Deves Piston Ring Gap

[GavinT]

New Deves rings on Mahle HC pistons, Nikasil liners, 910 HC Turbo. Anyone know if the gap is the same as the Lotus rings per the manual, .010 - .023.  If so, is it better to go far a wider gap with an HC Turbo to allow for greater expansion?. Recommendations on gap size?.

Thanks.

 

[drdoom]

No experience for reference but with OEM pistons and liners and quality rings I see no case for deviating from factory specs. Are those manual numbers you cite for the HC?

Cheers

[NG5]

This is getting quite old now but a very interesting read with surprising info on piston rings and gaps.

http://institutiondiagnosticengineers.org/wp-content/uploads/2019/02/Ring-Gaps-vs-Knowledge-Gaps.pdf 

[sailorbob]

The best thing would be to check with Deves for their recommendation.

[GavinT]

8 hours ago, drdoom said:

No experience for reference but with OEM pistons and liners and quality rings I see no case for deviating from factory specs. Are those manual numbers you cite for the HC?

Cheers

Yes, out of the 1988 manual. The range is large and the manual doesn’t differentiate between N.A. and turbo engines. I would follow the manual but the Deves rings appear nothing like the Lotus rings. So rate of expansion is probably totally different.

Deves list two recommended ranges: min 0.010-0.018 & max 0.010-0.028, these are generic and not specific to Lotus and nor do they differentiate between N.A. or Turbo application.  My machine shop / builder is advising to use the larger range because of the extra heat generated by the turbo.

I’ll call Deves later today and ask. 

[philcool]

Yes gap very important to small and well wonder it Dibden seize up.

Thankfully no a Lotus a fridge compressor