The Stovebolt Site Forums The Shop Area Engine Shop Snug Crank

I’m rebuilding a 67 283. The engine is on a stand. This weekend I put the crank and new mains in. I used engine assembly lube. I checked the crank with a micrometer and it is std. All the new bearings are also std. After tightening the main caps the crank turns a little stiff. I can turn it by holding the counterweights but it seems a little Snug. I don’t expect it to “spin” free but I’m not sure if a little snug is too snug. Any suggestions or comments would be helpful.

Rick

It should spin quite smoothly using one hand with the caps tightened down, so you're right there's probably something wrong.

Yes crank is STD and bearings are STD - but did you check it with plastigage anyway? Mistakes have been made before, even if you trust the machinist and the parts this is a sure fire way to find any problems. Cheap insurance, just takes a little extra time.

Second thought: on my Willys Jeep I found the new rear main seal was defective, being about 1/8" too long when compared to the old one. Tightening down the rear cap sinched down the crank and it wouldn't return. Bought a replacement seal and it fit correctly.

-Boyo

If you don't have a way to measure the brg bores you can start by taking a cap off at a time
Start with the thrust cap
Turn the crank

crank should spin freely with no rods/pistons attached. Plastigauge the mains, I assume you should have between .001-.003" journal clearance. Could be tight rear main seal or a cocked thrust main. How did you find a 283 crank with a std journal size anyway? Rule of thumb is that if you can't spin crank with a few fingers on counterweight, its too tight.

I don't know about a 283, but on some engines I've rebuilt, the rod end caps are offset. If they are not installed in the proper orientation, the engine "binds" at certain degress of rotation. Just something to check, probably not relevant.

One cap at a time until you find the culprit

Thanks for all the suggestions. I narrowed it down to the second one from the front. The second one had a shinny spot on the edge where the bearing rubbed. I took out each bearing and cleaned under it for good measure. The same with the caps. Re-checked and the same thing, the second one was still tight. I think I'll pick up a new bearing and replace it and see if it was just one bad bearing. Other then trying that I'm kind of stumped.

Rick

Please pop out the brg and look at the contact marks left by the previous brg
Run your finger along the side of the cap at the bore...... is it rough?

Look at the radii in that main.....are they the same as the others

Torque the cap with the brg in and crank out
Now loosen one side and tap the bolt
Put a feeler gauge under the cap on the loose side
Is it the gap the same as the others?

That's about all you can do without proper tools

Any chance that #2 main cap has been replaced on the block? A block that needs a line-hone will exhibit strange binding problems, as the crank saddles don't line up due to the different cap(s). Or the crank is out of round or the brng shell is defective.

Get some plastigauge! Its a dollar!