2.0 Torque Specs

dharder · 10-10-2004, 09:15 AM

I'm installing fresh heads on my '73 2.0 and the book says to torque the heads to 23 ft lbs. Can this be true? It seems awfully low. Are there any other engine torque specs that may not follow the book?

Alfred1 · 10-10-2004, 10:50 AM

The 914 Technical Specifications booklet say 3.2 m*kg.

3.2 m*kg x (100cm / m) x (2.2lbs / kg) x (1 inch / 2.54 cm) x (1 ft. / 12 inches)

= 23.1 ft*lb .

Dave at Pelican Parts · Dave at Pelican Parts's Garage

And remember to go in the correct pattern. (Shown in the manuals.) I also approach the final torque in steps--I go through the pattern at ~15 lb-ft, then 20, then 22, then 23. And I'll usually come back the next day and go through the pattern again at 23, just to make sure.

--DD

SteveStromberg · 10-10-2004, 12:06 PM

I use four steps. Just snug the nuts I then use 7-14-21-23. If both heads are off then do both heads working back and forth as you go thru the steps. Ps you did lap the cylinders to the heads?

rsvp914 · 10-10-2004, 02:07 PM

Quote:

Originally posted by dharder
I'm installing fresh heads on my '73 2.0 and the book says to torque the heads to 23 ft lbs. Can this be true? It seems awfully low. Are there any other engine torque specs that may not follow the book?

I would think that the low torque values are to compensate for thermal expansion where the cylinder meets the head.

karlp · 10-11-2004, 05:15 AM

I felt the same way - That the tourqe spec was awfully low.
I tightened 'em up to what I thought was appropriate. Probably not a smart thing to do and I'm not recommending it and I've always had a hard time following instructions.

So far so good.

Karlp

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Karlp, you're setting yourself up for leaks. The engine will expand as it gets warm, and the "effective" torque on the head studs will go up. Way up. I would not be surprised to find that your heads warp and lose compression somewhere down the road.

Tightening the head nuts to "what seems reasonable" is not a good way to go.... The people who designed the engine had something of a clue about the torques needed to keep everything together without killing anything. That's why I recommend following the torque specs as written.

--DD

karlp · 10-11-2004, 10:15 AM

I know, I know....
I've always been my own worst enemy. That was over a year ago, though, and it sure does run nice*.
As I said - not a recommendation!

(*Unless you leave it out in the rain during a tropical storm. I think I've got a case of wetbrain.)

Karlp

david c. · 10-12-2004, 08:28 PM

I lapped my cylinders to the heads and torqued to the factory specs. Skipped the head gaskets per the tech bulletin and this boards recommendations. Guess what. It has leak between cyl 1 and cyl head.

Alfred1 · 10-12-2004, 09:35 PM

John Larson (Cap'n Crusty) has different ideas about how to seal a head to its cylinder. I think it's the opposite of what you did - don't lap and do use the sealing rings.

david c. · 10-13-2004, 05:30 AM

I went with what the conventional wisdom was on this board and on the STF board. It was against my instincts to skip the sealing ring but that's what everyone, including John from AC.net, told me to do.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

The Kap'n disagrees with just about everyone on this topic. VW issued a tech bulletin on the subject, telling their techs that any time you had the heads off the motor that the "head gaskets" should be removed. The bulletin is on the Web somewhere... Wow, I just completely dug up the URL from memory!! http://www.dolphinsci.com/techbull.html

--DD

Alfred1 · 10-13-2004, 09:36 AM

I think Larson points out that that tech bulletin wasn't for the 914 and neither Porsche nor VW issued one for our motors.

eki912 · 10-13-2004, 02:29 PM

So , should I then use those headgaskets or not? Soon starting a head/cyls & pistons swap.

The gasket/seal between case & cylinders is needed. Where to get the right ones ?

erkki

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Up to you. Most people say to do without the head gaskets.

As for the cylinder base seals/shims, we can supply them.

--DD

914GT · 10-16-2004, 09:03 AM

Can anybody provide me a link to all the torque specs for a 2 liter? I couldn't find it in the PP tech specs area. Thanks!

Alfred1 · 10-16-2004, 09:43 AM

This is all that is listed in the 914 Technical Specifications booklet. Multiply m*kg by 7.22 to get ft*lbs.

Engine Torque Specs

dharder · 10-17-2004, 06:44 AM

Without having seen the tech bulletin and without having seen most of these responses, I installed the freshly rebuilt heads (off a spare motor) with gaskets and torqued to 23 ft lbs-without lapping the cylinders to the heads. Car runs great. One of the gaskets between a cylinder and head, when I took this 105k mile original-from-factory engine apart, was pinched. The gasket was actually folded over into the combustion area with only 1/16" to 1/32" of the gasket actually sealing. Took some pictures if anyone is really interested.

The reason I did the head/ring job wasn't because of compression, the compression was great- it was because of excessive smoking (the car, not me). It was obvious after disassembly that the reason it was smoking was because of blow-by past the rings. The heads were in good shape and the rings were hammered.

The car is back on the road, without smoking, and runs like a bad-dog. The only issue is one that existed before the rebuild and I'm going to post another question...

Thank you all