How do I spin the crankshaft?
 

Ok, I am new at this engine rebuilding stuff so please bear with me. Wayne's book states that the crankshaft should "spin freely" once the flywheel and front pulley are attached in the final stages of rebuilding the case. How do I check this? I can't seem to make the crankshaft spin.

I did search this topic and read the "snowman's" thread about his car having trouble turning over. OMG please say it ain't so... Please be gentle

I don't have Wayne's book in front of me so I don't know just where you are in the book you are but..
-If just the crank without rods is in the case, it should spin easily and smoothly
- If you are spinning the crank with the rods attached, are your rods supported somehow (rubber bands)? If the rods are just hanging they will hang up when you turn the crank.
Probably doesn't help but I thought I'd mention it.
-Chris

What Chris said, if you don't have the piston attached and just have the rods hanging, they tend to catch on the edges of the case. If you have the engine buttoned up with the heads on and you can't rotate the engine (might be a bit stiff, but still should rotate freely) you have a serious problem. Let us know at what stage you are at.

Thanks for the quick replies. I don't have the pistons on the arms yet so they might be hanging up. I will go down to the garage and put rubber bands on them to hold them up. Should I just be able to turn the flywheel by hand? Maybe I can take an image and show you better? Let me try getting the rods up and off of the case.

Bet you anything one of the rods is hanging up on the edge of the case. At the stage you are at the crank should turn quite easily.

You engine sounds like it is at this stage, only cleaner and without the pistons:
http://forums.pelicanparts.com/uploa...1095817851.jpg

any chance this is a mag case?

if all your rods flop up and down easily you should be able to spin the crank freely for at least a quarter to half turn before a rod binds on the case.

if you have a mag case it may be warped and the main journals are binding on the crank.

Kurt,

Just lifted to rods with rubber bands holding them up and I am trying to spin the flywheel but the crank will not turn over! Oh man what have I done? and what am I in for now? The front pulley is attached as is the flywheel. I just sealed up the case this afternoon. Before I put the case together the rods spun quite freely on the crankshaft.

it is a magnesium case in same state as Kurt's pics, but cleaner without pistons. No previous problems when torn down.

Double check that neither the rods or the timing chains are catching on anything. How about the flywheel? Catching on the engine stand bolts? If all is clear, then I fear Alan may be correct on the warped mag case. Or you got the wrong main bearings (possibly undersized?)

Did you read this in Wayne's book? “As the magnesium case is exposed to thermal cycles and combustion forces, it will deform in many different directions, bending, stretching and twisting across many axes and planes. The case-bearing saddles will become egg-shaped and the entire case itself will twist. In addition, the magnesium case will relax and deform farther after it has been disassembled. The stresses placed upon the material have a tendency to create hidden stresses on the case that are not apparent until the case is split. When the case is bolted together, the two halves support each other and help to keep the proper structure of the case.
You can sometimes observe this when you separate your case halves. Before you split the case, make sure that the crankshaft can turn freely in its bearings. Split the case and let it sit overnight. Then retorque the case halves together with the crankshaft and bearings installed. It is not uncommon for the crank to become stuck and offer resistance to being rotated. The is because the case halves – no longer supporting each other- have relaxed into their natural, deformed orientations.”

Also look at these two threads:
Crankshaft Seized

and nose bearing leak

Cassidy -
How are you trying to turn the crank? I used a long 19mm wrench on the pulley to turn the crank most of the time during the rebuild. Let's run through some questions here:
Have you tried turning the crank CCW a few degrees to free up any hung rods, and then suspending the rods with rubber bands so they don't hang up in the future? You should be able to grab each rod and move it from the top of the spigot to the bottom. If you can't, it's hung up and needs to be investigated.
Are your timing chains binding up, or fallen partially/completely off their sprockets?
Is it possible you dropped something in the case?
Did you check your oil pump for smooth, non-binding action with no discernible force required to 'start' the pump turning?
Was your mag case properly measured out and repaired as necessary by an experienced machine shop (that's QUESTION 1, actually)?
Is your crank straight? Did you use the correct bearing size?
Did you check the backlash of the crank and intermediate shaft gear mesh, at the very least by eyeballing and feel, if not with precision tools?
Did you perhaps misassemble the flywheel to the crank, such that the flywheel is now binding up against the case (unlikely...)

Guys, I just used a 19mm wrench on the pulley and it turned freely. I think that perhaps one of the timing chains was sticking? Seems fine now and I will check it in the morning. Thank you all very much for your help and assistance.

This will probably be one of many questions posed as this project progresses.

We just breathed a collective sigh of relief for you!
-Chris

Very glad to hear it!

One of the biggest lessons from my first build - was that as I started to get tired or frustrated, I had to IMMEDIATELY set the wrench down and walk away. That's when the decisions became poor and the work got sloppy.

walking away when tired is a good rule for many projects. I think I am so nervous about making a mistake that my paranoid sensor was on overload last night. Thanks to all and I will keep you posted as work progresses. I have started this project knowing that the book and this board are available to me. The ability to ask questions of those that have been there before is so important and assuring. Thanks again.

Whoo hoo! That is good news! With the cases sealed up, the hard part is over. Now on to assembly and timing the cams.

Trust me, you will make mistakes. Taking your time and not making any big ones is the key. I've made the big ones so I have experience with it. Take your time (my first mistake), walk away when necessary, and all should be fine.

Michael

working on installing the piston rings this afternoon and evening. Hopefully, I can post an image to show my progress. Thanks for the encouragement.