Cracked flexplate, BIG problem need help

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Cracked flexplate, BIG problem need help

Postby knever3 » October 15th, 2012, 5:44 am

I have a cracked flexplate and cannot locate the correct replacement since the timing windows are about 1" off. Here goes:

I have posted this on another site also but can't seem to find the right answer. Here goes:

Specs first,

1987 Jeep Comanche had 4.0L 2wd ba-10/5

Installed aw-4 trans, 242 case and all under hood wiring and fuse box from 1990 XJ. Ran fine until I noticed the flex plate knock. Thought it was a rod bearing so I decided to install my stroker motor. '96 block and head, kept all the renix stuff including the flywheel from the last motor, which was from the '90 donor.

After noticing the noise was on the new motor I removed the flex plate and ordered a new one for an '87 Comanche. I noticed that the windows in the outer ring were in different locations than the old one I pulled. Sure enough, installed it and the timing is so far off it won't start. Ordered one for the '90 XJ and it turned out to be the same part.

So here's the update today. I went to Advance to get yet another flexplate for a '90 XJ/MJ. It was sealed and when I opened it up to compare it was exactly the same as the first three I saw. I took some comparison pictures for you all to noodle on.

Old one with the crack, reason for the whole debacle.

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Old one vs. new one.

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As you can see what I was talking about the timing windows are "off" between the two.

Here's some pics of the CPS.

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I bought another flexplate from Crown, I even checked the box to make sure. The same result. The windows are in the wrong spot. I guess I should put it back in and just adjust the dist untill the timing is correct. That is really crazy since the dist is supposed to be set to TDC 0 degrees and the computer is supposed to adjust the timing according to the knock sensor and such.

Picture of all three, my original on the bottom, Advance Auto's ATP/Dorman, and the Crown is on the top. The flexplates do have different holes drilled in them in some locations most likely for balancing.

Image


Back to square one...


Please direct me to anyone that can help with this problem. I need to get my truck going ASAP. Thanks!!!!
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Re: Cracked flexplate, BIG problem need help

Postby SilverXJ » October 15th, 2012, 6:40 am

Clean up the original one and see if you can pull a part number off of it
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Re: Cracked flexplate, BIG problem need help

Postby racing89 » October 15th, 2012, 7:17 am

All 87-90 renix are the same.( #33002675 chrysler . not amc #) Your supposed replacement doesnt look like a 91- either. Chinese miscalculation perhaps?
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Re: Cracked flexplate, BIG problem need help

Postby yuppiexj » October 15th, 2012, 7:34 am

You may luck out and have some built-in timing advance.
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Re: Cracked flexplate, BIG problem need help

Postby knever3 » October 15th, 2012, 7:52 am

I can clean it up but even the new ones don't have a part number stamped into them. Doubtful if it exists. As for timing advance the truck won't even start with the new aftermarket one installed. Any more ideas?
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Re: Cracked flexplate, BIG problem need help

Postby Muad'Dib » October 15th, 2012, 2:59 pm

When i purchased mine, i didn't even check to see if the windows lined up. I just installed it and it worked.

From what i understand all RENIX are the same.. and they have the windows like what you posted. I guess its possible that some weird chinese knockoff or some kind of other weirdness is associated with the ones you have been purchasing. You didn't mess with the Distributor while doing this work did you? Your positive you have lines these up correctly?

A link to the one i bought is in my build thread. I ordered it off RockAuto and its the OMIX-ADA brand. No problems with it at all on my Stroker..

viewtopic.php?f=8&t=2317

I also have a good used one sitting in my garage.
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Re: Cracked flexplate, BIG problem need help

Postby 604rail_king » October 15th, 2012, 5:48 pm

i was just going to say maybe try another parts source.
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Re: Cracked flexplate, BIG problem need help

Postby the_wrench116 » October 16th, 2012, 3:13 pm

Ive got a few spares pay shipping and 10$ its yours.
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ATK on the way then an OBD 2 swap so flyin ryan can tune.
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