Head gasket gone. Again + again +again + again.

[wanderinstar]

Have lost count of the times I've changed it now.
It all started when bypass hose went. Engine got very hot. Started to use lot of water 3pts in 8mls. No leaks and no steam from exhaust. Changed head, thinking it was possibly warped. Since then have fitted numerous head gaskets. Fitted Cooper head which has been skimmed .080", definatly flat. Also checked block with small block plane with wet and dry, block OK.
After speaking to someone at Minisport they suggested increasing torque. So tightened it down to 50ft/lb. That seemed to be working for 10 weeks but this morning it went again. So this time I fitted 998 mini head bolts and tightened it down to 55ft/lb. So lets hope that this will cure it.
Does anyone have any further ideas?
I know torqueing it down to 55ft/lbs will have some people up in arms, but I'm getting desperate. Oh I forgot to add that it runs on LPG though I cant see that that would make any difference. Oh and it also has Riley brakes. LOL.
Ian.

[bmcecosse]

Ah - it's the Riley brakes that's doing it! All that hard braking is throwing the water forward and then the engine overheats.
Where did it blow this time ?
Better hurry on with the new engine.

[Cam]

Something is clearly wrong with the mating surfaces or gasket(s) you are using. The standard torque setting should be fine under normal conditions. I would take both the block & head to a REPUTABLE machine shop and get them checked out. Then order a good quality copper head gasket & fit it.

[eastona]

I second that I'm afraid, with a flat head, block, properly torqued with a good quality copper gasket, the world's yer oyster.

a) how do you now the head is flat? did you get it machined yourself?
b) is your torque wrench working correctly.
c) are you sure your block is true
d) correct order of bolt tightening (you can probably do it in yor sleep now!)
e) good quality gasket?

I'm sure my 998 mini us tightened to 60lbft, but DON'T take that as gospel. I'll check my notes tonight.

Andrew

[chrisd87]

With the new copper gaskets some people run them for 30 seconds before filling up with water to get a better seal. I have a couple of asbestos gasket sets 'in stock' as they aren't allowed to sell them anymore (AFAIK).

[wanderinstar]

In the past I have used Minisport gaskets, but this time used gasket from ESM rebuild kit. So will see if that does any good.
Roy, its blown between 1 + 2 this time.
How do you check a torque wrench? I always return it to zero when I've finished with it.
Ian.

[rayofleamington]

How do you check a torque wrench?

easiest way is to chaeck it against a calibrated torque wrench that has a dial gauge.

[ColinP]

You could take it to a tool shop who can calibrate it (or return it to the manufacturer);

Alternatively, use a ruler and spring balance! After all, 50 ft lbs is a pul of 50 lbs at 1 ft from the centre - or 25 lbs at 2ft - I'm sure you get the idea...

Might not be very accurate, but will certainly indicate if the wrench is way out!

I second (or third) the suggestion thatt he block & head are re-checked for flatness - unless the block's been bored out (?) there must be some irregularity somewhere...
You haven't got oversize bores ? (Apart from this lot ;-)) - if it is oversize, you may have flexibility problems with the actual block.

All the best,

Colin

[bmcecosse]

The 80 thou skim on the 295 head 'might' be the problem - it could be quite thin. Some of the Mini 'experts' advise against over-torquing the head nuts - claim this leads to early failure. But really - it must be something wrong with the mating surfaces. Does it always blow between 1 and 2, or is it random ?

[Willie]

Did you check the block for flatness with the head studs removed? The metal around the stud holes in the block can be raised by over zealous tightening
which could prevent the head from mating down properly.

[eastona]

You haven't got oversize bores ? (Apart from this lot ;-)) -
Colin

haha LOL

hadn't thought of overtightening TBH, but a really good check of the block should turn up that kind of damage.

not sure overskimming a head would lead to it repeatedly going, but I'm certainly no A series expert

Andrew

[bmcecosse]

The deck on the 295 head can become extremely thin if over-skimmed, and this one may just have been skimmed already - before it was skimmed again - if you see what I mean!! Easy to tell - all heads start life at 2.750" thickness from face to rocker cover face.

[wanderinstar]

Grasping at straws here but does this make any sense?
If as Eastona says 998 minis go down to 60ft/lbs and moggy only goes down to 40ft/lbs, could there be any difference in makeup of gasket. Cos all the gaskets I've used in past have been from Minisport i.e. mini gaskets. this last one is from ESM so will see if this lasts.
Roy it seems to favour 3-4 but twice its gone 1-2.
Ian.

[eastona]

Thought I'd replied, but maybe I did something wrong.

apologies, but I checked my manual and I did do them to 50lbft, and usually work to the book (much to the amusement of my grandfather).

So huge apologies for my dodgy memory, but I'd check the mating faces and head gasket quality.

Apologies if I've posted twice.

Andrew

[bmcecosse]

I think 60 ft lbsf is too much - great danger of doing some damage. What did the new gasket look like - was it copper faced on at least one side - or was it made of cardboard like material ?!

[Kevin]

A couple of things, I dont see that using a block plane and wet and dry as a good method of checking flatness of the block it can really only done at home with a piece of plate glass and some engineers blue.
Also I assume that you remembered to re-torque the bolts after 500 miles when using a copper gasket, and are you sure the replacement head is flat has it been chequed using the above method or by use clock guage.

[wanderinstar]

Roy,
It had copper on one side and something like aluminiun on the other side.
So how come The mini is tightened to 50 ft/lbs and the moggy is only done to 40ft/lbs, is it not down to different gaskets?
Ian.

[bmcecosse]

Sounds like the 'good' gasket to me. Over the years they increased the strength of the studs and this allowed the torque to be lifted to help contain ever higher compression ratio. The last of the 998 Minis had 10:1 CR as standard. However - the same studs are used to contain the head on the MG Turbo engine! There will be a limit as to what the block can stand - and at 60 ft lbsf I think you must be risking pulling the studs out the block. Are you definitely using steel (or sinter) rocker pillars ? The older aluminium pillars can crush down under load - and so release the clamping force on the gasket. It's odd it should sometimes blow 3-4 and other times 1-2. Is it possible it is actually detonating when running on LPG - but maybe that can't be heard as it can when running on petrol ? Detonation is death to gaskets - and pistons !! Do the pistons show any pitting marks ?

[Dominic]

was it copper faced on at least one side - or was it made of cardboard like material ?!

I have just discovered the reason behind the mayonnaise inside the rocker cover, and the excessive oil consumption.... The gasket (as above - "cardboard variety") had blown in several places. I therefore spent a few happy hours yesterday fitting a new "proper" gasket. Torqued to the nail at 50lbs, or at least as accurately as possible using the pointer and scale type of torque wrench. The helpful chap at MGM spares in Wigan advised that rather than retorquing at 500 miles, it is better to re-torque after about 12 cycles of fully cold - fully hot and back again. Hopefully that'll be the end of engine work for a while!

[wanderinstar]

Kevin,
Can you explain the plate glass and blue method.
Ian.