Flex Plate and Mini-Starter Not Working Together :(

So, after six months of waiting to take possession of our 66 coupe, we finally got the "Red Devil" to her new home here in New Braunfels, Texas.  While in Florida, my brother-in-law replaced a suspect 302 with a Blueprint Engines fully dressed 347 Stroker; which was then connected to a Monster Transmissions heavy-duty C-4.  Shortly after, the car started eating up flex plates and mini-starters; thus the car's being dubbed the Red Devil (yes, its color is red =).  We're not talking just one flex plate, at last count I believe we're talking at least "4" of them and 2-3 mini-starters...before we found what was thought to be the fix (along the way we found there were two different gear drive sizes for the mini-starter, affecting the degree of engagement the starter bendix had on the flex plate).  Alas, thinking the problem was solved, we had the Red Devil shipped to Texas.  After one day of starting and cruising, the flex plate/mini-starter issue once again reared its ugly head.  I can only describe the last start-up attempt as a bunch of clunking, pinging noises, followed by the whizzing sound of the starter bendix trying to find something to engage with.

So, here we sit perplexed (or should we say per"flexed").  Has anyone experienced such an anomaly?  If so, what was your fix?  I'm trying to contact my brother-in-law for more technical info, as all this has been a long-distance affair...with us being here in Texas and the Red Devil in Florida.  I believe the flex plates used were of the 157 tooth variety and the starters were of no particular brand (all were purchased through an Orlando Speed Shop).   Thanks...our 66!  

wow.... there are issues here...

first.. there are different flywheels for the early motor and the later motors..  do to balance issues..   but... there are also differences in the distance back from the block rear face...

on early motors there are different starters... depending if you have a C4 or a manual transmission..    

in conventional starters a 3124 fits with a C4 transmission..

a 3132 fits with manual transmissions..  

the overall length of the starters is the same length.. but the proportion of the nose cone is different ..


see if you can get part numbers from the receipts..  or call the engine builder to see which flex plate it needed...  28 ounce inch or 50 ounce inch..     some stroker motors might also be internally balanced.. and use a ZERO unbalance flex plate.. so knowing what the engine builder or balance card says.. is the place to start....

its mostly the starter you have to carefully select to match the engagement depth of the flex plate..


if you have pictures of the damage that might be helpful..    can you measure from the back of the block face to the front of the flywheel ring gear when the starter is removed..

i drop by this forum a few times a day to check the active posts..  find some info on the part numbers and brands.. perhaps some measurements i will try to help..  

Wayne...you are awesome.  You've replied to all three of the issues we've posted and we find your knowledge and information to be invaluable.  I will get to work on gathering the data you mention...in hopes of getting the Red Devil up and running again--this pony is way too nice to put down so soon after her resurrection!  THANK YOU...our 66!  

i took the time and tossed some images together..



3124 and 3132..  the 3124 is usually for automatics and the 3132 is for the manual transmission apps




ford starter shims... please drill the holes to 9/16 or 5/8".. as they are incorrectly small.. and that is being corrected at dorman... in new product being shipped as i understand..

 

and yes.. i know you have a mini starter...

i just had this ready...  

other thing you could try is using a bell housing alone (i have cut off the front of an AOD ) and install that with a new flex plate, and stater. disable the starter from turning,  but allow the pinion to enguage into the flex plate and check how far its going in and the contact point of the teeth..  

absolutely the correct thing to do..

one can also measure the distance from the block separator plate to the ring gear.. and then see if that allows clearance with the starer when its disengaged. and also when its engaged. that its NOT going out too far..  

Hi everyone...really appreciate the feedback on our flex plate/starter issue.  Finally able to gather some information (part numbers, etc.).  The engine is a Blueprint Engines 347 Stroker.  In speaking to Blueprint tech, the proper flex plate is a 28oz externally balanced one (only way they build their Stroker's). The tech indicated selecting a compatible starter was important, and a spacer between the crank and flex plate may be necessary.

As mentioned previously, the Red Devil has laid waste to 4 previous flex plates.  I have receipts with 3 different part numbers (bought through National Parts Depot and Murray's Speed Shop).  P/N BNM 50236 (Flex Plate C-4), P/N 6375-9A (Flex Plate Auto Trans 15/F211), and P/N PRW 1830204 (Ford 302 157 Tooth 28 oz).  Starter P/N CHM 8703 (Starter Ford 302 A/Trans 4&5M).  The current starter being used was a Powermaster 9600 Mastertorque (it's a rebuild of the starter from the 302 that was replaced by the Stroker).  Before removing the starter, we manually rotated the engine a bit and were able to briefly start the car (prior to that, we were only able to hear the bendix trying to engage).

We then proceeded to remove the starter, which had a lot of magnetized metal shavings all around the open bendix area (the gears did look worn).  We also found larger pieces of metal in the area, that looked to be remnants of some type of ring (bendix related?).  Oddly, one of the bolts holding the inspection plate in place had backed out and we found that lying in the driveway (which did give us a good view of a portion of the flex plate).  We then marked the flex plate and manually rotated the engine 360 degrees, looking for damage along the way.  While we didn't see any broken teeth, there were some teeth that looked somewhat worn, while others didn't.  We did take a measurement from the back of the engine block to the face of the flex plate and came up with a distance of just a tad over 3/4" (don't know if that measurement was properly taken).  We took pics of the flex plate inspection and a short video of the starter bendix engaging (which my partner didn't like the operation of).  Unfortunately, I don't know how to post to this forum (but could e-mail).  

Not knowing at this point, what the real cause for the problem is.  So, don't have a specific direction to move in (pull back tranny, remove flex plate, etc.)?  Also read article in another online forum that indicated this issue could be caused by a starter/starter swith/solenoid wiring problem, too; whereby the starter bendix stays engaged for a couple seconds after returning the key from start position (wasn't fully understanding that one?).

This is all we have to this point.  Thanks again to all for your helpful insight.

Our 66