Flywheel screws won't torque up!
 

Based on experience, What are my options?

I'm torqing up the fly wheel screws on a 1980 3.0 (9 screws, 10 x 1.0), crisscross pattern as per WD's book.

Two screws will not come up to final torque, so I FULL STOP.

I think my options are:

1. Do nothing (Always option #1 in my world)
2. Remove wheel. Install inserts. I figure the drill will follow the exisitng hole and I don't want to do Option 3.
3. Do Option 2 after removing crank from case.

:confused:

i guess you mean flywheel to crank bolts. 66ft lb. never had a problem with them. the early engines went about 115ft lb, on the 6 bolt models. forget about drilling or inserting the crank threads. they're probably still ok, being they're harder than the bolts. what torque spec do you have?

If it was me I would:
- Compare new bolts to old bolts.
- Pull flywheel and examine holes.
- Check torque wrench.
- Make sure I was torquing them to 66ft-lbs, not the much higher torque of the earlier 6 bolt flywheels.
- Check threads of new bolts for deformation from over torquing.
If I overtorqued them I wouldn't use even the ones that did torque up.
-Chris

We have been having problems with flywheel bolts on both 6 and 9 bolt cranks so we replace them with new ones. If you install new bolts and still have a problem, look to the threads in the crank.

Some late model flywheel bolts are torque to yield bolts that should be replaced. I imagine you are attempting to reuse a set that are deforming on you. Take them out before you break one off in the crank and get a new set.

The torque to yield bolts started with the dual mass flywheel cars (964's).
-Chris

I dunno about that, I know the late model flywheel bolts are a 'replace after use' bolt which leads me to suspect a TTY.

Check your torque wrench for calibration. I had a Snap On that was way off and snapped the bolts on a ford rocker arms.


Kevin

Until this summer that's what I thought that too. When I checked the manuals I discovered that previous to the 964, the factory manuals don't say to replace them.
-Chris

The flywheel bolts on a 1970 911T are single use, torque to yield bolts, I would suspect that most of the others are as well. IE use once and then toss them. And it don't matter what the manual says, these bolts MUST be replaced.

Thanks for the replies. The bolts are new and were supplied by... (Wait for it!) ... Pelican. I haven't done autopsy yet, as there's two more sources I want to consult. Jack, the history of the crank (remember: it's a 3.0 circa 1980) is unknown and the engine didn't have a flywheel on it when purchased. Hmm. Thanks again for everyone's valuable input. I'll be back.

Dumb questions from the backrow:

Is the clutch plate assembly correctly assembled?

did you run the bolts into the holes to finger tightness before assembly to make sure there were threads to begin with?

Are you using the little $10 tool to center your flywheel assembly?

David,

Clutch Plate Assembly not installed yet. Finger assembly and prelim torque-up was A-OK and felt good.

There's a tool for one of these mills that only cost $10 ?

PEL-TOL-CA2 Clutch alignment tool

http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_clutch_pg7.htm#item25

Sorry, $8.65 each! :-)

I made my own tool for free with a piece of plastic stock and a lathe. :cool:

"Kids these days with there fancy lathes. In my day we had to use a broom handle."

"Broom handle? Musta been nice. We had to whittle our own out of wood with a pocket knife."

"Geesh, wish we had pocket knives. We had to use a pointed stick."

"Pointed sticks?!! We would have given our right arm for a pointed stick..."

Sorry, I think I need to adjust my dosage... :D
-Chris

Jeez, you guys had RIGHT arms ?

Always triple check and if possible cross check torque specs on Porsche parts. I once used a newer torque spec on a diff part, stretched the bolt out like a piece of spagettie, wrong spec.

Diassembled bolts and found three that are stretched. The photo is not too focused, but you can see the elongation. I'll be more careful on the next batch.http://forums.pelicanparts.com/uploa...1106236088.jpg :p

you never said what torque spec you were using.

Sure looks like more than the 66.4 ft lbs recommended.
That is assuming the 930 bolts get the same torque as the same model year 911.

John W,

I was using Wayne's 911 Engine book. I'll probably never know root cause, however I speculate operator error (Hey, it can happen.) and my trusty Snap-On clicker (vintage 1971) deserves a calibration session.

66ft lb? yes? no? just trying to clarify. come on, fess up.

Gary,

hopefully 66 ftlbs! Please let us know as it will help diagnose.

I was also using two clicker style torque wrenches on my car. I found out the hard way (broke a cv bolt) that one was reading waaaaaay to light and one was reading waaaaay too heavy!!! I had to go back over everything with a T-Bar style wrench to set torque. FWIW...

OK guys OK... it was 88 ft-lbs and she said she was 18 and...

Wait. That's not right. Forget that last part... however, it's true... I torqued up to EIGHTY-EIGHT FOOT POUNDS!!!

Waaaahhh!

I did not refer to the Torque Spec Table and mis-read the text. In my (feeble?) defense I was thrown off by "..911s.." and interpreted it as "...911's...".

and lastly, did I say Thank You All for the input, even you ball-breakers. Thanks.SmileWavy

Gary,

If it makes you feel better, I've never done that before!!! (yeah, right)

Glad the bolts didn't fail - I haven't heard of any others with problems.

Get that wrench calibrated (as I say in the front of the book). Otherwise your engine may fall apart or explode when you go to start it :) .

-Wayne

How often should a torque wrench be calibrated ?

Our shop checks our torque wrenches about once a month but they are always fine so I imagine that once every year or so should be good enough.

The secret to keeping one from going out of whack is to set the torque setting down to almost nothing when its not being used.

A quality wrench should come with a recommended cal schedule. Unfortunately it also depends on use and other factors. For home shop use or for that matter any shop use ALL new tools need 100% calibration by an independant shop. I have worked in a big time cal lab at Xerox when I was a student engineer. We calibrated 100% of everything new. We found an astounding number of things way out of spec. From $10 tools to $100,000 tools, no exceptions. After that, for home use, on a torque wrench, get two and cross check every once in a while, eg ck your 50 ft lb wrench at 50 against your 150 ft lb wrench. If ok use it. (This is a TOTAL NO NO for any commercial use and not a recognized cal technique, but for home use, what the heck)

Yup, all manuals and books say not to do this. HOWEVER, if you have a bar wrench like this one:

http://images.google.com/images?q=tb...Torque.jpg</a>

you can do that trick quite well...

-Wayne