Vaccume Advance problems
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Freshman User
Joined: Nov 2003
Posts: 38
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From: Beaverton OR
Vaccume Advance problems
I'm trying to isolate the reason my vaccume advance is giving me problems. I beleive it's the vaccume advance because having recently replaced the vaccume advance diaphram on my 352, 99% stock, my truck stopped pinging under load. for awhile it was like a new truck. I installed a holly 2300 2 bbl and the truck still ran great, all kinds of power. all at once (with new air filter)
it started pinging again badly. I have it timed at 10deg @550 rpms. and was thinking of tying the vaccume line into the full manifold vaccume fitting verses the carb connection. also I've put lead additive in the fuel and it doesn't seem to make any difference........
Any ideas?
Thanks in advance
it started pinging again badly. I have it timed at 10deg @550 rpms. and was thinking of tying the vaccume line into the full manifold vaccume fitting verses the carb connection. also I've put lead additive in the fuel and it doesn't seem to make any difference........
Any ideas?
Thanks in advance
Elder User
Joined: Mar 2003
Posts: 541
Likes: 1
From: Phoenix Az, by way of Fre
vacuum advance diaphram?
where is this?
how do I inspect mine?
i have part throttle detonation issues like you would not believe, if this fix'd yours...
Otherwise, I'm considering plugging the vacuum advance.
where is this?
how do I inspect mine?
i have part throttle detonation issues like you would not believe, if this fix'd yours...
Otherwise, I'm considering plugging the vacuum advance.
Senior User
Joined: Mar 2001
Posts: 379
Likes: 0
Alot of those advances are adjustable. If you stick an allen wrench (can't remember what size) in the end where the vac. line connectes you can taylor the advance. Turning it clockwise will decrease the advance while CCW will increase.
Elder User
Joined: Sep 2003
Posts: 908
Likes: 4
Did you make sure to put the tiny E-clip over the vacuum advance lever inside the distributor? The breaker plate can become disengaged if you don't and can float all over the place.
Hooking the vacuum advance to manifold vacuum is not an answer. You won't have vacuum advance at all - you'll have vacuum retard. The point is to get the engine running correctly, with the vacuum advance working properly.
You need to pull the dist. cap and make sure everything is correct inside there. Then, with the cap off, pull the vacuum line from the carb and suck on it. You should see the breaker plate move. If it doesn't, the vacuum can is bad. Yes, even new ones can go bad - the quality of some of these parts can be atrocious these days.
Find out why your timing is floating around and fix it. Aside from the vacuum canister, the distributor could have a badly worn shaft bushing.
Hooking the vacuum advance to manifold vacuum is not an answer. You won't have vacuum advance at all - you'll have vacuum retard. The point is to get the engine running correctly, with the vacuum advance working properly.
You need to pull the dist. cap and make sure everything is correct inside there. Then, with the cap off, pull the vacuum line from the carb and suck on it. You should see the breaker plate move. If it doesn't, the vacuum can is bad. Yes, even new ones can go bad - the quality of some of these parts can be atrocious these days.
Find out why your timing is floating around and fix it. Aside from the vacuum canister, the distributor could have a badly worn shaft bushing.
Thread Starter
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Freshman User
Joined: Nov 2003
Posts: 38
Likes: 0
From: Beaverton OR
Found the problem, the points were bad. i took the opportunity to switch to the breakerless electronic point system.
installed it, set the time and rpm's.......no pinging, valve noise ect...
great power for a used 352
thanks for the responses.
installed it, set the time and rpm's.......no pinging, valve noise ect...
great power for a used 352
thanks for the responses.
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