60' 290Hp crankshaft?

[Norbert R.]

Would there be any difference in the spec's of the Orig. crankshaft to any other 283 crankshaft used in the 290hp engine? Counter weights? (weight)?
I have the orig. and could have it conditioned, anyone have an idea of cost to turn a crank these days? or purchase one ready to install?
Any comments?
Thanks,

[Pat Bush]

Re: 60' 290Hp crankshaft?

Norbert ---

I cannot speak to the specifics of the crankshaft you have versus others. Many times there are differences based on composition and performance but to adequately compare, you must get the casting numbers off the crankshafts in question to understand their differences. There are several fellas out here who are absolute number gurus and can answer that question.

As for usability, a shaft from one 283 will generally work in another 283(as the stroke, rod, and main journals will usually be the same) but you should always inspect the shaft to make sure things like the nose bolts, counterweights fit the block and do not bind, pilot bushings, and the like are the same. Sometimes these things changed between engines as improvements were made.

We usually mike the shaft first to determine if it even warrants a re-grind. Many do not. Often times a well-maintained engine will only need a cleaning and polishing of the journals and you can keep it standard. And you can often get .001 under bearings for chevy engines that have marginal wear.

As for grinding the shaft, we generally charge $11.50 a journal including polishing. I always recommend magnafluxing the crankshaft to make sure there are no cracks before machining. Chamfering oil passages is an additional charge of 2.00 per throw. The whole job usually runs around $140.00 including tanking, magnafluxing, grinding, and chamfering. Please note, I am not selling my services -- just giving you an idea of what we charge.

In terms of new replacement shafts, they are widely available for large journal 350 engines, but I don't see too much for 283's anymore. I think it has to do with supply and demand. If your existing crank is in good shape, I would reuse it. That's not to say you won't find one -- its just not something I see on a regular basis.

Hope this helps -

Pat

[Norbert R.]

Re: 60' 290Hp crankshaft?

Thank you very much, it'll have to be checked out. I'd rather use the orig. and at that cost I will! I live in south In. I need to find some place I can depend on for the work? Any Ideas? I take it, you do This work? Email me info. ohevan@aol.com
Thanks

[Joe L.]

Re: 60' 290Hp crankshaft?

Norbert-----

The crankshafts used for most 1955-61 Corvette applications generally carried forging number 3735236. So, the basic forging and material were the same. However, there were several different part numbers machined from this forging and, usually, these cannot be distinguished by any known markings that I am aware of on the crankshafts, themselves.

The crankshaft used for 1957-61 Corvette applications with mechanical lifters and FI was GM PART #3772064. This crankshaft PART NUMBER was uniquely applicable to these Corvette applications but, as I say, it carried the 3735236 forging number like the others. I am pretty sure that the difference related to balance due to the slightly heavier pistons used for the mechanical lifter, FI applications.

The value of this balance difference would be negated if you have the reciprocating components of the engine (crank shaft, con rods, pistons, flywheel, balancer) custom balanced. I would never rebuild an engine without custom balancing of the reciprocating components. Also, since it is unlikely that one would use the original pistons or, even, exact replacements for the originals, the value of the original balance of the special FI crankshaft would be "0", anyway.

In any event, I would, at least, try to stay with a crankshaft of the original 3735236 forging number. However, I think that any of the following forgings could also be used with a custom balance of the reciprocating assembly:

3815822
3836266

As Pat mentioned, crankshafts for 283 cid engines are getting to be a "vanishing breed". Most of these have been made into foreign cars by now. If your present crankshaft can be kept at standard or 0.010" under, I would definitely use it (assuming that it also "mags out" ok).

In order to purchase a new forged crankshaft (the material originally used for all Corvette 283s), you would likely have to order a custom-manufactured aftermarket from a crank source like Crower, Callies, or others. Here you'd be talking BIG $$$$$$$$. I don't think that any manufacturer offers an off-the-shelf, forged crankshaft for a 283 anymore.

[Pat Bush]

Re: 60' 290Hp crankshaft?

Joe ---

I know how you feel about grinding beyond .010.... But gosh darn -- to save an original that is only driven occasionally? I've done so many motors .020 and .030 on rods and mains with no repercussions even after 10 years on Cudas, Stangs, Vettes, Chevelles, and Camaros -- is it just me? There are some things I won't do -- like sleeve more than one cylinder on a side to a max of two (on opposing sides), but for the "normal" restoration, I gotta wonder....

Please don't take it as an assault -- it's just I have this penchant to save these motors and their original parts if I can. I respect your opinion greatly.

Regards -

Pat

[Joe L.]

Re: 60' 290Hp crankshaft?

Pat-----

I fully realize that grinding cranks to .030" US is widely done and in the vast majority of cases, it presents no problems, whatsoever. My reasons for, personally, disfavoring U.S. cranks are these:

1) On some cranks, the journals are "Parkerized" or "Tuft-Trided". This process surface hardens the finished journal and resists wear. Grinding the crank removes or thins this area. The crank can be "re-Parkerized", but it's not often done with most cranks after re-grinding. I don't think that most shops are really set-up to do it. The necessity of the Parkerizing for most cranks may be questionable, but removing it degrades the piece to one extent or another. I don't like using components which have been degraded to any signifcant degree. In the case of 283 cranks, none were Parkerized so this is not really an issue in this case;

2) When a journal on a crankshaft is ground undersize, the crankshaft IS weakened. The more undersize that it's ground, the greater the weakening. For example, in the case of a 2.00" crank journal, when it is ground 0.010", the crank is weakened by 1%. When it's ground .020" US, it's weakened by 2% and when it's ground .030" US, it's weakened by 3%. None of these represent much of a loss of strength, but, as I say, the part is degraded somewhat and I don't like to use degraded parts. It's just my own little "foible".

For a crank like a 283 (or, even a 327), going with an U.S. crank may be necessary in many cases. If the journals are not "up to snuff", the crank will have to be ground. Finding a good standard crank might be difficult and finding a NEW standard crank will be near-impossible unless one goes the custom-ground route. That's totally impractical and unnecessary for a street car.

[Clem Z.]

Re: 60' 290Hp crankshaft?

joe keeping the radius in the corners is the key to reground crank life. i have used 350 chevy cranks offset ground from 2.100" to 2.000" to stroke them to 3.562 from 3.480 and never had a failure.

[Clem Z.]

confessions of cheating engine builder

on some of those 3.562 stroke engine we would only bore 7 cylinders .030 over and leave one at 4.000. the track rule was max 358 cubic inches and they checked with a P&G checker. with a 3.562 stoke and a 4.000 bore the engine would measure 358 cubic inches and if the bore in that cylinder was 4.030 the engine would have checked at 363 cubic inches. the longer stroke added torque to the engine. we always made sure they check the "correct" cylinder. i know i is "BAD"

[Mike M.]

Re: confessions of cheating engine builder

clem: i never could get the tech guys to p&g the cylinder of my choice. how'd you convince them to do the one in eight that wasn't thirty over? mike

[Clem Z.]

Re: confessions of cheating engine builder

i always made sure it was the easiest cyl to get to and volunteer to do the dirty work on the hot engine. they only checked the engine once and put a seal on it and as long as the seal was there they never checked it again. never got caught,lucky i guess

[Tom D.]