ok, we just got my brothers motor all put together, and it is hard as hell to turn over. I mean hard, we even broke a ratchet. When we installed the crank, it spun freely. Once the rod bearings and rods were installed it started doing this. We didnt know if it was just cause everything is tight or if they sent us the wrong rod bearings.

standard bore
new pistons and rings
new rod, main bearings

the crank spun freely with just the mains on so Im pretty sure its the rod bearing size but just wanted to see what you guys think or if this has happened to anyone else.

Is the head on yet? If so I would double check piston to valve clearance. If not then just try undoing the rod caps one at a time to see which one is the problem or if it is all of them.

Did you use assembly lube when you put the bearings in?

You have your rod caps switched around or possibly backwards. I've seen it happen a hundred times to people that DIY stuff.

I would say look at cap orientation (Mitsu77 said) and torque specs on those.... a thin coat of assembly lube never hurt and now that you have had problems, once you figure out what was up, pull all of your rod bearings out and make sure that you haven't flat spotted them or caused excess wear on them from things binding up... bearings are made of very soft babit type material very easy to damage

Very true. You can actually damage them from your fingernail, I've seen it done.

Engines should never be hard to turn, if you were cranking on it hard enough to break a wratchet you should have stopped to investigate the problem before going any further.

If it was me, I wouldn't trust those bearing as being good any longer. But I'm probably overly conservative when it comes to things.

I would at least recheck all the bearing clearances. You did check the clearances (with at least plasticgage) the first time, didn't you?

Next time, don't crank on it that hard. If it doesn't turn with just a little bit of elbow grease that should be your first clue that all is not well.

I have yet to try this but yeah the head is on!

Yes, we used assembly lube on the bearings!

the rod caps being reversed could be a possibility!

Thanks for the input guys and I will check all of these things over the week and update you guys on what it was this weekend.

I actually didnt assemble the bottom end, my brother did and it was his first time. The motor has no miles on it and I bought it off him , and his car.

Ok guys, I finally got a chance to work on the beast and came to this. I loosend up the rod bolts and the crank spun freely. This means the bearings are to big! Well, I then removed the bearings and noticed that they were indeed stamped " standard " . So now my question is what size bearings do I need now? I know that clevite offers a .010 under bearing.

Also, the weird thing about the whole deal is when we pulled the bearings out of the spare engine they measured .059 , which is exactly what the new bearings measured in it and the old ones had 144k on them. i am almost believing that I have an oversized crank but it hasnt been tinkered with. NO machine work , no nothing. We didnt think to check what the original bearings were stamped as but now I need to know what to get.

Let me know guys!
Thanks

Oversize bearings would only make your problem worse.... they would be thicker because when you turn the crank you are removing material. You're bearings are most likely right, you probably flipped the main caps around. At this point you may have to have the block line honed to get everything straighened out.

Did you ever check the bearing clearance with plasticgage??? Are they all tight, or just 1 or 2?

On a small block I rebuilt, I had one bearing that was out of spec. Had to buy another set to get the clearance right.

I will check the main caps but I dought that is it causeit only does this when I install the rod caps. I will check them and see but like i said it only does it when the caps are torqued down.

now one question I do have about installing the rod caps? do the little notches on the caps line up with the ones on the rods or do they go on seperate sides. We have them on seperate sides right now.

When you take them apart, you should mark them so that you can put them back together the same way. Sounds to me like you may have the caps on backwards.

yeah , could have happened cause I didnt take it apart or put it together the first time. SO i guess my ? about the nothces will have to se solved on my own though , huh?

Unless you mark them when you take them apart, there's not really a good way to match them back up.

The cap have to go in the correct orientation (opposite) and on the same rod they came with. You cannot mix the rod caps between rods. If they're mixed you probably should get them resized to get the clearances back in line.


Do it right or be prepared to make a sacrifice to the ENGINE GODS!

I know that they are on the same rods they came off of, because when he pulled them he put them right back together until they were installed again. Im just not 100% on them being backwards. i will check tomorrow and let you guys know whats up!

Ok, thank GOD! Finally got her going this holiday evening. It was indeed the rod caps, they were backwards and one of the bearings was ruined on the first install. Cylinder #3 bottom cap bearing was dented causing the crank to sease when torqued down. So I took one of the old rod bearings that was still in good condition and it works fine. The new bearings measured .060 and the used one measured .059 so I dont really think anything will happen.

Started her up and she runs great and doesnt leak to my knowledge yet. Hopefully be on the streets in the next couple days after a few little things.

good to hear i hope that cap doesn't cuase any problems in the near future