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Fully counter balanced L24 cranks


RACERZ

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Already may have been covered but does anyone know if there is a fully counter balance crank available for the L24s I have seen some for the L28s but we cannot run them and was wondering if any of the U.S. mfgs of cranks makes one? If so who would I need to contact?

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Alex, the cranks are counterbalanced, but only partially...plenty good enough for 95% of usages I can think of. Only the first 3K or so (I think, It's been a bit since I looked that number up) L24 cranks were different, with fewer counterbalance weights on them...the rest of them had more, but are still just shy of "fully Counterbalanced".

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Thanks I will check with them. We have a problem with a harmonic at 8200-8300 if you hold it in that range for more than a coulple of seconds bad things happen so we were looking for one that will hold together. the way we are carbed/geared the sweet spot is about 8500 so we are trying to get an option, to deal with it.

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Bad Things Happen? Elaborate?

We run the L28 crank for minutes at a time at that range. The shorter cranks should easily handle that and higher. What damper are you using?

Our L20A is just starting to pull at 6K, and pulls to 9500 shift points, and will accommodate much higher rpms if we get the right head/cam to flow up higher.

 

I could say gear lower to pass through it quicker, or higher to not reach it, but that is a range that should not be an issue. What problems are you having?

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We run E production in SCCA and have to run stock SUs and the problem is they run out of air about then and we cannot bore them out and if you hold a "stock" L24 crank at those RPMs a harmonic sets up and the crank shatters (BIG BOOM) most racing motors pull to 9-10k and pass through that "sweet spot" quickly so no problems, I am told it is a feature of the crank that is why you see a lot of the racing L28 cranks made fully counter balanced since most racers run the L28s (again not legal for our 240). As a side note you dont want to knife edge them either tends to amplify the problem. The stock carbs are good to about 85-8600 then run out and on a long stright you would hit that sweet spot. I was told this by the previous owner and the motor builder DO NOT RUN ABOVE 8200 period or expect to buy a new motor. They tried it in the car and on the dyno and just wont work. That is why I am looking for a crank builder to see if we can get a fully countered crank at a resonable price(less than a grand) made to test if it would work.

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Your price point is fantasy. Don't bother asking the guys I mentioned, for what you quote Velasco's might do a nice race prep but you aren't finding a billet crank under $3500 is my best guess.

 

Volkswagen T1 Billet Strokers were 749 about 20 years ago. Forged counterweighted Berg Cranks were 2500 then...

Edited by Tony D
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Marine Crankshaft Inc as well... We had a customer who ordered 3 TR3 (4 cylinder) cranks in a group buy and even with that price break they were about $2600. Normal price was like Tony said. Though, if you go with a billet crank, you could go for a different journal size so that you can get some nice cheap rods. The TR3 guy I mentioned had them do a journal size that fits Chevy rods. Set of 8 rods for like... I don't know what they're at, $500-$600?. That was enough for two of his motors. :)

Edited by josh817
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If you can run an aftermarket crank that's the correct stroke, can you run aftermarket rods as well? Just thinking out loud here, but couldn't you offset grind a L28 crank with more counterweight back to an L24 stroke? You'd have some fairly small journals but people seem to offset grind the other direction that INCREASES stress and manage to live to a moderate degree of success.

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No joy you can run aftermarket but must be stock dimentions bore stroke and journal size. I was hopeing someone would have already had an existing setup instead of 1 off customs (that is where the big cost comes in) You can buy V8 billit cranks all day for under a grand in all kinds of dimensions but there is a big demand. That is what stinks the rods are relatively inexpensive for the L6 rods in billit but no luck on cranks. We run the corrilo now in our car.

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"You can buy V8 billit cranks all day for under a grand in all kinds of dimensions but there is a big demand. "

 

Welcome to "Import Performance Charges" in the world of GM, Ford, and Dodge...

 

Millions compared to thousands does that to pricing.

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We run a stock crank dapner with no problems but if we rebuilt the motor we were looking at BHJ Dynamics they look like they offer several verities (looks like Robello uses their dampners). We were looking at building a "super" EP motor all billit driveline all ARP bolts lighten block ect. Looks like the bottom end would run about 10 grand for parts plus sundries to build plus cost to freshen the head. To freshen our motor as is will run about 4 grand. Not that I have 4 grand laying aroud to spend.

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