M40 Head bolts torque

[ivo316]

OK, so I'm finally putting together my engine, all new gaskets, new studs and nuts, repaired cylinder head (the new one was too expensive) new valve seals, and I'm stuck with a problem.

On the manual, the torque specs for the M40 say:

M40 four-cylinder engine
Stage 1 . . . . . . . . . . . . . . 30 Nm
Stage 2 . . . . . . . . . . . . . . Angle-tighten an additional 90°
Stage 3 . . . . . . . . . . . . . . Angle-tighten an additional 90°

I converted Nm to ft pounds and ok, but when I angle tightened the first time it reached 80 foot pounds of torque.

I tried for the second angle tightening and got to 100 footpounds and chickened out at 45º.

Does anybody know if 100 ftpounds is ok or it should be more ?

I'm really scared of breaking a bolt, I know usually manuals are right, but well, 100 ?

[Rocla]

Hey that's not m40 engine :)

Look specs for m10 engine :)

[porsche gt1]

you must go the full 90 degrees otherwise you will not have the correct seal and you will have to redo the job. The bolts are made to take this type of torque do not worry.

[ivo316]

thanks, now I read that the m40 has hydraulic lifters, mine is mechanic.

ok, now I know the engine type, the specs say:

M10 four-cylinder engine
Stage 1 . . . . . . . . . . . . . . . . . 60nm = .....44.28 foot-pounds
Stage 2 (wait 15 minutes) . . . . . Angle-tighten an additional 33°
Stage 3 (engine at normal o/t).... Angle-tighten an additional 25°

So I started at 30 (the other specs, instead of 60, then I angle tightened a total of 90 + 45º
I should have started at 60 and angle tightened a total of 55º.

I guess I am about right, end result 100 foot pounds, I wish the specs were a single reading

I'll give it a shot like that, i don't feel it's rright to pull the head and retighten it.

[porsche gt1]

no, bad idea to re-tighten. The bolts are made for a single use as is the head gasket. You have overtightened it, I would be worried about the bolts being siezed in there now.

[ivo316]

Well, I'll just start it that way, I figure that if I already f***ed up, there is no harm in triying to run it, at least with my previous cars, you had to retighten the head after 1000 km, so maybe it will loosen a bit, and if the bolts are siezed, then they will stay there until I have to rebuild the engine.:(

Thanks for the help.