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78mm Stroker Crank Forged or Cast??
Posted: Sat Jan 24, 2004 2:58 pm
by Floyd
Has anyone had any experience with cast Stroker cranks?
I'm building a 2007cc daily driver, I'm searching for 78 crank,
I see cast and forged availble, are cast cranks really risky?
I have no experience in this area.
If any one has used one for sale please let me know.
Thanks.
Posted: Sat Jan 24, 2004 7:18 pm
by turboblue
Scat catalog says 5500 rpm and 130 HP for a cast crank.
Me? I'd use a forged......
Posted: Sun Jan 25, 2004 11:03 am
by JC-ATL
Forged, Floyd, forged.
Where ya been, man?
Posted: Sun Jan 25, 2004 6:14 pm
by gerico
CB sells a "4130 forged" and nitrited 76mm stroker for a bit under $200. Sounds waaaay to good to be true. Anybody ever use one of these???
Posted: Sun Jan 25, 2004 6:30 pm
by Type 5 Joe
I have used the C.B. Cranks....
The 4140 Cranks for $189.95 are not nitrided.
Actually its an extra expense option on the 4340 Crank..... $50.00 extra.
Their site is sometimes inconsistant with the info.
- Joe
Posted: Sun Jan 25, 2004 7:04 pm
by Floyd
Hey John,
I've been here and there.
I have a set of 90.5 long stroke pistons. Guess i can't use em with the 76 stroke?
Posted: Sun Jan 25, 2004 7:10 pm
by Glenn
The only thing cast cranks are good for is a door stop.
It's cheaper to buy a forged crank to begin with than to buy one after replacing everything that went when a cast crank breaks.
And it will.
read tag line below
Posted: Sun Jan 25, 2004 8:16 pm
by gerico
Joe, you said you have used the CB cranks. Were you happy with them?? Is nitriding worth the extra $50?? $190 to $240 for a decent forged 76mm crank sounds like a great deal. Emphasis here is on "decent". Hate to be cheap but budget constraints won't allow a $400+ crank and I would rather go with a high quality forged German 69mm crank than a poor quality stroker.
Glen, I agree. Somebody said you can tell the difference between a cast and forged crank by tapping them with a hammer and listening to the sound. The forged crank rings, the cast crank breaks.
Posted: Sun Jan 25, 2004 9:20 pm
by Type 5 Joe
They are a good value....
You can only get the Nitride option on the 4340 Cranks.
I just ordered another 76mm last Friday for a customer.I wouldn't be buying any if I have had problems.
The only thing the Nitride Treatment does is increase the wear-resistance slightly... If your on a budget, go with a full-flow oil system, ect..
Proper Machine work / Assembly / Engine Combo / Maintenence... Will be the best investment in any case.
Run a German Dog-House Cooling system with the flaps / Thermostat
Be realistic about your application... Most street / Off-Road motors like small ports and small duration cams.
Good Luck, - Joe
Posted: Sun Jan 25, 2004 10:26 pm
by gerico
Joe,
Thanks for the feedback on the crank, they sound like a REALLY good buy.
If I go with one of the CB 76mm cranks I'll use 90.5 P&C, CB cromoly rods, 40x35 heads, and either an Engle 110 or possibly a Web 218 cam, maybe about 7.5 compression, and a 1 1/2" merged header. Get Rimco to balance everything. It's going to be a daily driver...my primary transportation so it has to be reliable and have decent throttle response in trafffic. I have a doghouse system, the parts for an external filter, a 1 1/2 qt sump, and a couple of AJs kads w/ aluminum manifolds. Probably use a 5800 rpm rev limiter.
Sound OK?
Posted: Sun Jan 25, 2004 10:34 pm
by Type 5 Joe
Sounds Good!
I would run 8.5 to 1 compression....
set up your rocker-arm geometry, use cut-to-length pushrods, ect...
use some Curil K-2 on the case halves.
Sounds like a good plan!
- Joe
Posted: Mon Jan 26, 2004 6:25 am
by JC-ATL
Floyd, if you use those long-stroke pistons with a 76mm crank, you'll have a bitch of a time getting enough compression.
Go buy a forged crank, too.
Posted: Mon Jan 26, 2004 11:52 am
by RoWaMe
A few years ago I bought a new 78mm cast crank for relatively cheap at a local swap meet. The engine for it is nearly finished- also a 2-liter (78x90.5), stock-valve heads (home-ported), engle 110 cam, 7.9:1, and 1 3/8" headers. Topped with used German tin/thermostat/flaps and 36 Dell's- it'll be for a highway cruiser engine with no drag-starts nor high revs. If I can only get the too-tight endplay finally set...
Posted: Mon Jan 26, 2004 12:35 pm
by gerico
T5 Joe and JC-ATL,
Any idea how a 2L will work with mild cam, 35x32 valves, and 1 3/8" headers??? Sounds like a reasonable low dollar hyway build but I thought a setup lile this would run hot.
Posted: Mon Jan 26, 2004 12:53 pm
by JC-ATL
Just by that info, it wouldn't necessarily run hot, if it was built right. It would be more of a torque machine than a horsepower maker.
Personally, I don't see a need to go that big if you're not gonna give it something to work with.