Road Runner Nest

How tight should a crankshaft be?

Put In new main bearings in the other day.When i torqued the mains down I was spinning It after every torque,making sure everything was spinning correctly.After i did the rear main the crank was really tight.The seals are installed properly and all but its really tight.I can still rotate it but it takes a lot of effort.I must have had the crank torqued 3 times so far making sure it wasn't my bearings and seals.I'm using lubrication.Cranks out right now until I get my cam bearings in. Is this normal?should i skim a tad bit off the bottom of the seals so its not so tight?

Make sure the oil passages on the crank were chamfered. I had a crank turned locally and they didn't chamfer the holes. When I picked the crank up, I asked them about it, they said it wasn't needed, and they guaranteed it to be ok. I was MUCH younger. Installed the crank and noticed it was pretty tough to turn over, sounding about like what you're describing, fired it up for break in, and it ran about 5 minutes before it locked up, HARD. I pulled it down, found bearing material shaved off the crank going thru the passages and into the next bearing. When I took the crank back to make them replace it, what I got was "It's been installed, there's nothing we can do about it"

Everything Is fine dealing with the crank and bearings, I made sure of that,honestly I was obsessed about that.The crank was in and out being torqued and then undone making sure nothing harmful was happening.Nothings catching,grinding,rubbing raw,en even or anything.Its just really tight when the rear main goes on with the seals.After my cam bearings are installed Ill put the crank back in and Ill record how tough It spins.Maybe Its normal I just need to know for sure

Dont mess with the seals it will just lead to problems down the road.Heres what i would do first:Check every bearing with plastigauge to be sure the clearances are within specs,make sure everthing is perfectly clean and reassemble using motor assembly lube (on the seals too) not just oil.

BRIAN

Sorry, but one test for a bent crank or poorly machined assembly is a tightness in a part of the rotation of the crank. Make sure all bearings are seated correctly, including NO OIL under the bearing shells installed in the block. Re check everything the machine shop did yourself. Mic every journal, plastiguage every bearing assy. Don't run that assembly, you have a problem. I have seen an incorrect ring gap cause rotational problems (too tight) check everything twice, DON'T RUN IT, you have a problem.

Well i never said anything about a shop doing anything regarding my crank or bearings,...

I have said before I have had a machinist(who is also a mopar guy) measured everything for me before I even ordered my bearings.

The bearings are fine,crank was straight.nothing is abnormal as far as they go.I have checked them many many times.And of course I'm using assembly lube...

i read online that some builders measure the resistance of their crankshafts using a torque wrench not sure how to go about that though.And btw my pistons aren't installed yet.All i have Is the crank torqued down when this problem occurs.

Did you lube the seals, too?

Yesss

I think I have some good news.I torqued all the caps down again.And this time its not that tight,tight but not crazy tight like before.I did nothing differently,everything's the same.Like I have before I checked all of my bearings and they are all fine.Could It be the the seals were just so hard from sitting in the box and they softened up a bit from the torquing and the oil?When i first found out how tight it was I have had my crankshaft sitting in my engine coverd up not torqued.I last messed with It a week ago.I guess seals need to be broken In also.haha

Anyway for a typical crankshaft how tight should It be?I can wrap my pinky finger in one of the holes on a counterweight and rotate it that way,couldn't do that before,now i can.Id say that's a good thing.

Maybe the rear main bearing you have is mispackaged and is an undersized bearing, like a ".010 under that could certainly cause that problem. I am guessing you have a stock piece and just refreshing the motor? Install the bearing, without the crank, and mic the inside diameter, then measure the crank journal, that should give you the answer.

Like I said before the bearings are fine.2 people i know who have built engines are gonna be here over the week Ill see what they say.Like my last post i think the problems solved.that seal isn't so hard now.

one word plastigauge?
if the plastigauge says your good your good.

Try pulling the rear main seals out and then re-torqueing the mains and see if that makes a difference, if it does then it the seals and not to worry, if it doesn't ... then you've got problems!

JosephGiannini wrote:one word plastigauge?
if the plastigauge says your good your good.

What he said.

But, if you can spin it with your pinky , you should be good...it's not going to free-spin like a bike wheel, but I would deff check all clearances with plastigauge...it's dirt-cheap insurance.

Good luck