[malarson]

I read your other posts......someone suggested checking your power brake booster, have you done this? You mentioned your brakes were getting worse, maybe the diaphragm is shot in your booster. Mine was bad, causing a very rough idle.

 

[Guest]

You should be able to diagnose the problem with the help of the following URL...

Vacuum Gauge Readings-

 

[C0V3R]

The booster isnt connected to the manifold at all any more. Nor is the transmission. Or anything that draws vacuum. The booster probably is on its way out, but theres also the underlying problem of low vacuum.

 

[C0V3R]

That site is really great! Im not 100% sure about what category mine falls under, but based on that site its either worn rings, or timing/ignition problems combined. Im going to change the plugs and see if I can get my hands on a timing light tomorrow.

 

[Huskinhano]

What shape is the motor in? What's the milage? Ypu've seem to have checked a lot of things and no one has mentioned a timing chain. I think you've got a worn chain and skipped a tooth.

 

[C0V3R]

The motor seemed to be in good condition when I got it, no idea about milage. Looked to have been somewhat recently rebuilt, but the car was a daily driver. Thanks for the idea of the timing chain. Ill look into it.

 

[C0V3R]

Would a timing chain make any noises etc? There arent really any odd or unusual noises.

 

[Huskinhano]

A quicky way to check; put a timing light on, rev the engine a liitle and release. If the timing bounces all over the place, the chain is worn. If it advances and retards smoothly in relation to rpm, it's ok.

My bet is a worn chain.

 

[Guest]

What compression readings are you getting. Also, are you hearing any noise from the lifters. Your vacumn readings are way low and you are likely looking at either rings or valves as the source of the problem.

 

[C0V3R]

Compression test will happen tomorrow along with new plugs, and hopefully some timing light tests. No noises from lifters at all.

 

[Guest]

Any backfiring through the carb under acelleration? If so, I'd pull the valve covers and observe the ammount of travel each rocker arm has. Could be a wiped lobe on the cam. I once had this problem, and my 6-71 blower was only giving me 3 lbs of boost and the pop off valves were going nuts. Pulled off the blower and then it was backfiring into the carb under acelleration. New cam and lifters fixed it. If no backfiring, maybe a burned or bent valve. Do the compression check!!

 

[Mudcat]

Since you've done all the standard checks and you were able to get the vacuum up to 14 with a maxed out advance I suspect the timing chain has jumped a tooth. You will need to pull the cover and check the cam timing alignment. /forums/images/icons/frown.gif