The Stovebolt Site Forums The Shop Area Engine Shop do I need a new head gasket?

I just torqued my head on a 55.1 235 after slipping in the pistons. I turned the engine over to attach the rods to the crank and discovered one of the rods was 180 degrees backward. I used a brand new head gasket (copper sandwich type). I suppose I am going to have to pull the head off to rotate the piston, unless it is ok to just rotate the piston from below. I assume the pistons are to be oriented just one way. If I do take the head off, will I need a new gasket or can I use the torqued new one again?

Were the rods removed from the pistons during the teardown? If not, all you need to do is unbolt the cap, push the rod up, rotate it a half turn, and retorque the cap. If the piston was reversed on the rod, you'll need to pull the head again. If the engine hasn't been started and warmed up, it's OK to reuse the gasket.

Edit: Normally, the rod and cap numbers will be on the camshaft side.
Jerry

This is a total rebuild with new pistons and rings. I am using the original rods. I have no idea if I placed the rod on the piston wrong or if I inserted the whole piston/rod into the cylinder 180 degrees backward. Each piston had a notch indicating forward facing(I believe that the notch was for that reason). I am going to have to get a scope and look into the chamber and see if the top of the piston is oriented like the others. But it is ok to reuse the torqued gasket? The engine has not yet run.

you should be able to use a small flashlight and look up from the bottom to make sure the rod is on the wrist pin correct.

I found out that the rod is backward by looking up from the bottom. I need to know if I can just rotate the piston with the rod or do the pistons need to be oriented the same way. Is there a front and a rear to the piston?

Yes, the piston needs to have the notch pointed toward the front of the engine. The wrist pin is offset, and a reversed piston will cause an annoying slapping noise that will eventually collapse the piston skirt. I doubt if the offset is enough to see from the bottom, however. To be safe, better pull the head and check it out. If you haven't warmed up the engine, go ahead and reuse the gasket.
Jerry

Thank you Jerry and Don for your replies. I'm just going to take the head off and make sure everything is oriented the right way.

Pulling the head, it is recommended to use a new gasket.

Say there Buff, why don't cha get the shortblock assembled before you put the head on 'er???
Denny G

Funny thing, Denny, it was all put together. I had used the wick rear seal and the crank felt way too tight after torquing the rods and the main bearings. As I was going about trying to replace the seal, I fortunately found that the one piston was backward. Like I said, it was fortunate that I went back in. You're right though, it is good to put it together in order. Thankyou for your reply.