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Molnar 360 rods |
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Ken_Parkman
AMC Addicted Joined: Jun/04/2009 Location: Ontario Status: Offline Points: 1814 |
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It's still the better plan to sell the rods, then buy rods more optimized for a stroker. Use the Molnar 6" long 2" journal AMC rod.
Rod ratio makes very little difference, but it is a good guideline to use a rod a minimum of 2" longer than the stroke. This guideline can be broken, but you better know what you are doing. The crank counterweights may require cam machining to clear the pistons, and that is getting to be pretty radical. Going with the more optimum stroker rod gets you much better bearing availability, easier machining, and a better piston. Not all crank grinders will widen the cheeks for .940" width, but some will. The conventional "Detroit" crank will give you a 3.85" stroke widened for the .940" journal, the rods bolt in with the correct offset, and the CH works for 1.265-1.270 and a very nice package. One other thing to mention is a good grinder will index the throws a bit for better material thickness from the rod corner rad to the oil drilling. Not paying attention to this has ruined a few cranks. Make sure your grinder knows what he is doing. Edit - scratch all of the above. I see you are trying to use existing pistons. You are probably going to have to back off the stroke and make everything fit. Or sell the pistons and go with something more optimum. In the long run it will probably be cheaper unless you are doing the machine work yourself. Edited by Ken_Parkman - Dec/02/2016 at 2:05pm |
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SKeown
AMC Addicted Joined: Jul/30/2009 Location: Texas Status: Offline Points: 3085 |
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Actually with a 3.900 stroke, 6" rods and .927 wristpin the counterweight is 1/16" further from the wristpin than a stock 401. SKeown
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tsanchez
AMC Addicted Joined: Jul/09/2007 Location: Arizona Status: Offline Points: 4303 |
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Steve, you didnt have my pistons lol center of pin to bottom of piston pin pad was far, my wisecos were way smaller and would have cleared by a ton
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SKeown
AMC Addicted Joined: Jul/30/2009 Location: Texas Status: Offline Points: 3085 |
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I realize the design of a piston can pose clearance problems. I was referring to center line of crank journal to bottom of the wristpin. Another thing, the counterweight sweep can differ from crank to crank and front to rear of a given crank. I do recall you got a bum set of pistons along the way. SKeown
Edited by SKeown - Dec/02/2016 at 5:37pm |
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xspiriment
AMC Nut Joined: Apr/27/2009 Location: New Mexico Status: Offline Points: 379 |
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xspiriment
AMC Nut Joined: Apr/27/2009 Location: New Mexico Status: Offline Points: 379 |
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Well I got around to mocking up a stock 401 crank 6" rod and the pistons with the 1.425 c/h. Had about a .250+/- between the crank weight and the pin boss. So as it turns out the 360 Molnar rods will not work for the stroke, sure was hoping though. Guess I'll continue with the 360 build and use the Molnar rods for that. Hey, that's what they were made for anyway. Thanks for every ones input.
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Hawaii-Jav
AMC Apprentice Joined: Apr/03/2017 Location: Pearl City Status: Offline Points: 28 |
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So are you doing a 360 or 401? I have a set of Carillo rods, that are AMC specific 360 rods. They've been sitting for awhile when I was going ot get my 360 build going. They've been magnafluxed as well as shot peened. There sitting in motor oil right now, so no rust can attack them. Would be willing to sell them.
Ron
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