SmokingI on decel

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Sep 26, 2013 | 04:59 PM

rttmike

Thread Starter

Racer

Joined: Oct 2011

Posts: 440

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From: Mukwonago Wi

SmokingI on decel

Having a strange issue. The car runs great but if I run it high up in the RPM's driving hard, it smokes a lot on decel while engine braking. It seems to come and go. I do have a home mad catch can in place as well. Any ideas?

Sep 26, 2013 | 05:35 PM

Kmcoldcars

Melting Slicks

Joined: Jan 2009

Posts: 3,181

Likes: 286

From: Puyallup Washington

Smoking on deceleration is usually a sign of bad rings. You may want to do a leakdown test and/or a compression test.

Sep 26, 2013 | 07:06 PM

racebum

Race Director

Joined: Jan 2008

Posts: 16,028

Likes: 170

From: oregon

even a manifold vacuum test would let you know if there is a major compression issue or if the motor is just getting worn

as stated above a leakdown would be best

Sep 26, 2013 | 07:56 PM

Evil-Twin

Team Owner

Joined: Mar 2001

Posts: 21,325

Likes: 3,841

From: small town in S.E Pa. PA

St. Jude Donor '03-'04

Quote:

Originally Posted by Kmcoldcars

Smoking on deceleration is usually a sign of bad rings. You may want to do a leakdown test and/or a compression test.

Smoking on decel is " Never" a sign of bad rings.. it would smoke on accel as well. the signature of decel only smoking is valve seals.

Sep 27, 2013 | 12:44 PM

rttmike

Thread Starter

Racer

Joined: Oct 2011

Posts: 440

Likes: 0

From: Mukwonago Wi

I planned on doing heads anyway. I wonder if I should just wait for that and hope it's not rings. Car has 92k on it.

Sep 27, 2013 | 04:16 PM

Bill Curlee

Tech Contributor

Joined: Dec 1999

Posts: 32,910

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From: Anthony TX

CI 6,7,8,9,11 Vet

St. Jude Donor '08

Quote:

Originally Posted by Evil-Twin

Smoking on decel is " Never" a sign of bad rings.. it would smoke on accel as well. the signature of decel only smoking is valve seals.

100% Nail on the head!

Intake valve seals. Normally replacing the intake & exhaust seals remides the issue BUT, while you are in there, you really should upgrade the springs if they are high mileage springs.

I would also replace the rocker arm trunions to the new improved COMPCAMS Trunions.

My 2 cents

BC