tommye

Hi guys,

Reading JLturpins post about his 89S engine build this morning, I just realised that there's been a LOT of cylinder scuffing threads over the last few years.....
Just for peace of mind for myself and other listers, I think it would be useful to understand the reason behind this.
I assume the cars in question run non-stock boost pressure.
So, for the gurus out there, what is your feeling about this?
Is it due to:
- running too lean causing excessive combustion temperatures ?
- running too rich breaking down the oil film on the cylinder walls ?
- a combination of the 2 at different load/rpm regimes?

Has anybody been running high boost over a long period of time and then been able to verify the condition of the bores ? With or without proper AFR fine-tuning? Using which chips ?

Cheers,
Tommy

Ian Carr

my car was completely stock when i found out that 2 cylinder walls where scored badly.

Probably because the PO's beat the car up and didn't take care of it.

If you keep good care of your car, it should last. Letting it warm up every time you drive, oil changes, proper tune, driving the car compared to beating on the car all the time...

Matt Sheppard

In my experience, a leaking injector will cause a scratched cyl. as well.