Possible piston repair? Budget build....

[rewguy]

If no repair possible.....how do I locate this ONE particular forging? Ive been looking all over and Im running out of options. Shortblock is assembled. Other seven are perfect. Engine apparently blew a head gasket at one point, this piston got hot and soft, and squeezed the ring lands. Can this be put on a lathe, and in the one inch span of damage, could the ring grooves be straightened? I know it will widen the ring grooves in that area for certain, but its only an inch span.....could that even be done? Its a budget build, and like I said, The rest is together. The original piston is an old Lunati/Taylor from the 1999 era. It has 1/16, 1/16, 3/16 ring grooves. It has a 2 1/2" .927 pin. It is a 1.550" compression height, and a 4.155 bore. It is a 11cc reverse dome (not dish). It is for a 377 small block Chevy. Lunati told me that these pistons are older 4032 TRW forgings. I suppose like older Manley, or Diamonds. What can I do aside from an entire new set? Engine is so close to done. If anyone has the same forging, Id consider buying it, but it may be obscure. Could Revco fix it? Anyone else?

[Carnut1]

I had a similar problem once. An hour or so with a good needle file did the trick. Ran for years after. The amount of care to have a ringland not only fit the ring but seal is high but worth a try.

[Kevin Johnson]

Continuing with the suggestion, you might consider buying a needle file and either grinding away the "teeth" on an edge and flat (to make safe surfaces) or filling them in with epoxy. The latter might be better in order to preserve the "flatness" that could be distorted by the heat of grinding.

[MadBill]

My first thought was 'forget it' but the critical seal is on the bottom of the groove, so yes judicious work with a one-surface needle file should work. Of course the piston will still be soft...

[m900]

How about lapping the topside of the ring?
Paul

[Schurkey]

the piston will still be soft...

If the piston got hot enough to soften, you'd have to heat-treat it after "fixing" the ring groove.

I've heard of desperate folks welding holes closed in piston crowns, then work-hardening the weld by peening--but I have NO idea how you'd harden the ring-groove area "in the field".

[farmengines]

From your picture I would say yes, that piston can be fixed. Lathe, needle file, sand paper. Whatever you use be sure to spend some time checking progress often by rolling an old ring around. I've done it a couple times, always with good luck. In a worse case scenario I chose to weld up and remachine an obsolete melted piston. It was an old diamond piston in a 13 to 1 406 with a small shot of nitrous. I worried about that one but never had any trouble with it.

[Hairyscreech]

If you have an idea of aluminium grade then you might be able to achieve some level of heat treat in yoyr domestic oven. It won't be accurate but it will be a heat treat.

Otherwise find a local casting company and ask when they are next doing a batch of alu. See if they will stick it in the oven for you.

[billet]

Nobody has anything to say about the glass beaded ring lands????? IMO they ain't gonna seal very well even if they was straight and true after being glass or sand blasted?

[MadBill]

I was hoping that was a trick of the camera.

[englertracing]

Nobody has anything to say about the glass beaded ring lands????? IMO they ain't gonna seal very well even if they was straight and true after being glass or sand blasted?

[billet]

I was hoping that was a trick of the camera.

I was sort of checking myself, but appears that way and I'd assume the 7 other pistons were likely blasted also so.........

[Dan Timberlake]

the blast finish on the OD and dome looked to me like what results from real abrasive in the media, not fresh fine glass beads.

Like others said, if the grooves, especially the lower sealing face, has been blasted like that, the seal will be compromised. I don't know if the effect will improve after 1000s of miles or not.

[JohnnyB]

Nobody has anything to say about the glass beaded ring lands????? IMO they ain't gonna seal very well even if they was straight and true after being glass or sand blasted?

That's what I was thinking when I saw the picture.
Was hoping I was wrong.
Looks like the entire piston was glass beaded. That would pretty much screw up the lands I thought, and make that one a blowby oil burning cylinder. Might last a day or two before it started.....

[af2]

I believe I see ring witness marks on the bottom lands so they could be OK..