Re-ringing chrome cylinders

[doc]

Well, the cylinders on the project out of Blackfoot has P20 cylinders, and we were going to grind the valves & seats, etc, and they actually cleaned up really well, but have now discovered that the few rings still available must be made of platinum because the couple places that I found who had them want approx. $300 PER CYLINDER(anyone got a set of P20 Chrome rings they want to part with reasonable?)?!? anyway I have another O-320 that had fairly young rebuilt cylinders though the bottom might(long story, but it boils down to conflicting log book entries)be high time. Unfortunately that engine is a 150hp low compression version(same cylinders though, just different pistons). I have nice weight matched 75089 pistons for it, and new rings are on the way, but here is the question & I can't find a definitive reference anywhere:

Just to break the glaze & re-crosshatch it to seat the new rings, what is the best grit of hone???

Doc

[mmoyle]

ECI’s nickel ceramic cylinder renew kit...if it’s still available...great hone for cross hatching hard chit!


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[doc]

Sadly a LOT of things that ECI USED to make/se;; are no longer available...

[Steve Pierce]

I have no experience refinishing chrome clinders. Do you have a cylinder shop close by or dealt with one you could call?

[doc]

Steve,

Thanks, yes there's a machine shop about 30 miles south, unfortunately the standard answer is bring them to us and will rebuild them from scratch at $$$. The engine they're on ran well, had good compression, 2@450hr, 2@250hr. Only reason it came off was that it was a 150, which somebody put on a PA 22 160 back in the early '60s, and I replaced it with a 160 horse engine. When I'm trying to do is just replace the 7 to 1 compression pistons with 8.5 to 1 pistons and use those cylinders on a 160 hp engine that has P20 cylinders and the rings for those are either unavail or crazy expensive

[Steve Pierce]

Wide deck?

[doc]

I wish, no, Narrow deck, and yes, I know that some cylinders off 150's shouldn't on a 160, specifically the "spot faced" ones. I've never found where they "can't" be used in writing(it may exist, but I never cared enough to look hard since I already decided I don't like the idea), but to me logically that hollow under the banana clip/reinforcing plate would lead to issues with losing torque.

I "think" I've located 3 low-time N/D std size steel cylinders that are appropriate for the project(I haven't actually got them in hand yet, but it's local and I know the history), I'm now looking for the 4th. There was a NEW ECI one(not A/D'd) on thE Bay about a week ago, I didn't buy it because I would still need 3 more, dang timing sucks...

Wide deck?

[doc]

Steve,

I should also mention that the engine I'm working on IS a 160, so it has the longer studs & I do have the reinforcing plates. This whole thread started because I've read/heard how difficult it is to re cross hatch a chrome cylinder, I've since also been told it isn't as bad as some say, but it does tear up stones, well stones are pretty cheap, so maybe we'll just give it a try. The P20 cylinders I have seem to be a great candidate for either Channel-Chrome or NU-Chrome, or for that matter Gibson also does Ceramic Nickel(Cerminil was ECI's trademark name, but basically the same process). I'm likely going to send the cylinders off to be plated, though I haven't decided on which process yet, the only down side is the 6-8 week lead time.

Wide deck?

[Steve Pierce]

Marshal Gibson told me when they got the first nickel cylinders back for overhaul after 2000 plus hours the bores still measured to new tolerances, no wear, and they won't rust.

[doc]

I've also spoken to Marshall a couple of times in the last few days about this, initially he thought he had a set of cylinders but had to check, ultimately no stock... There aren't too many places doing actual plating anymore, ASA is who Gibson uses, Harrison is another. I'm kind of leaning towards Harrison, in that they will completely go through the cylinders, the bare cylinders that is and send them back ready to go with just the installation of valves pistons rings... At $400 each, I'm currently leaning towards the NU-chrome process, mainly because I have a set of new rings to go in a chrome cylinder already