A few important qeustions (head gasket)

[Tim Harrison]

This afternoon, I intend to replace my head gasket, as it blew on me today.
Whilst I could spend hours searching for the relevent information on this forum, I am in a bit of a rush so if anybody could answer my questions, it would be greatly appreciated!
Head stud torque settings?
Any general information on tappet resetting? (I'm pretty clueless as far as that's concerned)
Anything else I should know? I have the workshop manual, but is there anything else that makes the job any easier?
Thanks in advance, excuse my ignorance!
Tim.

[lambrettalad]

best slow down and take it slowly ,it is a straight forward job,however lots can go wrong ,look at the manual and prepare your workshop plan ,eg tools ,specs etc,where nuts bolt and rods are you keeping in the right order for storing etc are going.
also what else to change whist the head is off etc

I wish you luck

[Matt Tomkins]

cylinder head torque to 40lbft
ensure that you keep the pushrods in the right order. a piece of stiff card with "F12345678B" marked on it, and holes to match is useful for this.
when you remove the pushrods, do so carefully as not to unseat the cam follower -- if you do this, take the tappet chest cover plates off and re-seat them.
before removing the rocker assembly, it sometimes proves helpful to slacken the tappet adjustment, making reassembly easier. be sure to keep things clean and organised, the rocker cover, for example, acts as a perfect holder for the rockers :-p
ensure that the head bolts are torqued in the correct order, as per the workshop manual.
torque gradually in order, 10, 20, 30, 40.
give the engine a heat cycle, then retorque to 40, undoing 1/4 turn, then retightening each in turn.
remember that tappets will need to be reset after each re-torque,
retorque after 10 miles, then 100 miles, then leave it alone.

If you get into difficulties, post back on this thread and i'm sure people will lend advice,

where abouts are you located? if you're in oxford area and need a hand, i'm bored :-p

[les]

Something that caught my eye in the post by Matt-----slacken 1/4 turn then re-torque. Not heard that one before!?

[bmcecosse]

NO - DO NOT slacken anything ! Torque to 44 ft lbf - and then once again after the first heat cycle - and then leave well alone. Fastest way to do head gasket is to take the carb off and lay to one side (with cables etc still connected) - and undo the exhaust clamp. Drain down the water - slacken the bypass hose clamps - rocker cover off - slacken the 1/2" nuts holding the rocker pillars - then the 9/16" head nuts. Lift away the rocker shaft, then jiggle the pushrods and lift them out -hardly worth keeping the order, but do so if you wish. Lift away the head - remove the gasket - clean everything carefully, and make sure the studs are all tight in the block. Fit a new bypass hose (not the ghastly concertina one...) - smear a thin wipe of grease on both sides of the (copper I hope) gasket. Refit the head - and the push rods - and the rocker shaft. Pull down the head nuts in order, bit by bit - then the rocker pillar nuts. Set the gaps - 12 thou inlets and 15 thou exhausts. Tighten the new bypass clamps and fill with water (and antifreeze). On with the rocker cover, refit the exhaust clamp - and finally the carb! Run up to temperature -leave to cool (not necessarily cold) - retorque and reset the gaps. Job done ! Simples.....

[Matt Tomkins]

i was taught to slacken then retighten when fitting a head to a racing b series, was told that it allows the gasket to settle. but bust only be done one stud at a time, in the correct order.
i think hg is one of those things which everyone has their own slightly different method of doing; mine works for me, as well as several historic race teams i have learned from.

[bmcecosse]

You risk slackening the stud in the head - definitely NOT a good idea and no advantage whatsoever that I can see.......

[les]

Well each to their own, it would be interesting to know where all these ideas originated from, not just this one but lots of others. Some you can see the logic behind but as far as letting the gasket settle, hard to see slackening one nut would allow the gasket to do much settling as the other nuts would prevent this. My first thought when reading this was maybe to back off, then tighten and give some momentum to the nut enabling it to tighten past it's original position. However after one heat cycle the nuts are unlikely to have 'stuck'.

[mike.perry]

This afternoon, I intend to replace my head gasket, as it blew on me today.
Whilst I could spend hours searching for the relevent information on this forum, I am in a bit of a rush so if anybody could answer my questions, it would be greatly appreciated!
Tim.

More haste less speed.
If you rely on remembering everything you have been told then you are going to forget something important.
Read the workshop manual carefully and settle down to the job with a cup of tea at hand.

[bmcecosse]

Nah - it's a side of road job - one hour max. Unless of course you have to walk in to town to get a gasket - and then back to the car...... which takes another hour or so. Now always carry a spare!

[MarkyB]

For you, maybe.
Take your time and cups of tea is much nicer.

[katy]

That's what the old Mexican told me many moons ago: "slow down and get finished sooner".

[bmcecosse]

If time is not of the essence - the valves should be pulled/cleaned/reground - and new stem seals fitted........

[lambrettalad]

one hour at the road side I know people who could rebuild the whole engine ,grind the crank and have toast in that time

[les]

one hour at the road side I know people who could rebuild the whole engine ,grind the crank and have toast in that time

----and after a cup of tea put it on ebay as fully reconditioned!

[bmcecosse]

[lambrettalad]