civigov

Hey guys how’s it going. So basically pulled my motor with trans on because she was burning oil and chuchin smoke, so I decided to change out piston heads and re do rings along with buy new rod bearing, this is my first engine rebuild hoping with more to come and to get out of n/a soon, but when I started reinstalling the new pistons I started building up insane compression, pulled them out and did it again, thought maybe because I didn’t seperate trans(manual) and had it hanging this was my problem. Well today I bolted back down into car and tried spinning the crank with a big breaker bar, I put all my weight and snapped my breaker bar, now it didn’t have this much compression before. Do I need to take the motor back out, is it just this tight until I start it the first time and the rings can seat and everything breaks in??? Any help is insanely appreciated thank you.

Colin42

Did it spin nicely with the head off?
did you buy standard rings, or oversize? Did you measure all your clearances? Ring gap?

civigov

That’s where I feel I may have fed up I did not measure and I did not buy oversized rings nor did I bore the cylinders out, I honed them though.

chozobody

Stock rings? Something else is going on.
Did you use assembly lube during the rebuild process?
Did you check your timing to make sure you don't have a piston contacting a valve?

Those are two questions I have off the bat.

BrotatoChip

If all you did was hone, you would still use the stock ring/piston size.

civigov

yeah I did use stock rings, and as far as timing goes it’s damn near perfect I believe, I’m beginning to think I installed rings upside down or didn’t put the bottom connecting rod caps on backwards or wrong, I believe this would cause a binding no?

Colin42

If the rod caps are backwards that could be it. Did you not rotate the engine before putting the head on?

BrotatoChip

It's either in time or it isn't, no guessing here. Timing being off would only cause "seizing" if pistons are pushing against valves. You'd have to be a long ways off. Does it rotate backwards at all?

Is the transmission in neutral? Try to spin one wheel by hand with the other on the ground. If something is wrong in the transmission, it would prevent the engine from rotating. Have someone hold the clutch while you try to rotate the engine.

civigov

that was the thing too when I had it out of car it would rotate easier backwards before I put the head on, and transmission was in neutral but even still without the pistons in the crank spun freely, did not disconnect tranny left them together, but once I had all of them in it was harder to spin the correct way because this engine is a counter clockwise spin, and I was believe maybe because I had it hanging on cherry picker it was giving me trouble to spin due to that, I’m hoping I iust put the rod ends on backwards ? This time around I’m going to measure the rings in the cylinder but idk what the spec is for that yet, and also the timing was hard because of how much pressure I needed to spin crank. So it would over spin by like 2 millimeters.

BrotatoChip

Sounds like you've narrowed it down to an issue with the pistons/rods. Did the pistons slide into the cylinders easily? Rod bolts torqued properly? Assuming you didn't check clearances on the rod bearings?

civigov

Possibly thinking either those rod bolts are over torqued and did not check clearance on rod bearings, not 100 percent sure on how id see that, and once the rings got down into the cylinder the rods were easily pushed down.

BrotatoChip

Sounds even more likely that it's an issue with the rods. But then how were you spinning the crankshaft to tighten down rod bolts? Or was it difficult to spin?