Banshee Motor Problems. Need Advice.

[ceetwarrior]

Hey guys, I'll try to make this short. '92 Banshee with bolt-on's. I can't get it to run and stay running after months of being down.

 

Left cylinder has 20PSI compression, right cylinder has 45PSI. The symptoms I am having are consistant with Clymer manual describing crank seal leaking oil into cylinder.

 

It's SMOKING like crazy and blowing oil out of the right side pipe and crank case breather hose. Backfiring, and won't stay running or drive under power. Am I on the right track with the crank seal.

 

IF the running and oil problems are the bottom end, then what about the top? Do I need a new top end as well? Any help in right direction would be great. Thanks

Edited November 26, 2010 by ceetwarrior

[68chevyc10355]

Take the clutch side cover off and then do a leak down test. This will tell you if the crank seal is bad. Also, for a motor to have that low of compression in both cylinders something major would have had to have happened to both cylinders/pistons. It would have a hard time starting with 90 psi, but if you are getting readings of 20/45 I would consider checking your compression with another tester because something doesn't sound right. Once you have completed the leak down and determined whether or not the seals are leaking, take the top end off to see what the problem is there.

[12 0 Clock P I M P]

even with seal issues your compression should be much higher!

[ceetwarrior]

even with seal issues your compression should be much higher!

 

Thanks for the advice....!

 

Dumb question, but when I do the compression test, do I have to have the other spark plug installed?

 

Also, the clymer manual describes the leak down test as pretty extensive/hard. Saying it requires special plugs to seal it up properly.. etc..

[68chevyc10355]

When I do a compression test I leave the other spark plug in and hold the throttle wide open while kicking. A leak down is not hard, but if the crank seal is leaking it is going to extensive work to replace. I use a 12 to 15 inch radiatior hose between the two exhaust posts and pvc fittings to go in the carb boots. Expansion plugs can also be used and aren't that expensive.

[hercalmighty]

A leak down tester only cost about $20 to make and takes about 1/2 hour to put together. Then just let the sealant setup over night and your good to go. There is thread on here on how to make a leak down tester. It is well worth the time and money to make one.

 

As for the compression, are you kicking it until the needle stops moving and holding the throttle wide open? Also, are you using the correct adapter? It should be the same length as the threads on your spark plug.