stock crank ?s

are the internal balance cranks any better than the external balance cranks for high rpms? at what point should i consider upgrading to a forged crank? this would be in a pulling engine

The factory cast cranks are some really good pieces, and would be able to handle about anything you can throw at them. What block are you going to use?

Define high rpm...

Depends on a bunch of things... but I got a Adney brown prepped oem cast crank in a 472 inch pulling engine and it routinely sees 8600-9000 rpm... haven't had anything bad happen yet... knock on wood...

over 7,000 RPM I'd prefer an internal balance crank, but am sure some have made the external work. Personally I like the internal cranks simply because I prefer not have to deal with balance weights on a flywheel.

You can take the late model crank and internally balance it, the weight isn't in the counter balances as provided, BUT, with high performance parts the counter weight is extremely less than stock anyhow.

I had to cut 3lbs out of my billet crank before I could even start balancing it. Nothing turning the counter balances down a few inches couldn't handle. BUT... it does tell that new high performance bolt on parts might make the stock crank internal balance with very little Mallory at all.

The ONLY differences between an INTERNAL balance OEM crankshaft and an EXTERNAL balance OEM crankshaft is the rear oil "slinger" diameter and the diameter size of the counterweights. SOME have a different diameter torque converter recess as well.

The metallurgy is exactly the same.

schmitty wrote:The factory cast cranks are some really good pieces, and would be able to handle about anything you can throw at them.  What block are you going to use?

I would like to use the block and crank from my '97 F350 if possible.

cool40 wrote:Define high rpm...

7,000-8,000.

If you are going to spin it that high, a 4 bolt main block would be a good idea, and priority main oiling. The crank will not be the weak point.

7000 is one thing,8000 is another.i'd go with a good block and crank.JMO  

8000 wasn't super expensive..... 9000 was a whole new world for us.... but the truck works there... we will continue to go there until we can't afford to... or the class dies out.... internally balanced with light parts up top... fun stuff for sure...

the key subject here is "pulling engine".........pulling=run the hell out of  

I have to use cast iron intake, heads and exhaust. I don't know for sure how high it will be able to rev, I've heard others in the class run in the low 7000's.

cool40 wrote:the key subject here is "pulling engine".........pulling=run the hell out of  

If I read it right ... Cody's 8,600 to 9,000 RPM engine is also a "PULLING" engine.

EDIT: Personally, I have used an OEM, offset ground, cast nodular crank in a 1,200 horsepower drag boat engine for 3 years untill it finally showed some fillet cracks.

mitch wrote:I have to use cast iron intake, heads and exhaust. I don't know for sure how high it will be able to rev, I've heard others in the class run in the low 7000's.

you'll have no problem with stock crank and block with those rules. 

rmcomprandy wrote:

cool40 wrote:the key subject here is "pulling engine".........pulling=run the hell out of  

If I read it right ... Cody's 9,000 RPM engine is also a "PULLING" engine.

yep,i missed that.guess the big truck pic with the wheels knee high cought my eye. 

Our stock truck pulling classes have those kinds of rules... we are running in the low/mid 7000's seems we hit a limit with the stock rocker arms... the push rods were piercing the rocker arms at anything over about 7300 rpm... this was a 466 with solid flat tappet cam cj intake and PI exhaust manifolds.... vacuum secondary carb and a set of dove heads... damn thing still runs good to this day... as for the blue polebilly pickup truck... I never thought it would carry the tires and still be streetable... its pretty slow but still a fun ride on the street... thanks again to rick brown for the pictures again... I never get sick of seeing this picture...

bluef100fe wrote:Our stock truck pulling classes have those kinds of rules... we are running in the low/mid 7000's seems we hit a limit with the stock rocker arms... the push rods were piercing the rocker arms at anything over about 7300 rpm... this was a 466 with solid flat tappet cam cj intake and PI exhaust manifolds.... vacuum secondary carb and a set of dove heads... damn thing still runs good to this day

I will be doing almost exactly the same thing but i would use roller cam and rockers.

mitch wrote:

bluef100fe wrote:Our stock truck pulling classes have those kinds of rules... we are running in the low/mid 7000's seems we hit a limit with the stock rocker arms... the push rods were piercing the rocker arms at anything over about 7300 rpm... this was a 466 with solid flat tappet cam cj intake and PI exhaust manifolds.... vacuum secondary carb and a set of dove heads... damn thing still runs good to this day

I will be doing almost exactly the same thing but i would use roller cam and rockers.

Then the weight of your valves/valvetrain will be your limiting your rpms to 8000.... we were breaking rocker studs at that rpm with the heavy stainless valves.... after that we went to shaft rockers and titanium valves.... our stock class rules mandated non roller rockers and lifters.... good luck with your adventure... pulling is just as addictive as any other Motorsports...

I guess this is a hijack-- but what kind of diam. difference is there in slingers between the two?
Perry

hpwdboss1 wrote:I guess this is a hijack-- but what kind of diam. difference is there in slingers between the two?
Perry

Just about a half inch.

rmcomprandy wrote:...Personally, I have used an OEM, offset ground, cast nodular crank in a 1,200 horsepower drag boat engine for 3 years untill it finally showed some fillet cracks.

Badass.

hpwdboss1 wrote:I guess this is a hijack-- but what kind of diam. difference is there in slingers between the two?
Perry

I just finished executing our Stage 1 Oiling Mods to a D9TE-AB block for a customer, and he also needed the block prepped to accomodate his 2Y Series internal balance crankshaft. And so I went into our inventory and pulled out 3 crankshaft cores for rear slinger comparison: The 2Y series, the 3Y Series, and the commercial 429 steel truck crankshaft. Here's what I observed:











Remember, these are very high volume, mass production parts, so your exact dimensions may vary.

I think that just turning the slinger down to the seal riding diameter is fine, that's how the Scat crankshafts currently are.

Paul