stripped hole, transmission to bell-housing

12539 Views 25 Replies 11 Participants Last post by opelgt722002, Oct 8, 2004

ging

Discussion Starter · Oct 5, 2004

stripped hole on bellhousing

hello everyone,
This is not Ging. It is her husband/mechanic/lawncare specialist. We are slowly reassembling her 70 GT and ran into a snag this weekend. The hole in the Bellhousing (top passanger side) where the gear box attaches stripped out when I was torqueing it. I've read all the treads about Heli-coils, studs, jb weld, lock-tite... I'll probably just drill it out and install a larger bolt. Now for the question(s). I'm out of town for a while so I can't crawl under the car to look at the details but I'm sure many of you can pull the answers off the top of your heads or probably have matching bellhousing endtables with 1/4 tempered glass tops to refer to in a pinch.

1. is there enough meat around the existing hole (in the bellhousing) to allow me to use a larger bolt without weakening the structure?
2. is there enough meat around the hole in the gear box so if I have to enlarge that hole I don't weaken it?
3. does the hole in the bellhousing penetrate the inside of the housing? I don't want to remove the housing to do this unless there is a good chance I'll get metal shavings inside. That would be bad.

To me, it doesn't matter if I use Metric or SAE. I might even have a metric tap I used on my Honda. Anybody want to make a quick tip on a new hole size and tap size... Hint, hint.

BTW. My wife loves you guys and your willingness to help others. She is really proud to be associated with this whole group. She is impressed on a regular basis. I too could wander around this site for days and not get bored.

Thanks for any input

Dan AKA (Mr. Ging)

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1 - 20 of 26 Posts

BQS4

· #2 · Oct 5, 2004

Dan (aka Mr. Ging)
You can drill and tap a new hole, or you can do the heli-coil, either way is possible. I do have two extra bellhousings here if you want to go that route. The threaded bolt hole does go all the way through. There is also a little lee-way on drilling the corresponding hole in the trans itself. But, if you're going to go that far, why not come get one of the extra housings I have.
Gene

GTJIM (R.I.P.)

· #3 · Oct 5, 2004 (Edited)

Chips!

Either retapping bigger or a helicoil are viable - the helicoil will be the best as it will not need the hole in the bellhousing openned up. The hole will guide the redrilling for the helicoil too. Just load the drill (and helicoil tap) flutes with wheel bearing grease to capture the swarf so as little as possible ends up inside the bellhousing.

kwilford

· #4 · Oct 5, 2004 (Edited)

Well, don't I feel bad. Ging had asked me about the torque values for the tranny to the bell-housing, so I gave them to her (sorry, but until JUST now, I had forgotten that ging was a "she". Is "ging" short for Ginger?). 32 to 36 lbs-ft, right from the FSM. I checked it twice!

But I have had this happen myself, since the threads in the aluminum bell-housing are, well, aluminum! I ended up drilling and heli-coiling ALL of them, because I had a VERY bad experience with a tranny losing all its oil when my bolts loosened up on a long trip. TOTALLY wrecked the main-shaft (it didn't like being starved for lubrication).

So I suggest that you at least heli-coil the hole (M10 as I recall), and maybe take Gene up on his generous offer. And even then, four heli-coils are cheap insurance compared to a ruined tranny.

And the M10 bolt is a tight fit anyway, so a bigger (7/16" or M12) would be VERY tight. Many folks heli-coil the bell-housing holes, and then insert studs that are JUST long enough to get a nut over them.

JM2CW

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nobody

· #5 · Oct 5, 2004

I've been down this road too and found that much bigger bolts don't fit in the tranny too well. I'd do the helicoil or replace it. JM2CW

GTJIM (R.I.P.)

· #6 · Oct 5, 2004

Torque

The FSM notes: "Transmission to Flywheel ... 32-36 lbs.ft."
However the other manuals I have all note: "Tighten the mounting bolts to 29 lbs.ft. evenly and diagonally"

Don't think 3-7 lbs.ft. difference would strip the threads and I do wonder what 'trans to flywheel' actually refers to.

ging

Discussion Starter · #7 · Oct 5, 2004

GTJIM said:
The FSM notes: "Transmission to Flywheel ... 32-36 lbs.ft."
However the other manuals I have all note: "Tighten the mounting bolts to 29 lbs.ft. evenly and diagonally"

Don't think 3-7 lbs.ft. difference would strip the threads and I do wonder what 'trans to flywheel' actually refers to.

I did stop at 29 lbs but that bolt just wouldn't tighten. I just thought I hadn't bottomed out yet. I'm guessing that 'trans to flywheel' might mean transmission (gearbox) to flywheel (housing).
I was looking for a relatively painless but strong fix for this but this is my sweethearts baby. A little more time removing, tapping and coiling now will hopefully same me some time in the long run. The bell housing only weighs 10 lbs anyway. Ounce of prevention....

I won't be home to work on it until next weekend but I'll keep you posted
Thanks so much for all the input.
dan

bear

· #8 · Oct 5, 2004

Dan, First off, do not drill out the hole in the bellhousing for the heli-coil, you don't have to. Here's my story: Same thing happened to me on my T-5 bell housing. I went all over looking for an odd ball drill size required for the metric heli-coil kit that I bought at the local NAPA parts store. Finally, I decided to try and run the tap through the existing hole in the bellhousing, it went right through with no problems cutting the new threads for the heli-coil like a hot knife through butter. Then I figured out why, the tap is tool steel, the bellhousing is aluminum. Really simple. The heli-coil kit was pricey at NAPA, but includes the tap, 4 helicoils, and an insertion tool. I've had the bolts in and out a couple of times during the mating stage of the engine and tranny and the heli-coil is still holding up great and takes the full torque recommended by the manuals for the Camaro/S-10 bellhousing to engine mounting bolts. HTH.

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BQS4

· #9 · Oct 5, 2004

Just to set the record straight, and a little off-subject, "Ging" is female, and her real name is Virginia. Dan, aka "Mr. Ging" is a joke, as it was Ging that contacted us first and Dan has always been in the back ground. I started the "Mr. Ging" as I didn't know Dan's name at the time. These two are wonderful people and have the most ernest inspiration to become "Opel-holics"

ging

Discussion Starter · #10 · Oct 5, 2004

The REAL Ging and the FSM

Yes, it's me. The wonderful, fantastic, only ... GING.

Heh, heh. Keith, it's okay - the de-evolution goes Virginia, Ginger, Ging. We won't go into the other things I've been called.
Now here's the part I need to find out. The FSM, of which I am beginning to think I have a really bad misprint of or I am totally and completely blind, is giving me different torque values than the ones I'm seeing here. The reason Keith checked it twice I believe is because I asked him if he was sure on the torques since mine said 29. After reading these posts I went back and checked about twenty times and came up with 29 repeatedly.
1970 1.9 GT
Pg 60-24 Transmission to clutch housing attaching bolts 29
Pg 71-8 Transmission to clutch housing 29
Pg 72-22 Transmission to flywheel (?well,you know...) 29

So you all are freaking me out. Where are you finding the 32-36?

And GTJim, would it just be best to yank everything rather than take the chance that any 'bits' get in there if we use helicoils? After this crank fiasco I'm a total textbook paranoiac (hah, well past that) about even specks of bad air near the entire engine... .
Thanks repeatedly until you're sick of hearing it,
Ging
P.S. Oh, and Gene, could I just have an entire car rather than getting the parts one at a time?

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BQS4

· #11 · Oct 6, 2004

Ging;
At this time, I don't have a whole car to spare. In fact, I need to get my GT in the garage to get started on the nose body work. But, you're still welcome to the bellhousings

greensmurf20

· #12 · Oct 6, 2004

i got 2 cars if you seriousely want another GT to fix or for parts. ones stricly parts, other is a easy fixer upper.

kwilford

· #13 · Oct 6, 2004

ging said:
The reason Keith checked it twice I believe is because I asked him if he was sure on the torques since mine said 29. After reading these posts I went back and checked about twenty times and came up with 29 repeatedly.
1970 1.9 GT
Pg 60-24 Transmission to clutch housing attaching bolts 29
Pg 71-8 Transmission to clutch housing 29
Pg 72-22 Transmission to flywheel (?well,you know...) 29
So you all are freaking me out. Where are you finding the 32-36?

Interesting. Strictly academic, since the difference between 29 and 36 lb-ft isn't all that much, but still...

You must have a '70 FSM, which is the only year I don't have. I looked at my '69 FSM. Page 71-10, section 71-14, "Installation of Clutch", paragraph 7, it says "Install flywheel housing and torque bolts to 36 lb.ft". Maybe that means the bell-housing to the block? The same manual, page 72-14 (Transmission), under Specifications and Adjustments", says "Transmission to Fly Wheel...29 lbs.ft". The '71 FSM is at least consistent, with both specs being 29 lbs.ft (and is more specific, calling it "Transmission to Clutch Housing" under the Transmission section). But the '72 FSM calls for 32-36 lbs.ft for the "Transmission to Clutch Housing" (page 71-9, bolt tightening specs) ,and 32-36 lbs.ft for the well-known "Transmission to Flywheel" bolts. The '73 FSM says 32 - 36 lbs.ft in both sections. Repeated verbatim in the '74 FSM. So clearly, the answer is between 29 and 36 lbs.ft. Or, maybe NOT so clearly!

But again, any value between those should be fine.

HTH

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ging

Discussion Starter · #14 · Oct 6, 2004

Manual Chaos

Thanks Keith.
I was more worried that I had screwed up somewhere in my reading or manual info location than a little torque difference. Like you said, it's not that much - just wanted to make sure I wasn't going into an area where it might end up making a big difference if I somehow was reading the swahili version unaware. It is interesting that there is that difference for the 'one' year. Lord, I just know I'm stuck with the queer car and the queer problems. Won't the learning be fun! (Gag, choke, cough....)

GTJIM (R.I.P.)

· #15 · Oct 6, 2004

Torque Talk

The clearest info I can find is in the current Brookland Books "OPEL GT Ownwers Workshop Manual" which is one of the better manuals still available new.

Clearly stated therein : Clutch Housing to Cylinder Block 36 lbs.ft.
Gearbox to clutch housing 29 lbs.ft.

One of the problems is that the original German specifications were in Kilogram/meters and the translation of the terminoligy from the German to English may have been a bit shakey. We all know how, even amoung "English" speakers how many different terms are used for car parts.

It is always better to remove an item for repair - and in this case all the gearbox mounting threads can be replaced with helicoils much more easily if the bellhousing is out of the car.
Probably save some grief in the future.

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kwilford

· #16 · Oct 7, 2004

GTJIM said:
The clearest info I can find is in the current Brookland Books "OPEL GT Owners Workshop Manual" which is one of the better manuals still available new.
Clearly stated therein : Clutch Housing to Cylinder Block 36 lbs.ft.
Gearbox to clutch housing 29 lbs.ft.

kwilford said:
...the '72 FSM calls for 32-36 lbs.ft for the "Transmission to Clutch Housing" (page 71-9, bolt tightening specs)

As I stated, the '72, '73 and '74 Genuine Opel Factory Service Manuals clearly state to torque the transmission to bell-housing bolts to 32-36 lbs.ft. Nothing ambiguous about that, after you get over the fact that each of the previous FSM's had a different, and conflicting, value.
Reminds me that the '71, '72, '73 FSM recommended torque values are 36 lbs.ft. for the pressure plate to flywheel bolts (referred to as the "Clutch cover" in the FSM's), which will nicely twist off those poor little grade 8.8 M8 bolts. The '69 FSM gets it right in the text (at 15 lbs.ft.) but still says 36 lbs.ft in the specs. Oh, the inconsistency of it all!

Dmcbrass

· #17 · Oct 7, 2004

If you study the science of torqueing bolts it will drive you nuts. There are dry torque settings (without lubricants) and wet torque settings (with lubricants). It turns out that neither of them guarantee the proper stretch on the bolt, which is what we are really attempting to do by torqueing bolts. Different grade bolts require different torque settings. New threads vs. old worn threads, accuracy of the machining of the threads, and all kinds of other variables. The bottom line? Don't worry too much about the difference between 29 and 36.

ging

Discussion Starter · #18 · Oct 7, 2004

How to torque

Let's write our own manual.
Some basic torque values could be expressed this way:

Hand tighten.
Give it a good pull with the wrench.
Haul on the wrench a little.
Give it a good yank.
A good yank with a second sharp yank.
A good yank with a few sharp yanks.
Put all your weight on the wrench and groan.
Pull till you dislocate a joint or tear a muscle.
Stand on the wrench and bounce or jump up and down.
Harness several friends to the wrench and crack the whip.
Forget it. You'll never get it tight enough.

Hey, it seems more explanatory and specific to me.

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nobody

· #19 · Oct 7, 2004

I agree completely but you left off a couple.

Wrench on it till your knuckles are busted
How tight and where,... you must be kidding
Wrench till something gives

ging

Discussion Starter · #20 · Oct 7, 2004

Perfect!! I've done all those!
(I've also thought the 'use tool JA3-173=13850987551' meant the tool made in one year of production only, two were offered for purchase, both belong to a wizened old man in a remote corner of Germany and are somewhere in his barn and he has no intention of looking for or selling them and the barn is going to be bulldozed tomorrow with no items removed or allowed to be removed. In other words - it don't exist.)

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