Twin 360's

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   Here are the rebuilt engines. Still have to do some finishing touches.
I have a dyno date May 11th.
On the keyway issue, I drilled a .250 hole 1" deep between the crank snout and the balancer's bore and tapped in an oversize pin.

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
pipefactory Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Jul/27/2012 Location: Superior, Wi Status: Offline Points: 405	Post Options Post Reply Quote pipefactory Report Post Thanks(0) Quote Reply Posted: Apr/21/2017 at 8:24pm
	Here are the rebuilt engines. Still have to do some finishing touches. I have a dyno date May 11th. On the keyway issue, I drilled a .250 hole 1" deep between the crank snout and the balancer's bore and tapped in an oversize pin.
	Face distorting torque 10.99@121 mph

Boris Badanov Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209	Post Options Post Reply Quote Boris Badanov Report Post Thanks(0) Quote Reply Posted: Apr/21/2017 at 8:42pm
	Run "harmonic crank failure" on Google images and you will see that it is a common failure to this day. Crank mass and strength can work against you at times.
	Gremlin Dreams

304-dude Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082	Post Options Post Reply Quote 304-dude Report Post Thanks(0) Quote Reply Posted: Apr/21/2017 at 8:42pm
	Donno if you can add another, but rounded keyway like that leaves less bite than squared off keyways. And go 2 inches, to go further down the snout to offset the stress at the snouts end. Yep, I over engineer just because it's how I think.
	71 Javelin SST body 390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker

shootist Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: May/24/2012 Location: Triad, NC Status: Offline Points: 1023	Post Options Post Reply Quote shootist Report Post Thanks(0) Quote Reply Posted: Apr/21/2017 at 10:55pm
	Oh, I definitely am catching what you are throwing on the harmonics issue. Everything has a resonant frequency (of course that varies on shape, size, density, composition etc.) and that is why you see failures within a certain RPM range. Now when I say resonant frequency I do not mean audible as most think ok it, I simply refer to the transmission of vibration through a medium. Anyway, I agree with what you guys are saying but in this scenario without any testing I would be reluctant to say the torsional strength is there. I just don't know what the upper/lower tolerances of cast AMC steel is. There is also the consideration of different material suppliers, foundries, composition, etc. These very things could really cause the harmonics between the two cranks themselves to resonate into each other and therefore accelerating the harmonic failure that was mentioned. This is really all just bench racing/hypothesis based discussion and I am enjoying every moment of hearing the other concepts disclosed to this point. All B.S. aside this is still the coolest thing I have seen anyone undertake in the AMC world and I wish it the best success. We are just running the doomsday scenarios really as typical of any good engineering mind.


Boris Badanov Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209	Post Options Post Reply Quote Boris Badanov Report Post Thanks(1) Quote Reply Posted: Apr/22/2017 at 5:55am
	"All B.S. aside this is still the coolest thing I have seen anyone undertake in the AMC world " Ditto!
	Gremlin Dreams

304-dude Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082	Post Options Post Reply Quote 304-dude Report Post Thanks(0) Quote Reply Posted: Apr/22/2017 at 6:22am
	Oh yeah, not knocking at all one bit... just we all would love to fit that under our humpster hoods. Mwhahahahahahaha! I bet it could be done with a wee firewall cut here and there and extending the radiator supports out further with a double cross member contraption. Pipe factory... gots a humpster in your stash somewhere? Oh, for you guys about torsional twist and harmonics. The reason I am a wee bent on round key ways, its that roundness could allow a small shift in timing of harmonics, shared by both cranks. That wee shift can amplify the harmonics and cause more shifting until stress at the hub and further increase odd harmonics. Not a lot of shift mind you, but adds to the twist already created by loads. Though we are talking about above 5000 RPM where such stress can really show it's stuff against the type of coupling used. You can prolly get by with round key ways, but every torque intensive shaft coupling I have seen were never cut half circle. Pins can roll and force out under harmonics and stress. I don't call it BS, just being cautious to a critical manner. All input is good as it allows opening up of ideas before failure. Edited by 304-dude - Apr/22/2017 at 6:40am
	71 Javelin SST body 390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker

shootist Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: May/24/2012 Location: Triad, NC Status: Offline Points: 1023	Post Options Post Reply Quote shootist Report Post Thanks(0) Quote Reply Posted: Apr/23/2017 at 4:44pm
	I am just wondering if pipe is going to purposely push it to failure or just push it to reasonable real world limits. But yeah, would be pretty wild in a stretched out car body like the Javelin/Hornet/Gremlin etc. Heck it might fit under the hood of one of the big long nosed cars.


pipefactory Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Jul/27/2012 Location: Superior, Wi Status: Offline Points: 405	Post Options Post Reply Quote pipefactory Report Post Thanks(0) Quote Reply Posted: Apr/23/2017 at 9:13pm
	Been working on what I call my DECCC (dual engine command control center) I'll be using 2 Mallory modules before it hits the dyno. Also one side exhaust is done. I can't wait till this project is done, my shop is looking like a sh t hole. I know, I know, please sand blast and coat the manifolds. Edited by pipefactory - Apr/23/2017 at 9:16pm
	Face distorting torque 10.99@121 mph

Red20 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/29/2013 Location: Oceanside CA Status: Offline Points: 1556	Post Options Post Reply Quote Red20 Report Post Thanks(0) Quote Reply Posted: Apr/23/2017 at 9:18pm
	It sure would be neat to see an FC150 cab with an RV body behind it and this twin 360 drive train.
	1969 Javelin SST "Screamin' Banana" - Totaled Feb 2018 1973 Hornet Sportabout X "yellajack" - 360/727/TracLoc DAILY DRIVER

Boris Badanov Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209	Post Options Post Reply Quote Boris Badanov Report Post Thanks(0) Quote Reply Posted: Apr/23/2017 at 10:05pm
	A Sh t hole is what I refer to as "Critical Mess"
	Gremlin Dreams