Piston ring gap question
 

I am stock rebuilding a 4.8 to go in an 85 c10. Got the block back with new cam bearings and cleaned up cylinders. I got a set of standard rings which I assume are drop in. The specs say multiply .0040 time 1 inch of the borer the minimum so my question is have I figured correctly...

.0040 x 3.78 = .015

The specs do not specify any difference between the top and 2nd ring so I assume I should gap them the same?

Any information/advice/suggestions will help. Thanks!

Re: Piston ring gap question
 

That sounds about right I would have to check my service manual . Typically top rings are gapped alittle larger 020-.025" depending on boost or nos etc . I just rebuilt my 6 litre not long ago and the rings were gapped on the high end like 025"-030" they were not file fit rings like Ive always ran in other engines BBC/sbc etc . My bores were within spec for wear and i tried two different sets/make of rings no change. I called hastings about the excessive gaps and they told me run them .. So dont be supprized if your gaps are on the high end for clearance

Re: Piston ring gap question
 

Got them from Clevite. I do plan to call them before I install just to make sure. Service manual specs have top ring .009-.017 and second ring .017-.027. I would be within spec on top ring but need to double check on the second ring. Thanks for you help!

Re: Piston ring gap question
 

That sounds a little narrow to me. I'd want to be 22-25 for safety on an LS motor, as they have been known to butt ring ends. I would WAY rather bleed some minuscule amount of cylinder pressure off than pop the top off a piston!

The fashion/trend on what to do with the second ring seems to change every 5 years, but right now I'm gapping them about the same as the top.

http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf

Re: Piston ring gap question
 

Thanks dave. According to that chart if I'm rebuilding stock then I should follow the chart for "late model stock" and gap .005 for top ring and .055 for second ring? Is this what you are recommending?

Re: Piston ring gap question
 

jrusher I called clevite and you are exactly on spec.

20-25
25-30

thanks again!

Re: Piston ring gap question
 

Right on perfect. After i checked and rechecked my measurements I was almost thinking i should of went up a size on my cylinders but after talking to the ring manufacture they assured me they run these gaps larger on these engines. I hope to fire mine in next couple weeks my swap went sideways when I decided to put a new floor in my cab

Re: Piston ring gap question
 

Can't see the chart, but if that's per inch of bore, sounds about right, though I'd go a little more.

0.056 * 4 would give you 0.024

Re: Piston ring gap question
 

.056 *4 = .224, not .024 ;)

i think you mean .006 * 4 = .024

Re: Piston ring gap question
 

Just checking to see who reads my posts :-)