FlexPlate or Starter Issue

arhame

Hello Everyone, I have a 77 CJ7 that originally had the 304/TH400/Quadratrac combo. I've completely rebuilt the jeep from the ground up over the past 4 years, except, I've used a 360 instead of the original 304. I'm having a problem with the starter or flexplate however. I was using a Powermaster starter with the 360 to begin with. But, when I was trying to fire up the motor for the first time to break it in, it made a horrific noise, such as the starter was grinding. I went to the local parts store and picked up a remainufactured starter to see if that would alleviate the issue. It still makes a loud noise, but isn't as bad as the powermaster starter was. I've been going round and round with the machine shop that built the engine, powermaster and even mean-green to try and figure out what is going on. Everything seems to be pointing to something with the flexplate. The flexplate on the motor is for a 360 but something still isn't right. Does anyone have any suggestions, or, is this a known issue when performing this kind of swap? Thanks for any info anyone might offer. Aubrey

ironman_gq

is the flexplate supposed to have a spacer behind it to put it in the right location. Could the starter not be long enough to engage the ring gear fully and is just grinding. could the starter have the wrong gear on it for the year flex plate your using. I would check these things out to be sure.

arhame

1. Spacer behind flexplate - This one I have no idea. The motor was removed from the jeep and sent out to the machine shop over 18 months ago and I am having a difficult time getting any info from the machine shop. How else could I go about determining whether or not it does need a spacer? Would the spacer go between the crank and the flexplate to push the flexplate out a bit? If so, I believe it would hit the starter housing. 2. I've tried multiple different starters. The starters will turn the motor over and actually start it, it just makes a terrible grinding noise when it does. I know the pitch on the flexplate is a 12/14 pitch, and the pitch on the stater (this info came from the guys at Mean Green starters) is supposed to be a 10/12 pitch. I haven't found any other flexplates that are supposed to fit the 360. Anything else? Thanks for the reply.

jeepsr4ever

Hmm I wonder if they put the flexplate on backwards

arhame

I was kinda wondering that myself. Problem is, I'm not sure which way it went on to begin with.

Here are some pics of the setup now.

http://www.meangreenjeep.com/misc/Picture004.jpg
http://www.meangreenjeep.com/misc/Picture006.jpg
http://www.meangreenjeep.com/misc/Picture009.jpg
http://www.meangreenjeep.com/misc/Picture004.jpg

Here's what the remanufactured starter looked like after about 10 different starts.

http://www.meangreenjeep.com/misc/Picture011.jpg

Thanks for the replies and any other support anyone can offer.

Aubrey

jeepsr4ever

I have heard of a offshoot company making the wrong OD flexplates for AMC applications. Is that a Pioneer flexplate?

arhame

I believe it is. Part Number FRA120 I believe.

jeepsr4ever

Fra120 is a flexplate for a AMC 360 with a th400 application...hmmm. Does your std starter work or what was the deal with it?

arhame

I have purchased two starters for the jeep. My first starter (which is what I was hoping to use) was a powermaster. The starter will actually turn the motor over and start it, you can just seem metal grinding off of the pinion of the starter and hear a VERY loud noise when you do turn it over. I removed the powermaster and went and purchased a remanufactured starter just to see if that would correct the issue. Although the noise wasn't quite as loud, it was basically doing the same thing. I visited with the people with Powermaster, and they told me that they had never seen this issue before. I contacted Mean Green, and sent them pictures of what everything looked like, and took measurements. I spoke with them again this morning, and they are thinking that it has something to do with the flexplate. They asked what the original flexplate looked like, and I had to tell them that I had no idea. It had been over 18 months ago that I removed the engine and brought it to the machine shop (yes, they took their time with it, but it did turn out great). I contacted my guy at the machine shop, and he can't seem to find the original. I've gone over as much as I can, as far as pitch, pinion engaugement, multiple starters to rule out a bad starter, etc. etc..... I've been posting to various boards to see if anyone has experienced anything like this before, and so far, this has been the most information I've received. I guess I'm going to go ahead and go through the process of removing the transfer case and transmission so I can get to the flexplate. Bad part is, I just got all this back together after 4 years of work, and put engine,transmission,transfercase, hell, entire driveline together with the body off. Oh well, if it wasn't work, everyone would be doing it. Any other ideas? Thanks for the response.

AMX69PHATTY

I'm no expert. Could it possibly be a flexplate for later AMC's made to work with the Mistubishi starter Chrysler changed them to vary late in production before they dropped the AMC V8 all together ? The flexplate used with the Mitsu starters are different than the others as I understand it. Don't know the specifics on year of change to Mistu starter. Sure someone here has more specific info about the Mitsu starters. Guess the starters you have are fitted with 9 tooth gears ? First PowerMaster XS starter I got was fitted with the wrong 11 tooth gear, where the correct gear is a 9 tooth for the "old" non-Mitsu Flexplates. Don't know the tooth count on a Mitsu starter. :-|

jeepsr4ever

If It was for a mitsu starter it would have not been a fra120 flexplate but a flexplate for a 727. I would blame the flexplate...are you sure the starters are fitting properly?

arhame

Yes, each starter fit properly. They are the same type as the older ford starters. there is a lip that must fit within the mount in the bell housing and the two ears for the bolts. Borth starters fit perfectly flush. I'll begin the process of removing everything in order to get the flexplate off to see if that helps.

Goose

uh ok.. maybe I am being a DA here.. but it appears to me that the flexplate/ringgear is on backwards.. the bevel cut on the ringgear is facing the trans..not the oilpan and since the ends of the teeth on the starter are getting ground/broken off, wouldn't it be a good assumption that the bevel on the ring gear teeth is there to smooth the engagement?? :-|

AMX69PHATTY

Does look like the Flexplate is on backwards in the pics. #-o

Flexplate "cup" should be towards the trans, tooth chamfers towards engine.

edit - sorry if I was wrong about the tooth chamfers, can't see'em clearly in my low res pic
Did look at a stock '73 401 flexplate, no chamfers either side.

Not the best pic, but can see "cup" in this one.

arhame

Ok, I've finally had time to pull the drivetrain out so I can inspect the flexplate.

Here are a few pictures.

www.meangreenjeep.com/misc/Picture016.jpg
www.meangreenjeep.com/misc/Picture017.jpg
www.meangreenjeep.com/misc/Picture018.jpg

The cup is towards the transmission, but the teeth bevel on the side of the transmission also.

Does something look obviously wrong here?

Thanks for any replies.[/url]

AMX69PHATTY

Boy, I'm not sure, what a puzzle, gotta be aggravating. Hopefully someone else here has the answers. :-|

Goose

Wow, Is that flexplate from a another engine or is it a new one?? Cause my guess is they welded the ringear on the flexplate backwards..

jeepsr4ever

Goose all flexplates and flywheels have the large chamfer facing the rear end. :wink:

Goose

:shock: they do?? (Ok I bet at this point you can tell how many auto trans cars I have messed with..) It just seems counterintuitive (holy crap I spelled it right!) to have the bevel away from the engagement side..Sigh...another lesson learned.

AMX69PHATTY

edit - sorry if I was wrong about the tooth chamfers, can't see'em clearly in my low res pic
Did look at a stock '73 401 flexplate, no chamfers either side.