Crank hard to turn

[Tom N]

Fixing a crankwalked 7 Bolt. Put in a new crank and new main and rod bearings.
After install the crank and bearings it has a spot where it cant be turned by just grabbing the counter weights and turning it. You have to put a wrench on the end to turn it. The bearing are all within clearance. Any idea`s what could be making it hard to turn in part of the rotation?
There are no spark plugs in the car so its not the compression stroke.

 

[donniekak]

I can't turn a longblock over by hand. It's the tension of the valve springs. You should be able to turn it over with a 6" ratchet though, without superhuman effort. Just to be sure, the timing belt is on it, correct? If not you could be contacting the valves with the pistons.

 

[Tom N]

I can't turn a longblock over by hand. It's the tension of the valve springs. You should be able to turn it over with a 6" ratchet though, without superhuman effort. Just to be sure, the timing belt is on it, correct? If not you could be contacting the valves with the pistons.

Yes the timing belt is on and correct.
You can`t turn a engine over by hand with the plugs out?

I know it cant be turned over by hard with plugs in do to the compression stroke.

 

[steve]

You can`t turn a engine over by hand with the plugs out?

Depends on how strong you are. You still have to compress the valve springs as the cams turn.

 

[donniekak]

Yes the timing belt is on and correct.
You can`t turn a engine over by hand with the plugs out?

I know it cant be turned over by hard with plugs in do to the compression stroke.

I don't think anyone can just grab the nose of a crank barehanded, and rotate the engine with the full longblock setup. If you mean by hand, with a ratchet in the crank bolt, then yes, i could probably turn it over with just a stubby ratchet, just need something to hold on to.

 

[Tom N]

Let me clarify. With the oil pan off you can grab one of the crank counter weights and turn the crank by hand to a certain point then it gets to hard to continue turning like this and you have to put a ratchet on the end of the crank to continue turning it.

 

[donniekak]

Let me clarify. With the oil pan off you can grab one of the crank counter weights and turn the crank by hand to a certain point then it gets to hard to continue turning like this and you have to put a ratchet on the end of the crank to continue turning it.

It's probably just the valvesprings.

Did it rotate easily before the head was installed?

 

[Tom N]

It's probably just the valvesprings.

Did it rotate easily before the head was installed?

Did not remove the head.
Swapped out the crank and bearings due to crankwalk.

 

[donniekak]

Did not remove the head.
Swapped out the crank and bearings due to crankwalk.

If the block and head weren't taken apart and cleaned, there is a ton of crank, and bearing material in the oiling system waiting to cause problems. It's like just swapping out a crank and rod, after spinning a bearing, temp fix.

But, it's perfectly normal to have varying resistance throughout the rotation of the crank, due to the pressure exerted by the valvetrain.

 

[LunarEclips]

another common issue that causes the crank to be hard to move is that people put in the bearings in the wrong place. The biggest misconception is where each of the main bearings are put in place. Double check your installation. Also, check for clearance tolerance. This can cause the same problem. Mic the crank and make sure the bearings are the same tolerance for the crank. Lastly, the bearings need to be lubed prior to installation with a thick weighted oil. Im not saying you did, but alot of do-it-yourselfers forget to even lube the bearings at all. Alot of people use gear oil.

 

[Calan]

Did not remove the head.
Swapped out the crank and bearings due to crankwalk.

Did you try to rotate it before putting the t-belt back on?

 

[Tom N]

Did you try to rotate it before putting the t-belt back on?

No. Wouldn't the pistons hit valves if I did that?

 

[nightmares GS-T]

No. Wouldn't the pistons hit valves if I did that?

If you had the cams in then yea it likely would have runined some valves and possibly more.

 

[Tom N]

If you had the cams in then yea it likely would have runined some valves and possibly more.

Yes the cams are in. Im not sure it would do any damage if you were slowly turning it by hand with the timing belt on. The pistons would touch the valves but not at a hard rate.

 

[delta448]

If you had the cams in then yea it likely would have runined some valves and possibly more.

Not if you take out the rockers and/or have the cams aligned at where they naturally fall to while timing.

Yes the cams are in. Im not sure it would do any damage if you were slowly turning it by hand with the timing belt on. The pistons would touch the valves but not at a hard rate.

Again, not necessarily. You can tell when the cam is holding a valve open.

You need to remove the T-belt, remove the rockers from the valves and then turn the engine over by hand. There should be uniform resistance. If you feel anything catch at all, you must have the mains checked for bore alignment and corrected with an align hone if found out of spec.

BTW, you aren't going to fix CW by doing what you're doing, if the block is eating thrust bearings, it's too late.

 

[Calan]

Wouldn't the pistons hit valves if I did that?

Not if the cams are straight up with the valves closed, and there isn't a timing belt on it; unless someone's shaved a crap load off the deck and head and the valves aren't completely closed.

If you are really worried about it, do as Zack suggested and pop any rocker that looks like it may be holding a valve partially open. You can pull them out and replace them without pulling the cams, if you're good with a large screw driver and/or pry bar.

Im not sure it would do any damage if you were slowly turning it by hand with the timing belt on. The pistons would touch the valves but not at a hard rate.

With the t-belt on, the pistons should never touch any valves...unless it isn't timed correctly.

 

[delta448]

Yes the cams are in. Im not sure it would do any damage if you were slowly turning it by hand with the timing belt on. The pistons would touch the valves but not at a hard rate.

Craig, I was assuming he misspoke and meant to write "off".

You're right. I shouldn't assume.

 

[BogusSVO]

Get an old swing beam style torque wrench and measure how much torque it takes to spin the engine over.

Drop the time belt, pull the cams out and the spark plugs. If auto trans disconnect the torque converter so the engine can free spin.

If you go over 25 ft lbs then you have some binding issue you need to locate and fix.

Like those above have said, you have a done a patch repair.
Personally I would like to see the engine come out and be repaired properly.

Depending on how bad the CW was you man have distorted a main bore.

 

[Tom N]

There is still resistance with the timing belt off and the cams out.
The engine is out of the car with the transmition off.
Tolerances measure out with in spec.
Taking the motor to the machine shop Monday to have it checked out.

Craig, I was assuming he misspoke and meant to write "off".

You're right. I shouldn't assume.

You assumed correct. I miss typed and meant "off".