crankshaft worries

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   Well i received my crankshaft back from the machine shop i sent it to. He did everything that i wanted done. I had a 401 crank destroked to 3.566 and 2.100 journals. I have never built an engine with a detroked crank. I didn't consider how much the oil holes would move and thats what worries me. Someone that has gone through this before what are my options do i need some kind of correction. My only thought is to put a little more chamfer towards the journal center if needed. Look at my pics and tell me your thoughts, am i OK the way it is or extra work needed. Thanks

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xspiriment Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Apr/27/2009 Location: New Mexico Status: Online Points: 379	Post Options Post Reply Quote xspiriment Report Post Thanks(0) Quote Reply Topic: crankshaft worries Posted: Dec/04/2021 at 3:46pm
	Well i received my crankshaft back from the machine shop i sent it to. He did everything that i wanted done. I had a 401 crank destroked to 3.566 and 2.100 journals. I have never built an engine with a detroked crank. I didn't consider how much the oil holes would move and thats what worries me. Someone that has gone through this before what are my options do i need some kind of correction. My only thought is to put a little more chamfer towards the journal center if needed. Look at my pics and tell me your thoughts, am i OK the way it is or extra work needed. Thanks

PROSTOCKTOM Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jun/20/2010 Location: Indiana Status: Offline Points: 2450	Post Options Post Reply Quote PROSTOCKTOM Report Post Thanks(0) Quote Reply Posted: Dec/04/2021 at 3:57pm
	I see nothing wrong with it, but wonder why you would destroke a 401 crank? Tom
	Molnar Technologies Full Service Dealer - Crankshafts & Connecting Rods 1969 AMC Rambler Rouge Race Car 1974 AMC Hornet Hatchback, Wally Booth Outlaw Nostalgic Pro Stock Race Car Project

SC397 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Apr/30/2009 Location: Michigan Status: Offline Points: 5475	Post Options Post Reply Quote SC397 Report Post Thanks(0) Quote Reply Posted: Dec/04/2021 at 4:42pm
	Those don't look bad. If you are worried about the mains, you could have channels like these put in. 100_2328 by Rick Jones, on Flickr

xspiriment Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Apr/27/2009 Location: New Mexico Status: Online Points: 379	Post Options Post Reply Quote xspiriment Report Post Thanks(0) Quote Reply Posted: Dec/04/2021 at 6:12pm
	Hi P/S Tom, This is what i ordered the 6" rods for from you a few months ago. It all started many years (20) ago and i was thinking about rod length ratios and bore to stroke ratios. It all looked good on paper so i am now moving forward with this plan. i could never seem to get my hands on a 401 block so this is going in a 360 bored at 4.125. 401's blocks are to hard to fine here in new mexico. This crank had a big gouge in#2 journal so it seemed to be a good choice to destroke this one. I get 381ci out of this combination. Have a custom bullet solid cam. 291C heads and a new torker bought in the early 80's. Planting this in a 79Spirit AMX. It's enough engine for me. Paul

DragRacingSpirit Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: May/27/2009 Location: Mo Status: Offline Points: 903	Post Options Post Reply Quote DragRacingSpirit Report Post Thanks(0) Quote Reply Posted: Dec/04/2021 at 8:32pm
	I don't see anything wrong. I think it looks fine. No different than my 3.9 stroke 401 cranks...and I have never had a rod journal bearing issue. I am running them at 750 horse and 7600 rpm and a 2" journal. I assume that a de-stroke is stronger than a stroke because there is more journal overlap.......especially with a 2.1" rod journal size. That should be one strong crank....although personally I would never de-stroke a crank. IMO you should have shot for a 3.8 stroke with a 2.100 journal size. Proven a good combo over and over again in high hp applications using a stock crank! All of that rod ratio stuff is a bunch of crap. The correct rod length is the one that the pistons clears the counter weights and gives you room on the pistons for a reasonable ring package. Edited by DragRacingSpirit - Dec/04/2021 at 8:55pm
	Best 1/4 mile 8.99, 1/8 mile 5.71, 60 foot 1.27, no power adders

xspiriment Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Apr/27/2009 Location: New Mexico Status: Online Points: 379	Post Options Post Reply Quote xspiriment Report Post Thanks(0) Quote Reply Posted: Dec/05/2021 at 12:10pm
	Thanks for your encouraging words that its ok. This has been a very slow build so the ratio is something i read a lot about long ago. Any way i now have a forged bottom end stuck in a 360 block, oh well it should work fine. I have one flat flange 401 crank left in my stash of parts. Probably won't ever use it. Thanks all