Technical SBC untapped crankshaft

I have a 3 inch diameter, 3 inch thick, piece of round bar steel stock I use to drive a dampener on. Wood just seems to splinter and break apart, and I don't need to hunt down some hardwood to install a dampener. I block the rear of the crank with a wooden wedge that gets tapped in behind the crank hub with the engine on a stand, then the dampener goes on, the steel stock put in place, and the BFH comes out. There's a very recognizable sound when the dampener seats; the tone changes and it's VERY obvious. Just don't think you have to be Thor with the hammer; controlled tapping is all it takes, not a big swing with lots of force. Never a problem, and I don't have to pick up pieces of wood.
But that's just me. I am Butch/56sedandelivery.

 

So it looks like this is a used motor, you're not really sure what it is, haven't looked up the numbers, it's on a stand but you don't want to take it apart, you've degreased it the best you can. Seems to me the damper bolt is the least on your worries. Why not open it up first., find out what you're working with (https://www.mortec.com/)? Why shortcut it?

 

The early small dampers were made for a press fit. The later, larger ones were slightly looser and require a bolt. All of the ones I have seen that were slung off, they had put a larger damper on an early crank without a bolt.

I would bolt it, even if I was using the early damper.

 

Really? Have you measured the ID of them? I never noticed any difference in fit between them...but I do see a difference in rotating m***, as well as the commonly used pulley depths with both style dampers.

 

Don't remember which is which, but the 283, 327, and 350 have a different shaped rear flange on the crankshaft.
One is fully round the others have either one or two notches in them.
I would ***ume it's round w/o notch for 283, one noch for 327 and two notches for 350.
But why guess? I agree with Blues4U. While you have that thing out and on a stand, pull it down and check it out. All you are risking is a set of gaskets and some time.
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The one who pulled it out of the car drove the car before pulling it. Its been rebuilt once as evidenced by the numbered connecting rods, and had an aftermarket cam that I saw. Its a known runner, and clean. Just now looks like were unsure of displacement. This is a budget build thats gone way over, so not wanting to get too deep into the motor.

 

Paging Dr. @squirrel, Here's all the casting #s I can get, looks like block is a 302 or 350, heads are 2.02.
Crank has no humps, dummy me didnt get a very good shot of it. Aside from pulling and measuring, how does one decide 302 or 350.

It is a 4 bolt main

 

Resisting the temptation to tell the whole ridiculous story, I was stranded in Ithica Michigan with a 283 equipped '51 Chevy that the damper kept falling off. Pushed it into a car wash during a rainstorm, borrowed a 1/2" drill and a tap and hand bored and tapped the crank for a hardware bolt and washer, didn't get it straight, but it did the job and we never had any trouble with that again.

 

3970010 is a 4"bore 350 casting, it comes in either 2 or 4 bolt main. The heads are 327 cast in late 63 they are large valve, either 1.94 or 2.02 depending on what horsepower engine they came on. That is a very odd date code being it is recessed instead of raised. It is possible it is a Canadian casting. Are there any stampings in the block deck in front of the right cyl head?

 

From the very little I could see of the crank flange, it kinda' looks like a run of the mill, cast 350 crank. I think that the bolt might have broke off in the snout and got mushroomed over from the balancer remover, making it look like the crank isn't drilled. JMHO.

 

There was, but it's very faint and I can't read it.
I think it's a photo trick. Im pretty sure the date code is out, not recessed as it appears.

 

I think that crank might be a large journal 3 1/4” for a 327. I’d like to see a photo of the complete flange.
The heads have 3927142 springs, those were color coded with that reddish brown paint. They are 100# at installed height, about 20# over a normal SBC spring. They went with the ‘140 “off road” cam designed for Chevy’s Trans Am Series racing. There are also aftermarket screw in studs, the tops are faced off (or ground flat) to be used with posi-locks if aluminum rockers were used.

 

I just rebuilt a 67 283. The crank was not drilled and the keyway was all hogged out. I had to get a new crank. I put a Steel crank in it. It was not drilled either. It is now.

 

I have hand drilled a 283 an tapped for a blower hub... Was it perfect... Good question, did it come loose at 7300 rpm..
Nope, never a problem.. blower application was the only reason I bolted it, Definitely like the idea mentioned above with backing up the rear flange... Note made!

 

I have never worked on a small block without a drilled crank, but I have a fair amount of experience regarding installing parts requiring an interference fit. I would be careful not to overheat or whale on the damper, because I would not want to screw up the bond between the rubber and the metal.
If you can source some dry ice, (I used to get mine from the local dairy), just use the dry ice to cool the nose of the crank, and the crank snout will probably shrink enough that the damper will slide on with a little persuasion from a hammer and a block of wood.
Bob

 

@Gearhead Graphics , do you have a better photo of the crank flange?

 

1970 350 at a first glance....note the crank has a bit that sticks out past the flange circle. Casting number 010 was used from 69-79, yours was cast Jan 1970. There's not a bolt broke off in the crank, is there?

 

Probably was a bolt broke off. I ordered the tool from 12bolt.com and was able to get it drilled and tapped nicely now

 

If you drilled and tapped it, surely you would have noticed a broken off bolt.

 

Nothing to talk you into. You got the mill and you are not planning to take it apart. Just put the balancer on and run with it. Done deal

If the balancer fit right and I was not planning on spinning it into the stratosphere I would not be a bit worried about it.