Forged/Cast....internal/External????

[65coronet440]

How can you tell if you have a cast or forged crank... or a internal or enternally ballanced engine.. i have a 65 coronet with a 440 RB. i am trying to find a suitable SFI Fluid dampner for the engine .. any suggestions would be greatly appreciated.

 

[Red63440]

What is the year of the engine?

 

[1badgtx]

The only true way to see what you got for a crank is to pull the pan...Forged are internal balanced...Cast are external...I have a 68 block in my car....So I just figured that it had a cast crank...Not the case here though....I was installing a miloden oil pan on my car...Popped off the stock one and to my surprise it had a cast crank!!!Yet the crank was internal balanced,,,I could see were it had been machined..I guess back in the day they would use the internal balanced cast cranks for drag racing...They are lighter than forged and spool up faster...Hope this helps..
Petty Blue 67 gtx

 

[SirSixPack]

Thickness of parting line. Thin "sharp" line is on cast cranks. Thick "beefy" line on forged cranks.

 

[65coronet440]

So the only real, definite way to find out is by dropping the pan..that sucks...lol..would a cast of forged. Balancer not work. Ton the opposit e..or can u tell by the old balancer. My old one has so me drill holes in it...would that be a sign of a externally balanced engine..i can post some pics if needed

 

[65coronet440]

The engine year is unknown...im thinking a 68 though

 

[67 coronet]

no way to be sure by looking at the outside.sounds like some one did some machine work,so thay could have ballanced either crank.you could have either crank in any block,no matter what year.some machine shops have switched cranks on freinds of mine before.sorry,only way to be sure is too look at it.

 

[Meep-Meep]

The counterweights on the crank are to offset the rod and piston weights and if the crank doesn't have enough mass (one difference being the density of the material - cast being lighter than forged) then the cheapest way to solve the issue is by adding weight to the flywheel / flex plate and the damper. This assumes an unaltered factory assembly. Now to throw a wrench in the works, someone can have a cast crank assembly balanced with "heavy metal" added to allow the use of a zero balance flywheel and damper combo, and if you were unaware of that situation and added the "correct for the year" flywheel and damper, you will have an out of balance engine. Best is to see what you have now assuming your engine is running without vibration and duplicate it from there. For example if you have a damper that is completely uniform in density then configure the fluidamper to be the same. Any offset weight at some distance from the axis of rotation is considered external balance and can be duplicated on the fluidamper if you give it and your existing damper to the balance shop to use as a set up guide. What they would have to do is add the same amount of weight at the same radius and phase angle relative to the key. Or add more or less weight depending on radius but maintain the same phase angle. You can either add the mass or remove the equal amount at 180 deg. Same result.

 

[Norwoodville Speed Shop]

Does the engine have a stock balancer on it now. If it does, then take a look at it and see if it has a counterweight on the front of the balancer. If it does, then it more than likely is externally balanced. If not, then likely internally balanced. The Six Pac engines in 69-70 were externally balanced. All others were internally balanced until 1973 (I think that is accurate) That is the case with 440's. You can get an SFI balancer for either.