A Shadetree's 930 Rebuild - Page 3

Alan L · Alan L's Garage

OK, the situation gets weirder.
In spite of what Tom has suggested, I get very squeemish about using so much force on an unknown problem. There is a chance of causing more damage.
Is there any way, with the pistons you have out of looking into the case with a torch and mirror. If it is locking the crank up, you would hope it is obvious - not too many options in there.
Alan

Kemo · 03-01-2011, 06:22 AM

is there anyway to remove a link from the chains and get them out of there completely? That would certainly solve any concerns about chains binding.

Also, are the pistons re-usable? If not, here is a drastic and probably the worst idea ever. break out the hole saw and cut a nice hole thru the crown of the piston...then you can use a sawsall to cut the wrist pin on each side and pull whats left of of the piston out.

anxious to see how this all plays out.

tom1394racing · 03-01-2011, 07:35 AM

Rob

Before you cut up any potentially reusable parts, try my suggestion. If the crank does not turn, try a wood block and hammer on the nose of the crank to free it up.

jpnovak · 03-01-2011, 08:09 AM

Looking at the picture of a partial short block i see that your chain has dropped all the way into the case. This is likely what is locking the crank in place.

Even though you have pulled them out of the case they are probably not pulled ALL THE WAY out and tight against the crank timing sprocket.

I suspect the crank will rock back and forth just a few degrees allowing brief relief in chain tension. You are going to have to work carefully to free the chain, make sure it stays tight against the crank pulley until you get the case split.

Alan L · Alan L's Garage

I agree with Jamie - even with the chains looped outside the timing case, if they dropped in before, they can still be bound up. You need to be able to see the sprocket teeth clearly around the crank from both sides of the timing cases. If this is so, please let us know and we can eliminate this possibilty. believe me I have been stuck at this point before also, and was tempted to lean heavier on the crank pulley. All I would have done is munched the chains and block.
Unless the chains have been replaced with the aftermarket version, there is no joining link - they are continuous.
If they are jammed in the bottom of the case, they can be freed.
Alan

930LDR · 03-05-2011, 07:45 AM

Thanks guys for all the suggestions. Just got back into town and will be working on this later today.

I'll give the chains a thorough inspection one last time before proceeding but realize that the crank was locked up before the tear down even began so odds are we're dealing with something within the case. Spent some time on the phone with my mechanic in Chicago yesterday and he's thinking I may have friction welded one of the rods to the crank. Looking at the number 2 piston this morning I noticed it doesn't have the same back and forth play relative to the crank as the others so this may be the issue.

His suggestion was to put the flywheel back on, bolt a long piece of angle iron to it and use some force to break that rod free. May try this in conjunction with the earlier suggestion to turn the motor 90 degrees so that the case seal is perpendicular to the floor.

If this doesn't do it I may be looking at drilling through a couple of pitions (fortunately I was likely going to need a new set anyways.

930LDR · 03-05-2011, 07:48 AM

Tom -

Can you elaborate a bit on he use of the wood block? Is the suggestion to give it a good whack as though you were trying to push it through the case?

Regards

PFM · 03-05-2011, 08:55 AM

930LDR,

This is just not fun. If the motor locked up at idle I doubt the rod micro welded to the crank. If the number 2 rod will not rock on the crank clearly that is a problem. Something in the oil pump will make it all feel locked up but you should feel a little play in the crank. Does the crank move at all in the inline direction, nose to flywheel, if it does skip the wood suggestion the crank is not frozen in at the mains.

If you feel reversing the motor will get you some movement in the crank reinstall the flywheel it will allow you to rotate the motor in reverse rotation, to possibly un bind something.

Good luck and keep us posted.

Alan L · Alan L's Garage

What a mystery. But as I understand it, you were puttering around in the backyard when it stalled. If you were giving it death on a track I could understand the bearings getting tight. It must have had a main bearing starving for oil if this is the case. Are you able to squirt any lubricant - WD40 type, on a the plastic tube extension nozzle, down around the suspect rod bearing. Then see if it frees up. If in fact it is a tight bearing, you will do no more harm by levering the engine another 90 deg. The bearing is already toast and the crank will stand the force. But until you know what you are forcing I would suggest more investigation before applying brute force. With what room you have to move, the rod should be able to rock back and forth freely. But if it is locking the engine, you will not be able to move it AT ALL. If you can move it, then you can rotate the crank against it.
Can you get a torch and small inspection mirror down thru the gaps into the case?
Alan

Flat6pac · 03-05-2011, 12:22 PM

Cut the chain and pull it through, remove a possibility. Put the flywhee back on, put studs in the flywheel and a long bar and turn it backward to relieve the chain if thats the problem.
Bruce

CaptainCalf · 03-05-2011, 01:06 PM

Good stuff count me in and good luck freeing that crank 930LDR!

930LDR · 03-05-2011, 03:09 PM

There is enough play in the crank that it can be rocke back and forth until that number 2 piston hits up along the case... then I'm stuck.

930LDR · 03-05-2011, 03:11 PM

At this point I'm worried about putting too much force against the crank as I don't want the number 2 piston to damage the section of case that its coming into contact with.

Flat6pac · 03-05-2011, 03:28 PM

If you are supporting the #2 piston square there should be no interference with the case. Only with the piston rocking and not square can it hit the case.
Bruce

930LDR · 03-05-2011, 03:40 PM

Understood. Whats the suggestion on holding it square while trying to rotate the crank and get it to break free?

PFM · 03-05-2011, 04:02 PM

930LDR,

Remove the rings from the piston and slide a cylinder over it. The cylinder will keep it from getting into trouble. If the rock stops with the cylinder in place the rod is locked to the crank.

tom1394racing · 03-05-2011, 05:29 PM

Sounds like the rod for #2 piston is "welded" to the crank journal.

PFM · 03-05-2011, 08:04 PM

Tom,

Do you find it a bit odd that it welded at idle? Just asking.

930LDR · 03-05-2011, 09:41 PM

The issue was the number 2 piston. Bearing broke and spun around on itself jamming the rod. The solution was to drill through the piston so that I could get a 6" extension and 11mm 12-pt socket down to the rod nuts. Once those were off I was able to pull the piston and rod as one piece and this freed up the crank. Was able to get the remainder of the pistons out and split the case without issue.

Thanks for all the suggestions guys. BTW... I was suprised at how soft the piston actually was... standard 3/8th drill bit and a cordless drill cut right through the damn thing... sure wasn't pretty though. surface of the piston is so chewed up because I tried to use a 3" hole saw which just ended up jumping all over the place.

village idiot · village idiot's Garage

Wow, that must have made you queasy drilling into the piston like that