head bolt tork@60 & 90 degrees?

[TSNAPCRACKLEPOP]

well, reading at clarks garage, and printing some instruction sheets to take with me out to the shop, , and considering throwing my 944 together this weekend, i am curious as to what these torque values mean at the "second and third tightening"? my question is, what is the 60 and 90 degree application? i am doing a 1987 na with no modifications.
thanks in advance
tomwhat is the 60 and 90 degree application

[TSNAPCRACKLEPOP]

this question refers to the section called "cyl-03 cylinder head tight. seq. and tork spex.." mine is 87, so its 15ft/lb, 37ft/lb, and finally66ft/lb......but down at the 944s and turbo, it has angles listed for those cars in steps 2 and 3. just curious!

[944 boy]

Yay! i can answer this.
When you bolt on an aluminum head you dont want to warp it. So you follow the pattern given. (there is one right) and tourque down to the first spec. Then the second, then the third which is the final tourqe spec.
Im not sure of the 90 degree question, i know of the tourque spec because im helping rebuild a 2.0L lotus motor.

[ae1969]

It just refers to turning the nut 60 or 90 degrees... instead of using a torgue value.

This way it stretches the nut. I don't really like the idea of using a degree turn...............cause you can't go back and check.

[AFJuvat]

It is called torque angle - you tighten to a given torque, then tighten 90 degrees, then an additional 90 degrees.

If you don't have a torque angle gauge, mark one side of the nut (nail polish or liquid paper works well) after you have torqued it to the first value. then turn the nut 90 degrees, then an additional 90 degrees.

Ex: torque to value - mark nut at 12:00 position.

2nd: tighten until the mark points at the 3:00 position

3rd: mark at 6:00 position.

AFJuvat

[TSNAPCRACKLEPOP]

so these torque angles are calculated from the known stretch valvue of the bolt or nut, to tighten the bolt, but short of actually stretching the threads. 90 degrees sure sounds like a lot....but i guess the thread pitch is also calculated here, to pull the head down tight, compressing the gasket. with torque angles, one could approximate torque prettty close in a pinch without a torque wrench. 60 plus 90 equals 150 degrees, so that is pulling the head down nearly one half turn of the threads beyond the initial tork. also, would be a useful metnod when you only have a low value torque wrench available.

[customtec]

I've recently read that all 944's should be torqued as follows:

1st: 20nm
2nd: 90 degrees
3rd: 90 degrees

I rebuilt a BMW 325i last year and this was the same torque method on it... It was easy to do. The engine has worked great for over a year. It seems this is common on head stretch bolts.

The trick was to put a mark on each bolt so as to know which one has been turned to which position in which sequence.

[TSNAPCRACKLEPOP]

should i use oil as directed on clarks website, i heard it can freeze lug nuts on.....use antiseize compound instead??

[customtec]

The stuff I have read say "a light coat of oil" on the threads... nothing more... and no antiseize.