Finally some good news!

[Mnemonic]

Just tested compression on cylinder #3 that was down from 175 to 75psi a few days ago, after leaving fogging oil in that cylinder for about a week now it tests back to about 180! Guess it freed up that sticky ring.<br /><br />Question for yall - How the hell do i access cylinder #6? The lower part of the cowl is on and i cant figure out how to get it off without taking the motor off the stand. Any ideas?

 

[Mnemonic]

Re: Finally some good news!

Dammit!<br /><br />i guess #3 hates me, just re-tested and its back down again. Here are the results (ran comp on each cylinder 2 times)<br /><br />#1 - 160<br />#2 - 185<br />#3 - 110<br />#4 - 175<br />#5 - 175<br />#6 - 190<br /><br />DAMMIT!!!!!!

 

[Moody Blue]

Re: Finally some good news!

You've got different results for each of the two tests. Test again to see if the third test compares to either of the first two. You may be doing something a little different each time and are getting different results. Results should be reproduceable from time to time - within reason.

 

[AMD Rules]

Re: Finally some good news!

Good point. Worth checking the threads and sealing surface on that hole too to make sure the gauge is getting a good seal.

 

[Charlie T]

Re: Finally some good news!

I am not an expert, but several people have told me that the compression should range from 120-140 lbs depending on the lubrication inside of the cylinder. My mechanic tells me that the correct way to test this is to start the engine and let it run for 5-10 minutes. Then check each cylinder's compression. If your readings are that high, I would believ that something inside the cylinder is being compressed other than air/fuel (possibly oil). Anyway, the compression between the cylinder should not vary more than 10 lbs from top to bottom.

 

[imported_scott_m]

Re: Finally some good news!

Could the excessively high compression come from a cylnder that is full of carbon build-up? If there's less room in the cylnder to compress, yet the motor pulls in the same amount of air, wouldn't this in essence create a higher compression ratio? Sort of like shaving the heads or going with a domed piston in a regular motor? You might want to try some sea foam or deep creep both to clean the carbon and maybe free up a sticky ring.