While assembling my engine last night I checked the torque spec for the front pulley - to crank bolt. The book (Haynes manual) read 42.5ft/lbs.
This seemed high to me but some times I have had the occation to use titainium bolts that have extremely high torque values. So I looked at the end of the bolt, it had an 8.9 on it (metric) but I am used to imperial markings so I just assumed it was high enough strength to hit 40 ft/lbs. I still wasn't convinced so I set my wrench at 30.......snap!
Now I know 8.8 is the equivilant to a grade 5 bolt, not very strong.
I looked it up in another manual, 18 ft/lbs. I should have done that first.
The good news, I was able to remove the broken stud with a pair of needle nose pliers.
What did I learn? 8.9 grade, 8mm, self locking bolts are not available off the shelf in Timmins.

exactly where in the book do you find that number?

i can't seem to find 42.5ft/lbs for that bolt ...
Andy

I'll scan it tomorrow and post it.

just tell me the page

There's a reason they're known collectively as the Haynes Book of Lies (HBOL), at least by the British community.

Is it the bolt that attaches the hub to the crank??

I torque that sucker as tight as I can without snapping off a grade 10 bolt! Thats a special bolt and must not be confused with any other bolt.

My video has the correct torque, even though we don't pay attention to it... Once you loose an entire engine because of a loose one it scares ya! that was the last one!

If it was the bolts that hold the fan to the hub I use 21 pounds on those and replace them with grade 10s also.

nice tip .

kevin

Yes it is that bolt. I didn't even get to 30 ft/lbs and it snapped.
Suggestions for a new bolt? This one had a locking surface under the face of the hex. I haven't been able to find a new one like it. I don't like using locktite or thread sealants in the end of crankshafts but still want to lock it down with something better than a lock washer.

As for the page, I believe it is on the pages with all the engines specs.(near the front of the book) At the end of the tolerances section is the torque section. Book is at the shop right now or I would have given a page number.
Tx
Doug

Use a small bit of red loctite just at the top of the threads nearest the bolt head.

The bolt is special, and has small serrations on the bottom of the head that dig into the thick hub washer and lock it.

I have never broken one- thats a tough ass bolt!

Not mine... do you have a spare "tough" one to sell? I can't seem to find one up here. (or at least know where I can find one?)
I have a spare motor, siezed in a box. Can I get the bolt out of it through the fan by taking off the little rubber cap? I don't want to tear down the spare just yet for one bolt.

What are the specs on the bolt (size & lenght?) I'll see if I can get you one from a local supplier

Yes, remove the cap in the center of the fan and the bolt is accessable.... Their is no other bolt that will work correctly there thats easily attainable...

Jake,
the flywheel bolts are a pet peeve of mine. I had to replace the flywheel on an engine ten years ago. It had been apart a few times I believe. I had never had problems reusing the bolts when I tightened to spec. This time it came apart on the fellow while I was on holiday. I had to pay another shop to fix it. Later I spoke with a few fellows who said to only use new bolts and use Loctite also. Now I keep new bolts on hand as well as the big washer. What is your experience with these bolts?

I have ARP make new ones for us. They hold 95 ft/lbs easily and work well with our 5 doweled cranks and flywheels.

The flywheel bolts are strong special units like the front hub bolt... I have seen them shear off and cause a failure in bus engines before. Busses are hard on those bolts if you cross a mountain with a load... I 5 doweed my bus and used our ARP bolts..

If you have new ones change them, for sure.. Take note that 914 bolts are longr than bus bolts due to the thicker 901 flywheel . Don't use bus bolts on a 914 or the thread protrusion is less and weaker.

My ARP bolts are 5 bucks each but the engine is worth it!

For "special" bolts, go to the dealer or talk to your favorite Porsche (or VW Type IV) specialty outfit. Those are the type of thing you won't find at your local hardware store, or metric fastener specialist, or Caterpillar dealer.

--DD

Flywheel Bolt = "Gland Nut?"

I thought that was something like 120+ ft-lbs (at least on my T1).

Dave,

he's in Timmings. The closest porsche dealer is here or in Toronto.

There is a specialty nut/bolt fastner place here. All they sell, row upon row of bins full of nuts & bolts. If they don't got it, it don't exist.

OOPS, my bad!!!! Haynes wasn't wrong, just confusing.
It appears I cannot read very well. (but am willing to admit it)
Had I continued to read the next page I wouldn't have confused "small V-belt Pulley - 43 ft/lbs" for "bolt for blower impeller hub - 23 ft/lbs". Ouch
The other manual I have has it called "fan hub screw - 20 ft/lbs"

The good news is I was able to get the one off my spare 1.7. through the blower opening.

Maybe I can get the admins here to change the "Too Much Torque" in the heading to " Or maybe they weren't"

Then mail-order is the way to go.



Doubtful. Even for "row upon row" of fasteners, it is very unlikely in the extreme that any place will carry all of the oddball special purpose fasteners used by every make and model of car. It is worth a try, however... But I wouldn't be surprised if they didn't carry this bolt (for instance)--which makes it a dealer-only or Porsche/VW-specialist part.


BTW, the Type I gland nut is significantly different from the Type IV fan hub bolt.

--DD