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Starter and flex plate basics for newb like me

tonytheplumber

Jr. Member
Joined
Sep 1, 2012
Messages
114
Loc.
Lowell, IN
I'll start off by saying I did not cut my teeth working on Fords so the differences and interchangability is something I know nothing about. I know my way around GM stuff as that was playground.
So, that brings me to the issue at hand. I have, newly installed in my Bronco, an early 90s mustang 5.0 which had a T5 behind it. As I'm wrapping up this install and hit the key for the first time to find that the starter spun but did not engage. Through internet searches and reading I found that the 157 tooth 50oz. imbalance flex plate I get from Summit is likely incorrect. Out came the trans and in when the Scat 64 tooth 50oz imbalance flex plate (Ebay purchase). Now the stater engages but sounds horrendous (grinding). Through MORE reading (on this wonderful forum) I have discovered that Ford uses a different starter for auto trans applications than for manual trans. Since I used the starter from the donor Mustang (manual trans) I have the wrong starter.
So, what application would actually be the 'correct' starter? Is there a certain year? Make? Model? Is the gear reduction "mini starer" better? If so, again, what application? Remote solenoid is not necessary since I can wire it up either way (preferred starter mounted solenoid).

I should mention that the block plate is in place. It's a steel one, for an auto trans., bought from WH, or Bronco Graveyard (I don't recall which).

Thanks in advance for holding my hand on this, and please shoot out any questions that I should have already covered.
 

DirtDonk

Contributor
Bronco Guru
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Nov 3, 2003
Messages
47,355
Yep, lots of compatibility things to run afoul of with Fords.
While the Mustangs did use the same starter part number for both manual an automatic transmissions for some years, most other vehicles like we're going to be familiar with had different starters.
Factory started using mini starters (officially "PMGR" or permanent magnet, gear reduction) in the late eighties on some vehicles I think, and '92 on the trucks. So we typically use a mid-nineties vintage truck or Bronco with 5.0/302 or 5.8/351W engine.

What transmission are you using? Was it out of a truck or a car originally?

For the starter, '92 to '96 F150's and Broncos industry numbers for the PMGR starters are #3205 Auto and #3223 Manual.

Even Ford continued to use the remote mounted relay/solenoid/thingy to power up the solenoid on the starters, so I would too if I were you. Keeps the ignition switch from having to handle the extra current drawn by the solenoid, vs just the lighter load of the original fender mounted relay.
And it serves to isolate the starter motor from the rest of the system, to avoid any issues of feedback causing a starter run-on situation.
Besides, it also acts as a very convenient spot to mount other wires, of which there are usually several.

I'd keep the relay.

Paul
 

DirtDonk

Contributor
Bronco Guru
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Messages
47,355
And yes, as was mentioned by the classicbroncos ghost;);D you may still have a bad starter.
It didn't used to happen with the starters near as much as with the starter relays, but it is happening more and more.
Same old crap problem, different part...

However... And this is a big problem too, in these days of many swaps, but what application was the flexplate from? And which auto trans, and what applications were the torque converter and transmission from?
Not all transmissions have an offset issue with the wrong flexplate, but some do. So for sure we need to narrow down the whole list of parts at this point to see if you might be dealing with multiple compatibility issues.

Good luck.

Paul
 
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tonytheplumber

tonytheplumber

Jr. Member
Joined
Sep 1, 2012
Messages
114
Loc.
Lowell, IN
And yes, as was mentioned by the classicbroncos ghost;);D you may still have a bad starter.
It didn't used to happen with the starters near as much as with the starter relays, but it is happening more and more.
Same old crap problem, different part...

However... And this is a big problem too, in these days of many swaps, but what application was the flexplate from? And which auto trans, and what applications were the torque converter and transmission from?
Not all transmissions have an offset issue with the wrong flexplate, but some do. So for sure we need to narrow down the whole list of parts at this point to see if you might be dealing with multiple compatibility issues.

Good luck.

Paul

I'm using the pan-fill C4 which came in the Bronco. I've got no history on it or what it came from and it was all alone (along with the transfer case) in the chassis when I bought the truck since it did not have an engine. The flex plate is a Scat unit not designated for a specific application, only stated as "externally balanced at 50oz" and SFI certified. I can try a starter for an auto trans F150 as you specified and see if I get lucky. The current starter does crank the engine but sounds horrible.
 

Rustytruck

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Joined
Feb 24, 2002
Messages
10,875
When you put the tranny up to the engine and motor plate were the studs on the converter already up tight to the flex plate or did the converter need to be pulled up to get the nuts all the way on? if it was already up tight then the converter wasn't all the way in. when installing the converter you put it in the tranny and turn it as you push the converter in you will hear it go clunk 3 times as it engages all its parts. When installed the converter studs will be just barely into the flex plate.

The converter flex plate not only has different diameters and tooth counts but also several different offsets from the crankshaft and different converter bolt patterns. Do you have the part numbers for the converter and the flex plate that may help someone to help you.
 
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tonytheplumber

tonytheplumber

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Joined
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Messages
114
Loc.
Lowell, IN
When you put the tranny up to the engine and motor plate were the studs on the converter already up tight to the flex plate or did the converter need to be pulled up to get the nuts all the way on? if it was already up tight then the converter wasn't all the way in. when installing the converter you put it in the tranny and turn it as you push the converter in you will hear it go clunk 3 times as it engages all its parts. When installed the converter studs will be just barely into the flex plate.

The converter flex plate not only has different diameters and tooth counts but also several different offsets from the crankshaft and different converter bolt patterns. Do you have the part numbers for the converter and the flex plate that may help someone to help you.

No converter installed. I just had the bare bell housing bolted up, not even the trans.

Flex plate is a Scat with a part number FP-302L
 

DirtDonk

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Wow, smart guy you are. Hooking it all up and cranking before the assembly is complete to see if it all works?
Using one of those special brackets to mimic the bell housing presumably?

When you said "wrapping up this install" in the first post it sounded like you had it all installed. Trans and all.
Is the body on or off?

Paul
 
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tonytheplumber

tonytheplumber

Jr. Member
Joined
Sep 1, 2012
Messages
114
Loc.
Lowell, IN
Wow, smart guy you are. Hooking it all up and cranking before the assembly is complete to see if it all works?
Using one of those special brackets to mimic the bell housing presumably?

When you said "wrapping up this install" in the first post it sounded like you had it all installed. Trans and all.
Is the body on or off?

Paul

I unbolted the bellhoising from the trans so I could bolt it up to the engine by itself and play peekaboo with the starter gear if needed. When I say “wrapping up this install” I guess I mean I’m closer to the end than the beginning, but I’ve still got a lot of work to do before this Bronco hits the road. The body is on it but the starter is very accessible due to the 2” body lift and Maddog fenderwell headers (for which I had to trim the inner fenders, which was not a big deal since I’m working with a fiberglass body anyway).

So I did buy a replacement starter for a 94’ Bronco 5.0 auto trans from O’Reillys yesterday. It was their most expensive but may still not be great. When matching up with the existing starter I have they appear to be identical. That was not encouraging. I installed the new starter anyway and while it does sound much improved, it is still not a clean crank. Sounds like a starter that needs to be shimmed. I shimmed it out with a single washer on each bolt, the washers being 1/16” thick. That sounded better but still not great. Added another washer (2 on each bolt) and it got worse. Maybe the Scat Flexplate is garbage?? I hate to purchase a third flexplate but I really don’t know what else to try. It would be an OEM flexplate from Ford for a 94’ Bronco 5.0 if so. I would hope the quality would be good that way.
 
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DirtDonk

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Messages
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Well bummer. Too bad it started sounding worse with the second washer, because they make shims for Ford starters that are about 1/8" thick or so.
Had never heard of a Ford starter needing to be shimmed before I started seeing the shim kits on the Dorman "HELP" spinner racks in stores. First instance of someone I knew needing one was just about four years ago, and since then there have been several.
Not sure what's up, unless it's the garbage we're getting, or just a pattern of all the different engine/transmission/flexplate/flywheel combinations we've been Frankensteining together in recent years.

What is the part number on the starter you bought? Got a picture of it you can share, next to your other starter?
The fact that they were looking the same is not a good sign, because the visual differences are very distinct between the two styles when next to each other.

Good luck.

Paul
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
Do you have the block plate installed? It is the thick sheetmetal spacer between the block and the bellhousing. You have to install it before the flexplate. The main thing this does is correctly space the starter. you also need to have both dowel pins in place between the block and the bellhousing, those are the critical reference points. The bolt holes themselves have way too much slop in them.

The flexplate sounds correct, but there is one more thing to check. Is it for a C4/AOD/4R70W or C6/E4OD? Those two different familys of transmission have a different convertor offset but share all the other specs the same. Get it wrong and it will put a preload on the front pump of the transmission.
 
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tonytheplumber

tonytheplumber

Jr. Member
Joined
Sep 1, 2012
Messages
114
Loc.
Lowell, IN
Do you have the block plate installed? It is the thick sheetmetal spacer between the block and the bellhousing. You have to install it before the flexplate. The main thing this does is correctly space the starter. you also need to have both dowel pins in place between the block and the bellhousing, those are the critical reference points. The bolt holes themselves have way too much slop in them.

The flexplate sounds correct, but there is one more thing to check. Is it for a C4/AOD/4R70W or C6/E4OD? Those two different familys of transmission have a different convertor offset but share all the other specs the same. Get it wrong and it will put a preload on the front pump of the transmission.

Yes sir, the block plate is in place. I have only the bare bellhousing installed currently so there is no preload on the flexplate due to improper trans family. But now you got me concerned about the flexplate application. This might drive me a little crazy.
 
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tonytheplumber

tonytheplumber

Jr. Member
Joined
Sep 1, 2012
Messages
114
Loc.
Lowell, IN
Well bummer. Too bad it started sounding worse with the second washer, because they make shims for Ford starters that are about 1/8" thick or so.
Had never heard of a Ford starter needing to be shimmed before I started seeing the shim kits on the Dorman "HELP" spinner racks in stores. First instance of someone I knew needing one was just about four years ago, and since then there have been several.
Not sure what's up, unless it's the garbage we're getting, or just a pattern of all the different engine/transmission/flexplate/flywheel combinations we've been Frankensteining together in recent years.

What is the part number on the starter you bought? Got a picture of it you can share, next to your other starter?
The fact that they were looking the same is not a good sign, because the visual differences are very distinct between the two styles when next to each other.

Good luck.

Paul

Sorry for the delay, but here are the pics of the 2 starters. Old starter was the one I got with the Mustang 5.0 with which I also received the flywheel and the T5 it was attached to. I did not hear this engine start and run so I cannot testify to the mesh of the starter but I do know for sure it was mated to a manual trans.
I don't know if these pictures show it with the goofy angles, but both the starters hold the same dimensions. That's not to say the Chinese made "new" starter from O'Reilly's is correct for the application of "94 Bronco 5.0L auto trans" which I specified.
 

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tonytheplumber

tonytheplumber

Jr. Member
Joined
Sep 1, 2012
Messages
114
Loc.
Lowell, IN
Well bummer. Too bad it started sounding worse with the second washer, because they make shims for Ford starters that are about 1/8" thick or so.
Had never heard of a Ford starter needing to be shimmed before I started seeing the shim kits on the Dorman "HELP" spinner racks in stores. First instance of someone I knew needing one was just about four years ago, and since then there have been several.
Not sure what's up, unless it's the garbage we're getting, or just a pattern of all the different engine/transmission/flexplate/flywheel combinations we've been Frankensteining together in recent years.

What is the part number on the starter you bought? Got a picture of it you can share, next to your other starter?
The fact that they were looking the same is not a good sign, because the visual differences are very distinct between the two styles when next to each other.

Good luck.

Paul

Do you have the block plate installed? It is the thick sheetmetal spacer between the block and the bellhousing. You have to install it before the flexplate. The main thing this does is correctly space the starter. you also need to have both dowel pins in place between the block and the bellhousing, those are the critical reference points. The bolt holes themselves have way too much slop in them.

The flexplate sounds correct, but there is one more thing to check. Is it for a C4/AOD/4R70W or C6/E4OD? Those two different familys of transmission have a different convertor offset but share all the other specs the same. Get it wrong and it will put a preload on the front pump of the transmission.

Ok, so check this out. Evidently I had the "correct" starter from the mustang. This does explain a lot.

https://static.speedwaymotors.com/images/pdf/91067433.pdf

This doesn't explain why the starter still sounds like crap though...

Also, I suppose I can use a flex plate from a mid 80's 5.0L Bronco and it should be correct in relation to the torque converter positioning?? As well as being 164 tooth and 50oz imbalance?? And I guess I'll toss the new Scat flex plate aside since it doesn't list a specific application :-[
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
Mid 80's 5.0 Bronco flexplate is probably INCORRECT. You will find a C6 transmission in those. Wrong offset for the C4. But an early 90's mustang will be correct.
 
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tonytheplumber

tonytheplumber

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Sep 1, 2012
Messages
114
Loc.
Lowell, IN
Mid 80's 5.0 Bronco flexplate is probably INCORRECT. You will find a C6 transmission in those. Wrong offset for the C4. But an early 90's mustang will be correct.

That’s what I had in there originally, which I bought from Summit. Unfortunately it’s a 157 tooth so it’s the incorrect size for the c4 bell. Any other options?
 

Broncobowsher

Total hack
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Messages
34,835
157 is the tooth count for an early 90's mustang manual transmission flywheel
164 is the tooth count for an early 90's mustang automatic transmission flexplate

To make matters worse there is also a 157 tooth flexplate used in early mustangs with a C4. But an early mustang different C4 than a Bronco C4. The bronco used the full sized flexplate with 164 teeth. The Mustang early 90's mustang AOD flexplate just so happens to be the same as the Bronco C4 only with the updated engine balance.

We have not gotten into the bastard Bronco torque convertor yet. Check the bolt circle on the convertor. The early and late ones (73 and 77) are 11-7/16" bolt circle. Most of the ones in the middle(74-76) are 10-1/2". The 10-1/2" bolt circle 164 tooth flexplate is obsolete and cannot be found anymore, and was never offered in the new engine balance, and never an aftermarket offering either. Good thing is a normal 11-7/16" C4 convertor will go right in. This one stings people who just lost a tooth or two on the flexplate and just wants a new flexplate. They have to get a new torque convertor as well. And anyone doing a late model engine swap as well. The 10-1/2" Bronco convertor can still be bought although there is no reason for them to exist at any parts warehouse.
 
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tonytheplumber

tonytheplumber

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Messages
114
Loc.
Lowell, IN
157 is the tooth count for an early 90's mustang manual transmission flywheel
164 is the tooth count for an early 90's mustang automatic transmission flexplate

To make matters worse there is also a 157 tooth flexplate used in early mustangs with a C4. But an early mustang different C4 than a Bronco C4. The bronco used the full sized flexplate with 164 teeth. The Mustang early 90's mustang AOD flexplate just so happens to be the same as the Bronco C4 only with the updated engine balance.

We have not gotten into the bastard Bronco torque convertor yet. Check the bolt circle on the convertor. The early and late ones (73 and 77) are 11-7/16" bolt circle. Most of the ones in the middle(74-76) are 10-1/2". The 10-1/2" bolt circle 164 tooth flexplate is obsolete and cannot be found anymore, and was never offered in the new engine balance, and never an aftermarket offering either. Good thing is a normal 11-7/16" C4 convertor will go right in. This one stings people who just lost a tooth or two on the flexplate and just wants a new flexplate. They have to get a new torque convertor as well. And anyone doing a late model engine swap as well. The 10-1/2" Bronco convertor can still be bought although there is no reason for them to exist at any parts warehouse.

I can't believe this has become so involved. Well, I just ordered a new flex plate for a 92' Mustang 5.0L. I do not have a torque converter currently since the stock one I had a few years back would have not worked well with the cam I have. My new TC is on order through the shop which is building my trans so I should probably touch base with them and make sure they aren't looking for a unicorn torque converter. My head is kinda spinning here ?:?
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
In one of Viperwolfs many transmission posts he listed the right flywheel and stock converter to use. Just have to dig deep enough to find it. One thing that may make the starter sound odd is you cranking on a flex plate and not a flywheel. With a flex plate with no converter attached you don't have a very stiff assembly. Then you jamming the starter gear on the very edge of the flex plate. Bolt on the converter the support comes into the end of the crankshaft and the converter will stiffen that flex plate and help to take the ring out of it. Then when the tranny is mounted the assembly is further stiffened when the converter is riding in the transmission pump bearing.
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
The 164 tooth flex plate and converter with 10-1/2 bolt pattern was also used in the same years 2WD Econolines. The 10-1/2" bolt pattern converter was a large car converter Modified for the Bronco and Econoline by welding a cup plug on the stub that resides in the crankshaft. This is all moot now since its been a very long time since you could buy a new flywheel with the small pattern converter.
 
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tonytheplumber

tonytheplumber

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Messages
114
Loc.
Lowell, IN
In one of Viperwolfs many transmission posts he listed the right flywheel and stock converter to use. Just have to dig deep enough to find it. One thing that may make the starter sound odd is you cranking on a flex plate and not a flywheel. With a flex plate with no converter attached you don't have a very stiff assembly. Then you jamming the starter gear on the very edge of the flex plate. Bolt on the converter the support comes into the end of the crankshaft and the converter will stiffen that flex plate and help to take the ring out of it. Then when the tranny is mounted the assembly is further stiffened when the converter is riding in the transmission pump bearing.

You do make a good point there. I suppose there is nothing to deaden the resonation. I don't have a converter to bolt to it right now. Also, I ordered a flex plate from an early 90's 5.0L mustang as it sounds as though it's the correct one for my application, and being OEM Ford there shouldn't be any quality or fitment issues. Fingers crossed!
 
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