I just checked my records. My head bolts are done to 90 ft-lbs. This works well for me.
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I just checked my records. My head bolts are done to 90 ft-lbs. This works well for me.
Thanks Dougal and isuzurover. Ill put it on 90 and see if thats the extra 50 degrees or thereabouts
The turbo tension procedure was no doubt (in my mind) specified to achieve higher pre-tension in the head bolts, in consideration of the higher cylinder pressure.
For a particular engine bore and stroke, the output torque is a function of mean effective pressure acting upon the area of the piston.
When bolt pre-tension reaches a certain point, the friction, and particularly the variability of the friction coefficient, renders the accuracy of tightening torque as a measure of bolt tension extremely doubtfull. In such cases it has be proven that torque control can only achieve approximately +/- 25% of the desired bolt tension, far worse than achieved by turn of angle methods.
With my 4BD1T, the goal is much more torque than stock so I replaced the stock headbolts with ARP studs, and because they use a fine thread for the nuts, the prescribed Isuzu tightening procedure was not applicable. However if I was closer to stock 4BD1T (or putting a turbo on a 4BD1) I would use the stock 4BD1T MLS head gasket, bolts and tightening procedure.
John, can you share the thread pitch and torque proceedure you used on the ARP's?
The quote below is what I posted some time back, in another thread.Quote:
Originally Posted by Dougal
I can't remember the thread pitch, but will check when I have a chance.
Also can't remember the final torque I used. It was what people are using with the same diameter ARP head studs for Cummins engines. Edit 90 lbf ft is ringing a bell in my mind.
Quote:
I have ARP studs for the head on my 4BD1T, but have not used them with a 300Tdi, which they should help.
When I fitted them (4BD1T) I used the tightening torque that ARP recommended. They had a finer thread pitch for the nut end of the stud than the stock bolts, so using the stock bolt tightening angle would have given a different tension, thus clamping force on the gasket.
I used a tensioning method recommended by diesel engine builders with much more experience than I. Use many small tension steps, much more than the 2 or 3 stages often used (tighten in the same order as stock).
When all studs/bolts are tensioned to the usual 2nd from last stage, release the tension (reverse the normal tightening order and do this in stages). The reason for this is that the mating threads (male & female) settle better. Then tension the bolts by stages as before, to the final tension.
The thread of stock Isuzu head bolts is M12 x 1.5 pitch. The thread for the nuts on the ARP studs that I used to replace the stock head bolts is M12 x 1 pitch.Quote:
Originally Posted by Bush65
I'm fairly certain that I tightend the nuts to 90 lbf ft. Also lubricated the threads and washer face with MoS2 grease.
Well 90ft/lb,s turned it another 20 degrees so I left it at that.Quote:
Originally Posted by 123rover50
As I mentioned earlier there was a lot of oil floating around in the engine bay after a run. I thought this was coming from the breather as all the joints were good. Ordered a Provent from Western Filters then on further investigation found the oil coming from the case of the new beaut alternator I had just fitted. The leak was getting worse so removed it and took it into my sparkie. They had removed the vac pump to give me a wire to feed the tacho (which didnt work) I dont know if that had any bearing on it or not but he replaced it with another new one with another tacho feed. The alt works OK but havnt hooked up the tacho yet.
Hooked up the trailer to go pick up another series one yesterday and all is good. Pulls up hills in 4th I would normally change down for but have to watch the EGT,s.
Try and mount the Provent as high as possible in the engine bay. Make sure there are no low spots in the breather lines to it (so "wall flow" will flow back to the engine or to the PV, rather than pooling in the low spots).Quote:
Originally Posted by 123rover50
Also use a check valve in the drain (if plumbing back to the sump). If you didn't buy one with the PV, the check valves in the vacuum lines of 80's japanese cars are metal and will do the job well.