Crankshaft Mystery!

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Evill Ed
Posts: 161
Joined: Thu Jan 25, 2001 3:01 am

Crankshaft Mystery!

Post by Evill Ed » Thu Mar 14, 2002 5:49 am

When the flywheel is removed, the crank can float forwards and backwards in the case. When you turn it, the timing gear for the distributor goes out of alignment, and causes the crank to lock. It does it worse in one direction, I don't remember which one. I just went through this while assembling my 2.0L on the stand. Without the flywheel, the crank would lock when turning it. Put your shims back in, install and torque the flywheel. It should be fine again. If all was okay in the case when you removed the flywheel, it should still be okay.

Ed

GarnerAF
Posts: 6
Joined: Wed Apr 03, 2002 3:01 am

Crankshaft Mystery!

Post by GarnerAF » Wed Apr 03, 2002 8:05 pm

I recently replaced my clutch, and found that after removing my flywheel, the crankshaft won't turn more than 170 degrees. It hits a hard stop at each end. I didn't open any cylinders, and have removed the rockers to be sure I didn't have a valve seat drop. All seems to be in order. Crank has end play in both directions. I have spoken to several techs and this seems to be both unusual and baffling to everyone. If something had fallen into a cylinder, them the crank should travel almost 360 degrees. I am looking at an engine drop, but don't know where to start looking. Does anyone have an idea about what may be going on here?

Bulley
Posts: 98
Joined: Thu Mar 21, 2002 3:01 am

Crankshaft Mystery!

Post by Bulley » Wed Apr 03, 2002 10:19 pm

I'm going out on a limb here, having had a beer, and having never encountered thie exact situation...

If your measurement of 170 degrees is correct, then something inside the block is to blame.

A spanner at in the oil bilge. A socket left on a connecting rod bolt. Something in the bottom end is preventing the crank from making a revolution.

If it were a valve seat, or a 13mm bolt in the cyllinder, you'ld see a 290-310 degree rotation.

I'm sorry. If it makes you feel better, I once assembled a 914 motor minus a crankshaft dowel pin. At about 30k, I was rolling with an Audi on a remote 4 lane at about 105-110 mph for 20-25 minutes when the bearing drifted enough to cause a catastrophic failure.

"I feel your pain" W.J.Clinton.


------------------
Matthew
412@bulley-hewlett.com

Towns can't pave thier way to beauty, or drive their way to prosperity.

Zeke
Posts: 259
Joined: Fri Jan 18, 2002 3:01 am

Crankshaft Mystery!

Post by Zeke » Wed Apr 03, 2002 10:37 pm

If you pull the crank back towards the flywheel before turning does it still do it? It's real easy to let the crank slide into the bore w/o flywheel mounted.

------------------
Milt 914 2.0 Race Car (under construction)

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Racer Chris
Posts: 665
Joined: Sun Jan 13, 2002 3:01 am

Crankshaft Mystery!

Post by Racer Chris » Wed Apr 03, 2002 11:51 pm

I seem to remember experiencing the same thing before. If it goes away with the crank pulled back you are ok I'm sure. I have no idea what caused it though.

GarnerAF
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Joined: Wed Apr 03, 2002 3:01 am

Crankshaft Mystery!

Post by GarnerAF » Thu Apr 04, 2002 9:04 am

Thanks, everyone! I have tried to turn the crank with the flywheel on and the crank pulled back all the way(shimmed). I still seem to have the problem. The car was running when I started the project, and I haven't had the crankcase open to leave anything behind in it. I didn't even remove the spark plugs! I too suspect something has gone wrong in the crankcase, something attributed to the open end play, but no one seems to have a good idea of what to look for. Any more ideas? I may soon be starting the engine drop and an unscheduled rebuild. Thanks. AG

Billyisgr8

Crankshaft Mystery!

Post by Billyisgr8 » Tue Apr 16, 2002 12:35 am

Maybe one of your center main bearings has broken into pieces and is getting hung up in the crank oil hole.

My motor did this exact thing and had me puzzled until I took it apart only to find a broken bearing in lots of chunks.

GarnerAF
Posts: 6
Joined: Wed Apr 03, 2002 3:01 am

Crankshaft Mystery!

Post by GarnerAF » Tue Apr 16, 2002 9:11 am

Thanks, I am dropping the engine this weekend and will look for the problem. This is a good possibility. This engine is 28 years old without a rebuild.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Billyisgr8:
<B>Maybe one of your center main bearings has broken into pieces and is getting hung up in the crank oil hole.

My motor did this exact thing and had me puzzled until I took it apart only to find a broken bearing in lots of chunks.</B><HR></BLOCKQUOTE>

TwoLiter
Posts: 23
Joined: Tue Oct 30, 2001 3:01 am

Crankshaft Mystery!

Post by TwoLiter » Tue Apr 16, 2002 11:25 am

I second Evill Ed. The distributer drive gear is hanging up. Make sure the crank is pulled all the way back before you turn it.

GarnerAF
Posts: 6
Joined: Wed Apr 03, 2002 3:01 am

Crankshaft Mystery!

Post by GarnerAF » Tue Apr 16, 2002 12:16 pm

Thanks, I will check this also, but I have decided to pull the engine and replace the front crank seal and do the work on the bench. I plan to pull the distributor and drive and check this possibility before I open up the engine. When I find the final solution, I will post it. I am grateful for so many replies to my posting. Lots of help means faster and better solutions.

Thanks to all.

AG

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by TwoLiter:
I second Evill Ed. The distributer drive gear is hanging up. Make sure the crank is pulled all the way back before you turn it.<HR></BLOCKQUOTE>

HotRod
Posts: 118
Joined: Tue Nov 06, 2001 3:01 am

Crankshaft Mystery!

Post by HotRod » Wed Apr 17, 2002 10:31 am

My guess would be what Evill Ed said, the alignment of the gears is causing it.

hardflex

Crankshaft Mystery!

Post by hardflex » Thu Apr 18, 2002 9:33 pm

could you have used bolt which was too long in fastening the clutch to the flywheel? maybe it's going through the flywheel and hitting a spot on the block.

Just a guess, since i don't have my engine out

GarnerAF
Posts: 6
Joined: Wed Apr 03, 2002 3:01 am

Crankshaft Mystery!

Post by GarnerAF » Thu Apr 18, 2002 10:07 pm

Well, I have tried to turn the crank with the flywheel removed, and still the problem exists. I am hoping to get to the distributor drive this weekend to see if this is the problem. Otherwise, the engine is coming out. Thanks for the suggestion. <BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by hardflex:
<B>could you have used bolt which was too long in fastening the clutch to the flywheel? maybe it's going through the flywheel and hitting a spot on the block.

Just a guess, since i don't have my engine out</B><HR></BLOCKQUOTE>

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