sb69coupe

I just got around to running a compression test on my stock '69 L-46 350/350 motor. I know, I know, shoulda done this BEFORE buying the car 4+ years ago. :eek: The things one learns over time.....

Anyway, I pulled the plugs and each of them was a light greyish-tan on the electrode with no carbon or oil deposits, and they were all uniform in appearance. Thanks go out to Lars for the rebuild on my stock Quadrajet, since I used to get carbon fouled plugs from the old rich-running replacement carb.

The compression test yielded a range of 135 to 145 psi on all cylinders. Is this a reasonable compression result in terms of absolute cylinder compression? I know that the varaince between cylinders is well within spec. The motor doesn't burn any oil, and it runs really strong. The only problems curently are leaking front and rear main seals.

Given these results, I'm considering leaving the motor in the car and just replacing the seals while I do the clutch and front suspension in the next few weeks. Opinions?

Shannon

Smokehouse69

Shannon, I might get some flack over this, but I'm a firm believer in not fixing things that ain't broke. When you replace the rear seal, you'll get a chance to look at the rear main bearing, while you are there you can check your other bearings at the same time. If they look good, put it back together and go with it.
Replace your timing set and oil pump and you'll be good to go.
Just my opinion.

zwede

The most important thing to look for in a compression test is that the cylinders have roughly the same pressure. General rule is that the highest and lowest reading should be within 10%. With readings between 135 and 145, you are within 10%.

rainman69

350/350 with stock cam? Yep, that's plenty compression. And it's within the 10% cylinder to cylinder.

Just replace all the rubber/cork gaskets. Leave the heads, pull the intake if you're brave and want to deal with realigning the distributor. :auto:

rainman69

EDIT: Wrong thread. :jester


[Modified by rainman69, 12:54 AM 1/10/2003]

sb69coupe

Thanks for the advice gentlemen! I can honestly say that this was the first time that I have been pleasantly surprised with ANYTHING on this car :D So now I get to tear into the radiator support replacement and front suspension rebuild. Wish me luck!

Shannon