'69 all original numbers matching engine
Thread Starter
1st Gear
Joined: Feb 2010
Posts: 1
Likes: 0
'69 all original numbers matching engine
350 350 horse 11 to 1 compression. Took engine apart had a broken ring due to detonation. What are corvette owners doing to drive their cars on the street with this high compression? My mechanic wants me to go down to 9 to 1 compression. Has anyone had any experience with lead additives? Your comments and any suggestions would be welcome.
Pro
Joined: Jul 2002
Posts: 723
Likes: 0
From: North Port, FL
Burning Brakes
Joined: Sep 2008
Posts: 753
Likes: 0
The real Tetraethyl Lead additives work. Here is a link http://www.maxlead2000.com/
use premium gas and add Toluene 10%. i have experienced problems with more than 10% ( cylinder bores dry).
retard timing , go for at least 3.70 rear end
Racer
Joined: Jan 2010
Posts: 348
Likes: 2
From: Lowell MA
Yes, I have experience with leaded additives. Also have a 1969 L46 and use premium 93 octane mixed with Cam 2 leaded 110 octane racing fuel and before that octane boosters w/lead as mentioned above. Never had a problem with pinging or detonation. I run my timing between 10 to 12 BTDC and recently set my distributor for timing all in (36 degrees) at about 3000 rpm. Only drive my car in late spring and Summer so I won't be able to test it for a few months. Hope I helped somewhat.
Drifting
Joined: Feb 2000
Posts: 1,591
Likes: 53
From: Central MN
jean claude............My mechanic suggested the same thing (although I did not have a broken ring.) He put new pistons in, but left the compression at 11:1. Now, I just three ounce of lead per gallon of 91 non-oxygenated gas. Without the lead, the engine will ping
Drifting
Joined: Nov 2007
Posts: 1,716
Likes: 281
From: New York
Remove the engine, put in storage.
Put in what you want. You'll have your original engine when you want it.
The other alternative is find someone who sells leaded racing gas around you.
It is very expensive....
Put in what you want. You'll have your original engine when you want it.
The other alternative is find someone who sells leaded racing gas around you.
It is very expensive....
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
The solution is simple and has been around since the '60s: http://www.snowperformance.net/
You can tune some of the pump gas detonation tendancy out by richening up the mixture, taming the timing curve, and spark plug choice. All of these have an affect on performance that you may not be happy with and they may not safely and completly address the detonation issue. The water/methanol injection allows your engine to perform without these compromises.
You can tune some of the pump gas detonation tendancy out by richening up the mixture, taming the timing curve, and spark plug choice. All of these have an affect on performance that you may not be happy with and they may not safely and completly address the detonation issue. The water/methanol injection allows your engine to perform without these compromises.
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Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
Listen to your mechanic. When I rebuilt my 350/370 long ago because of collapsed ring lands due to detonation, I used 9.6-1 pistons. After that it ran better and smoother than it ever had before on premium pump fuel.
