ZXR Turbo stripped AGAIN!!!!

[jpbikeboy]

What a fuck up! It was using heaps of oil and i mean heaps. 1ltr per tank of juice. So ipulled off the brand new head off the brand new barrels to expose the brand new pistons with oil all over everything. These JE pistons are going to be the death of me. The oil rings are way too low in tension and with increased crankcase pressure with the turbo, the oil is pissing in. Pistons are going to mod'd after xmas to take bigger high tension oil rings. then back together yet again. I've been offered a very nice and heavily mod'd TLR1000 for a bloody good price and i'm very tempted as the zxr project is driving me NUCKING FUTS!


Oh and Merry XMAS to all.

[I-K]

I don't get it... unless you've converted this to a two-stroke, why would the turbo lead to such an increase in *crankcase* pressure?

[mike-s]

maybe theres a bit of blowby into the crank regardless? only thing i can geuss at.

[jpbikeboy]

That's it. all turbo's will produce a little blow by, increasing the crankcase pressure. But if your rings are shit, it exagerates the problem. Genarally anything that comes standard with a turbo has high tension oil rings to reduce or eliminate this problem. When i bought these pistons i specifically asked the JE people if these rings were suitable for my application and they said" Yep, you won't have a problem". I think not.

[fat460]

Here's my 2 cents.
I'm curious about having so much oil in the combustion chamber when you pulled it down. I'm used to working on cars so let me know if I get it wrong but when you get excessive blow by it allows combustion pressure past the rings into the crankcase thus over pressurising it yes which normally ends in excessive oil leaks from seals and gaskets especially if the crankcase ventilation system is not flash. Poor oil control ring tension will cause excessive oil consumption/burning irespective of crankcase pressure. I wouldn't expect excessive blow by to leave a heap of oil up the top, but also that seams way to much oil consumption from an oil ring prob. I'm interested. I would be keen to know:
how the crankcase vents?
is there an oil pressure feed to the turbo?
is there any traces of oil anywhere else (manifolds etc)?

Paul.

[HemiDuty]

Is it such that the Blow by is that bad that it is pressurizing the crankcase so much that it is blowing oil back up the pistons that have the inlet valves shut? As in when one cylinder's inlet valves open, and through the compression stroke too, the charge is blown in past the rings into the crankcase, and back up past the rings into the chambers of cylinders on different strokes?

Would it not be better to just get different piston and ring sets JP? Although I realize they have cost a lot.....

[jpbikeboy]

Thanks for the input guys. I,ve checked the breather-good. Yep there's a pressure line to the turbo-good. No signs of oil in the inlet or in the turbo. I'm kinda thinking down Hemiduty line of thought. I had this exact setup on the 750 with no problems at all. the only difference is the pistons and rings. I'm trying to keep the cost's down as i have a KSRC junior on the way, so i'm trying to make do with what i have. The piston machining is only $9 a piston. Having said that, if this doesn't work i'll be going for new pistons.