fly wheel bolts

Slow Mo

Slow Mo

New member
Joined
Jan 3, 2009
Messages
44
Anybody else ever have problem with fly wheel to crank bolts backing out?
Heres the story,I had my DTT mostly billet (everything but intermediate and output shafts) built using my 8000 mile ,all stock motor no heavy trailering (under 6000 lbs) trans as core.I,m happy with it firm shifts (hard actually ,just the way I like).Every things good then approx 3000 miles later (a year actually truck is mostly a toy not DD) it starts shifting very soft then not past second and eventually not at all (this took place over about a five mile stretch tring to get it home).So I trailer it back to builder.I,m told converter locked up?? and broke bolts off between crank and flywheel resulting in destroyed billet flywheel ,converter (triple disc) and pump.Tranny gets rebuilt again new converter and flywheel under warranty (another $1000 ,now up to $8000).All,s good again, now over the week end I,m 200 miles from home and I start getting a noise from bellhousing area but only when very slow or stopped when over 20mph or so it sounded fine.So I limp it home in middle of night to minimize having to stop any more than necessary.Today I pull out tranny and find all but one bolt between crank and flywheel backed out and now the end of my crank is pretty much junk with the about the first 3/8" or so of all the holes being stripped and wollowed out from bolts hammering around.This happened less than 2000 miles after first incident.This truck for the most part gets driven normal most of the time,but yes I have twins and what not for a reason,It has made two pass down the track both less than 10 psi launches which resulted in about 400 ft burnouts peddling it and about four similar atempts on the street (all in unpopulated rural areas) but other than that its all been just normal driving and after all there was a reason I spent $7000 to begin with.
Now sorry about being long winded,but just woundering if anyone else has had a problem with these backing out.And at the moment I,m am assuming that no error was made on install (for now) since it was done by a very reputable DTT builder so please leave that out of your replies for now ,I,m just trying to figure out were to go from here.Again please keep replies civil this not ment to bash any one,but no I,m not happy about spending $8000 and getting less than 5000 miles out of it.I guess mostly I,m just venting.
 
You can go ahead and assume error on install. Its hard to imagine the crank was in any kind of shape after the first time.
 
I'd be looking for an installer error as well.

Never heard of any problems with those bolts other than that.

And like was mentioned, no crank damage?
 
Ya I know your right I,m just trying to stay a little positive,you know between seeing red.$8000 kinda hurts when your working class then end up with a junk crank to boot.
 
I would also research the flex plate. From what i know a flex plate is supposed to flex thats why there called flex plates. The billet plates are thick and ridged so the don't flex. Could be what made the bolt back out. I run a double laminated plate that can still flex. Thats my thought hope it helps.

Bob.
 
Ya thanks for reply ,thats also kinda what I was thinking also.I was just looking for other opinions and personal experiences (and I was a little upset ,well still am but wasn,t thinking real staight yesterday)
 
Was there any coating on the flexplate? I heard of a few that were powdercoated for some idiotic reason, so the bolts were able to get torqued correctly, but over a period of time the powdercoat wore away or cracked or whatever and then the bolt had a chance to work it's way out.
 
Yeah wow, 8 grand and its going to be quite a bit more to get it going again, this is a botched job right from the get go, I'd bet a bag of marbles the bolts wern't torqued right the first time and worked loose.

This should have been taken back to the installer, its error on their part right from the start IMO.
 
Ok one at a time.

Yes the flex plate was coated black,could be powder coat but didnt show any signs of cracking or chipping.

Next ,it was TRAILERED back once (900 mile round trip x 2 trips) now I have junk crank thats why I,m talking it apart now ,sooner or later you have to cut your looses.

And yes DTT flexplate.
 
So the powdercoat didn't wear away at all wear the head of the bolt goes? Well, there goes that theory!
 
Did the installer use the longer bolts? When I switched from a stock flex plate to a billet 1 on my truck I had to order longer bolts as the stock 1's only engaged about 5/16" into the crank.
 
Slow Mo said:
Ok one at a time.

Yes the flex plate was coated black,could be powder coat but didnt show any signs of cracking or chipping.

Next ,it was TRAILERED back once (900 mile round trip x 2 trips) now I have junk crank thats why I,m talking it apart now ,sooner or later you have to cut your looses.

And yes DTT flexplate.
Click to expand...

Bill at DTT told me to grind off any powder coat on those flexplates . Since then I believe the plates are anodized gold.

I use thread sealant on flexplate bolts for that very reason . The stuff won't harden up but still keeps the bolts inplace and does not back out.
 
I took apart a truck one time that was built just like yours 04.5 twin turbos fully built htt trans and billet flexplate. The bolts that hold the convertor to the flexplate came loose and destroyed the flexplate. When I took it apart I found one bolt in the crank broke off and rest loose. We put a factory flexplate back in and left the one broke bolt in the crank. But we had to get all new bolts to go in the crank as they were all messed up on the end. It also took out the pump in the tranny. Haven't had any issues with since then though. Not much help I know but its pretty crazy how similar they are, I would like to know what really happened as well.
 
Jared ,I didnt say it didnt were away cause it did along with about .030" of the metal,just that it wasn,t chipped or cracked next to holes.And my flexplate was black not gold anodize.

fw.jpg


ck.jpg


tc.jpg


crckbolts.jpg


and thanks for keeping this constructive and not bashing .Right now I,m just trying to figure out my options.And speaking of which opinons on helicoiling or over size bolts on crank (ya I,m not crazy about either but alternative is yanking motor and replacing crank which finacially is probably not a good choice either,job not real secure, and ya realize oversize would mean drill new flexplate that I,m not really fond of)
 
You can helicoil the crank . The flexplate can be drilled out and have collars installed .
 
Thanks for reply ,sure would save a lot of work just wasnt sure about them in this application.
 
Slow Mo said:
Thanks for reply ,sure would save a lot of work just wasnt sure about them in this application.
Click to expand...

Take your time and go slow . Helicoils are just as strong if not stronger than the original threads themselves.
 
You must log in or register to reply here.
Back
Top