Flexplate Question

[gonecrazyi]

As many of you know, I just put a another motor in my 89. Well, before my other motor quit I was looking at an 86 f350 cc 4x4 that had a cummins swapped into it.

Well that trucks back up forsale again for 2000 and Im kinda leaning towards buying it. The conversion was all made from scratch and looks pretty descent, only problem that the guy keeps having is that the motor keeps breaking the flexplate of the c6 tranny.

I talked to the owner of the truck and he says that he made the tranny adapter in the machine shop that he used to work at. The only thing I can figure is that the adapter is not right and that its putting odd amounts of stress on the flexplate.

Heres a link to the truck, tell me what yall think.

http://lakeland.craigslist.org/cto/1302319560.html

 

[Mat J]

makes me want to buy it but I cat have 3. depending on the motor shouldnt be a big deal to either throw in a dodge trans or buy an adapter and a different ford trans.

 

[icanfixall]

Sounds to me like the adapter is drilled off center... That will be very difficult to measure or even fix. The price is right but the problem is kinda big...

 

[icanfixall]

Thats a great looking truck but... The flexplate from the C6 will handle the torque easily.... So buy it and install a proper adapter hoping it doesn't throw off all the mounting demensions...

 

[gonecrazyi]

I can get the money, if anything I could put my 5sp out of my truck or just buy the adapter for 700 to solve the problem.

 

[Ironman03R]

I wonder what trans it has, gas or diesel. If they converted a gas truck maybe the flexplate is just too weak. Adaptors are avalibe for the conversion now but they are expencive.

 

[gonecrazyi]

I think he said that the truck originally had a 351 in it, so im assuming that he used the gasser trans.

That may be a problem if i want to run a ford diesel tranny.

 

[71cc]

Sounds to me like the adapter is drilled off center... That will be very difficult to measure or even fix. The price is right but the problem is kinda big...

If this were the case it should be trashing front pumps as well. I wonder where the cracking occurs..I have read that using fully threaded converter bolts instead of shouldered ones will crack the flexplate where it attaches to the converter.The other scenerio is cracking at the crankshaft area. The e4od flexplate uses a clamp washer to prevent stress at the bolt holes. FWIW the later e4od went to a 6 lug convertor after 95 or so. I personally would not have the C6 behind the cummins. That is a lot of trouble to go threw and be limited in gearing and efficiency.

If you decide to purchase, upon dissambly I would inspect convertor pilot very well. If it is loose in the adapter it Will stress everything else. I machined an adapter plate and hub for a gm trans behind a 460 ford. As long as everything is dialed in concentric and the endplay into the transmission is correct it should work.

 

[Sycostang67]

Thats a good looking truck, I would get it and throw in a 5spd.

 

[icanfixall]

Darrin Tosh runs a C6 behind his Cummins swap..... As I recall he fabricated a flexplate and is not having any trouble...

 

[gonecrazyi]

According to the owner, the breaks in the flex plate are in different spots each time. Hopefully tomorrow Ill have a chance to drive down and see it.