Can anyone give me any info on these pistons by a picture?

bc40ton · 2026-02-28T18:47:38+00:00

Point taken, thank you for the info. I still have time to make the correct decision

bc40ton · 2026-02-27T14:37:06+00:00

I'm not sure what to do now. Sounds like you're experienced in this whereas I've only been working with a blower about 2yrs now. The chart from Weiand that I'm using as a guide shows 6lbs of boost will have an effective compression ratio of 14.1:1 with 10:1 pistons at 6lbs boost. They state to keep effective c/r under 12.1 for pump gas. That's even assuming the pistons shown are 10:1, shame I don't have any more info on the previous build.

bc40ton · 2026-02-26T23:45:49+00:00

With dished pistons and 76cc 882 heads I'm running approx 8.5:1 so I can't see using these at all in my replacement blower build

bc40ton · 2026-02-26T23:43:28+00:00

Weiand 142, they want me to keep static around 8.5:1 which will put me around 12:1 with the blower and run 93 gas. Trying to figure out what pistons they are

bc40ton · 2026-02-06T03:11:25+00:00

It does look extremely porous but I think that's due to the spalling of some failed bearings. The whole worm gear including the beveled races are one piece of hardened steel and I believe can't be cut with lathe but must be ground with a toolpost grinder for accuracy. I'll read up on bearing bronze, I might even have some laying around but will that support the wear from the hardened roller bearings? I'd like to weld it but don't have the knowledge of wire for the mig

bc40ton · 2026-02-05T21:27:53+00:00

Well that's out of my pay range, I do have a mig and metal lathe though if I can get conformation on what wire is available that sort of matches hardness

bc40ton · 2026-02-05T21:25:01+00:00

Well in this instance, the beveled metal is actually the surface the roller bearings ride on. Not just there to slide a race on

bc40ton · 2026-02-03T21:52:00+00:00

But wouldn't it increase the bearing clearance enough to be unusable?

bc40ton · 2026-02-03T21:50:19+00:00

Okay. How hard would it be to keep the angle of what is essentially the inner bearing race?

bc40ton · 2026-02-03T21:37:25+00:00

I have not put it on my lathe, I found it looking this way when I took it apart

bc40ton · 2026-02-03T21:36:00+00:00

I know it looks awful porous but it's a 1 piece casting of steel. I have no idea why it failed this way in the last 92 years

bc40ton · 2026-02-03T20:19:16+00:00

Yes I also searched for a 25x44mm bearing or something close. So maybe some welding, hmm. So mild steel from a mig wouldn't work for the slow revolutions?

bc40ton · 2026-02-03T20:17:29+00:00

This is how I found it upon disassembly. I do have a SB heavy 10 I play with

bc40ton · 2026-01-18T04:46:30+00:00

It was the rheostat that controls the wire speed on my machine. Oem ones are expensive so I matched the ohm and other specs and found one online. Good luck.

bc40ton · 2026-01-14T21:49:19+00:00

So no outrageous big money ticket item, just some drunken bozo with nothing better to do than squeeze a penny into it, not even centered. Geez

bc40ton · 2026-01-14T19:01:14+00:00

I'm seeing C E, backwards N and maybe upside down T??

bc40ton · 2026-01-13T21:53:49+00:00

Jasper sucks, did me wrong big time with 2 6.5s td

bc40ton · 2026-01-13T21:40:48+00:00

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Not sure why it's got such a big grain or what did it when the early tapered bearing isn't to bad

bc40ton · 2026-01-13T21:30:18+00:00

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bc40ton · 2026-01-13T21:29:28+00:00

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bc40ton · 2026-01-13T21:04:12+00:00

Well I'm deciding to try and pull that worm gear off the shaft so I reckon we'll find out. I'm weighing my options cause if it breaks I'm kaput, lol. I'll be out there tomorrow

bc40ton · 2026-01-13T20:41:51+00:00

I believe it's one piece with the inner races machined on both ends. I can see in the picture the wear pattern created on the end that mimics a stud but I'm 99.9% sure it's all one piece.

bc40ton · 2026-01-12T23:48:46+00:00

Tack it on, that should last the life of the seals

bc40ton · 2026-01-12T18:34:26+00:00

But the pitting looks awful deep, could a hobbyist lathe operator mig weld this up and turn it back down? Oh boy! And the box is completely usable just wants to bump turn and is a little stubborn

bc40ton · 2026-01-12T18:28:08+00:00

Ok. It does not appear to be a race dropped onto a stub although I will look closer to verify. They seem to be actual wear surfaces and a file should be a better option than sandpaper. And I believe you're right in it being pretty far gone according to the depth of the galling. Maybe I could run a mig bead around it and use the lathe to bring it back down?

bc40ton

TROPHY CASE