[25stevem]

I just watched on YouTube once agin the very informative and interesting Pontiac film called " Pontiac 455 casting and machining for original production in 1970"

My question is how did the factory install the pistion pins without the heat marks showing up on the rod small end like always takes place in a aftermarket auto machine shop due to the rod ovens they imploy?

Did the factory assembly line just use a much more controled heating process?

[Keith Seymore]

I'm not sure I understand the question.

a) You are talking about pressed fit piston pins (as opposed to full float)?

b) You are saying that when you receive set ups done by an aftermarket shop there are obvious heat marks on the rod? (I have not experienced this, I guess all mine have been full floaters).

My guesses would be either the factory uses a more controlled temperature (as you suggest) across the whole rod, or a lower temperature. I would also guess they have the machinery and wherewithal to press them in cold if they chose to do so.

K

[mgarblik]

Not a definitive answer, but based on experience. I have heard that the pressed pins were installed with heat, but no mention of how hot. So from that, I have to assume they were not pressed in at room temp. In the aftermarket using common shop tools like the Sunnen rod heater: The pins can be installed without discoloration if your really careful, and have the tools set-up just right. Most times the discoloration is primarily caused by impurities on the surface of the rods. If the rods are extremely clean and dry, (no oil), they can be installed with little to no color. If you greatly overheat the small end, then certainly you can turn them blue. If the rod has ANY oil on it, you have to heat it much more to have time to install the pin. Best case scenario, you have 3-5 seconds to insert the pin before it cools enough to stop moving. I just re-watched the section of that video showing the pin installation. If you look closely, some smoke/steam is seen as the pins are pressed into the rods.

[Half-Inch Stud]

That movie had an image of Rods and Pistons upside-down, fixtured, and pins being thrust in, and i think a lady loading/unloading the pistons. But no direct evidence of induction heat.

Had to beinduction heat built-into the metal wall fixture that held rods and pushed pins.

[Pav8427]

Dont recall where I saw it and pretty sure it wasnt Pontiac specific, but I saw a production line where the where the rods were being heated by a soft flame torch as they came down the line prior to pin install.
So already expanded enough for a hand install.
Would explain difference in colors compared to induction heating used these days.

[25stevem]

If you watch the film, these where not hand installed pins.

[turbo69bird]

Mc carthys book said you could tell forged rods used by the factory Vs over the counter by the flame / heat marks from installing the pins. So sounds like some rods were heated to insert pins . I just ran across that in his book last week don’t remember if it was specific to SD 455 rods or all forged rods

["QUICK-SILVER"]

I've seen a slight little end color difference on aftermarket bushed full floaters.

Put SBC's together with a 475°F difference in temps. 500°F for the rods and 25°F for wrist pins. 500°F aint enuff for a color change.

Clay

[Schurkey]

Originally Posted by 25stevem

I just watched on YouTube once agin the very informative and interesting Pontiac film called " Pontiac 455 casting and machining for original production in 1970"

https://www.youtube.com/watch?v=9LuX...oPonchosGarage

A decade ago, there were seven episodes on Youtube, each one a section of a longer film. This is one section.

I saw the whole film back in '78 in High School (Engine Mechanics class.)

Far as I know, those seven pieces of the overall film are gone from Youtube. I haven't been able to find 'em for years.