Best to use pins that are matched to pistons or rods?

[biggreen96]

I'm putting the turbo pistons into the NA block tonight. Is it best to use the pins that match the turbo pistons, or is it better to use the pins that match the NA rods?

I don't imagine that it's SUPER important but I would use the pins matched to the rods if I didn't have access to the forum to ask you guys.

[gijonas]

Thats a good question.Wrist pins act as a bearing at the connecting rod not the piston.Someone correct me but i believe that when the aluminum piston gets warm it locks tightly onto the pin (if not already seized) but the pin remains as a bearing inside the connecting rod.Thus i would definately have made the same decision if i was made to choose.

[biggreen96]

well they are in. I used the pins that matched the rods and DAMN is getting that last pin in a BITCH! The first three were easier since I could align the rods to meet the piston, but the last one I had to tip the block up and let gravity center the rod...


I can't believe this actually worked!

[douglas vincent]

Fucking GHEEEEETOOO!

Yeah, normally you set the block on end (both ends of course) to get the pistons in...

[log1call]

If you have a piece of metal with a hole in it and you heat the metal the hole behaves in the same way the metal that is missing would have behaved, had it been there... So, the pistons loosen on the pins as the pistons heat up. The aluminium expands at three tmes that of steel, so the rods to pin clearance is going to remain almost the same, while the pistons are going to loosen quite a bit on the rods.

If the pins are different then you need to concider whether they are perhaps different weights... which wil effect balance.

Al bit redundent now the pins are fitted but...

[gijonas]

If you have a piece of metal with a hole in it and you heat the metal the hole behaves in the same way the metal that is missing would have behaved, had it been there

Ive been corrected as asked

[Imprezive]

For future refference:

Use the turbo piston pins. And keep track which pin came out of which piston.

Those pins are supposed to be a floating type pine which means they should slide through both the piston and rod EASILY, you should be able to push them through with your finger. To make sure the clearance isn't TOO MUCH you should slide the pin through only the piston, then through only the rod, if there is excessive wobble in either you'll probably be needing some new components. Its best to measure these things but often one can go by feel if they've got some mechanical aptitude.

IF they don't want to go through the rods easily you can take the pistons/rods/pins to a machine shop and have them hone the rod bushings so the clearance is right for each specific pin. This will cost you like $30...