engine diagnostic help please
Thread Starter
Melting Slicks
Joined: Dec 2000
Posts: 2,130
Likes: 1
From: mesa,az
engine diagnostic help please
couple things.
the engine is a 327 with with a edelbrock RPM cam, heads, and airgap manifold. running about 10.5 to 1 compresion. using stock distributor and points.
1) when i tighten down my distriputer clamp the last couple turn it will change my timing by a couple degrees?
2) my engine returns to idle slowly and i am only making about 8 in Hg of vacume at 800 RPM. i suspect a manifold leak but is there a good way to check?
thanks (edited for nomenclature)
greg
the engine is a 327 with with a edelbrock RPM cam, heads, and airgap manifold. running about 10.5 to 1 compresion. using stock distributor and points.
1) when i tighten down my distriputer clamp the last couple turn it will change my timing by a couple degrees?
2) my engine returns to idle slowly and i am only making about 8 in Hg of vacume at 800 RPM. i suspect a manifold leak but is there a good way to check?
thanks (edited for nomenclature)
greg
Last edited by panchop; Jan 13, 2006 at 03:05 PM.
Le Mans Master
Joined: Jan 2006
Posts: 8,319
Likes: 7
From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
some help
When you tighten down the clamps it should'nt change it at all if it does, make sure the distributor is seated properly.
As far a checking for vacuum leaks, get a vacum gage and a chiltons. depending on how the needle moves i.e
steady low, steady high, jumping needle etc. you can tell where you have a leak as well as idle mixture and such. id put it here but i dont have my chiltons handy
hope this helps
tim
As far a checking for vacuum leaks, get a vacum gage and a chiltons. depending on how the needle moves i.e
steady low, steady high, jumping needle etc. you can tell where you have a leak as well as idle mixture and such. id put it here but i dont have my chiltons handy
hope this helps
tim
Melting Slicks
Joined: Mar 2004
Posts: 3,472
Likes: 18
From: Lake Ozark, MO
Sounds like a vacuum leak if the idle returns to normal.. slowly. You can spray carb cleaner around the manifold and carburator gasket surfaces (with engine running). If the RPM goes up, you have found where the leak is.
Can't help on the distributor ?
Can't help on the distributor ?
Melting Slicks
Joined: Sep 2004
Posts: 2,655
Likes: 19
I've seen the distributor effect before, not sure if it's a real problem. Could be a little excess in the end play, or just compressing to it's seat position.
Not sure of the specs on the cam, could be a lot of overlap. Mine does about the same thing and has about the same vacuum. It's just due to the big cam.
Gary
Not sure of the specs on the cam, could be a lot of overlap. Mine does about the same thing and has about the same vacuum. It's just due to the big cam.
Gary
Le Mans Master
Joined: Jan 2006
Posts: 8,319
Likes: 7
From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
curious
Originally Posted by Garys 68
I've seen the distributor effect before, not sure if it's a real problem. Could be a little excess in the end play, or just compressing to it's seat position.
Not sure of the specs on the cam, could be a lot of overlap. Mine does about the same thing and has about the same vacuum. It's just due to the big cam.
Gary
Not sure of the specs on the cam, could be a lot of overlap. Mine does about the same thing and has about the same vacuum. It's just due to the big cam.
Gary
Do you have the gasket in place withthe distributor?
Instructor
Joined: Dec 2005
Posts: 135
Likes: 39
From: Chardon Ohio
Originally Posted by panchop
1) when i tighten down my distriputer clamp the last couple turn it will change my timing by a couple degrees?
Melting Slicks
Joined: Sep 2004
Posts: 2,655
Likes: 19
Yep, just seems to change a couple degrees when tightened. I've seen it several times.
That's why you always recheck it after tightening.
That's why you always recheck it after tightening.
Originally Posted by sweethence
Do you have the gasket in place withthe distributor?
Thread Starter
Melting Slicks
Joined: Dec 2000
Posts: 2,130
Likes: 1
From: mesa,az
vacume leak turned out to be a bad/wrong type gasket on the power brake booster end of the connecting hose between the manifold and brake. pulled my distributor. found about .058 of end play. don't know if that is the culprit. i will also change to a solid type hold down clamp as i do have the spring type.
thanks
greg
thanks
greg
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