Late Model 5.0 W/C4 flexplate issues

JohnJohn · Jun 16, 2016

I installed a 1992 5.0 in my 70 trail rig. I am running the 92 harmonic ballancer and all of the serpentine stuff. The 92 5.0/302 roller originally came with a manual trans behind. I removed the flywheel/clutch, pilot bearing and installed an early Bronco C4 behind it. I went with a 164 tooth 50 ounce flexplate and a early Bronco automatic starter.

My problem is the weight that is welded on the flexplate is making contact with my new automatic engine plate.

I just pulled the trans out and ordered another 164 tooth 50 ounce flexplate from Autozone (again) to see if it was just a manufacturing defect.

I guess I am looking for advise just in case I am going in the wrong direction here or have the wrong parts.

Keep in mind I ran this for a bit and it screeched like hell on start up or under heavy throttle when the flexplate would flex and contact the engine plate but I was able to drive around for a bit before I pulled it.

JohnJohn · Jun 16, 2016

Am I superposed to have a Flexplate Reinforcement Ring? And would this be installed in between the flexplate and the crank (spacing it out)?

I found this article and it says I need one.
http://diyford.com/install-ford-c4-c6-transmissions-step-step/

75junebug · Jun 16, 2016

looks like you install the flex plate first, then the reinforcement ring, then bolts.... I have never seen one personally....

JohnJohn · Jun 16, 2016

I just ordered a reinforcement ring for $15. I will inspect the new flexplate tonight and see if I have a solution.

JohnJohn · Jun 17, 2016

So there are two 50 ounce 164 tooth flexplates for a 1992 Bronco 5.0 with an automatic. My local Autozone ordered both so I got to compare them. The Pioneer brand FRA-214 was the same part I had installed and when I set it flat on the shop counter you could see that the weight was almost touching the counter. The FRA-214 was also listed as being for the AOD trans.

The FRA-231 was listed as being for the C6 trans and when I set it on the counter you could see the weight had about 1/8" of clearance. I am almost 100% sure I just fixed my clearance issue with the FRA-231 flexplate.

Now I just need my C4 rebuilt and I should be back in action.

brewchief · Jun 17, 2016

As I understand the offset on the c-4 and c-6 for flex plate are different so they don't interchange.
You do have the block plate in place between the engine and transmission correct?
Reinforcement ring goes on top of the flex plate under the bolts so won't space it out any.

tasker · Jun 17, 2016

happened to me too John...i couldn't even get it installed never mind run it....sorry but might have wiped out the front pump if that's the case

JohnJohn · Jun 17, 2016

The trans is going to the rebuild shop next week so I will find out but it was pumping good when I tested it.
I am running the engine plate. That is what the 50 ounce weight was scraping on in the pics above.

The C6 flexplate looks just like the AOD flexplate but the teeth of the sprocket and the weight is set back away from the engine roughly 1/8".
there is no way for me to run the AOD plate I was trying to run unless I ditch the engine plate maybe.

JohnJohn · Jun 17, 2016

I did some searching and now I am very confused. Everything I read says the 164 tooth 50 ounce flexplate for the AOD should have worked but I have seen two now that look identical and both have weights that will contact my engine plate when installed.

The C6 flexplate has enough clearance but can I run it with a C4?

Viperwolf1 · Jun 17, 2016

JohnJohn said:
I did some searching and now I am very confused. Everything I read says the 164 tooth 50 ounce flexplate for the AOD should have worked but I have seen two now that look identical and both have weights that will contact my engine plate when installed.

The C6 flexplate has enough clearance but can I run it with a C4?

Sounds like you have it figured out now. Something other than the flexplate is causing the problem. Can you move the crankshaft back and forth in the block? And maybe the blockplate is getting bent out of shape when it gets sandwiched.

75junebug said:
looks like you install the flex plate first, then the reinforcement ring, then bolts.... I have never seen one personally....

brewchief · Jun 17, 2016

I couldn't see the pics earlier, that looks like an aftermarket block plate that is flat since they are just plasma cut, I thought the stock ones were stamped and were offset in slightly, can you create some clearance with a big hammer?

JohnJohn · Jun 19, 2016

I looked into things more today. The engine plate is flat and not warped. I then held the AOD flexplate (that was scraping the engine plate before) up to the crank it looks like it should have about 3/16" and not scrape.
I am wondering if I installed the torque converter with the drainplug not aligned with the open hole?
I am thinking this may have caused my scraping problem.

So now do I return the C6 flexplate and try the AOD plate again?
The AOD plate does not look warped.

Sent from my SM-G930V using Tapatalk

tirewater · Jun 19, 2016

If the TC drain plug wasn't aligned with a hole, then I doubt you'd be able to pull the TC forward enough to engage any of the threads into the flex plate.

Are you sure your block/splacer plate is the proper one? I don't have your block combination ('76 block w/ C4), but my plate has reliefs pressed into it.

JohnJohn · Jun 23, 2016

I have more info. I happen to have my fully restored 77 with a stock C4 and 302 next to my trail rig.
I removed the inspection cover on the trans and measured the gap from the engine plate to the flexplate teeth. I got 3/4" gap.
I then put the C6 new flexplate on my 92 5.0 and also got 3/4" gap from the new engine plate to the teeth of the flexplate.

Everything I have read says I should use the AOD flexplate but I am not seeing it.

The reliefs on my stock 77 engine plate would not help my clearance issue because it does not push the plate back all the way around the blick.

I will post pics when I get back to my laptop.

Sent from my SM-G930V using Tapatalk

Viperwolf1 · Jun 23, 2016

Good luck with it. The C4/AOD flexplate should work. C6 flexplate is wrong. Maybe you should try a different brand. http://www.bulkpart.com/2/product/F209.html

JohnJohn · Jun 24, 2016

I ordered the Wild Horses 50 ounce 164 tooth flexplate for late model 5.0 engnen and C4 transmissions this morning. I also don't trust the Pioneer brand from AutoZone. When I get the WH flexplate next week I will compare all 3.

My trans is being rebuilt and I will be picking it up late next week so I am trying to find a flexplate solution before I get the trans back.

I am attaching 3 pics. The first two with the Ford blue oil pan are of my stock 77 with a 302 and a C4. You can see I have close to a 3/4" offset from the engine plate.
The third pic is of the 92 5.0 with the engine plate and the C6 flexplate. You can see it has the same offset as my 77 stock stuff. I did not get the tape measure in the pic because I only had two hands to take the pic.

tasker · Jun 24, 2016

NOT possible you had the two flex plates mixed did you? any stampings or numbers on them? As Viper said, the AOD and C4 use the same plate and C6 and E40D use the same

NicksTrix · Jun 24, 2016

yeas ago i had to remove the dimpled section of a motor plate so the big 50 oz weight wouldn't rub on it. jeff doing your trans john?

JohnJohn · Jun 24, 2016

Randy,
I had Autozone ship another flexplate and I compaird them so I am sure I have the correct part numbers and parts.

Nick,
I noticed the original engine plate has dimples going both ways on my 77 so I could see the need to hammer it but the plate on my 70 with the 92 5.0 has a new/aftermarket flat engine plate with no dimples. I am hopping the WH plate will solve my part issue.

Nick I thought I would let you know I won your spindle removal tool and key chain at this years MEB Roundup. I have been wanted one for a while so I was stoked.

tasker · Jun 24, 2016

and there was no cheating involved...i swear! ;D

Late Model 5.0 W/C4 flexplate issues

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