Gti-6 Head Torquing Sequence And Values..

[Stu 18]

Hi all,

 

Ive searched, and have got the 'official' values for the '6 head bolt torques and such:

 

Stage 1: 35Nm

Stage 2: 70Nm

Stage 3: Angle Tighten 106 Degrees

 

BUT... Does a method exist using JUST a staged torque setting? I usually do MI's at 25ftlb, then 50, leave them overnight then do a final torque up to 75ftlb, but the '6 being a cast block i guess this doesnt really apply..

 

Never been a fan of the angular method, would much rather get a 'click' off the wrench when i know its there!

[welshpug 1,666]

stage 3 is 160 not 106

 

did wonder, but never found one so just cracked on with the angle gauge and a big bar, never had any problems.

[B1ack_Mi16 67]

Last few times I've assembled XU iron blocks I've just torqued the bolts to 95Nm as stage3.

 

Haven't had a problem with that, and then can re-use the bolts without any issues.

 

Even the 2.3 race engine holds together with that torque on the head-bolts and re-used steel head gasket

 

Just make sure the threads are completey free of any debris. Ideally run a tap down the threads to clean them out first, then lubricate before assembly.

 

It's critical to get a even clamping force between all the bolts, which is much easier to acheive when stretching them, with the 160 degree method, as then they will clamp equal even though the applied torque might be quite different between them if there are dirt in the threads etc.

[welshpug 1,666]

xu10 dont use stretch bolts though, so tightening method has no bearing on the re-use of bolts, only that they are within the specified length.

[B1ack_Mi16 67]

Well, if the length has changed after the stage3 160 degree procedure indeed they will have been stretched, why bother checking the length if they are not stretch bolts?

 

Afaik they are stretch bolts, as some XU10's (well at least diesel) I believe the 160 deg is changed for 270 degees and I have problems understanding that the bolts won't stretch.

 

Haven't done any calculations on it thought, but should be quite easy to do knowing distance between thread in block and washer in head.

[welshpug 1,666]

stretch bolts should always be replaced regardless as they will stretch.

 

non stretch bolts should always be checked for their length as they still do stretch but not due to their design, they are re-usable as long as they are within specs.

 

iron block xu/xud do not use stretch bolts afaik.

[Stu 18]

Ill be re-using mine anyhow, i think the check dimension is 112 and mine were all at 110ish so they'll be reet

 

I might just do it as i always have then, that final 95nm is just over 70ftlb so ill go with the 25, 50 then 75 i think..