Engine rebuild question

n51hj · Post by **n51hj** » Sat Oct 09, 2004 10:02 am

I'm rebuilding my U20 and have a question or two. I sent the bottom end to a shop for the machine work and elected to do the reassembly myself. After installing the bearings and rear rope seal, I tightened the bearing caps to check clearances with a Plastigage. They were OK, but after cleaning the plastigage residue off the bearings and re-installing the caps, the crank is kinda' hard to turn. I suspect the rope seal is what is making it tight. Any other ideas?
Also, I'm looking at H20 parts, such as pistons. I know they have a slight dish to them but I'm not terribly concerned as I've taken some off the block and head. Any comments on the H20 stuff?

Thanks in advance,

SLOroadster · Post by **SLOroadster** » Sat Oct 09, 2004 4:56 pm

Steve,
How hard is it to turn? It should be a little more diffucult, but not much more difficult (if that makes any sense.) The H20 pistons will work, and they are dished, but I wouldn't push it hard as they are for a forklift and might not do so well being reved high. You will be way down in the compresssion with them (I will take a wild guess and say less than 9.0:1) Do you know exactly how much was taken off both the head and the block? Make sure you use some cam tower shims of the right size, otherwise you will have timing chain issues later. Make sure you can turn the cam with 2 fingers after you install the tower shims, it should turn fairly easily.
The engine should go together fairly easily and straight-forward.

Good luck,
Will

oilleak · Post by **oilleak** » Sat Oct 09, 2004 6:35 pm

You need to soak the rope seal in oil for a few hours before you install it and you need to press it into the grooves well - I use an old aluminum steering wheel adaptor that's around 2-1/2 inches in diameter to seat the seal well before installing the crank. If it's not in the groove all the way, it'll be hard to turn the crank and you'll stand a better chance of damaging the seal on startup. Really, I like to bolt the first four caps down first to see how hard it is to turn and then do the rear cap. If you didn't oil the rope seal well - take it back apart now and do it again. Better now than later

Post by **dbrick** » Sat Oct 09, 2004 9:43 pm

What are you using for assembly lube? I always use 50/50 mix motor oil and STP, kinda sticks better. With the seal in right and soaked, it should spin pretty easily, if not I would loosen 1 main at a time and see when the crank rotates freely.

n51hj · Post by **n51hj** » Sun Oct 10, 2004 7:14 am

I'm using Lubriplate #105 assembly grease. I'll try lubing the rope seal and while it's out, I'll spin the crank and make sure it isn't one of the bearings.

Thanks,