The Stovebolt Site Forums The Shop Area Engine Shop Crankshaft question...

Hello again Gents,

ok, time for an update, I have the 261 completely torn down save for the camshaft, I built a wooden stand to support the crank on the four main bearings. Question: Most of my harmonic balancer was missing. There appeared to be just a sleeve left that fit over the tip of the crank coming out of the front main. I managed to wedge the sleeve off but I think I managed to mess up part of the key (I think that's what it is called, it is the pin that locks the balancer in place as well as the crank gear). In addition to that, it appears that the PO grinded part of the tip of the crank off or at least notched into the tip. Would it be possible to build that metal back up with a welder, or is it even worthwhile or necessary? Also, could I get that pin out of the crank and replace it? What do y'all think, is the crank shot? Thanks, I hope y'all can tell me what I want to hear... Oh yeah, any suggestions on getting the cam out? Thanks!

That pin is called a woodruff key. The buried part is round. You can buy them at a parts store or a hardware store. Usually you can get a chisel under one end and drive it out.

Cranks can be welded, but it's not cheap. Running with a damaged balancer scares me. It can easily damage the crank, bending it or causing fatigue, shortening its life before it cracks and breaks. I would be looking for another crank.

Look closely at the main bearings. You will be checking for wear patterns that are skewed. If there are any, the crank is definitely bent, and I would ask about having the mains line bored, to be sure everything is straight.

Also, when you take the block in for machining, tell them about the balancer. Be sure they magnaflux the block before any machine work is done. This a an inspection procedure done to check for cracks.

Hopefully Chiphead will see this and chime in. He has far more experience in dealing with screwed up engines than anyone else here.

Thanks for the input Fred,

I am in the process of locating just a balancer, b/c I am certain that I'll need at least that, I might also start looking for a crank, in anticipation of what the machine shop has to say.

How'd you get the crankshaft out without pulling the cam? Usually the timing plate that goes around crank makes it hard to remove. Typical dissassembly procedure is to pull the cam, remove the front timing plate, then pull the crank. To remove the cam, rotate the cam gear until the two holes in gear line up with two bolts or screws behind gear. These two fasteners hold the cam thrust plate to the front timing plate. Remove these two fasteners, and camshaft, gear and thrust plate will come out as a unit. Then you will be able to see the rest of the bolts/screws that hold the timing plate on.

A good engine shop can tell you if the crank is any good. You want to find a shop that has experience with 235/261s, cuz they've got some quirks: Each main bearing is a different diameter. The front main is the smallest, the rear main is the largest, and the crank thrust is taken by the rear intermediate main brng (#3 main)

Stoveboltengineco.com or patrick in arizona may have a good replacement balancer, and other parts you'd need.

Have the block, crank and head magged for cracks. A really good shop maggs everything before they work on it. The block's main caps can crack up the bolt holes when subjected to high rpm or a bearing/balancer failure.

The 261 crank is the same as a 235 crank. Have it drilled for a balancer bolt, have the rear main seal area polished to reduce rear main leaks, have a new pilot bushing installed for standard tranny. Use recon rods. Have everything balanced and have the block zero-decked.

that should get you started, good luck!

any more questions just come back to the 'bolt!

CMOTTI (chiphead)