Oversize Piston ring replacement vendor

outsider347 · 07:22 AM

Howdy been a while. Health issues, better now

Ring Gap Confusion

Getting back to my first time 79SC 911 3.0 nothing modified, engine rebuild. I had the cylinders measured/honed by local Porsche guy, Said that cyl looked great

Checked ring gaps on my new std bore Goetze rings
All three rings look to me to have too large gap. 0.43
The Dempsey book range is 0.15 to 0.30

Looks like I will need to find a vendor for over size rings.
I don't mind filing to fit
Tks Gents
ed

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HaroldMHedge · HaroldMHedge's Garage

Glad to hear your doing better.

I would check with Pelican user Henry Schmidt or one of the other well know shop owner contributors here on Pelican Parts.

Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
https://supertecperformance.com/

Ollies930 · 10-01-2020, 10:34 PM

Henry is awesome. He has a great stock of unusual stuff, but If he does not have what you need, he will know where to get it.

flyingjay · flyingjay's Garage

I've used Grant piston rings, they have every size imaginable.

stownsen914 · 10-03-2020, 04:14 AM

I believe Total Seal also makes about everything you could want. Note that they make conventional rings (I used to think of them or gapless rings). I just ordered a set for my rebuild that will have CP custom pistons.

safe · safe's Garage

Quote:

Originally Posted by outsider347

. I had the cylinders measured/honed by local Porsche guy, Said that cyl looked great
.

He honed them??? I hope he just cleaned them with scotch brite or something.

stownsen914 · 10-04-2020, 04:07 AM

If they're nikasil, it's valid to hone - not to increase the bore like you might do on an iron liner, but to get some texture in the surface.

RedCoupe · 10-05-2020, 06:05 PM

Quote:

Originally Posted by stownsen914

If they're nikasil, it's valid to hone - not to increase the bore like you might do on an iron liner, but to get some texture in the surface.

If I increased the “texture” of my Nikasil cylinders, I would want to check them for surface roughness with a profile meter. Nikasil is so hard that if you get it wrong and have the cylinders too rough, the rings wear out very quickly and the cylinders stay rough. Not like typical cast iron where the cylinders start rough and smooth out as the new rings seat.

safe · safe's Garage

Quote:

Originally Posted by RedCoupe

If I increased the “texture” of my Nikasil cylinders, I would want to check them for surface roughness with a profile meter. Nikasil is so hard that if you get it wrong and have the cylinders too rough, the rings wear out very quickly and the cylinders stay rough. Not like typical cast iron where the cylinders start rough and smooth out as the new rings seat.

That is my thinking too, Nicasil is to hard to "wear in". On my 3.6 rebuild I cleaned the "glase" off with Scotch Brite and WD40, that gave me a duller finish. Seemed to be the safer way for someone lacking a RA gauge.
I think there was a lengthy thread about Nicasil and RA here somewhere....

stownsen914 · 10-06-2020, 04:09 AM

To be clear, if you hone a nikasil cylinder, it would be smart to leave it to pro with experience honing nikasil (and ideally a way to measure RA). The OP mentioned having his done by a pro.

brighton911 · 12:01 PM

Glad to hear you are better. Something is not right with this picture. New Goetze std rings in a std bore will end up with about .015" end gap. Seems like the bore is not std, hard to do on a Nikisil cyl. Further investigation is required.
I agree with the concerns voiced re "honing" Nikisil. Give Total Seal a call. They have excellent customer service and you can actually talk to a rep.