I hate to ask, but.

[WaA420]

This last weekend I put a 951 head on and torqued it using the 15-90-90 method using a widefire head gasket.

My dilemna is that the second 90 degree torque seemed more difficult than normal and when I checked the actual torque it was around 100 ft. lbs. Has anyone else experienced this and also has anyone ever checked when there end torque was using this method?

[ae1969]

When I checked my 15-90-90 .......the end torque was close to 70-75 ft/lbs.

[Tidybuoy]

Originally posted by WaA420
torqued it using the 15-90-90 method

Just curious, what is the 15-90-90 method? I've never heard that before.

[nynor]

initial torque of head nuts to 15 lbs. subsequent torquing is tightening the nuts 90 degrees.

[Eldorado]

but as you torque the bolts, doesn't that change the torque value of the adjacent bolts?

[deekay911]

exactly, thats why you can torque to 90, and then go round and torque to 90 again..

[nynor]

don't ask me... just going by the updated WSM. that is how i did it on my 83 with stock studs. seemed to have even torque, as i did use a torque wrench. on my turbo with race tech (or raceware, i can't remember for sure) studs, i did normal stages with a final torque of 75 lbs.

[legoland951]

This is the reason why I trust my snap on torque-o-meter more than the 15/90/90 method and I have never had problems with the 50 or so 944 heads I have replaced in the past. The torque difference between individual studs can be as much as 30 ft lb with that method. Use some anti seize on the studs and clean the threads well before you torque the head down. I normally take a break between each tightening of torque and let some time pass before I clamp the head down.

[924Sman]

WTH is a Snap on torque o meter?

Dal

[deekay911]

sounds like a $300 Torque wrench :-)

[924Sman]

The fact the last to torques are done by degree at 90 is one good reason for unequal readings in Ft.Lbs.....Meaning who is to say the wrench was actually turned a full 90, maybe 85 or 94. Unless there is a protractor or what not I find it hard to get a pure 90 degrees from 15 ft.lbs. accurately. Also let the fasteners rest for 15-20 minutes between tightening to allow for stretching and compression of the new head gasket material and fasteners.

Dal

[legoland951]

Sorry... the torque-o-meter torque wrench is a "dial indicator" type of wrench where you can see the torque reading as you apply torque and not the "clicker" type. They are said to be much more accurate and are recommended by some aftermarket bolt/stud manufacturers so I bought one a few years back. Head torque is probably where a good torque wrench is needed along with the mains/rod caps so it pays to be careful.

[924Sman]

I see. Thanks

Dal