Head bolt torque question .

[JeLani]

Can i re-torque a head that hasn't been fired yet? the bolts are new VR ones with brand new oem washers. It was my first time doing it and want to make sure i did it right. I did the 22 torque with the two 90 degree rotations, again the car has not been started but does that make a difference on the condition of the bolts?

[Fsnow]

Since they are torque to yield bolts you can only torque them once. You could buy new ones and try again but If you followed the correct procedures then it should be fine.

[Kershaw]

If you followed the correct procedure it should be fine. If you overtorque them, they may snap. If they snap, you're in a world of shit.

If you followed the correct procedure, why are you worried?

[JeLani]

My torque wrench was a shit one and i kept having to re calibrate it and not sure if i did the final 90* torque on #10. At this point i am unsure now but at the same time i may have actually done it.

[101]

Never reuse standard head bolts. Ever.

Based on what you've said, you're best bet is to get a new set of head bolts and do the job over. It's cheap insurance and peace of mind.

Starting from the center of the head (same pattern as the Bentley recommends), ONE AT A TIME, remove each head bolt, replace it and fully torque it (both the 22# and the angle torquing) BEFORE moving on to the next bolt. The idea is that you don't want to release the pressure on the head gasket as you're doing this.

BTW - this is the same procedure that BMW recommends when updating the head bolts from the older "hex head" style to the newer "torx head" style. I've done this on two of my cars with no issue.

When each new bolt is completed, put a small dab of paint on it or otherwise mark it so there's no forgetting which ones you've done.

[jeffnhiscars]

The final 90 has nothing to do with how accurate your torque wrench is since it's by degree not ft lbs

[JeLani]

The final 90 has nothing to do with how accurate your torque wrench is since it's by degree not ft lbs

Oh :( , well i did the initial torque and 90* for all of them of course , not knowing it was about degree and not torque level (and this being my first time using a torque wrench) i kept re adjusting and now im not sure if i did my final 90* turn on bolt #10 :((

[vpilarrt]

So are you saying you did 90 ft-lbs for the 90*? It's supposed to be 90° of turn.

[nando]

New bolts are like $20. Do it again, correctly.

[JeLani]

So are you saying you did 90 ft-lbs for the 90*? It's supposed to be 90° of turn.

22 ft lbs 90 degree turns, 90 ft lbs wouldve snapped the bolts for sure lol.

[JeLani]

New bolts are like $20. Do it again, correctly.

I will

[estoguy]

Never reuse standard head bolts. Ever.

Based on what you've said, you're best bet is to get a new set of head bolts and do the job over. It's cheap insurance and peace of mind.


BTW - this is the same procedure that BMW recommends when updating the head bolts from the older "hex head" style to the newer "torx head" style. I've done this on two of my cars with no issue.

Question... my '86 Eta still has the original head bolts... 30 thirty years later and over 430K km... I was thinking about doing this when I do my next timing belt, as I'll be checking my valve clearance as well.

Honestly, if I've had no failure, should I even bother???

[nando]

are they hex bolts? the BMW repair was only for the hex bolts. Either way though, if they haven't broken I wouldn't worry about it.

[101]

I respectfully disagree on that point, nando. $hit happens. Just want to share my personal experience ...

At 220K miles the previous owner of my '87 IS had two of these bolts fail. One bolt head drifted harmlessly to one of the oil drain holes and stayed there. The other bolt head got wedged between the camshaft and the head, destroying both and ultimately hydro locking the motor. Game over for her. That's when I became the new owner.

Two other lower mileage cars in my stable also received the new head bolt treatment. Hard to believe they had not been updated previously, but I wasn't going to take any other chances.

It's a relatively painless job while the valve cover is off. Unless of course one of the bolt heads comes off when trying to remove it, which I guess is a possibility. And if one has already fractured, can a head gasket job be far behind?

[redlightpete]

I had one of the hex heads break off and didn't do anything about it. About two weeks later the head cracked right below the broken bolt. I think it is very likely that having zero clamping force in that area was the cause of the head crack.