904/999 Starter and Flexplate issue solved

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blownhemi

blownhemi

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Hey guys, so I've been putting together a tough 318 recently that's mated to a A-999 and I've had a few interference issues with flex plates and starters.

I've chronicled some of this on our youtube channel - Streetmachinetv

After researching the problem here a bit (be cause this is always the best place to find answers to questions like these), I realised I needed a Mopar mini-starter with the appropriate cut out the large double-drilled flex plate. Even they I discovered that there are flexplates and there are flex plates. Some will fit and some won't.

So we've done this little. video showing the issue, and how you can fix it without machining things (because not everyone has that option).

I'll point out that this is only a problem with flex plates that are double-drilled for 904/727 and fitted with a 904 style trans. Given that this is MOST aftermarket flex plates these days, it's starting to become a more common problem.

I also found that some flex plates like the TCI 145600 still won't work with the Mopar Mini Starter be use they are too big in overall diameter and will collide with the starter despite being advertised for 904/727 use.

I ended top using the disc style flexplate similar to the B&M 10230 and the Mopar Mini Starter as shown in the video below to make it work.

Anyway, here's the video. The relevant stuff starts around 9:26 if that helps.

Hopefully this will help get people out of a jam and no repeat my mistakes. :)

 
So the conclusion is that a 727 flex plate won't work with a 904...um..NO, NOT ALWAYS. General statements like that are all over the web.
 
CudaFactHackJob said:
So the conclusion is that a 727 flex plate won't work with a 904...um..NO, NOT ALWAYS. General statements like that are all over the web.
Click to expand...

The problem is that these flexplates are advertised as being suitable for 904 and 727. So people buy them for their 904s and find out that the flexplate hits the starter.

I'm just sharing the solution.
 
The aftermarket....................started to find that out in the early 70's.................LOL
 
CudaFactHackJob said:
So the conclusion is that a 727 flex plate won't work with a 904...um..NO, NOT ALWAYS. General statements like that are all over the web.
Click to expand...
OK I am confused.
I have a mopar performance sfi flexplate and the mini starter.
The flexplate was installed on a 727. Everything fit fine.
Later I changed the trans to a 999, bought a 999 converter from turbo action, same company as the 727 converter.
The same flexplate fit no problem on the 999 and so did the starter.
So is this a problem caused by the converter?
 
Duane said:
OK I am confused.
I have a mopar performance sfi flexplate and the mini starter.
The flexplate was installed on a 727. Everything fit fine.
Later I changed the trans to a 999, bought a 999 converter from turbo action, same company as the 727 converter.
The same flexplate fit no problem on the 999 and so did the starter.
So is this a problem caused by the converter?
Click to expand...

904 converters tend to use the small bolt pattern, 727 uses the bigger bolt pattern. But many flexplate manufacturers are making flexplates double drilled for both and claiming one size fits all, which it doesn't.

Did you use the same holes on the flexplate for your 999 and 727 converters?
 
Last edited:
blownhemi said:
904 converters tend to use the small bolt pattern, 727 uses the bigger bolt pattern. But many flexplate manufacturers are making flexplates double drilled for both and claiming one size fits all, which it doesn't.

Did you use the same holes on the flexplate for your 999 and 727 converters?
Click to expand...
Yes that's what I am questioning. I changed tranny to 904, bought new 904 8 inch converter, used same mopar performance Sfi flexplate.
 
Duane said:
Yes that's what I am questioning. I changed tranny to 904, bought new 904 8 inch converter, used same mopar performance Sfi flexplate.
Click to expand...

But what I'm asking is, is your flex plate multi drilled. Does it have more than four holes for the converter bolts?
 
TCI still makes the small pattern 145200 flexplate for the 904
 
was the starter found to be the issue in any of this? Discussion on differences (?) in RAM style denso mini starters....
 
blownhemi said:
That is interesting. I guess whoever made your a-999 converter used the 727 bolt pattern. Or vice versa.
Click to expand...
I think part of the issue is the size of the converter flexplate bolts.
My bolts are 7/16 I believe. I thought the oem 904 used much smaller bolts. I believe that Turbo action who is closely affiliated
With mopar performance standardized the bolt size and pattern used for a performance application.
 
Duane said:
I think part of the issue is the size of the converter flexplate bolts.
My bolts are 7/16 I believe. I thought the oem 904 used much smaller bolts. I believe that Turbo action who is closely affiliated
With mopar performance standardized the bolt size and pattern used for a performance application.
Click to expand...

I think you're right. It makes sense to standardise them and the 7/16 pattern in the same diameter as the small 5/16 pattern. Which means it won't cause interference issues with the starter.
 
As an update to this. I fired my 318 up yesterday and can confirm that the starter and flex plate combo I have at the moment worked fine.
 
blownhemi said:
As an update to this. I fired my 318 up yesterday and can confirm that the starter and flex plate combo I have at the moment worked fine.
Click to expand...
Good information you're sharing here. Thanks for that. Can we get some big pictures of the wagon in your avatar?
 
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