Clubsport Oil Loss
Discussion
I've got a problem of oil loss in my Clubsport.
After the last race day ('08 Birkett) there was about 2/3 litre of oil in the catch tank and after allowing to fully settle, the oil was about 2cm below the lower baffle in the dry sump oil tank. It's not leaking and I don't believe its burning oil - though the loss of oil seems to be more than can be accounted for by the quantity of oil in the catch tank.
The standard engine has a little perforated baffle fitted to the underside of the breather cover (at the back of the engine), which I think is there to prevent any flow of oil through gallery that leads up from the sump. My engine doesn't have this baffle fitted - I'm not sure if it's supposed to be fitted on a Powertec-modified engine or not (bearing in mind it has the Powertec breather pot fitted atop the breather cover).
The engine is reasonably fresh, having done about 3 hours running, and produces good power.
I did a compression test yesterday. With the engine warmed up, I got readings in the range 128 - 138psi (Haynes says it should be 128 - 190psi).
Any thoughts on what's happening?
After the last race day ('08 Birkett) there was about 2/3 litre of oil in the catch tank and after allowing to fully settle, the oil was about 2cm below the lower baffle in the dry sump oil tank. It's not leaking and I don't believe its burning oil - though the loss of oil seems to be more than can be accounted for by the quantity of oil in the catch tank.
The standard engine has a little perforated baffle fitted to the underside of the breather cover (at the back of the engine), which I think is there to prevent any flow of oil through gallery that leads up from the sump. My engine doesn't have this baffle fitted - I'm not sure if it's supposed to be fitted on a Powertec-modified engine or not (bearing in mind it has the Powertec breather pot fitted atop the breather cover).
The engine is reasonably fresh, having done about 3 hours running, and produces good power.
I did a compression test yesterday. With the engine warmed up, I got readings in the range 128 - 138psi (Haynes says it should be 128 - 190psi).
Any thoughts on what's happening?
Edited by Laurence7 on Sunday 8th March 10:55
ScottHughes said:
...looks like the compression is a bit low if the max should be 190psi, this could account for increased crankcase pressure due to leakage past the rings...
I think you could be right Scott, but I'm desparately hoping someone will tell me otherwise 
Haven't tried the WD40-down-the-bores trick yet - might give that a go next
Laurence
I was also thinking that a tuned engine is about 13.5/1 comp ratio which I believe is even higher than standard which again makes your readings seem low..? sorry I can't think of anything else.. did the engine have new rings and rebore at the last rebuild? or is it already bored out fully to suit big bore pistons? what happens if the bore's get worn with a big bore kit? new block?
Laurence7 said:
I did a compression test yesterday. With the engine warmed up, I got readings in the range 128 - 138psi (Haynes says it should be 128 - 190psi).
Are the cams the same as the standard ones that Haynes is talking about? You can get lower compressions in a compression test with cams with greater overlap (when they are truning at relatively low speed).I won't insult your engineering skill by asking if you had the throttle open Laurence!
Bert
My engine is standard Powertec, so not high compression or extreme cam profile.
I've just spoken to Ted at Powertec, and learned the following
1. Freshly rebuilt Clubsport Kawasaki should crank at about 200psi. Once the readings drop below about 150psi, the engine's getting tired.
2. The standard (cast) Kawasaki pistons, which are used for the Clubsport spec engine, are the weakest part of the 'bottom end'. Powertec replace them at each rebuild.
3. The standard con rods are the next weakest link. Powertec recommend replacing these every second rebuild.
4. Just because you don't want to spend the money on an engine rebuild, doesn't mean to say doesn't need doing
Dang!
I've just spoken to Ted at Powertec, and learned the following
1. Freshly rebuilt Clubsport Kawasaki should crank at about 200psi. Once the readings drop below about 150psi, the engine's getting tired.
2. The standard (cast) Kawasaki pistons, which are used for the Clubsport spec engine, are the weakest part of the 'bottom end'. Powertec replace them at each rebuild.
3. The standard con rods are the next weakest link. Powertec recommend replacing these every second rebuild.
4. Just because you don't want to spend the money on an engine rebuild, doesn't mean to say doesn't need doing
Dang!
Laurence7 said:
BertBert said:
...how did it get to be so tired Laurence after 3 hours?
A question for my engine builder perhaps 
I think I'll be going to Powertec from now on
Had ours compression tested by Powertec about this time last year >
All four cylinders gave exactly the same results; all 210 with 2% leakdown. I was told they would not expect any better readings off a factory fresh properly bedded in brand new motor. Yippee!
They could have told me anything (to generate and justify a meaty old bill), but they didn't; they just gave me the good news and charged me £50.
Therefore, I implicitly trust them (I have a philosophy that I trust someone until they try to shaft me, then I never ever trust them again) and I still remember the warm glow of relief at the good tidings.
forgive me for putting my 2 p in BUT i'm going to anyway. firstly i have to say i know nothing about this engine, but i was once involved with a mate that rebuilt a ford OHC engine (pinto engine) and decided to have it blueprinted etc. he built the engine up and did some really god work with vernier pullies and the like. because it was going to be used as a rally cross car (and because it was an expensive job) he decided to fit a high output oil pump to the engine. net result was that he was knocking out the bottom end, but oil pressure was extreemly good.
anyway i'll cut to the chase, it turned out the the oil pump was so good that it filled up the cam box with all the sump oil.
the fix was to fit a return to the sump from the cam box as the oil passages back to the sump didn't have teh capacity to return the oil fast enough.
just a thought, but i dont know where this breather pipe is in the crank case.
in my expirence with BIG diesel engine on generator plant, to be displacing that much oil in the blow by it should resemble a boiling kettle with the vapor its emmiting.
also a check we use to do was to measure the blow by with a manometer. this would show an unacceptable build up in pressure /blowby gass. and it can be compared to another engine if you find a friendly sole.
Dario
anyway i'll cut to the chase, it turned out the the oil pump was so good that it filled up the cam box with all the sump oil.
the fix was to fit a return to the sump from the cam box as the oil passages back to the sump didn't have teh capacity to return the oil fast enough.
just a thought, but i dont know where this breather pipe is in the crank case.
in my expirence with BIG diesel engine on generator plant, to be displacing that much oil in the blow by it should resemble a boiling kettle with the vapor its emmiting.
also a check we use to do was to measure the blow by with a manometer. this would show an unacceptable build up in pressure /blowby gass. and it can be compared to another engine if you find a friendly sole.
Dario
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