Cotter pins holding main bearing nuts

christian

christian

Senior Member
Today I spent 45 minutes trying to remove the cotter pin from the center main nut in the valve chamber. All I have to show for it are two bloody hands and a mangled cotter pin still in the nut.

Anyone have any tips on getting this thing out?

So far I have the carb, distributor, dist shaft and pump drive out for clearance.
 
If I can't easily get the cotter pins out of the two center main bolts when breaking down the motor for a complete rebuild I always just leave be cotter pin in place. Put the open end of a wrench on the nut, then get a socket to fit the head of the bolt, and I hit it with an impact gun and it'll back right off. I'm sure you could do the same with a 1/2 inch drive ratchet. It just snaps the cotter pin, and then once you get the bolt out you can take a punch and punch out what's left of the cotter pin in the hole. But for me time is $, so there's no point in spending longer than a few minutes trying to pull a cotter pin. If the bolt or nut gets messed up in the process, it's cheaper to replace them than spend a large amout of time removing them.
 
needle nose vise grips or angled needle nose pliers.
or what Logan said
or the pin may be trapped try to loosen or tighten slightly
 
Did you try a regular cotter pin removal tool - they are kind of like a spud wrench with a bent chisel on one end and a curved tapered end on the other. They are designed to get into tight spots.
From a time standpoint the impact gun is the way to go.
 
the pins ARE prolly needed since I find a lot of nuts that have been backed off to 30 lbs in order to get the pin in. You wouldn't wanna grind the face of the nut off to make it work right, now would you
 
Here are photos of my Craftsman cotter pin extractor


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i have a few cotter pin tools but i also use a hose pick at times. they are a little longer
 

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I do all my own work. But if I had my car in a shop and someone even walked toward it with a rattle wrench I would have it out of there in a big hurry.

Chet
 
Most engine rebuilders as well as new engines don't use the cotter pins, if the bolts are properly torqued the pins are unnecessary. You could use a lock washer but, again, the nut wont back off if securely tightened.
 
Just go to work with a wrench. The cotter will shear without noticeable effort as the nut turns. There is NO need for power tools, any wrench that will turn the thing without a cotter will turn it just as well while shearing the pin!
You'll have the eye and 4 little straight pieces left...I always make a point of collecting the bits after each fastener to avoid having loose metal that might affect the works or end up stuck in my flesh.
This is so easy you don't need to worry about more formal removal.
The hook type tools can be a fair aid if you must extract, but the best I have ever found is ancient...it is a pliers type thing with a patent date in the 1890's stamped on it, working a hook that ratchets back as you squeeze the handles. The crazy thing seems able to grip anything and to pull at any angle to the axis of the pin...the pin just oozes out of its hole like a strand of spaghetti. Completely unnecessary, but a pleasure to watch.
 
Bruce Lancaster said:
the best I have ever found is ancient...it is a pliers type thing with a patent date in the 1890's stamped on it, working a hook that ratchets back as you squeeze the handles. The crazy thing seems able to grip anything and to pull at any angle to the axis of the pin...the pin just oozes out of its hole like a strand of spaghetti. Completely unnecessary, but a pleasure to watch.
Click to expand...

would you post a photo?
 
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This is it...this might be an enhanced version, pretty sure mine has an 1890's patent.
The hook looks too clumsy, but in service will actually get a deathgrip on any cotter it can reach at any angle. From there, it never fails! If you see one at a flemarket, grab it!
 
If the cotter pin gives problems when trying to remove, I have never hesitated to break them off. It is easier and quicker. I just use a wrench and a socket and 1/2 inch drive pull handle. On the last two engines I used the replacement main bearing bolt and nut kit. This kit has special washers to prevent oil leaks and no cotter pins are used. This setup is easier to use and works better for me. Snyders part number is A-6327-MB price $36.95 on page A-123 of the new Snyders catalog.
 
Thanks for all the responses. I got to work and ended up using a wrench and socket, sheared the pin right off.

Once I got the cap off I was very disappointed. The state of babbitt on the rods was excellent, groves looked factory and all had about 6 to 7 shims in place.

The mains turned out to be another story. No shims and shattered babbitt.
 

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Some of the vendors sell grade 8 main bearing bolts w/lock nuts and seals. once a castellated nut is brought to torque it is not advisable to back it off to allow installation of the cotter pin. Trying different nuts/thin flat washers; this can be a time consuming process especially in our get it done yesterday world.

Chet
 
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