Holy cow I think it worked [Bugeye compression]

[tdskip]

Hi folks. So I broke in the compression gauge (new tool - sweet!) as I'm starting to try and figure out exactly why she is smoking.

I got the following 1-140, 2-120, 3-130, 4-130. Cylinder 4 has a normal plug coloration, but 1-3 are oily black.

Do I need to do a wet test to get more data to diagnose?

This is a continuation of the following original thread; https://www.britishcarforum.com/ubbthread...p;page=2#218834

 

[RobSelina]

Re: Bugeye compression results

20 psi is a pretty big fluctuation. I'd get the engine warm, then do this test again. Once you do it 'dry', if you still have a pretty wide spread, I'd also do a wet test for good measure.

 

[tdskip]

Re: Bugeye compression results

Rob, I was afraid someone was going to say that about the spread....

Could the valve's just be out of wack?

Permission given to tell be bold faced lies if it makes me believe that I really don't need a rebuild. LOL.

 

[Kurtis]

Re: Bugeye compression results

The 20 psi spread is a little high, but in itself, I wouldn't think it would warrant an immediate rebuild. However, the condition of the plugs indicates that you may be getting excessive amounts of oil in the combustion chamber. It wouldn't hurt to adjust the valves and try again, but I don't think it will make that much difference.

As Rob suggested, make sure you warm it up and try again. A wet compression test will tell you if it's valve or ring related - If compression goes up after you a add oil, you have bad rings. But the pattern you described in the previous thread seems to suggest valve guide seals may be the culprit. If it is a problem with the valve guide seals, that may not be that big of an issue. I believe they can be replaced (if you're careful) without removing the head.

Good luck!!!

 

[jcatnite]

Re: Bugeye compression results

A good leak down test will help you isolate the problem with you engine as well. Combined with the compression test results, you will have a really good idea about what is going on in your engine. Oily black plugs are tough to correct without opening the engine up though bud. There are other avenues for oil to get into the cylinders but the amount they pass is usually pretty limited. I'm not familiar with your particular engine but a good check would be to see how much pressure the crankcase is venting while it is running. If there is a good amount of pressure coming out of the crankcase vent (blowby) and you have oily plugs, probably going to need new rings.
JC

 

[regularman]

Re: Bugeye compression results

[ QUOTE ]
Hi folks. So I broke in the compression gauge (new tool - sweet!) as I'm starting to try and figure out exactly why she is smoking.

I got the following 1-140, 2-120, 3-130, 4-130. Cylinder 4 has a normal plug coloration, but 1-3 are oily black.

Do I need to do a wet test to get more data to diagnose?

This is a continuation of the following original thread; https://www.britishcarforum.com/ubbthread...p;page=2#218834

[/ QUOTE ] I would take the intake loose and see if there is any oil in there from somewhere. Otherwise I would pull the head off and drop the oil pan and pull the pistons and look for stuck or cracked rings. It might have been run hot and this will do bad things to rings.

 

[jlaird]

Re: Bugeye compression results

yep the rings are worn but seemingly not all that bad in my mind, I think the valve guides and such are very suspect.

 

[tdskip]

Re: Bugeye compression results

OK - so I added a small amount of Marvel Mystery Oil (MMO) to do a wet compression test. Engine was cold for this test.

The results are;

Wet 1-150, 2-140, 3-145, 4-135.
Dry 1-140, 2-120, 3-130, 4-130.

This seems to confirm that the rings are the culprit, right?

Would adding a bit more MMO into the cylinders and crankcase and running her a bit help?

THANK YOU for all of your help - I really appreciate it.

 

[jlaird]

Re: Bugeye compression results

Noop, not at all. You found part of the problem. Plan on a valve job and new valve guides while it is apart along with main and rod bearings and prop a new oil pump as long as you are in there. Also check the clutch and throwout bearing, etc etc.

 

[tdskip]

Re: Bugeye compression results

Jack - this suggests the valves are more likely the cause?

 

[jlaird]

Re: Bugeye compression results

No but I would redo them while the engine is apart, hate doing things twice.

Stand by, we'll get more input before you turn a wrench, a second opinion is always good.

 

[regularman]

Re: Bugeye compression results

That mystery oil might loosen up the oil rings if they are stuck, but if they have been heated to where they have lost thier spring then that might be it. I would suspect the valve guides or seals more if it smoked on start up and then cleared up after a little run time. If it has oil in it after running then look at the rings. You can pull the head and the oil pan with the motor still in the car and pull the pistons out and check them.

 

[SilentUnicorn]

Re: Bugeye compression results

[ QUOTE ]
..... as long as you are in there. Also check the clutch and throwout bearing, etc etc.

[/ QUOTE ]

Love that line. Its how it all starts...

/ubbthreads/images/graemlins/cheers.gif

mark

 

[jcatnite]

Re: Bugeye compression results

Might as well...
JC

 

[tdskip]

Holy cow - I think it worked!

Hi folks,

So after two rounds of Marvel Mystery Oil (MMO) in the cylinders and letting her sit for 48 hours I fired up the Bugeye today and....no smoke! Not on start up, not after running her. She seemed smoother too.

Holy cow - I think it worked!

Thanks everyone!

 

[jlaird]

Re: Holy cow - I think it worked!

Wow, maybe you just had some gumed up rings, I hope.

Congratulations.

 

[zimmy]

Re: Holy cow - I think it worked!

i put MMO in my oil when i first started up and my 1275 runs wwaaaayy better then expected after its long sleep....; ) ...go MMO! try some seafoam next...spray on pistons, then try it in the carbs while the motor is running........zzimmmmmy