Old camshaft identification/.020 crank/rod bearings.

[fordkiller]

Hey there,

Getting back into the GN game after a long break... I've got a used engine I'm tearing apart to take a look at and might use short-term to get my car running again until I put together another engine I've needed to assemble for a while.

The used engine has .030 pistons (with no name on them like TRW, etc.) and the bore looks good with a lot of cross-hatch left and no noticeable ridge in the top of the cylinder so I'm willing to chance it and see how things go. What concerns me is the crank is at .020 on the mains AND rods! I've heard in the past that these cranks shouldn't be turned past .010 due to the fillets and the strength lost due to more material being ground off. Some of the main bearings had some dark discoloration in spots but the crank looks shiny and smooth still. I was planning on replacing all the bearings anyway but I wonder if something is going on why I'm getting the partial dark discoloration on the mains bearing surfaces.

I pulled the cam out to hopefully see what was in there and all I could find on the end of it were the numbers "F143" on the top and "930406" under the top number. I've Googled the numbers and don't come up with anything. Also it had no swirls machined into it like a stock cam I had from way back that had no numbers on the front of the cam but it did have swirling machined into the front of it.

Ideas on using this engine short term? If it wears out/blows up it's OK; I have the other one to fall back on. I know the engine is probably at it's limits as far as the crank goes and it being .030 for the pistons. Any ideas on what cam this car has?

Thanks,

DH

 

[lrayzer]

If the engine has sat a while the discoloration could be due to moisture, corrosion of the bearing surface nothing more, like billet alum that has sat outside, gets the dark spots.

 

[Mike Licht]

the crank is fine, no idea on the cam, if you put t in the block with a degree wheel you could figure it out fairly easy
Mike

 

[earlbrown]

It kills me how so many people think that a crank that's turned more than 10thou will snap like a toothpick. (even if the journals start out 1/4" or more bigger than other engines) A .020" crank has had .010" of meat taken off of the journals...... Notebook paper is around .009" thick. I can't imagine a crank being on such a ragged edge that such a small amount of surface material will make it brittle and weak.

 

[fordkiller]

Hey Mike thanks for the tip I'll get a degree wheel and check it out. I have to call or e-mail you and ask some tech questions/get some recommendations.

 

[fordkiller]

Hey Earl just going off of what was said way, WAY back on the fillets on the turbo Regal cranks and not going past .010 for strength. I'll drive the thing with .020 bearings and not think twice until it either wears out or blows up!!

 

[lrayzer]

Don't confuse size/strength with the case hardening depth which can be removed by excessive grinding, as long as the fillet radii are re-established properly, it does not create a strength issue.
Grind thru the hardened outer layer, and you have a whole new ball game.

 

[Mike Licht]

It kills me how so many people think that a crank that's turned more than 10thou will snap like a toothpick. (even if the journals start out 1/4" or more bigger than other engines) A .020" crank has had .010" of meat taken off of the journals...... Notebook paper is around .009" thick. I can't imagine a crank being on such a ragged edge that such a small amount of surface material will make it brittle and weak.

Lets not forget the BMS cranks that were cut .150 down to small block Chevy size bearings or offset ground to make the stroke longer .020 is nothing if done prperly