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Old 01-03-2004, 04:39 PM
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Ford Flexplate spacing

Eng. = '83 351W HO / 4bl / 164 tooth flexplate

Trans. = '69 C4 auto / 24 spline input / F48 torque converter 11 1/2 bolt pattern

With the bellhousing bolted firmly to the block, I still have a LOT of space between the flexplate and my torque converter. I am sure that the converter is engaged in all of its splines and sits as far into the transmission as possible. My problem is that the bolt-ends for the converter do not come through my flex plate yet. They aren't even touching the flexplate. I can spin both of them freely. I am worried that with this much spacing, if I try to pull the converter out far enough to bolt it up to the flexplate, I will pull it out of the pump and damage it. (see photo album for the last time this happened)

I picked up a flexplate shim .050 thick. It was the last one they had left and did not have any more thicker than that.

My question is this. How much space am I supposed to have between the flexplate and converter? If possible, would it do any harm to space the flexplate far enough into the bellhousing that it will sit flush with the converter, or does there need to be a minimal amount of space for play?

I don't think .050 will be enough judging on the depth of it now, so I may try to use the shim I have as a template to fabricate my own that will be thick enough. I just need to know how much space to allow.

I realize that the shim I may have to fabricate will have to be perfectly balanced, so I'll probably take it to a machine shop and have them make it. Any ideas as to how much space to allow between the flexplate and converter? Thanks in advance.

I have a more detailed image in my album.



MoocH
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Old 01-03-2004, 05:43 PM
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flexplate spacing

its been awhile since i did mine,however,i do NOT believe you have the correct parts combo here. there should not be that much space between the converter & plate when all is in the correct position.
when i had my trans rebuilt & i installed it, as the bellhousing/trans was bolted to the block, the bolts from the converter needed to be aligned with holes in the flexplate or the trans would not meet the block. after tightening all bellhousing/trans bolts, the converter would only move 1/8" till the nuts were tightened.
i hope this is clear to you. i will try to find out what you need for this year motor trans combo as time permits. luck with your project.

Last edited by FASTFORD; 01-04-2004 at 08:00 AM.
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Old 01-03-2004, 08:19 PM
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Like FastFord said, you have something wrong there. The convertor studs should be in the holes when the trans is bolted to the block. Spacing the flexplate back will likely cause problems with the starter.

Are you sure that you have the right bell housing?

Can you post a picture of the complete trans and bell housing?
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Old 01-03-2004, 11:13 PM
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From your photo it looks like it's out only a 1/4 inch, there is plenty of room on the seal surface and the splines to move the converter out that much. Normally it is a tight fit but this small amount of clearance is easily taken up by stock tolerances.

Bolt her up and give it a try, the starter is not an issue because the flexplate has the ring gear and it's not sliding. You'll find out in the first 30 seconds of starting her up...if it's not enough it will puke all your trans oil on the ground.

I wouldn't worry though, there is easily two inches of seal surface inside the trans and the splines are just as long. Remember tolerance stack on the assy line and normal running movement can cause the same situation...thats why there is plenty of sliding room on this part interface.

Not to mention flexplates are very...flexible.
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Old 01-04-2004, 06:01 AM
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4-Jaw... I never saw one that you could turn the convertor without the studs hitting the flexplate. Many times when doing trans R&R, I have seen where the studs werew in the wrong position(in the wrong holes) and the trans had to be taken completely loose from the block to be able to turn it, because the studs were so far in the holes. Since the studs pull all of the way into the holes and are longer than the thickness of the nut that goes on them, it is more than 1/4 " that it has to come out, probably 1/2" or more. It is likely that the flats will be pulled out of the pump gear or just barely in there. If the flexplate flexes toward the engine, it would likely pull out of the pump. That would put the flats of the convertor in the pump bushing area. Altho there is a large sealing surface, the seal only limits the minor amount of fluid that gets past the bushing, from leaking. The bushing, with the convertor flats there, will not stop fluid from coming out.

The comment about the starter was in reference to spacing the flex plate out to the convertor with a spacer between the flexplate and crankshaft. That will put the ring gear part of the flexplate further out from the starter, and may hit the nose of the starter.
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Old 01-04-2004, 08:07 AM
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Cool

You need to pull this apart.

Spacing the converter away from the tranny as suggested.... yes, there is plenty of seal area. The problem is you pull the converter hub AWAY from the pump gears. This will cause a problem !

On a ford of this era the studs on the converter ALWAYS stick through the flexplate when the bell housing is solid against the engine block. That is one of the pain in the butt items with installing a ford tranny..... the alignment of the converter studs to the flywheel.

Never space the flexplate on an automatic away from the crank to correct an alignment problem.

You have the wrong converter for the bell housing, wrong bell for the converter or something there.

Do you have a block plate between the engine and tranny?

I do not remember Ford flywheel & converter applications off the top of my head and the books are at work.. sorry.
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Old 01-04-2004, 08:19 PM
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Cros, no blockplate. It straight Bell to block.

I didn't think about problems with the starter engagement, so I guess I will have to abandon trying to space the flexplate. When I ordered the converter from Accurate Transmission , I told the tech that I had a '69 C4 with a 24 spline input shaft needing a 11 1/2 bolt pattern. He matched me up with part # F48. I am using the bellhousing from the C5 because they are both case fill and bolt to the case via pump bolts. It is the one with ribs halfway down the bell. It is the 164 tooth flexplate bellhousing, so I have no choice but to use this one.

Since I'm worried about pulling the converter out of place, I don't want to try to bolt it up the way it is. When I bolted up a C5 (bad transmission) a few weeks ago, the converter bolts did have to line up in order to bolt the bell to the block as usual. The studs did make it through and the converter BARELY slid forward when I tightened the bolts. I was using a different converter with the C5 though because it was the original one that came with the transmission. The C5 has a 26 spline, and my C4 only has 24, so I couldn't just interchange converters. I turned in the old 26 spline converter as a core for my new 24 spline, so I can't compare measurements.

Just a thought. Would anyone endorse the idea of me trying to find / fabricate a spacer to go between the converter and flexplate? I am thinking about a balanced steel ring with 4 holes to bolt to the converter, and then 4 offset studs pushed and welded securely to bolt to the flexplate? More than likely, I'd ask a machine shop to do this. Just wondering if it would hold up to the stresses.

My flexplate does dish outwards once after it bolts to the crank, and again before the torque converter holes. So it's already extended the converter holes towards the transmission now. I think a flat one would pull it farther away at this point.

Thanks for the help guys, I will post some more pics of everything while I take it out this week.

MoocH

Last edited by k2mooch; 01-05-2004 at 08:27 AM.
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Old 01-05-2004, 07:56 AM
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I replaced a FMX tranny in my 70 Galaxie with a C6 out of a 83 F250. I had the flexplate for both. Torque converter bolt pattern was the same for both, however one flexplate was "flat", more or less, the other was dished. I ended up re-using the original 1970 Flexplate (the dished one). Starter drive engagement would have been a problem in addition to the t.c. being pulled out the tranny more than I felt comfortable with. I think if you get a 69 flexplate, you will be fine.
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Old 01-05-2004, 12:47 PM
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bell housing

your C5 bell housing is the problem. It is deeper.

The F48 number I have crossed over & checked for aplications.

It is a 26 spline converter...

It is possible that is an incorrect cross over application...


I'd check the spline count if I was you!
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Last edited by Crosley; 01-05-2004 at 05:39 PM.
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Old 01-05-2004, 02:51 PM
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Thanks Cros. I just got off the phone with Accurate that sold me the F48 and they make an F48E (early model) that is the 24 spline. The salesman told me the F48 was a 24 spline, my bad for believing him. I still ahve my 26 spline input shaft I'm going to test it with to be sure tonight. If it drops into place, I'll know for sure that it's a 26 spline converter I have. I just want to be absolutely sure.

The tech at Accurate also told me that the bellhousing from a C5 164 tooth is deeper than the C4 version. Even if they are both case fill to a 351 bolt pattern. I never knew.

Anyway, I am going to drain the F48 and send it back, order a F48E and try to find the bellhousing from a C4 case fill transmission to bring things up nice and tight. Thank you all for your help. I know I'm still a ways away from getting this thing to move, but at least I'm headed in the right direction.


MoocH

P.S. Always second guess a salesman with a tech.
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