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#1
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Billet cranks vs Scat or Molnar forged
I’ve got a few deals going for an aluminum block for my 535 deal. I have a set of 380 HPs already ordered. Do ALL you guys run billet cranks or do any of you use a forged crank? I’m looking for opinions as I’m spending a butt load of money. Wondering about rods as well. Thanks
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1965 TriPower GTO, 1967 GTO, 1969 GTO, 1969 Judge, 1972 GTO, 1977 Smokey and the Bandit, 1989 TA ProStreet, 1968 Firebird NHRA 10.90 racecar, 1963 Tempest S/Gas |
#2
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Depends on rpm, hp and rods (steel or aluminum) what crank you need.
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#3
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I would guess I’ll make 850-875 ? I would think never over 7500 rpm. Running mostly in Super Street. At 2820 Ibs I’m looking for 10.90 at 150. My old 505 would go 148. My BBC 565 would go 158. Right now my 467 runs 138-139. I like being the chase car.
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1965 TriPower GTO, 1967 GTO, 1969 GTO, 1969 Judge, 1972 GTO, 1977 Smokey and the Bandit, 1989 TA ProStreet, 1968 Firebird NHRA 10.90 racecar, 1963 Tempest S/Gas |
#4
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Forged is stronger than billet using the same base material. Grain pattern matters.
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#5
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I am planning close to your RPM and horsepower range. Going with Scat forged crank and Molnar Power Adder billet H beams.
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#6
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Molnar makes great products.
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#7
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But no forged crank comes fully counter weighted.
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#8
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I talked with Tom Molnar at length trying to talk him into look into making us a fully counter weighted forged crank.
Hundreds of thousands of dollars and you have to sit on them for years. Not happening. Talked with his #2 guy yesterday. He has been with him 25+ years going back to Oliver. I wanted to know more about their Power Adder rods and why they still had only a ARP2000 bolt vs the even higher psi bolts in use now. Said they did not need them and those bolts have their own issues too. He is on the engine building side of things.Built everything you can imagine. They have been getting engines back to dissect problems/failures ect. They have some 2000 HP NO2 engines that had oil system issues and seized up. Crank and rods are junk but they have not broken any Power Adder rods yet. The block was still good. |
#9
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Can’t compare......billet is way bettter but at your HP level Chinese will work if you get a good one! I just hate Chinese crap! JMO!
GTO George |
#10
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If you have the bucks for a Billet Crank then go for it since you can get made with the block life extending and Crank life extending, needed for true proper balance , 8 counter weights !!!!!
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#11
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I'm running a Molnar 4.375 crank and rods in my street car. Only 780hp, but fit the bill for what I was looking for. Machining was dead on right out of the box.
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65 Lemans Street Car - 521, T400, 3.70 9". 10.13 @ 135. 3770 lbs. Drag Week ‘14, ‘15, ‘17 63 Lemans Race Car- 8.81 @ 151, 5.60 @ 123(SOLD) 67 Bonneville ragtop 74 Firebird - 455, e heads, TK0600 in process |
#12
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Forged will be fine
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#13
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What’s the overall opinion on the Molnar products?
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1965 TriPower GTO, 1967 GTO, 1969 GTO, 1969 Judge, 1972 GTO, 1977 Smokey and the Bandit, 1989 TA ProStreet, 1968 Firebird NHRA 10.90 racecar, 1963 Tempest S/Gas |
#14
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I run a forged crank in my engine. I do have a crank support and double keys, because of the supercharger. 8,000 RPM.
Jim
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****'63 Tempest, 475" IAII, Wenzler Super Chief heads, converted to blown alcohol, Birdcatcher, Littlefield 10-71 high helix. Best pass to date: 7.67 @ 181.59 (1/4 mi.), 4.95 @ 143.67 (1/8 mi.), 1.18 (60 ft) 7.75 @ 178 pass: https://www.youtube.com/watch?v=Iez3...ature=youtu.be First seven second pass(7.98): https://wwwoutube.com/watch?v=DK17...ature=youtu.be Thanks to Paul Carter @ Koerner Racing Engines |
#15
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Jimmy, I spoke with the man at PRI in 2015. He has his "own" foundry in China which he holds to very high standards. That's so he can be sure of few rejects and issues before being machined here in US. He insists and gets high quality material. He explained his whole product line and all the QC process involved.
I plan on using his stuff for my build. I wish he offered a 4" stroke but will use a 4.25 from him and maybe destroke to somewhere between or maybe just go as is. ( I don't want to have to grind into a reinforcement rib in my 59 block any more than I might have to) . Yeah it's good stuff and even his wife knows a good amount about their products. A properly made forged crank can be stronger than billet. (Crower says the same thing)They both can start life from same material. Yes a fully counterweighted billet is better than a forged crank that isn't. But if forged had full counterweights it could be stronger. Grain structure from the forging process would be better. Good stuff. |
#16
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Quote:
What do the big nitro teams run forged or billet?? |
#17
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Ask anyone making lots of HP and is racing if they given both what would they choose they would go Billet over Chinese......there is a reason, just saying!!
GTO George |
#18
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Tom told me there are Street Outlaw guys running his cranks and rods @ 2000+ NO2 power and the rod bearings have come back looking almost perfect. Sure, bet they have the fully counter weighted forgings but plenty of knowledgeable people have told me I am fine at my HP goals of 900 and 7500 RPM with Scat forged and good billet steel rods.
They way I understand it is the Nitro guys don't want a real stiff forged crank. Plenty of movement happens with blocks, cranks and rods at 8000+ HP. Everything has to live through what is basically violent semi controlled explosions. Its another very expensive world. |
#19
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Quote:
Tom who the guy at Molnar......... IMO anyone running a Chinese crank at 2,000HP deserves what he gets. GTO George |
#20
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George, Tom Molnar is the real deal. You will not find a more knowledgeable or experienced connecting rod engineer/designer anywhere. Call him up and speak to the man. He is not trying to simply sell you his stuff, he will teach you all you want to know about rods and cranks. One of the best conversations I have ever had. Oliver/K1/Wiesco.
I am not going to run my USA made Crower steel billet rods in favor of his Power Adder offshore forged, machined here H beams. It will cost me almost as much to rebuild my Crowers with 220,000 bolts and they are good to 7500 RPM. I have to buy the 700$ 280,psi bolts for them to be good past 7500. And that is from Crower. To them, its all about the bolts. But those bolts, you can not even touch them with your bare hands or the oils could pit them and you have a problem. I will run the Crowers as is with their H11 bolts on a street engine. I can spend the 650$ on the Molnar Power Adders and still have my Crowers. BTW, my actual Scat crank is out of a batch that T Vaught had the steel tested. Its clean. |
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