First 40Nm stage of head tightening - checking before angle stages?

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M

moth

Member
Posts
38
When doing the first 40Nm we get to #18 in the sequence then #1 has slackened slightly because the gasket has compressed further since it was first tightened to 40Nm. I would tend to check them all again in sequence and probably a third time so that they are all starting at 40Nm before the 60 deg phases. What are your thoughts on this?
Cheers
 
There's no harm in doing this, but, it won't make any significant difference.

Compare the angle by which #1 bolt turns to return to 40Nm with the total angle turned through during the later stages of bolt tightening.

It's worth using tippex or similar to mark the bolt heads after the torque tightening phase - say a dab on each bolt head pointing to the crankshaft pulley end of the engine. Then after each stage of angle tightening, the marks will all point the same way, and any bolt that has been missed will be obvious. You can't re-check angle tightening with a torque wrench, and, if you're disturbed mid-sequence, you might easily lose your place.
 
Hi. That's a good point about the small remedial angle vs the extra 2x60deg. I don't have a handle on what the remedial angle would be to restore the 40Nm on this head/gasket. Interestingly I've seen video instructions for the 300tdi where they just do the one pass of 40Nm then the 2 60deg stages but there's an additional small angle on the centre bolts only at the final stage. Cheers for the tipex tip.
 
I was concerned about that as well and redid all of them to 1st stage before moving on.
I've learnt to have a friend/wife to point at the next bolt needing tightening using the guide saves losing where you were in the sequence.
It's not necessary of course but saves time and mishaps.
Don't forget to fit the lift lug under the bolts!
My torque wrench has a built in angle whatsit.
Did the job 6 yrs ago all good still.
 
Lift lug?
I've 2 engines here without anything extra under the bolt heads.
I notice that the spot faces for the two outboard holes on the nearside rear of the head are machined lower but the bolts for that row are all the same length. Is that where you mean? These heads are both sourced from 200TDi disco 1.
I only really noticed this when I thought I'd check the threaded block holes were clear enough for the length (+stretch) of the new head bolts when clamping through the thickness of cylinder head etc and so measured the head at the bolt locations. I didn't want the tip of the new bolts meeting some rust etc that might have built up just beyond the tips of the old bolts. So I've tested the threads by winding the new ones into the bare block by hand well beyond where they'll get to in the assembly. I've got new virgin length bolts but I was unsure of the number of times of the old ones had been re-used. They might even have been new at the previous fitting and there is the possibility of slight production variation in bolt length.
I do have a front lifting eye but that's bolted to the vertical face of the alu head itself and not through to the block.
I do not have one at the rear but I just imagined it would be a similar arrangement.
When I fitted the engine some years ago I just used rope around the flywheel housing. It had to shoehorn in under the extended Brownchurch, suspended from the FE35 front loader, on an ice rink!!
 
It goes on the offside , under two bolt heads roughly above the vac pump.
They are often missing which is a shame because the engine lifts lovely off that and the front one.
Want a picture of mine? When it stops raining:rolleyes:
 
'ear ya go.
Look between 3 and 4 injector pipes.:)
IMG_20180124_120532446.jpg
 
Totally wrong on my part!

Seems 300 only have front and rear flat ones and 200 can have all three.
But I think you will find the extra bracket is for ex freelander owners:D
Also note item no 25 neither of mine have that fitted either, has yours, wonder whats its for?

Screen Shot 2018-01-24 at 15.41.11.png
 
Thanks all for your very thorough attention.
I got my wires a bit crossed there: Those two holes I mentioned are indeed on the rear offside (not nearside as I mentioned previously).
So yes, those two holes are where item #20** would sit. The arrangement I imagined was with parts 19 (present) and 17 (absent). We need to flag this as a potential cause for the common rearwards blowing gasket failure if folk don't check the available thread depth when #20** is omitted.
[** EDIT - #20 should read #21 :oops:]
 
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