Volvo Penta D6-35 Cylinder Head Bolta Torque

[Lax207]

Good day folks!
Can you guys give advice about the tightening torques for the cylinder head on a D6-350? We are at the reassembling stage and have tighten up the bolts to Stage 3 of 150nm however having difficulty to do rotate sequence of 180 degrees. Our mechanic can only manage 145 degrees and it is very hard to go on and we are frightened it might break. They are not new bolts and still the original, and this is the first time they have been taken apart.
Is this normal? Would there be any other measurements outside the specification on the book? Any alternatives? Would rotating up to 145 degrees be enough rather than 180?


Thank you and your thoughts are highly appreciated!
Christopher

 

[spannerman]

I just consulted my Volvo D6 workshop manual and there are several things you should know.
You must always use new bolts as they are stretch bolts and can only be used once. You also will need a torque multiplier to tighten them and there are 5 stages
1 - 30 nm
2- 80nm
3- 150nm
4- 180 degrees
5- 90 degrees

 

[volvopaul]

I just consulted my Volvo D6 workshop manual and there are several things you should know.
You must always use new bolts as they are stretch bolts and can only be used once. You also will need a torque multiplier to tighten them and there are 5 stages
1 - 30 nm
2- 80nm
3- 150nm
4- 180 degrees
5- 90 degrees

Yes is agree with that. Just to add that any bolt that's tightened finally on degree rotation is usually a once on,y use bolt .

The reason you can't torque it correctly is because there is no stretch left in it , you must use new bolts otherwise you will risk damaging the head and the block.

 

[Boat2016]

I just consulted my Volvo D6 workshop manual and there are several things you should know.
You must always use new bolts as they are stretch bolts and can only be used once. You also will need a torque multiplier to tighten them and there are 5 stages
1 - 30 nm
2- 80nm
3- 150nm
4- 180 degrees
5- 90 degrees

Are you sure ? Just been discussing with a friend who has good experience of volvos and he said that the manual says use up to 3 times but not seen it myself and going on what he said

 

[[2068]]

Are you sure ? Just been discussing with a friend who has good experience of volvos and he said that the manual says use up to 3 times but not seen it myself and going on what he said

 

[Boat2016]

Check the D4-D6 manual 47700149 dated 09-17 page 17 and it clearly says for head bolts use 3 times, any authorised Volvo Penta engineer will confirm this, otherwise I would question their ability to be working on my engine, I have been shown this so can confirm it’s true

 

[Portofino]

Are you sure ? Just been discussing with a friend who has good experience of volvos and he said that the manual says use up to 3 times but not seen it myself and going on what he said

It's a fundamental thing with cylinder head bolts ,the stretch is designed in to cope with the slightly different coefficient s of thermal expansion of the components they are suppose to hold together .In this case keep the gasket separating gas. Water and oil .
The older air cooled 911's have no head gasket as such ( no water jacket ) the head bolts must be new every time and are a special metal slightly elastic a bit, resisting the head separating from the block and letting flames out -- single use only .

 

[[2068]]

Check the D4-D6 manual 47700149 dated 09-17 page 17 and it clearly says for head bolts use 3 times, any authorised Volvo Penta engineer will confirm this, otherwise I would question their ability to be working on my engine, I have been shown this so can confirm it’s true

Could be a later update to the manual.
But I would still splash out on new bolts if I had gone to the expense and trouble of taking the head off.