| Author |
Message |
Gus Causbie (Gusc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 19, 2006 - 8:42 pm: | |
What is the proper torque for the bolts holding the clutch bell housing to the engine? I have three manuals and none give this figure except the DD 71 Series Manual gives general torque values based on bolt size, thread count and bolt grade.
This is for the alternator bracket and the bolt is a 3/8"x16 TPI. The DD book says 30-35 lb-ft in general but this is into the aluminum block and I sure don't want to strip the threads. One of the three bracket threads is stripped already.
Does anyone know where to find this in writing? I don't want to guess on this. |
morgan Clough (Mclough777)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 19, 2006 - 9:00 pm: | |
a grade 5 bolt is 30
a grade 8 is 43
that is the general torquee of any 3/8 -16 bolt application. only other thing to effect that would be if anti- seize or similar compound is put on cap screw. |
Luke Bonagura (Lukeatuscoach)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 19, 2006 - 9:14 pm: | |
Hi Gus & Folks:
Morgan provides good info.
30 to 35 ft. lbs. is easily applied with a wrench or light socket drive.
With regard to having one stripped out hole already, I might suggest going to your local automotive store and buying a "helicoil" set.
You will drill out and tap the worn hole to accomodate the helicoil which provides "NEW" internal thread to accomdate your bolt and provide an even tightening of your 3 bolts.
If you are in doubt about the other 2 holes, then put helicoils in them and you can travel down the road with "Peace of Mind".
I Hope this HELPS!!!
Happy and SAFE!!! Bussin' to ALL.
LUKE at US COACH |
Gus Causbie (Gusc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 20, 2006 - 2:17 pm: | |
Morgan,
Thanks, but those figures are for bolts and nuts. These bolts are grade 5.
My problem is that these threads are in the Al casting of the flywheel housing (I incorrectly said the aluminum block in my first post) to which these bolts hold the clutch bell housing. I don't think they can take much torque.
All I can find is 30-35 lb-ft for attaching the clutch housing to the block which is cast iron. I don't feel comfortable using more than 25lb-ft on the Al but sure would like to know exactly because the alt bracket needs to be very secure.
Luke,
Thanks, I have all the necessary stuff for helicoils and may have to go that route yet. |
Sammy (Sammy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 20, 2006 - 5:56 pm: | |
You can also try another type of thread insert called a "keensert". They work GREAT.
They are thread inserts with 4 small "spikes" equally spaced on the outside of the insert.You install the keensert (I use a small amount of Loctite too)and then stake down the 4 equally spaced "spikes.It's not going anywhere when you're done.Best of luck with your repair. |
Gus Causbie (Gusc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 20, 2006 - 9:04 pm: | |
Sammy, thanks, sounds like some inserts I bought a while back for spark plug holes and luckily never had to use them.
I happened to have the helicoils on hand so inserted one in the stripped hole and torqued it to 25p-f which felt comfortable. However, when I torqued the other two they felt pretty spooky and I'm glad I didn't go over 25 p-f. You know that feeling of just before the torque all of a sudden drops to zero!
The alternator is nice and secure now, thanks to all for helpful ideas. |
Tim Hoskinson (Tdh37514151)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 20, 2006 - 10:28 pm: | |
Hi Gus I have been in your predicament myself. You know the bolt will take the rated torque but will the aluminum housing? If you like I will go out and pull a bolt down to 35 or 40 ft lb in one of my junk bellhousings as a test to put you more at ease. You shure don't want these bolts coming lose out on the road. Let me know and I will post the out come. Tim |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 20, 2006 - 11:44 pm: | |
I think what Luke is saying, is.... The bolts used are marked
according to what torque is specified for the application. If it
were a cast iron application, higher torque would be indicated
on the bolt itself. Trust the markings, if all bolts carry the same. |
Gus Causbie (Gusc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 20, 2006 - 11:45 pm: | |
Tim,
Thanks, I would appreciate it if you would do that test. I would think that 40 p-f max would be plenty tight.
I feel pretty good with what I have since the bracket only had two bolts holding it when I took it off. It's surprising how tight 25 p-f feels on the torque wrench.
The Al housing is the one bolted to the rear of the engine called the flywheel housing. The clutch housing bolts onto it. |
Tim Hoskinson (Tdh37514151)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 20, 2006 - 11:49 pm: | |
Gus disregard my post between having problems with my computer and not having read your last post I did not understand your problem correctly. Tim |
Gus Causbie (Gusc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 22, 2006 - 12:26 am: | |
John,
That theory is good only if the bolts are original grade, which is not the case.
This is an added on alternator bracket which required longer bolts so there is no way for me to know if the bolts are the correct grade. |
Tom Caffrey (Pvcces)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 22, 2006 - 10:35 pm: | |
Gus, look at the markings on the original bolts. Your longer replacements should have the same or equivalent markings.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 23, 2006 - 12:30 am: | |
Gus -
If in that much doubt, I'd go with the first thoughts. Tighten
to 25, and use locktite. as long as it hold the belts to the
proper tension, all's well! If not, tighten more!
Right? |
Gus Causbie (Gusc)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 23, 2006 - 1:08 am: | |
Tom,
My problem is that I have no confidence in any of these bolts being original after 52 years of being exposed to who knows what mechanics.
From the way the ones without the helicoil felt I will leave them and keep a close watch for any signs of looseness. I really don't expect any problems but one never knows. I'll check the torque again before I mount the alt.
Thanks to all for suggestions. |