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I am officially converterted to Marvel Mystery Oil club! VIP !

417 Views 1 Reply 2 Participants Last post by  jzack
If you may remenber, i almost had a stroke last summer when I first did a compression test on my Z.

Here are the original numbers:


150 148
140 150
130 145

After doing some reading and researching the matter, I felt that perphaps my low numbers were due to a stuck compression ring or valve, or something like that. I proceeded to Z foam the Z/run MMO for a few miles and my numbers came up quite bit for the cylinders reading 140/130 . Here are the results on the secondary compression test.

CYL #1 read at 150 ! and CYL #2? 155 !!! DRY TEST! Thats a big difference! from 130 to 155.. big jump.

that was last summer..

Now this winter, during my first NOOB plenum pull, I noticed I could see my valves with the plenum removed.. so I asked you guys if I could soak them up with MMO!. The response was "yes", so i dumped several spoolful to each cylinder/breathing hole.

which brings me up to today. I ran to the store and bought a compression tester and proceeded to run the tests.... and the news are...

all cylinders are running at 160 PSI. even cyl 6 is reading 160. The original cylinders with low numbers are now running at 160-162 psi! Just to add a note, I burned off the MMO weeks ago and the car has sat in storage for almost 3 weeks as well. ! I cant believe teh difference MMO did. I am also wondering if perhaps sometimes we jump the gun and rebuld the engines when maybe we just got stuck rings.... what do you guys think?
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Good the hear -- I had the same success last summer and used auto tranny fluid. Filled the offending 2 cylinders up by about 1 inch and let it sit for a few days. Uses a turkey baster + short hose to suck* it all out and retested. All was good too -- this was on an NA engine. Old timers have been using the ATF trick for long time on engines that had been sitting for years.

* also need to crank the engine a few times with a rag over the plug opening to make sure a majority of the fluid is gone.

I agree - this is something that's easy and cheap to try before pulling the block all apart. Something I'll recommend to anyone that has a cylinder out of range in comparison to the rest.
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