Moparts
torque converter bolts keep comming loose
Posted By: rook440
torque converter bolts keep comming loose - 02/11/14 03:08 AM
flex plate bolts wont stay tight ...I have fought this problem for years with a 8 bolt flex plate sfi approved ,3 passes and they are beating up the back of the block ,,,they are red locktighted and tight ,Jim VanZee is now having the same problem ...one guy years ago said buy "the wheel " but I never did Jim said some guys say it isnt the flex plate its the Harmonic ballancer ,,,whose got the real answer ,,,,???
Posted By: pittsburghracer
Re: torque converter bolts keep comming loose - 02/11/14 03:20 AM
If your flex plate bolts were oil-free and you used 271 (red) locktite and the bolts are coming loose that fast you have a real issue going on.
Posted By: Polarapete
Re: torque converter bolts keep comming loose - 02/11/14 03:31 AM
A couple of questions come to mind...1) has the engine been balanced as an assembly? 2) what size are the bolts you are using (Hemi converters use oversized bolts probably for that very reason). Of course, you couldn't be using the large holes in the flex plate with small bolts...could you?
Years ago, I fixed a bad rattle in a GM car that was traced to loose converter bolts. The young lady was very grateful
Posted By: Dunnuck Racing
Re: torque converter bolts keep comming loose - 02/11/14 03:37 AM
Ran into this last year after changing convertor in a customers car. The convertor fit fine on a 6 bolt crank but on an 8 bolt, the flexplate to convertor bolts hit the hub on the convertor before the bolts into the convertor were tight.
Look to marks in that area of the convertor from the bolt heads. Thin spacers between the two fixed the issue but we used longer bolts to ensure enough thread engagement.
Keith
Posted By: W5DART66
Re: torque converter bolts keep comming loose - 02/11/14 03:42 AM
What balancer is on this?
Posted By: Dduster
Re: torque converter bolts keep comming loose - 02/11/14 03:56 AM
If your flexplate has powdercoat, scuff off the coating with a grinder. I know, looks bad but your flexplate nuts won't loosen up. Same technique for flexplate to crankshaft hub area.
Posted By: hemi-hunter
Re: torque converter bolts keep comming loose - 02/11/14 05:54 AM
harmonics, check to see if your balancer bolt is also coming loose
Posted By: A/MP
Re: torque converter bolts keep comming loose - 02/11/14 06:13 AM
If it is a SB make sure the converter is balanced for the crank used, cast internal, cast external, internal/ external flexplate. Very common mistake with the SB.
Posted By: Kevins493
Re: torque converter bolts keep comming loose - 02/11/14 06:18 AM
Had this exact problem. The short block on my spare motor came from one that had run on the dyno before so we just checked bearing clearances and put it together. Got to the point I was checking converter bolts on every run. Took it out and took the rotating assembly to Burtonsville performance machine and they called back and said it was 140 grams out. Had to put it back in the car this year, no issues.
Posted By: loaderpro
Re: torque converter bolts keep comming loose - 02/11/14 06:38 AM
I used to fight this when I first started racing...many many moons ago. Assuming you have all the correct parts, balancer included, and a flexplate that has round holes...not oblonged. You won't like what I have to say but the number one reason they come loose is that they are NOT tight enough. I have helped countless Mopar racers at the track with this very problem! I have used the B&M 8 bolt style flexplates since their inception, before SFI, and currently. I use blue locktight and a 15" snap-on wrench, get the bolt at the bottom, set the wrench so you can push up into the engine while tightening. if done properly you should not have to hold the crank, 60-80 ft lbs and then some!
Posted By: bill_greenwood
Re: torque converter bolts keep comming loose - 02/11/14 08:49 AM
Put Teflon tape on the bolts. We used to do this on certain fasteners on lathes and mills and it was the only fix that worked on my 360.
Posted By: rebel
Re: torque converter bolts keep comming loose - 02/11/14 09:08 AM
change your balancer. i had bolt loosening problem for almost a whole season til i worked out it was the balancer. we were tightening our converter bolts after every meeting til it got to the point we were checking them after every 2nd run. i had a Fluid damper from the Source. ATI balancer now, no more problems.
Posted By: coletrickle
Re: torque converter bolts keep comming loose - 02/11/14 02:09 PM
On my old stroker 4inch bore hemi six initally it was tearing the flexplate apart then upgraded to a 426 hemi plate then the bolts started to come loose after every race eventulally had to weld the bolts on,i was 18 and didnt know any better.Turns out that the torque flight hemi blocks were machined with the dowel pin slightly off center and that was the cause of my bolts loosenig up every pass.Probally not your problem but thats my
Posted By: an8sec70cuda
Re: torque converter bolts keep comming loose - 02/11/14 04:00 PM
Make sure you're using a good set of converter bolts. NOT the Mopar Performance bolts. Get a set of the 12 point ARP converter bolts. Use red loctite on them. Spray the threads in the converter out w/ brake clean to make sure there's no grease or oil in them.
Something out of balance will cause them to loosen...as well as detonation.
Posted By: dvw
Re: torque converter bolts keep comming loose - 02/11/14 05:26 PM
My bolts never come loose. They have no thread locker. Why are there hundreds of cars out there W/O locktite that have no issue? If they come loose with locktite there's a real problem. The only real cause that I can think of is harmonics whether it's a balance issue, detonation, or other. Oblong holes shouldn't matter,the bolt is not driving the plate,the clamp load is what holds it tight.
Doug
Posted By: TheOtherDodge
Re: torque converter bolts keep comming loose - 02/11/14 07:16 PM
Had this issue and a change to a good harmonic balancer solved the issue.
Posted By: rook440
Re: torque converter bolts keep comming loose - 02/12/14 01:31 AM
I was running an ATI ballancer and Im sure Jim is running a good one too ....lots of stuff to ponder now ....thanks to everybody,,,,I will let u know what we find....
Posted By: loaderpro
Re: torque converter bolts keep comming loose - 02/12/14 05:16 AM
Quote:
My bolts never come loose. They have no thread locker. Why are there hundreds of cars out there W/O locktite that have no issue? If they come loose with locktite there's a real problem. The only real cause that I can think of is harmonics whether it's a balance issue, detonation, or other. Oblong holes shouldn't matter,the bolt is not driving the plate,the clamp load is what holds it tight.
Doug
Respect your opinion...but if oblong holes do not matter then they would come from the factory that way...
Posted By: W2DODGE
Re: torque converter bolts keep comming loose - 02/12/14 06:36 AM
I had the same problem turned out the shop did not balance it correct.
Posted By: Leigh
Re: torque converter bolts keep comming loose - 02/12/14 11:06 AM
Quote:
Quote:
My bolts never come loose. They have no thread locker. Why are there hundreds of cars out there W/O locktite that have no issue? If they come loose with locktite there's a real problem. The only real cause that I can think of is harmonics whether it's a balance issue, detonation, or other. Oblong holes shouldn't matter,the bolt is not driving the plate,the clamp load is what holds it tight.
Doug
Respect your opinion...but if oblong holes do not matter then they would come from the factory that way...
Respect your opinion as well...but most factory holes are anything but perfect in size relationship to the fastener employed. And why would they spend more on an oblong shape anyway, if not needed? Factory stampings are about cost containment.
Posted By: Chris'sBarracuda
Re: torque converter bolts keep comming loose - 02/12/14 11:12 AM
Quote:
flex plate bolts wont stay tight ...I have fought this problem for years with a 8 bolt flex plate sfi approved ,3 passes and they are beating up the back of the block ,,,they are red locktighted and tight ,Jim VanZee is now having the same problem ...one guy years ago said buy "the wheel " but I never did Jim said some guys say it isnt the flex plate its the Harmonic ballancer ,,,whose got the real answer ,,,,???
I would say find the common things about both of your set ups.
If you have the same engine guy, that may narrow down the balancing.. Same converter company.?? T/F or Glide..
Chris.. 
Posted By: dvw
Re: torque converter bolts keep comming loose - 02/12/14 02:53 PM
Quote:
Quote:
Quote:
My bolts never come loose. They have no thread locker. Why are there hundreds of cars out there W/O locktite that have no issue? If they come loose with locktite there's a real problem. The only real cause that I can think of is harmonics whether it's a balance issue, detonation, or other. Oblong holes shouldn't matter,the bolt is not driving the plate,the clamp load is what holds it tight.
Doug
Respect your opinion...but if oblong holes do not matter then they would come from the factory that way...
Respect your opinion as well...but most factory holes are anything but perfect in size relationship to the fastener employed. And why would they spend more on an oblong shape anyway, if not needed? Factory stampings are about cost containment.
I'm not saying thats correct. It's the result of loose bolts, not the cause. Some GM flex plates have oval holes at 90* to each other from the factory. If an oval hole was an issue they wouldn't have ever done that.
Doug
Posted By: CompWedgeEngines
Re: torque converter bolts keep comming loose - 02/12/14 04:42 PM
Quote:
Ran into this last year after changing convertor in a customers car. The convertor fit fine on a 6 bolt crank but on an 8 bolt, the flexplate to convertor bolts hit the hub on the convertor before the bolts into the convertor were tight.
Look to marks in that area of the convertor from the bolt heads. Thin spacers between the two fixed the issue but we used longer bolts to ensure enough thread engagement.
I have absolutely seen this as a problem with several cars. The bolt heads are barely rubbing on the rounded part of the converter housing, and they will back out almost every run, or every couple runs.
I think its already been said here.
1) Check for interference of bolts/TC cover
2) Balancing/damper ( we have no idea on this one, only YOU know if the shop balanced it.Get the records from them and see if anything looks suspect)
3) I agree 100% with torquing the bolts everytime. A converter bolt SHOULD NOT need red loctite to STAY IN. Only to be a preventative safety measure.
My
Posted By: pittsburghracer
Re: torque converter bolts keep comming loose - 02/12/14 05:10 PM
Quote:
Quote:
Ran into this last year after changing convertor in a customers car. The convertor fit fine on a 6 bolt crank but on an 8 bolt, the flexplate to convertor bolts hit the hub on the convertor before the bolts into the convertor were tight.
Look to marks in that area of the convertor from the bolt heads. Thin spacers between the two fixed the issue but we used longer bolts to ensure enough thread engagement.
I have absolutely seen this as a problem with several cars. The bolt heads are barely rubbing on the rounded part of the converter housing, and they will back out almost every run, or every couple runs.
I think its already been said here.
1) Check for interference of bolts/TC cover
2) Balancing/damper ( we have no idea on this one, only YOU know if the shop balanced it.Get the records from them and see if anything looks suspect)
3) I agree 100% with torquing the bolts everytime. A converter bolt SHOULD NOT need red loctite to STAY IN. Only to be a preventative safety measure.
My
To go into detail a little further we had an aftermarket damper that looked great last year but the outer ring spun 180 degrees. Double check top dead center to see if the outer ring could be moving. An ATI damper is going on this years engine.
Posted By: MR_P_BODY
Re: torque converter bolts keep comming loose - 02/12/14 05:33 PM
To go into detail a little further we had an aftermarket damper that looked great last year but the outer ring spun 180 degrees. Double check top dead center to see if the outer ring could be moving. An ATI damper is going on this years engine.
He is running a ATI damper but I would check 2 things..
check the zero and check the numbers on it to make
sure it fits his application(external or internal
balancing)... the only times I've seen where the bolts
came loose the balance was off or the trans was not
in alignment and needed offset pins... I've been
using the MP bolts forever and I use them twice then
put in new ones(mainly because the head will round
a bit)... I use a impact on them through the starter
hole but just give then a light rap a couple times
Posted By: 11secdart
Re: torque converter bolts keep comming loose - 02/13/14 02:32 AM
Like everybody else said and check to make sure the converter bolts aren`t bottoming out, i.e. too long, I had this problem that I kept cracking flex plates, turns out the bolts were one thread too long, we cut them , put loc tite on them , retightened them with an impact thru the starter hole ( Like Mr P body said) and haven`t had a problem since.
Posted By: dvw
Re: torque converter bolts keep comming loose - 02/13/14 02:57 AM
Good call, another possibility.
Doug
Posted By: DusterDave
Re: torque converter bolts keep comming loose - 02/13/14 03:23 AM
Quote:
Like everybody else said and check to make sure the converter bolts aren`t bottoming out, i.e. too long, I had this problem that I kept cracking flex plates, turns out the bolts were one thread too long, we cut them , put loc tite on them , retightened them with an impact thru the starter hole ( Like Mr P body said) and haven`t had a problem since.
I re-read this entire thread, and nobody else mentioned bolts bottoming out as a possible cause. Were your bolts coming loose? That's the problem the OP is experiencing, not cracked flexplates.
Posted By: 11secdart
Re: torque converter bolts keep comming loose - 02/13/14 04:45 AM
Sorry
I just thought it was something else worth checking