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A couple cast crankshaft questions
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Author:  daniel_depetro [ Mon Jan 09, 2012 4:21 pm ]
Post subject:  A couple cast crankshaft questions

I have a hydraulic slant six I pulled from a 1983 4-speed Dodge truck.

Does this truck have the roughly 60.5 lbs. crankshaft?

Were ALL the cast crankshafts roughly 60.5 lbs.?

Would this truck engine have a shot peened crankshaft, or were only the earlier forged truck crankshafts shot peened?

Author:  raPoM [ Mon Jan 09, 2012 5:39 pm ]
Post subject: 

Sorry I am no help with your question,but I have been wondering the same thing for a few days. Were the later truck engines built with stronger parts like the early ones?

My 87 engine revs up quicker than the forged crank engines,and feels smoother at higher RPMs too. The factory camshaft is pathetic though.Power feels like its all done at 3000-3500.

Author:  Supercharged SL6 [ Mon Jan 09, 2012 6:21 pm ]
Post subject: 

The truck crank shaft should be a heaver unit than what was used in a car not sure on exact weight but I think mine is around 65 LB check out my pics under KB K1 cast crank build see if it looks like that or looks like Docs 55 LB crank, light weight engine build.

Author:  Dart270 [ Mon Jan 09, 2012 8:19 pm ]
Post subject: 

I believe cars and trucks in the mid-late 80s got the same 60 lb crank. No idea about shot peening...

Lou

Author:  daniel_depetro [ Tue Jan 10, 2012 6:47 am ]
Post subject: 

Quote:
I believe cars and trucks in the mid-late 80s got the same 60 lb crank.

Lou
This is what I was hoping to hear, thanks Lou (and everyone else) for the help.

Author:  Doc [ Tue Jan 10, 2012 8:48 am ]
Post subject: 

1977 to 1984 has a heavy cast crank that weighs about the same as the forged steel unit. (75 - 76 lbs)
My notes say that the change-over year for the lighter cast crank was 1984.
DD

Author:  daniel_depetro [ Tue Jan 10, 2012 12:38 pm ]
Post subject: 

Thanks for weighing in Doc, even if it does crush my dreams... :lol:

Author:  Doc [ Tue Jan 10, 2012 1:30 pm ]
Post subject: 

Sorry for the so-called "facts" but to be honest... I often see "funny things" and stuff that does not go along with what Mopar history says.
In the end... you have to look at the actual part(s) to see what you really have.
DD

Author:  daniel_depetro [ Tue Jan 10, 2012 3:49 pm ]
Post subject: 

The facts are what I was in search of - Good, bad, or otherwise.


My next question is this: Is there any physical difference between the heavy cast crankshafts and the lightweight cast crankshafts that I can spot by removing the oil pan? (or is the only weigh to know to actually weigh the crankshaft)

Author:  Doc [ Tue Jan 10, 2012 4:04 pm ]
Post subject: 

I look for for the small center counter weight... and weight reduced counter weighting at the other locations. (cast-in depressions, to remove material)
The crank on the right is what you are looking for.
Those cranks look pretty "spindely" when you see one.
DD

Image

Author:  daniel_depetro [ Tue Jan 10, 2012 8:41 pm ]
Post subject: 

I have seen that photo before, but I thought the crank on the right was your super lightweight piece (~53 lbs.?) you had for the aluminum block engine (I believe it was?).

Once again, thanks for the info.

Author:  Doctor Dodge [ Tue Jan 10, 2012 9:23 pm ]
Post subject: 

That crank started as the 60 lb., 84 & up cast crank...
It ended-up at 53 lbs, after I removed more weight and had it rebalanced.
DD

Author:  hantayo13 [ Wed Jan 11, 2012 3:33 pm ]
Post subject: 

so my 85 should have the lighter crank...notice I said should...lol

Author:  Supercharged SL6 [ Fri Jan 13, 2012 5:10 pm ]
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The cast crank I am using is out of a 85 pickup and is the heaver unit, original 81 car crank was light unit, I believe cars had light cranks trucks have heavy cranks. Check front balancer if its a one piece with 3 pulley groves cut in it, its a heavy crank,if its a 2 grove with a separate steel pulley its a light crank maybe.

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