Shimming flex plate

[73 Mike]

The last part for my cheepo crate engine was the flexplate which came in on Thursday. It looked fine on initial inspection but on instalation this morning, I found that it is slightly cupped. The net result is that there is no clearance between the ring gear and the starter gear, even with the starter gear shim added (came with the starter).

I even tried turning the flexplate around and the gap is almost an inch. The starter gear just touches it.

The right thing to do is send it back but with the holidays, it'll take another two weeks to get.

My question. Could I shim out the flexplate to make adequate clearance? I would need about a washer thickness (~ 1/16th inch ?) based on a quick experiment. I've never had to do this before so thought I'd ask before I tried it.

 

[mrvette]

73 I have read that several times, I know the flexplates are slightly cupped, so that's not a issue...I THINK, as I recall, they only bolt on the crank ONE way...maybe I confused with another engine, or configuration??

when you say one inch, I have to assume it's fore/aft if mounted one way....which is obviously not going to work....

but I totally fail to understand the 1/8 inch 'shim'....I have never shimmed a flex plate....never had to...you sure you got the right starter? I have read many comments about starter variations, but I have never faced the problems they speak of, myself.....I know there are two possible tooth counts 153? and 168 for some odd reason....

:banghead:

 

[73 Mike]

73 I have read that several times, I know the flexplates are slightly cupped, so that's not a issue...I THINK, as I recall, they only bolt on the crank ONE way...maybe I confused with another engine, or configuration??

when you say one inch, I have to assume it's fore/aft if mounted one way....which is obviously not going to work....

but I totally fail to understand the 1/8 inch 'shim'....I have never shimmed a flex plate....never had to...you sure you got the right starter? I have read many comments about starter variations, but I have never faced the problems they speak of, myself.....I know there are two possible tooth counts 153? and 168 for some odd reason....

:banghead:

Yes the flexplate only is suposed to go on one way with the "bump outs" for the torque converter away from the motor. It's the same starter I've used on several previous engines so I'm pretty sure it's not the problem.

I've never had to shim a flexplate either. That's why I asked before I went ahead and did it.

 

[mrvette]

73 I have read that several times, I know the flexplates are slightly cupped, so that's not a issue...I THINK, as I recall, they only bolt on the crank ONE way...maybe I confused with another engine, or configuration??

when you say one inch, I have to assume it's fore/aft if mounted one way....which is obviously not going to work....

but I totally fail to understand the 1/8 inch 'shim'....I have never shimmed a flex plate....never had to...you sure you got the right starter? I have read many comments about starter variations, but I have never faced the problems they speak of, myself.....I know there are two possible tooth counts 153? and 168 for some odd reason....

:banghead:

Yes the flexplate only is suposed to go on one way with the "bump outs" for the torque converter away from the motor. It's the same starter I've used on several previous engines so I'm pretty sure it's not the problem.

I've never had to shim a flexplate either. That's why I asked before I went ahead and did it.

Which is why I fail to understand what shimming the plate, obviously? to the rear of the car, would do for starter engagement...the teeth would obviously be engaged at least somewhat, I had a issue with the starter recently, that it did not engage the flex all the way...only about 1/2 way and so wore out the flex, I could see the wear pattern....but it sounds like you are trying to lessen the engagement pattern....

?

:gurney:

 

[73 Mike]

Right. Put on the correct way with the starter in the resting position, the teeth touch the ring gear. I need the flex plate slightly further from the engine since I've already shimmed the starter to the max.

 

[mrvette]

Right. Put on the correct way with the starter in the resting position, the teeth touch the ring gear. I need the flex plate slightly further from the engine since I've already shimmed the starter to the max.

This IS a SBC, iron block, right?? I not familiar with LS engines one bit....never touched one....

I know that to get my mini starter to engage the new flex I have to move it back under the bolts to the rear of the car, far as it can go, then hammer the bolts home....been that way some ~3 years now.... but you say the bendix spring/starter cluth is engaging the flex when it's NOT energized?? there has to be almost 1.5" of toss on that shaft, if not more, when the typical solenoid is engaged....

you sure that bendix is returning to seat proper in the starter?? not some hang up....wonder if it's on the correct side of the solenoid fork, or if the return spring is not in there.....

:gurney:

 

[TimAT]

Not exactly sure what's going on, but something is way wrong. Your'e talking about adding a shim to the back of the crank to move the flexplate aft? Never seen one on a Chevy. They do have a balance plate that you can use to install a neutral balance flexplate on a external balance crank. And that does fit between the crank and the plate. But to add a shim? Something weird here somehow. :ill:

 

[big2bird]

Not exactly sure what's going on, but something is way wrong. Your'e talking about adding a shim to the back of the crank to move the flexplate aft? Never seen one on a Chevy. They do have a balance plate that you can use to install a neutral balance flexplate on a external balance crank. And that does fit between the crank and the plate. But to add a shim? Something weird here somehow. :ill:

Gotta agree here Mike. I can't recall EVER seeing a shim needed there.

 

[73 Mike]

A bad sign that none of the three of you have ever seen this. Looks like I'm off to the parts store for another one.

And Gene, it is an SBC 2 piece seal driver's dipstick block. Nothing special.

 

[big2bird]

A bad sign that none of the three of you have ever seen this. Looks like I'm off to the parts store for another one.

And Gene, it is an SBC 2 piece seal driver's dipstick block. Nothing special.

Shims on starters are even rare. Look carefully. Bendex retracted fully? Broken? Flexplate correct for app? Crank f***ed up? Rear bearing thrust surface broken/gone? Something just doesn't add up.

 

[73 Mike]

A bad sign that none of the three of you have ever seen this. Looks like I'm off to the parts store for another one.

And Gene, it is an SBC 2 piece seal driver's dipstick block. Nothing special.

Shims on starters are even rare. Look carefully. Bendex retracted fully? Broken? Flexplate correct for app? Crank f***ed up? Rear bearing thrust surface broken/gone? Something just doesn't add up.

All look ok and correct. Haven't checked the end play yet but did notice wear on the bearing thrust surface when I replaced the rear main seal. That would have to be an astonishing end play though. On the order of 3/16 of an inch.

 

[mrvette]

I think you starter is messed up somehow.....wonder if you have a China import nose casting?? bolt holes in rong spot....I bet engine/flex are fine....I hope this is outta the car so you can get to it.....

I would take that starter apart, fish around in there at this point....:gurney::crap:

 

[73 Mike]

I think you starter is messed up somehow.....wonder if you have a China import nose casting?? bolt holes in rong spot....I bet engine/flex are fine....I hope this is outta the car so you can get to it.....

I would take that starter apart, fish around in there at this point....:gurney::crap:

I don't think it's the starter but that's easy enough to check as I have an old GM starter from the original engine. The bendix is worn but it should suffice to confirm this.

The starter that I'm using is an MSD gear reduction one. Freeking expensive so it damn well better not be the problem. I also have used it on a number of previous engines.

 

[TimAT]

The rear face of the thrust bearing catches hell. In a manual trans car, it gets loaded everytime you push the clutch in. And automatic car, it shouldn't ever see any real load unless the convertor is too far forward, and IF that's the case, the trans is going to fail soon because the convertor is not properly seated in the pump. BUT, if the snout on the convertor is not setting in the rear of the crank because it's too big, then the flexplate will be pulled out of shape by the bolts like this: crank>(convertor.

IF the rear face of your thrust bearing is scored and chewed up, you need to figure out what's pushing the crank forward all the time. IIRC, endplay should be around .007, so with the crank free, that's .0035 on each side.

 

[Twin_Turbo]

What kind of starter is it? A mini starter? The ones with the alu 2 pattern mounting blocks can usually be shimmed away to the front of the motor....

 

[73 Mike]

What kind of starter is it? A mini starter? The ones with the alu 2 pattern mounting blocks can usually be shimmed away to the front of the motor....

Here is an ebay auction for the same starter. I did come with a shim kit to move it back, away from the flexplate but that's already in.

http://cgi.ebay.com/ebaymotors/MSD-...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Tim, the car (or truck rather) that it came from was a 4 speed. I don't remember which face was showing copper but I do remember that it was only one face because I thought it was odd.

 

[mrvette]

A bad sign that none of the three of you have ever seen this. Looks like I'm off to the parts store for another one.

And Gene, it is an SBC 2 piece seal driver's dipstick block. Nothing special.

Shims on starters are even rare. Look carefully. Bendex retracted fully? Broken? Flexplate correct for app? Crank f***ed up? Rear bearing thrust surface broken/gone? Something just doesn't add up.

The ones I'v seen those converter bolts are SO close to the block when everything is kosher, that even putting a washer under them would make the caps hit the block casting...I still vote starter is fucked, that bendix not retracting for some reason....

wait a friggin' minit....Jeebus, it's been years, I had a old Pontiac starter that showed something like that, there was a little like washer type dingy on the end of the motor shaft, and it stopped the bendix from hitting the housing, if that is not there, that bendix can come off the end of the spiral teeth and not retract.....my fucking mammory not worth a shit, should have thought of that right away.....:crap::flash:

 

[bobs77vet]

wow after reading this something sure doesnt seem right.....good luck

 

[FLATOUT427]

The rear face of the thrust bearing catches hell. In a manual trans car, it gets loaded everytime you push the clutch in. And automatic car, it shouldn't ever see any real load unless the convertor is too far forward, and IF that's the case, the trans is going to fail soon because the convertor is not properly seated in the pump. BUT, if the snout on the convertor is not setting in the rear of the crank because it's too big, then the flexplate will be pulled out of shape by the bolts like this: crank>(convertor.

IF the rear face of your thrust bearing is scored and chewed up, you need to figure out what's pushing the crank forward all the time. IIRC, endplay should be around .007, so with the crank free, that's .0035 on each side.

Never use a pilot bearing in the crank with an automatic trans.

 

[big2bird]

update???????