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flexplate hitting something?

SAC69

SAC69

Active Member
Donator
I was helping a friend with his '67 coupe and he has a problem. The engine is a newer 5.0, 52 or 54 oz flexplate (which ever if correct, the car has its original C4). He and a friend transferred the block plate from the original 289 to the 5.0 some years ago and the friend somehow bent the blockplate (according to my friend) and left a high point. He started the engine a week ago and it made a horrible noise, something is rubbing against the flexplate weight and my friend believes it's the blockplate. Subsequent checking in the inspection area revealed some metal shavings which he removed. He pried the trans back from the approx 1" and he then tried to smooth out the issue with the blockplate. However, when we started the car today there is still quite a racket coming from the bellhousing. He checked the inspection area and there are shavings again present and there are also scrape marks now against the inspection plate.

Is there something else that we can check (torque converter bolts?) or does the trans need to be removed so the bell housing can come off for a proper inspection? What could be rubbing against the inspection plate?

Any ideas short of removing the trans would be most helpful.

Thanks.
 
Have you checked that the torque convertor drain plug(s) poke through the hole(s) in the flexplate? There may be one or two plugs.

This is a pretty common problem.

Frank
 
I have had the balance weights on the flex plate rub on a warped block plate. I was able to use a mirror and flashlight to find the spot that was hitting and then got a pry bar ion there to work the plate so it did not hit.

Also, as mentioned, the converter drain plugs should be showing thru a hole in the flex plate. I have seen them miss alighned and they will bow the flex plate where it hits the block plate.

Another thing to check is if the starter gear is retracting far enough to clear the ring gear.
 
I have seen them miss alighned and they will bow the flex plate where it hits the block plate.
Click to expand...

This is a mistake you usually only make once. Been there, done that. Back before the days of internet forums this happened to me and it was a 30 minute "head-scratcher" trying to determine WTF happened.
 
If the torque converter drain plug is not properly poking through the blockplate hole, can it be spun to reposition it w/o removing the trans?
 
"SAC69" said:
If the torque converter drain plug is not properly poking through the blockplate hole, can it be spun to reposition it w/o removing the trans?
Click to expand...

Yes. [nb]Well actually it's going to depend on whether or not you can push it far enough back into the pump to clear the studs[/nb]
 
You'll likely have to move the transmission back enough to get the studs out of the holes in the flexplate. About an inch should do it.

Frank
 
thanks to sac69 for posting this for me. i got the car up last night and after removing the inspection cover...there is no contact with any of the bolts! i can see that there is some minor rubbing of the 50oz weight as it turns around, but i think it's worn it's own groove into the flexplate. now, when i go to reinstall the inspection window - THAT's where i have the contact. it appears that the insp.plate is supposed to tuck up and under the flexplate and then is fastened down by 2 small bolts. the 50oz weight is spinning and hitting the sides of the cover. i think i'll just reinstall the cover on the outside of the flexplate, instead of tucking it in. i didn't get a chance to start the motor last night to confirm, but i'll be doing that tonite. wish me luck.
 
You may be looking at the wrong thing. You need to look for the hole(s) in the flexplate between where the torque convertor bolts stick through. There will be one or two of these holes and there should be a hex head drain plug sticking out of it/them. You can also have someone turn the engine over by hand and watch the flexplate as it turns. If it looks warped, you probably have a drain plug pushing on it.

Oh, and welcome to Stangfix.

Frank
 
thanks for the tip, frank. i did check all the bolts on the convertor and the drain plug. all the bolt heads were nice and clean - not showing any damage or evidence of striking. i'm going to crank it again tonight and watch the clearance again and see if i can bend the plate out a bit to gain some minimal clearance. i held the remote trigger for about 5 secs and didn't hear any banging, so that's promising. who knows, maybe the noise is just an obnoxious exhaust leak. ?!?
 
Have to agree with Frank some converters have two (2) drain plugs. If yours does make sure both drain plugs are aligned with the holes in the flex plate.
 
ok...so, we determined there was some minor interference from the starter. so we added a few washers to the starter to act like shims to pull the starter out a smidge and that helped a bit. however, i'm still getting some interference from inside the bellhousing. there's some soft clanking in the upper part of the bellhousing on the passenger side. so now, i'm going to have to split the bellhousing from the block to see where this additional contact is being made.....
 
Is there a different starter you are supposed use with the 52oz flexplate or is it just a problem with this particular starter since it came off of the 28oz-flexplate engine?
 
The only difference I know of is the auto vs manual starter. One has a longer snout into the trans. I think.......
 
"SAC69" said:
Is there a different starter you are supposed use with the 52oz flexplate or is it just a problem with this particular starter since it came off of the 28oz-flexplate engine?
Click to expand...

The starters that are used with the 50oz flexplates/flywheels that come out of a foxbody mustang are the same for the automatics and manuals -- unlike our old 28oz imbalance. The automatic starters have the same depth on the snout as the starters on the fox body mustangs.

I'd verify that you're using a starter for an automatic and not a manual.
 
well, i can say with certainty that this starter was the same one hooked up to the original 289 that i pulled out. this "new" block is a crate/late model 5.0 with the 50oz flywheel....should i be asking for a new starter at kragen or autozone? or dare i say a ministarter?
 
"67resto-coupe" said:
well, i can say with certainty that this starter was the same one hooked up to the original 289 that i pulled out. this "new" block is a crate/late model 5.0 with the 50oz flywheel....should i be asking for a new starter at kragen or autozone? or dare i say a ministarter?
Click to expand...

To eliminate the starter as the soource of the noise... or verify it as the source of the noise...... start the car and then carefully remove the starter while the car is still running. If the noise is still present, you'll know it's not the starter causing the problem.

Just be careful......
 
ok...so i was able to start the motor and carefully removed the starter - pretty hairy task! the sound is NOT from the starter. but, i think this revealed something interesting....while watching the flywheel spin, i could see exactly where it was hitting the flexplate. if you look at the starter hole, picture a clock, and the 50oz weight is hitting around the 1 or 2'o'clock area. another thing i'm wondering...there seems to be very minimal clearance between the weight and the plate. i read on another site that you can install a shim on the crank to create some space between the flywheel and the crank. anyone else heard of this? i'm thinking the flywheel is just too close to the flexplate. is this shim the way to space it out? or should i get a new flexplate? and just another thought...the counterweight faces the front of the car, right?
 
Flywheel and flex plate bolt together......is the flex plate bent in the area it hits.

I think you are referring to the block plate...not flex plate. My block plate was bent in that same area from the sloppy PO work. I got a large screwdriver in to it and was able to bend it out of the way. If you are going to try a spacer....I think I would pull the block plate and straighten it or if not possible, buy a new one and leave the spacer out.
 
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