Mud-club

Vehicle & Technical => Discovery => Topic started by: disco maniac on February 20, 2008, 21:59:56

Title: head bolts
Post by: disco maniac on February 20, 2008, 21:59:56

i've just fitted a new head to a 300tdi and wondered what torque settings you all use.

Title: Re: head bolts
Post by: Wolfie on February 20, 2008, 22:07:47

Quote from: disco maniac on February 20, 2008, 21:59:56

i've just fitted a new head to a 300tdi and wondered what torque settings you all use.

You don't!

It's done by tightening through set angles*. All detailed in the Haynes manual.

*A far superior method from what I recall of the materials lectures at uni

Title: Re: head bolts
Post by: extreme90 on February 20, 2008, 23:46:01

off top of my head its goes along the lines of  this
pinch up bolts by hand
then torque up to 33lbft in sequence ( 1 - 18 is it ?  :-. )
then a further 90 degree in sequence
then a further 90 degree in sequence
then depending on what gasket thickness, 20 degree more on selected bolts ( info will be with the head gasket )

Title: Re: head bolts
Post by: Wolfie on February 21, 2008, 00:13:27

Quote from: extreme90 on February 20, 2008, 23:46:01

off top of my head its goes along the lines of  this
pinch up bolts by hand
then torque up to 33lbft in sequence ( 1 - 18 is it ?  :-. )
then a further 90 degree in sequence
then a further 90 degree in sequence
then depending on what gasket thickness, 20 degree more on selected bolts ( info will be with the head gasket )

Haynes BOL claims 30 lbft then 60^o then 60^o again, then an extra 20^o on the M12x140 bolts, but I haven't compared that to the proper LR BOL as I only have a 200TDi

Title: Re: head bolts
Post by: Range Rover Blues on February 21, 2008, 04:15:38

Off the top it's 60 degrees twice, then an extra 20 degrees on the inner rows of bolts, 10 of them closest to the cylinder.

I'm not a big fan of angle-torquing.  It actually relies on the bolt stretching which supposedly is more accurate than torquing properly because any oil on the threads can effect the clamping force, but if the angle torque isn't applied smoothly then the results can be just as varied.

Also the bolts are then limited life, you can use them 3 times on a TDi head (3 times on a Transit) but only once on some engines, the bolts cost more than the gasket.

Typically you tend to see them in bi-metallic engines, ie iron blocks/alloy heads because it helps deal with the differential expansion of the 2 metals.

Title: Re: head bolts
Post by: disco maniac on February 21, 2008, 10:29:15

thanks for that, how do i measure 60 degrees ? is it just a rough guestemite.( i know how far 60 degrees ish is )  or is there a way of measuring it.

sorry for being a dullard but i want to get it right, hopefully later today.

Title: Re: head bolts
Post by: Wolfie on February 21, 2008, 10:48:10

Quote from: disco maniac on February 21, 2008, 10:29:15

thanks for that, how do i measure 60 degrees ? is it just a rough guestemite.( i know how far 60 degrees ish is )  or is there a way of measuring it.

sorry for being a dullard but i want to get it right, hopefully later today.

http://www.machinemart.co.uk/shop/product/details/cht423-angular-torque-gauge/path/ratchets-torque-wrenches-2

Title: Re: head bolts
Post by: disco maniac on February 21, 2008, 10:53:45

thanks for your help wolfie. it will be up and running in a couple of hours.

Title: Re: head bolts
Post by: bilge rat on February 21, 2008, 20:27:50

got my angle guage from halfrauds , wasnt too dear. iff that helps..alan..

Title: Re: head bolts
Post by: davidlandy on February 21, 2008, 20:52:58

Trev

i have an angle guage if you need to borrow one

good to see the beast is nearly awake!