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Ring gaps 4.6 v8 1 bar of boost

Posted: Mon Jul 16, 2018 1:58 pm
by Tony22593
Hi guys,
I'm struggling with this part of the engine build as it seems there is definitive answer. I have a standard bore with Goetze rings. What gap would you recommend? We are aiming for around 400hp

Thanks in advance.
Tony

Re: Ring gaps 4.6 v8 1 bar of boost

Posted: Mon Jul 16, 2018 7:05 pm
by Tony22593
The strange thing is I have put the top ring in the bore and the gap was 0.55mm which is nearly 22 thou which is already quite large when referenced to the manual. The upper limit in the manual is 20 thou. I want it to be safe but at the same time not go through more oil than fuel!

Re: Ring gaps 4.6 v8 1 bar of boost

Posted: Tue Jul 17, 2018 5:29 pm
by Blown v8
IMG_3841.PNG
Hope this helps

Re: Ring gaps 4.6 v8 1 bar of boost

Posted: Tue Jul 17, 2018 7:07 pm
by Tony22593
Thanks for that. Have gone with 0.025" top ring and 0.032" second ring as reccomended by Allan (rossco). It was a bit strange that the gaps were so big in the first place I wasn't sure whether to leave them be or not. Maybe the material is slightly more expansive when hot.

Re: Ring gaps 4.6 v8 1 bar of boost

Posted: Tue Jul 24, 2018 10:13 am
by stevieturbo
Never ever too small.

And no...ring gaps have nothing whatsoever to do with oil use...unless the gap was like 10mm or something silly.

Bore finish is all vital when it comes to oil use. Not ring gap.

There are no downsides at all to a few thou over and safe.

As to top, 2nd gap relationships etc...it will depend on rings used and their design. It isnt generic as some rings rely on some pressure behind them to assist sealing ( pretty much all top rings do ), whereas others will not want pressure hence often the larger 2nd gap.

Re: Ring gaps 4.6 v8 1 bar of boost

Posted: Tue Jul 31, 2018 3:15 pm
by Tony22593
Thanks mate. Was a bit concerned. All built now and waiting for a day off to come so I can fit it!