wrist pin lockup

Get a load of this one,

I just rebuilt my 355 LT1. I had a set of previously used forged pistons from the same LT1 that I wanted to reuse.

I ordered a new set of I beam rods, sent them to the machine shop, had the new rods pressed onto the pistons.

I got them back, assembled the engine, prelubed the engine, put it in the car, turned it over until I got oil pressure, put the PCM fuse in, and fired it up.

3 seconds and 1 cylinder fire later, lockup!

So I took the engine back out to check all the bearings. All the bearings were fine, but the rods wouldn't move. I finally fight the crankshaft out, and the rods are stuck. 7 out of 8 of them.

I tear the engine back apart, and take them to the machine shop. I tell them what happened, and they tell me that it was my fault, and I should have soaked the wrist pin, piston, and rod in lubricant before installing it in the cylinder bores.

There was no heat marks on the piston, and only one side of each rod was bound onto the piston. The way we found this out was when they pressed the pin back out of the pistons, only one side of the pin had forged piston metal on the pin.

I still don't think that this was my fault, so I decided to share this with yall and get some more input. If it was lack of lube, wouldn't there be some blueing of the piston, or wouldn't it have taken longer than 3 seconds before a lock up due to piston pin unlubed. Don't get me wrong, I should have thought about this and lubed the pin, but my new machine shop told me that WD-40 would have prevented this, so there had to be nothing on the pin for this to happen.

Also, while I was assembling the engine, with no heads or anything on it, I noticed it was hard to turn over when I installed the first piston onto the crankshaft.

What do yall think?

By the way, the pistons was destroyed, and now one of my brand new rods are destroyed also due to the shop pressing the burred up piston pin back through the rod.

Now I have a brand new set of h-beam rods with floating pistons on the way.
Learning the hard way.

D Moss

Also, while I was assembling the engine, with no heads or anything on it, I noticed it was hard to turn over when I installed the first piston onto the crankshaft.

What do yall think?

Should have stopped right there. That should have told you something was not correct. If something does not "feel" or look right when assembling an engine you can either stop then and inspect/mic all the components in question or take a gamble and hope all goes well... first option is the only way.
Steve...

Being that this was the first engine that I'd ever assembled from the block out, I wasn't sure. I thought that it was wrong, but kept going.

It won't happen again. :(

This is a post for everyone wanting to tackle an engine for the first time, BE SURE TO LUBE THAT WRIST PIN. Soak the piston in ATF or 0 weight oil is what I've been hearing as for lubracation on the wrist pin. Everything else is too thick to get in there.

My dad told me that he used to use STP oil treatment with a paint brush, he'd coat everything below the oil rings. (He wasn't there the first build) I'm using this method this time, but I'm only using fel-pro assembly lube for the bearing faces and camshaft lobes.

D Moss

This is a post for everyone wanting to tackle an engine for the first time, BE SURE TO LUBE THAT WRIST PIN.[/b]

Let me add this...

If this is your first engine, have an experienced person do it and you watch. Either that or, buy some good books on engine assembly/blueprinting, read them back to back a couple of times taking notes along the way, then build your engine carefully.

Measure thrice, cut once! -unknown

Which book were you following on this build?

Soak the piston in ATF or 0 weight oil is what I've been hearing as for lubracation on the wrist pin. Everything else is too thick to get in there.

My dad told me that he used to use STP oil treatment with a paint brush, he'd coat everything below the oil rings. (He wasn't there the first build) I'm using this method this time, but I'm only using fel-pro assembly lube for the bearing faces and camshaft lobes.

Skip the brushes and the hairs, plastic bristles and stuff that falls out of them.
Use your assembly lube.... no STP.

Good luck.

-Mindgame

I got a stack of hanes manuals that I've read, and I also have a "building a small block chevy" there at the house that I read several times before I even touched this thing, and I didn't see anything about this.

I've built several engines from short block to complete, but this was my first complete assembly. I have this baby now, I'm just waiting on pistons.

The thing is, the only part that I didn't assemble was the pistons onto the rods, and that was the part that took it out. oooh, I was so pissed when I found it.

Now I'll have floating pistons, so I can assemble these myself and I'll know that they are right.

D Moss

Skip the brushes and the hairs, plastic bristles and stuff that falls out of them.
Use your assembly lube.... no STP.
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Very good point MG, dont use anything during the final assembly but oil/lube and fingers. Dont even keep a rag near you. Temptation may get you to wipe off your fingers leaving rag lint attached which will wind up in the motor.

I used a foam brush that had no bristles and left no lent or anthing else behind. I just used the STP on all the block shell where rust may want to start, on crank throws, lifter valley, and timing chain area, and the inner block under the piston cylinders.

Assembly lube on the cam lobes and bearings, main bearings, and rod bearings (when pistons get here), and I'll be sure to use assembly lube on the wrist pins.

I soaked the lifters in 30wt non detergent oil, and now they are in. Now my crane gold roller rockers are soaking in the oil.

Just waiting on those pistons.

D Moss

D Moss

If you use molly rings all you want on the cyl wall's is a film of oil.I soak a rag in Marvel oil,wring it out and wipe the wall's.The wrist pins should have had some kind of lube on them when the shop pressed them,if they didn't use the heat method.You always lube them with a squirt can before assembly by sliding the rod to one side and lube both sides then the reverse.
Can't understand the "only one side".Maybe that was the down side on the press and metal was pulled on installing the pin from improper line up????Easy to do if you don't take your time and use the proper pressing fixture's.

They did use the heat method.

I've gotten my pistons in yesterday, put the motor together and in the car last night, and fired it off this morning.

I've gotten a few things to go back and finish, but everthing seems to be fine.

I'm happy so far.

D Moss