Spark Knock

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Sep 9, 2007 | 10:27 PM

DP77Vette

Thread Starter

Burning Brakes

Joined: Oct 2001

Posts: 842

Likes: 3

From: Woodruff SC

St. Jude Donor '10

Spark Knock

77 Vette, L-48, stock except headers, Lars distributor upgrade, and intake. Timing is right and run mostly the 87 octane gas and never had a problem. I've changed to 93 octane and added STP Gas Treatment hoping to stop the spark knock. Didn't work!!

Any suggestions?????

Thanks in Advance!!

Sep 10, 2007 | 07:24 AM

Durango_Boy

Team Owner

Joined: Aug 2006

Posts: 24,125

Likes: 15

From: Columbia Missouri

Is the balancer stock? If the balancer has slipped then timing will be off even if it looks like it's dialed in.

Sep 10, 2007 | 08:20 AM

dmaaero

Pro

Joined: Dec 2006

Posts: 665

Likes: 0

From: wilmington nc

have you tried retarding the timing a couple degree"s

Sep 10, 2007 | 12:57 PM

BKbroiler

Le Mans Master

Joined: May 2002

Posts: 5,086

Likes: 786

From: Lebanon Township New Jersey

Try disconnecting, and plugging, your vacuum advance, temporarily. If the knock stops, you have too much total timing.

Sep 10, 2007 | 07:03 PM

DP77Vette

Thread Starter

Burning Brakes

Joined: Oct 2001

Posts: 842

Likes: 3

From: Woodruff SC

St. Jude Donor '10

Quote:

Originally Posted by Durango_boy

Is the balancer stock? If the balancer has slipped then timing will be off even if it looks like it's dialed in.

New balancer and timing chain!

Sep 10, 2007 | 07:05 PM

DP77Vette

Thread Starter

Burning Brakes

Joined: Oct 2001

Posts: 842

Likes: 3

From: Woodruff SC

St. Jude Donor '10

Quote:

Originally Posted by dmaaero

have you tried retarding the timing a couple degree"s

Yes!

Sep 10, 2007 | 07:18 PM

Durango_Boy

Team Owner

Joined: Aug 2006

Posts: 24,125

Likes: 15

From: Columbia Missouri

Are you sure it's pinging you hear? Have you pulled your valve covers to make sure all the rockers are positioned and aligned properly and to check for any collapsed lifters?

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