 pm
Location: Osnabrück/Germany(north)

Re: Vacuum Advance doesnt work correctly!

Post by KrautComet »

Hey,
here is my final update for ths topic!
I overhauled the oil pump ad installed the dist. yesterday, now the engine idles really smooth and accelerates really great. The vac. advance works again!
Also i refilled some transmission fluid in my 3 speed trans. Now i hear a strange loud noise from the drivetrain when the car is in thrust, so i couldnt drive it home.
I wonder how i got that much bad karma!

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