The Lotus Grand Tourers

AndyC wrote:new tightening method

Can you explain this new method ?

With manual I'd give figures, but it's basically, go to specific torque load, then turn by a number of degrees, then turn by another number of degrees, then leave it a few mins and then turn by another number of degrees. It gives the seal time to start to settle and so is more effective at sealing. A copy of the process should come with the head gasket, or i can dig through a manual later and put the figures on here, but probably somebody has already done this and it's just a question of finding the post.

Some general points on head bolt torquing which applies to most cars:

• * Ideally use new bolts or studs for rebuilds.
  * Otherwise all threads should be thoroughly cleaned.
  * Lubricate threads (I use copper slip type grease, some use a heavy oil).
  * Washers under bolt heads or stud nuts should be smeared with lubricant.
  * Tightening sequence radiates in a pattern from the centre bolts out toward the periphery of the head
  * Initially increase torque in stages of about 10 Ib/ft until recommended torque is achieved.
  * After fully torquing all bolts or stud nuts to recommended setting, loosen each bolt and re-torque back to setting following the recommended tightening sequence.
  * Repeat the loosening and tightening cycle FIVE times.
  This has a similar effect on head gasket compression as progressively tightening in degree increments but also allows bolt heads, washers and threads to bed-in and interlock effectively. It also negates the need to use a torque wrench calibrated in degrees. i.e. you can use a standard torque wrench calibrated in lb/ft.
  

Using this method you will not need to re-torque the head bolts after 200 -500 miles - which you should consider doing if you only torque the head down in one cycle only.

I was surprised to see in the workshop manual that the 3 center pairs get different torque setting than the front and rear one
Some conmments about that ?

Lotus-e-Clan wrote:Some general points on head bolt torquing which applies to most cars:

• * Ideally use new bolts or studs for rebuilds.
  * Otherwise all threads should be thoroughly cleaned.
  * Lubricate threads (I use copper slip type grease, some use a heavy oil).
  * Washers under bolt heads or stud nuts should be smeared with lubricant.
  * Tightening sequence radiates in a pattern from the centre bolts out toward the periphery of the head
  * Initially increase torque in stages of about 10 Ib/ft until recommended torque is achieved.
  * After fully torquing all bolts or stud nuts to recommended setting, loosen each bolt and re-torque back to setting following the recommended tightening sequence.
  * Repeat the loosening and tightening cycle FIVE times.
  This has a similar effect on head gasket compression as progressively tightening in degree increments but also allows bolt heads, washers and threads to bed-in and interlock effectively. It also negates the need to use a torque wrench calibrated in degrees. i.e. you can use a standard torque wrench calibrated in lb/ft.
  

Using this method you will not need to re-torque the head bolts after 200 -500 miles - which you should consider doing if you only torque the head down in one cycle only.

I used this method with ARP conrod bolts on racing engines.

Yep Kent glad you can confirm the validity of the method

Same story here... my ARP con rod bolts for the Clan came with this sort of recommendation... Imp racers do the same with head bolts and it works despite the 12:1 CR ratio and 10krpm.

Head need skimming.
Now at the machine shop.
I'm missing my car

1) Absence makes the heart grow fonder.
2) Think how much happier you'll be knowing the improvements you've made to its state of repair.

See, there are some good points.

A BIG DONT DO!
You must not turn the engine or rock the car while in gear with the head off this can move the liners out of position.

There is a useful guide on the forum somewhere, I found it very helpful when I did mine a while ago.

tricky wrote:A BIG DONT DO!
You must not turn the engine or rock the car while in gear with the head off this can move the liners out of position.

There is a useful guide on the forum somewhere, I found it very helpful when I did mine a while ago.

Sorry missed something who talked to turn the engine

I think Tricky is pointing out that everyone should be aware that the liners are not bonded in (unlike my 1040 Imp liners).

Turning the engine (absentmindedly) could move the liners. A special clamp tool is used to keep the liners in their seats enabling the engine to be turned (say if you want to check piston deck height or verify the accuracy of timing marks) without the head in place.

It's just a helpful "heads-up message" I believe.

ok clearer now

Hi everybody !

FIL is back on the road
After new head gasket, skimmed head, carbs overhauled and fine tune, and new starter motor
Money, money, money but it drives like a dream never found it like that no more flat spot
Only did 10 miles so I can't wait going to work tomorow

Good news!