Thread: 300tdi head measurements and head bolts

Cylinder head
Cylinder head maximum warpage 0.08 mm ...............

when you measure the head and the deck make a paper trace of each on the same piece of paper and mark on each where the high and low spots are. I do it on baking paper tracing the outline of the block then the head so I can fold them together (or I mark them on with lead pencil then remember to mirror the positions)

If you have 2 lows or highs together and they add up to more than .08mm then you're going to have problems. if you have a high spot and a low spot in the same place then you can get away with it if the difference is less than .08mm and neither measurement is greater than .08mm

If in doubt send them off for machining anyway.

The head bolts should not be re-tensioned after installation. There are some that say bolts can be reused a number of times, but in my opinion with all that work why take the chance, use new ones.
If you did use new bolts, were they tightened with plenty of lubrication? As mentioned in another post, dry threads can bind.
Just curious, did you use an Elring composite, or a layered stainless gasket?

used plenty of lubrication on head bolts last time and used elring gasket, bolts binding wasnt the problem, loosening off was, maybe it was the overheating that loosened them? used new bolts last time and got new ones this time

correct, the bolts will loose clamping on an overheat.

I usually put new bolts in if the vehicle has done an overheat or If i Dont know how many times the bolts have been reused.

so what might have caused a new head and gasket to go after fourish months, didnt have any problems putting it together, didnt have any problems/overheat after. used new thermostat, coolant tank cap and new rad, it just happened out of the blue with no warning????

Originally Posted by Blknight.aus

Cylinder head
Cylinder head maximum warpage 0.08 mm ...............

when you measure the head and the deck make a paper trace of each on the same piece of paper and mark on each where the high and low spots are. I do it on baking paper tracing the outline of the block then the head so I can fold them together (or I mark them on with lead pencil then remember to mirror the positions)

If you have 2 lows or highs together and they add up to more than .08mm then you're going to have problems. if you have a high spot and a low spot in the same place then you can get away with it if the difference is less than .08mm and neither measurement is greater than .08mm

If in doubt send them off for machining anyway.

Hey Dave I was always on the understanding that you shouldn't machine/skim a 300 head???? (thats what I have been told) I thought it was to do with the mating surfaces being hardened.

Your head may have gone porus.
you can machine the deck easily, the head can be done but you also have to do a hardness check on it.

i cant believe a brand new head from turners would go porous after four months