A dividing head/indexer from old pistons.

[Rickabilly]

(07-23-2012, 10:58 PM)dallen Wrote:

(07-23-2012, 09:45 PM)NevadaBlue Wrote: My son is getting his FJ40 engine overhauled and he saved me the pistons and pins I think. If so, I'll send a couple to you when I get them. They are essentially 235 Chevy 6 cylinder parts so they should be solid and fairly large. I'll try to contact someone at the local diesel engine place and see what they can save for me.
Pistonium is also good for casting as well as wheelium.

depends on the alloy thats in the pistons, most of them are cut from a bar of round stock and machined out. Some the alloy is way off out in left field due to the heat and pressure that they work in specially big construction equipment and truck engines

Sorry Dallen,
It's actually really rare to find billet pistons, 90% or more are cast and the heavy duty stuff is almost exclusively forged, they do cut a lump off the end of a piece of barstock then heat it to around 400C drop it into a Cup shaped Die, then push the male die into it the male Die forms the inner cavity of the piston, from there they drill, bore and finish the wrist pin bore and then registering on the wrist pin the top and skirt are machined last,
Pistons with significant crown features use a complex shape in the Cup die, where simple crowned pistons use a flat base in the cup die and the features are machined.

Sorry to contradict but I actually made a piston forming press a few years back for a specialist race engine company and I thought the process might be of interest. Where you are right is in the alloy department, they are specialist materials for sure, in my home town the local speed shop was using all the old pistons out of the recon engine department in a local foundry to manufacture aftermarket manifolds, it was common knowledge that while they worked ok they just couldn't be polished as the alloy wouldn't hold a shine, but they didn't crack or anything nasty like that. Most people didn't know where the alloy was coming from I only found out years later when I was talking to the guy from the foundry that used to cast the manifolds, he told me "Old Cainy didn't want anyone to know what he was using for feedstock, that's why we used to cast em on the weekend"

When i was working in Alternate fuel R&D we used to do a dozen or more rebuilds on one or two big road diesels each year, and used to keep all pistons as a record of the testing work, as you can imagine after eight years we had a lot of big pistons, we would often use wrist pins as spacers and such but don't go looking for them as a source of machining stock, hard stuff unless normalised, so hard HSS won't even think about it, Carbide just scratches it but won't cut and ceramics only just allow a fine glowing red shaving, if the lathe in use is super rigid. I tried to make punches out of them and even normalised they were tough going, I ended up just buying the proper grade and left the wrist pins alone.

Best regards
Rick