Sunday, March 22, 2015

W113: New Life Old Soul, Ch. 1 Relief

In an attempt to gauge engine health prior to tearing it apart, I figured I might as well pour some fresh oil into it, lube up the cam, mist some fogging oil into the combustion chamber and try to get some compression numbers on the engine.

Engine is stone cold (37* ambient) and valves have NOT been adjusted. Nothing was done to the engine mechanically outside of draining the fuel/oil out of the crankcase and lubricating what I could.

I hooked up my compression tester to cyl #1 and cranked over the engine with every single spark plug removed. I removed the fuel pump fuse, so any remaining fuel that may be injected into the combustion chamber will just blow out rather than keep washing down the cylinder walls.

To my surprise, the oil pump picked up the oil out of the crankcase and was pumping it through the oil spray bar like madness!! Great news!

I want to minimize the time this engine has rotating as the timing chain guide on one side seems to have collapsed from running off of no oil, but I have an entire baseline on the engine that I can only improve on with work.

Compression test results (engine cold, valves not adjusted, cylinders dry, throttle plate closed):

Cyl #1: 140 psi

Cyl #2: 130 psi 
Cyl #3: 145 psi 
Cyl #4: 135 psi 
Cyl #5: 140 psi 
Cyl #6: 165 psi 

Factory specification for this particular engine (M127) is 150 - 170 psi operating, 128psi minimum, with +/- 20psi across cylinders.

Now, I realize these compression numbers are slightly under what a "healthy" engine would be, but again, this engine hasn't run properly for the better part of a decade, has had no oil being pumped through it for a while, has valves that I don't know what the state of adjustment is, and is cold. Overall, I'm VERY pleased with the compression readings on this engine. There isn't a cylinder with a hole blown through it and the sodium filled valves haven't blown through either.

Now, I can confidently disassemble this engine and get the head prepped to be entirely refreshed. The block will be prepped and cleaned for the new head and all the old liquids will be blown out of it as well.

The pictures below are of an oil soaked valve train, huge improvement over the bone dry cam and chain I was looking at prior.

Poor picture, but this compression number was off of cylinder #4. 


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