I am building a 383 with slip fit pins. When I assembled the rods, some of the pins slipped through the rod end pretty easily but 2 of them needed to be driven through the rod ends with a plastic hammer. Now that they are assembled, these two rods can't be moved by hand along the pin, although they rotate pretty freely (pin rotates with rod). I am concerned that they might not line up with the crank rod journals and the oil hole in the top of the rod seems useless unless the rod diameter grows slightly as it heats up.

Do I need to rehone these rod ends for more slip or can I use them as is?

Forged rods, cast pistons.

I am building a 383 with slip fit pins. When I assembled the rods, some of the pins slipped through the rod end pretty easily but 2 of them needed to be driven through the rod ends with a plastic hammer. Now that they are assembled, these two rods can't be moved by hand along the pin, although they rotate pretty freely (pin rotates with rod). I am concerned that they might not line up with the crank rod journals and the oil hole in the top of the rod seems useless unless the rod diameter grows slightly as it heats up.

Do I need to rehone these rod ends for more slip or can I use them as is?

Forged rods, cast pistons.


They need to be fit to the rods, and I'd have a good machine shop do it. Never should have to be hammered in, even if it's a plastic hammer.

Jody

make absolutely sure it's clean in there. any bit of dirt or rag deposits can take up that clearance and make it appear tight. might not need to see the machinist just yet. also check for this first. a light touch arround the lead in and exit corners to make sure there are no buggers/burrs hanging over into the bore.

if so,, a small fine round file will get rid of any burrs there. then hit it with some 600 grit lightly with it wrapped arround your finger. then clean throughly and try again to see if it slip fits. sometimes the rods laying against each other in a box,, or on a table can rattle arround and dent the bushing/rod bore corners and effectively "tighten up the hole" as it can appear. hope that's all it really is for you.
andy

by the way,, welcome to nastyz Tennz28.
andy

Which is why we measure every new rod, both big and small end, press or full float, because production means occasionally one out of spec will pass through their inspection process. It is very common to have to hone the bushings a couple of tenths to get the clearances I want.

Thanks for the tips. I was pretty sure it wasn't right. I'll try recleaning and inspecting the mating parts again before I bring them to a shop.

For your situation, if the pin can fall through the rod with it's own weight you're good to go.

For your situation, if the pin can fall through the rod with it's own weight you're good to go.

A wrist pin will fall through at .0002 clearance which is not nearly enough clearance as we shoot for .009 to .0012 on the pin bushings and we also check the pin bores in the pistons and most of the time we have to hone up to .0004 to .0009 on some pin bores.

Most of the problem is .927 pins are coming through up to .9278 oversize.

It might be a good idea to retorque the rods and have the big ends checked for size as we have found on some of the after market rods after retorquing with the proper lube there sizes are all over the place.

I just want to thank everybody for their help. I had all the pin ends rehoned and had the big ends rechecked at the same time to verify diameters. Everything is going together real well now.

A wrist pin will fall through at .0002 clearance which is not nearly enough clearance as we shoot for .009 to .0012 on the pin bushings and we also check the pin bores in the pistons and most of the time we have to hone up to .0004 to .0009 on some pin bores.

Most of the problem is .927 pins are coming through up to .9278 oversize.

It might be a good idea to retorque the rods and have the big ends checked for size as we have found on some of the after market rods after retorquing with the proper lube there sizes are all over the place.

ditto,, i've found between .0002-.0003 they'll fall through. and with a steel pin on a steel rod bore at a .001 minimum or it'll stick/seize.