When did fitted pins become standard?

[Speedbump]

"As far as fitting the pin yourself... reaming or honing are downright ghetto procedures compared to a proper roller-burnished or ball-broached bore. Slide the pin out of any high quality piston and look at the pin bore; it will be an almost shiny gray color from the burnisher."

From a discussion and learning standpoint and no disrespect intended, I'm struggling with the idea that the Sunnen pin mandrels I've held on to and, like you, have never used are "ghetto". I use the rod bushing mandrels for rod bushing sizing on occasion which brings up the question; if the pin rides on a honed rod end, why would it be unhappy to do the same in the piston? and that answer might beg another question; Is the burnishing process more production friendly from a cost/time standpoint but the finish not necessarily better or worse than a honed finish.
I find this subject interesting and would find some information and perspective educational but I don't want anyone to get all argumentative and twitchy over it.

[dwilliams]

The first SAE paper I noticed on piston pin bore finishes was by some engineers at Lamborghini. Ferrari began doing it, and some motorcycle companies, to keep wear down at high power levels.

They roller burnished the rod bushings as well, though frankly I don't know why ball broaching (like a thinwall valve guide) wouldn't do just as well.

Most of the pistons I've used for the last ten years had some kind of burnished finish in the pin bores, so I'm assuming it's now standard industry practice.

[PackardV8]

Also be aware that Venolia makes no provision whatsoever for pin oiling. If you don't drill your own holes or reach in with an end mill, the only lubrication the pins get is what wicks in from the ends.

Thanks for that reminder. I've literally never seen pistons sent out with no pin oiling. And no, these old stock Venolias were naked. Now, we've got to figure out the most cost-effective way to not go deeper in the hole with these. Cutting oiling grooves inside the sprirolok grooves isn't the easiest thing I've tried.

[pamotorman]

older TRW pistons did not have drilled pin oilers. i made a fixture that i was able to drill them just using a hand drill

[PackardV8]

My machinist and I were discussing how comfortable we'd be sending these out with just a drilled hole through the bottom of the pin bore.

FWIW, a quick examination of the OEM cast pistons in the room showed most all carry the hole to the top of the pin bore. That's not an option with the forged Venolia, as they are solid above the pin.

An examination of all the forged pistons in stock showed oil reliefs at each side of the pin bore, but not connecting into the spirolok groove, if they have it.

[Truckedup]

About 15 years ago I ordered a set of pistons from Venolia for a GM 302 inline 6. They requested a plaster mold of the combustion chamber in order to get correct placement for the small dome ...The pistons did come with semi finished pin bores to fit BBC pins as requested...I don't remember about the pin oiling holes..I do remember the piston ring grooves were tight and had to be touched up...I also remember Venolia was very sparse with words, like you had to struggle to get them to talk on phone...