I bought a set of Speed Pro hypereutectic pistons and there were no instructions with them on the ring end gap.
In the advertisement though it said, use a "standard" top ring end gap.
Yet at the machine shop I was told that the top ring end gap should be wider.
Can someone with experience advise me on this, please.
This will be a N/A motor with a CR. of about 9/1.

Thanks

 

I'd suggest about .005" of end gap per 1" of bore diameter; i.e. about .020" if it's a 350. 2nd ring about .003" per bore inch. Oil scrapers should be fine as they are.

 

some hypers require a wider end gap on the top 2 rings. don't remember the % of increase now but if i recall you end up with a gap around .035. i'd go with what the piston makes says to run and not what some guy at the machine shop said.

 

There's something about this that still has me puzzled. And I think that guys who've bought a set of Speed Pro hypers knows what I'm talking about.
My pistons came with no specific reccomendations on ring gap, only the statement that Speed Pro hypereutectic pistons can use the "standard" ring gap, unlike thier competitors which require a larger gap.
Yet that's contrary to almost everything that I've been hearing or reading.
So as far as following the piston mfgr's reccomendations... I'm still confused.
Could someone out there who's tried a set of these pistons possibly tell me something more specific?
Or what is meant by a "standard" ring gap?

Thanks

 

i've heard of but not used hypers with a standard ring end gap. only hypers i've used have been silv-o-lites and they take an increased ring end gap. call the piston maker and ask them, if anyone knows they would

 

I have used them, in fact they're in this weenie 305 I'm driving around in my 83 car at the moment.

The piston instructions said to use the normal gap, but the ring instructions said to widen it. Considering that there's no real harm done by widening it, but instant total destruction is the consequence of not widening it, it wasn't hard to make the call.

Aside from being a weenie 305, my motor runs fine. It doesn't seem to have too much trouble drilling the stock or even near-stock TPI 350s.

 

Thanks, .005 / inch it is, then.

BTW, I finally did resolve to call the Speed Pro tech desk, which took 3 calls and a few holds, and I was told .005/ inch of bore on the top ring and .004/ inch on the second ring is the correct gap for my purposes. Which is N/A street/ performance.
That's a bit larger than the "standard" ring gap that is recomended originally, but it seems like the best bet.
...Just to set the record straight, and in case anyone searches this subject.