LOST JEEPS :: View topic - Beware of Torque converter bolts, may be not tight.

Any good mechanic knows to use Loctite on any spinning part.

CAUTION: It is essential that correct length bolts
be used to attach the converter to the driveplate.
Bolts that are too long will damage the clutch surface
inside the converter.
26. Install torque converter-to-driveplate bolts. Tighten
bolts to 31 N·m (270 in.lbs.).

BlackLibertyCRD wrote:

Any good mechanic knows to use Loctite on any spinning part.

False,a good Technician will only use loctite when specified.TC bolts need to be installed and torqued with dry threads,adding loctite lubricates the threads and you will end up over-torquing the bolts making them difficult to remove.

Quote:

SunCoast Torque converter, SunCoast specs recommend Red Loctite.
Having worked with bolts in special applications that required destructive testing, I will pass along some info that is beyond the Dealer Tech or Engineer training.
Engineering tables for bolt torques are very conservative and are rated so the poorer quality bolts in the batch will pass. Often any given bolt in the sample will take 20% to 100% of the rated torque before failing from torque or stretching. Good bolts which are being destructive tested will stretch and yield when they are over torqued. Poorer Quality Bolts will just twist off and not stretch when they are destructive tested.
The 5/16" X 1/2" Grade 8 bolts with 9/16" heads are designed specifically for the application premium quality (judging by their appearance) and not some Farm Supply Store sold by the pound and made who knows where bolts. At 270 IN-Lbs with Loctite the Torque converter bolts are not stretching and when continuous torque is applied to sense stretchering, they just stay there.
Since my old converter is going to SunCoast as a core and I salvaged the four torque converter bolts I could do a destructive test on the bolts and determine their Yield Torque to see where they start to stretch as I predict and not just twist off like junk bolts. To do the test, the threads will be lubricated with Loctite and the torque on the torque wrench will be brought up slowly until the bolt head starts to turn after being torqued to 270 In-Lbs.
I will report the results.

FYI: Red Loctite can either be shattered by striking the bolt head with a hammer or gently heating the bolt with a small torch to about 400f. By By Loctite.

Bolt stretch and fatigue is not the only issue you need to worry about,in this case the actual TC threads have to be taken into effect.

warp2diesel:

What ever happened to the destructive testing? I'm interested to see the results.

Thanks.

Author:	warp2diesel [ Mon Jun 14, 2010 8:42 am ]
Post subject:	Beware of Torque converter bolts, may be not tight.
I started the Transgo/SunCoast upgrade and when I removed the Four Torque Converter bolts two were tight as if they were torqued and two were not so tight, I could have removed them with my 1/4" drive ratchet (had the original stock converter before the upgrade). No evidence of any Loctite or other thread locker of any kind. SunCoast recommends Red Loctite and I will use Red Loctite after I clean the threads with Acetone. Production does as a general rule (as do most Five Star Steelers) what Engineering puts into the specifications. Engineering screwed this one up, at least they could have used the Blue Loctite like the do on the rear drive shaft. More Bean Counter Engineering. For those who need more proof of Bean Counter Engineering, help me find in the manual I read a few times where they say to use thread locker of any kind, it ain't there. Even for the Stock DieHards who want to keep the original converter, you may consider popping the access plug and starter R&R the bolts one at a time, put some Loctite on the Torque Converter bolts, and torque the bolts to 270 IN-Lbs. Cheaper than a trashed converter and flex plate.

Author:	DynoPax [ Mon Jun 14, 2010 11:51 am ]
Post subject:	Re: Beware of Torque converter bolts, may be not tight.
Interestingly, I came to the same conclusion with my aborted attempt to change the TC... When I removed the bolts, I was surprised at how easy they came off. So, for good measure, I torqued them properly when re-installing them, plus a dab of Loc-Tite on each. And since I will re-attempt to do that job again this summer, I made sure to use the non almost-definitive sort of Loc-tite, which I believe is the blue kind...

Author:	BlackLibertyCRD [ Mon Jun 14, 2010 2:31 pm ]
Post subject:	Re: Beware of Torque converter bolts, may be not tight.
Any good mechanic knows to use Loctite on any spinning part.

Author:	warp2diesel [ Mon Jun 14, 2010 2:48 pm ]
Post subject:	Re: Beware of Torque converter bolts, may be not tight.
BlackLibertyCRD wrote: Any good mechanic knows to use Loctite on any spinning part. Good Mechanic, yup. Regular Engineer after three failures, yup. Bean Counter Engineer, after a high power Law Firm cleans His/Her clock, maybe, maybe not. Centavo wise Peso Stupid!!!!!!

Author:	tjkj2002 [ Mon Jun 14, 2010 10:08 pm ]
Post subject:	Re: Beware of Torque converter bolts, may be not tight.
BlackLibertyCRD wrote: Any good mechanic knows to use Loctite on any spinning part. False,a good Technician will only use loctite when specified.TC bolts need to be installed and torqued with dry threads,adding loctite lubricates the threads and you will end up over-torquing the bolts making them difficult to remove. Quote: CAUTION: It is essential that correct length bolts be used to attach the converter to the driveplate. Bolts that are too long will damage the clutch surface inside the converter. 26. Install torque converter-to-driveplate bolts. Tighten bolts to 31 N·m (270 in.lbs.).

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Beware of Torque converter bolts, may be not tight. http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=53519	Page 1 of 1

Author:	warp2diesel [ Mon Jun 14, 2010 11:24 pm ]
Post subject:	Re: Beware of Torque converter bolts, may be not tight.
tjkj2002 wrote: BlackLibertyCRD wrote: Any good mechanic knows to use Loctite on any spinning part. False,a good Technician will only use loctite when specified.TC bolts need to be installed and torqued with dry threads,adding loctite lubricates the threads and you will end up over-torquing the bolts making them difficult to remove. Quote: CAUTION: It is essential that correct length bolts be used to attach the converter to the driveplate. Bolts that are too long will damage the clutch surface inside the converter. 26. Install torque converter-to-driveplate bolts. Tighten bolts to 31 N·m (270 in.lbs.). SunCoast Torque converter, SunCoast specs recommend Red Loctite. Having worked with bolts in special applications that required destructive testing, I will pass along some info that is beyond the Dealer Tech or Engineer training. Engineering tables for bolt torques are very conservative and are rated so the poorer quality bolts in the batch will pass. Often any given bolt in the sample will take 20% to 100% of the rated torque before failing from torque or stretching. Good bolts which are being destructive tested will stretch and yield when they are over torqued. Poorer Quality Bolts will just twist off and not stretch when they are destructive tested. The 5/16" X 1/2" Grade 8 bolts with 9/16" heads are designed specifically for the application premium quality (judging by their appearance) and not some Farm Supply Store sold by the pound and made who knows where bolts. At 270 IN-Lbs with Loctite the Torque converter bolts are not stretching and when continuous torque is applied to sense stretchering, they just stay there. Since my old converter is going to SunCoast as a core and I salvaged the four torque converter bolts I could do a destructive test on the bolts and determine their Yield Torque to see where they start to stretch as I predict and not just twist off like junk bolts. To do the test, the threads will be lubricated with Loctite and the torque on the torque wrench will be brought up slowly until the bolt head starts to turn after being torqued to 270 In-Lbs. I will report the results. FYI: Red Loctite can either be shattered by striking the bolt head with a hammer or gently heating the bolt with a small torch to about 400f. By By Loctite.

Author:	tjkj2002 [ Tue Jun 15, 2010 12:19 am ]
Post subject:	Re: Beware of Torque converter bolts, may be not tight.
warp2diesel wrote: SunCoast Torque converter, SunCoast specs recommend Red Loctite. Having worked with bolts in special applications that required destructive testing, I will pass along some info that is beyond the Dealer Tech or Engineer training. Engineering tables for bolt torques are very conservative and are rated so the poorer quality bolts in the batch will pass. Often any given bolt in the sample will take 20% to 100% of the rated torque before failing from torque or stretching. Good bolts which are being destructive tested will stretch and yield when they are over torqued. Poorer Quality Bolts will just twist off and not stretch when they are destructive tested. The 5/16" X 1/2" Grade 8 bolts with 9/16" heads are designed specifically for the application premium quality (judging by their appearance) and not some Farm Supply Store sold by the pound and made who knows where bolts. At 270 IN-Lbs with Loctite the Torque converter bolts are not stretching and when continuous torque is applied to sense stretchering, they just stay there. Since my old converter is going to SunCoast as a core and I salvaged the four torque converter bolts I could do a destructive test on the bolts and determine their Yield Torque to see where they start to stretch as I predict and not just twist off like junk bolts. To do the test, the threads will be lubricated with Loctite and the torque on the torque wrench will be brought up slowly until the bolt head starts to turn after being torqued to 270 In-Lbs. I will report the results. FYI: Red Loctite can either be shattered by striking the bolt head with a hammer or gently heating the bolt with a small torch to about 400f. By By Loctite. Suncoast recommends it for liability reasons. Bolt stretch and fatigue is not the only issue you need to worry about,in this case the actual TC threads have to be taken into effect.

Author:	warp2diesel [ Tue Jun 15, 2010 8:03 am ]
Post subject:	Re: Beware of Torque converter bolts, may be not tight.
tjkj2002 wrote: Bolt stretch and fatigue is not the only issue you need to worry about,in this case the actual TC threads have to be taken into effect. SunCoast like most aftermarket torque converter builders use a steel billet front cover. This provides a stronger material (than the bar stock Chrysler welds on) to bolt into it allowing their recommended torque with Red Loctite. Since SunCoast and other reputable Performance Torque converter builders actually test what they develop with Horse Power and Torque ratings greater than stock, they have gone beyond the Common Engineering assumptions that most Engineering consists of. True there is some Real Engineering Development that does take place in the Automotive Industry and the Engineers who get a chance to work in development are in a virtual Honeymoon compared with general run of the mill that goes on in Engineering departments, but since the torque is the same for the gasser as the CRD, Chrysler invested virtually nothing. To put this into perspective, all the development on the CRD was done long ago and the torque on the torque converter bolts was a passed on by assumption from other Chrysler products. In fact the Engineers most likely thought more about their cup of coffee than the torque converter bolts. SunCoast and other performance torque converter builders have invested more time and money than a few cups of coffee that the Chrysler Engineers had in the meeting where the torque converter bolts were on the list. To make the point for those who use a stock or Euro Converter, I will test the threads of my old converter when I do the destructive test of the bolts, I suspect the welded on threaded bar stock will survive and the bolts will stretch. This should dismiss any worries of torquing with Loctite.

Author:	kewaal [ Thu Dec 29, 2011 4:28 pm ]
Post subject:	Re: Beware of Torque converter bolts, may be not tight.
warp2diesel: What ever happened to the destructive testing? I'm interested to see the results. Thanks.

Author:	ebbnflow [ Thu Dec 29, 2011 9:47 pm ]
Post subject:	Re: Beware of Torque converter bolts, may be not tight.
Mine were tight when I removed my original TC. No sign of any thread sealer on the original bolts. I put blue Loctite on the new bolts and torqued them to spec.

Author:	warp2diesel [ Fri Dec 30, 2011 6:04 pm ]
Post subject:	Re: Beware of Torque converter bolts, may be not tight.
kewaal wrote: warp2diesel: What ever happened to the destructive testing? I'm interested to see the results. Thanks. Discussion: viewtopic.php?f=5&t=53555

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