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Piston ring?

General engine tech -- Drag Racing to Circle Track

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econo racer
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Piston ring?

Post by econo racer » Sat Nov 09, 2019 9:40 am

I have a 355 mild bracket 12 second motor. It has about 20 passes on it. The oil pump pickup cracked, so I took it down to the bare block. It set a little while and got mild rust on cylinders so I honed it and want to know would you run the rings again or replace? The gaps are still good. All bearings looked perfect. I will use the mains over but not the rod bearings. The rings are just cast iron.

Coloradoracer
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Re: Piston ring?

Post by Coloradoracer » Sat Nov 09, 2019 10:25 am

New rings are cheap insurance, but the biggest question is what did you hone it with? For any ring to seal properly, it needs a specific finish, which can also vary depending on the hardness of the block/liner, which in turn would require a specific grit of honing tool. Yes, I've got away with using a ball hone to knock rust off cylinders before and had no issues with ring seal, but sometimes you won't get away with it.

Bottom line, yes, you can put the original rings back in and they MAY seal, or get a new set and they MAY SEAL as well.....or take the block, have a machine shop hone it properly, and it won't take much, and use a fresh set of rings.....you have options.....
Mark Goulette
Owner/Driver of the Livin' The Dream rear engine dragster
Speed kills but it's better than going slow!
http://www.livinthedreamracing.com
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ClassAct
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Re: Piston ring?

Post by ClassAct » Sat Nov 09, 2019 10:59 am

Wipe the bores clean with ATF and a white lint free cloth until the cloth comes out with nothing on it.

Clean the rings and get them dry.

Put enough oil on the piston skirts so you have a very thin coating on the skirts (damn thin really...you don't want oil dripping off the Pistons and getting slopped all over) and put it together.

Those used rings will seal right up.

I never ever put oil on the rings or cylinder bores. Haven't for decades. By the time all 8 Pistons are in, there will be a very light coating of oil (I use Torco assembly lube on my skirts and very little of it...like I said...a thin coat is all it takes) on the bores and the rings.

The engine will fire right off, it won't smoke and the rings will be seated almost instantly.

Use what you have. You'll be fine.

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Re: Piston ring?

Post by steve316 » Sat Nov 09, 2019 12:06 pm

You can use WD-40 on ring & pistons and reuse your rings; have done so many many time with good results.

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Re: Piston ring?

Post by randy331 » Sat Nov 09, 2019 12:48 pm

I would replace the rings,... not cause I think they are in need of replacing,..but,.. because I hate cast rings. LOL

The stuff with cast rings I have seen wear the cylinders fast.

Randy

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Re: Piston ring?

Post by engineguyBill » Sat Nov 09, 2019 4:05 pm

Cast rings are not suitable for any performance engine, even a mild bracket application. Freshen the cylinder walls with light hone, using a torque plate, then install a ring set with ductile iron (or steel) plasma moly top rings, grey iron Napier second rings and standard tension oil ring assemblies.
Bill

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steve316
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Re: Piston ring?

Post by steve316 » Sat Nov 09, 2019 9:37 pm

I overlooked the cast ring part; they are not good on any kind of build. :oops:

randy331
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Re: Piston ring?

Post by randy331 » Sun Nov 10, 2019 12:21 am

steve316 wrote:
Sat Nov 09, 2019 9:37 pm
I overlooked the cast ring part; they are not good on any kind of build. :oops:
They are ok on one with a for sale sign in the window. LOL :lol:

Randy

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Re: Piston ring?

Post by tenxal » Sun Nov 10, 2019 8:52 am

engineguyBill wrote:
Sat Nov 09, 2019 4:05 pm
Cast rings are not suitable for any performance engine, even a mild bracket application. Freshen the cylinder walls with light hone, using a torque plate, then install a ring set with ductile iron (or steel) plasma moly top rings, grey iron Napier second rings and standard tension oil ring assemblies.
This! =D>

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Re: Piston ring?

Post by Krooser » Mon Nov 11, 2019 11:13 am

I think his screen name of "econoracer" says it all.

I can relate.

Run those rings and upgrade on the next build.

Go have fun.
Luxemburg Speedway Hall of Fame Member Class of 2019

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