Blown head gasket - best replacement?

[Grumbley]

Hi, I was hoping the techy folks on here might be able to give me some advice. My '68 Traveller had a new head gasket about 10 years ago after the old one blew (my most vivid memory of this was removing large amounts of mayonnaise from the underside of the rocker cover!). I don't do that many miles annually but the head gasket has gone again, this time between cylinders 3 & 4 so no mayo but a very, very unhappy car

The head gasket kits sold by the various Moggie spares outfits I've looked at are all as cheap as chips, but are they any good? I don't mind spending proper money to get decent quality gaskets that *might* be less likely to blow. I don't have the facilities or expertise to replace the gasket myself so the cost of labour is going to massively outweigh the cost of whatever parts I need to buy to the the car back on the road.

Does anyone have any thoughts or advice on the best option re. replacement parts? Any any other hints/tips that might prolong the life of the next head gasket would also be gratefully appreciated!

Thanks

[aupickup]

most morris minor places are good get a copper one or try any unipart spares place

[bmcecosse]

But why has it blown - and has it been driven any distance on the blown gasket? The 'best' is a copper/copper gasket - ask at your local Autoparts place for a 998 Mini gasket (NOT a 1275...) . It's an easy swap! Couple of hours at most, although it would be well worth while grinding in all the valves and renewing the (or fitting - if missing) decent oil seals on the inlet stems. Torque the head to 44 ft lbf, and retorque after the first heat cycle - this can be done while the engine is still 'warm'. Then reset the valve gaps 12thou inlets and 15 thou exhausts..

[Chipper]

most morris minor places are good get a copper one or try any unipart spares place

Sadly, Unipart have gone into receivership.

http://www.bbc.co.uk/news/uk-england-bi ... m-28460270

[kennatt]

If its blown again ,as you say after little milage,suggest you get the head checked/skimmed just in case.

[bmcecosse]

It was 10 years ago - as long as it looks ok 'visually' - I would try another gasket - properly torqued and re-torqued. Is there no-one near you willing to lend a hand ? 'Garages' tend to make a meal of a simple job like this......

[Chipper]

Payen head gaskets are good - they have a kind of 'sticky' coating on them to ensure a good seal.

They are available from the MG centre (for MG Midgets, etc.), plus other outlets, including E-bay:

http://www.ebay.co.uk/itm/Payen-AF070-C ... 3cdc958bd7

[bmcecosse]

Just a wipe of clean grease helps the seal - Payen are no better than any other copper/copper gasket.

[Grumbley]

Thanks guys! Much appreciated. My confession is that I have no technical aptitude whatsoever and am quite capable of b***ering up even the most mundane task, so although I will have a crack at a few jobs the idea of having a go at this myself really doesn't appeal. My mechanic is a diamond, he remembers Moggies coming onto the market in 1948 and has always been fabulous. The problem is that if the parts he uses are poor it doesn't matter how well he does his bit.

I think I'll make sure the gets head skimmed and try a Payen gasket. That's assuming it is the gasket, a mate's old Landy turned out to have a cracked cylinder head when something similar happened to it just recently I'm also hoping that limping home a couple of miles on 2 cyclinders hasn't caused whole lot more grief - but it happened in a heavy rainstorm & my phone network was down when I tried to call the recovery people Sigh! Just as well I love my car.

[chickenjohn]

Limping home a couple of miles won't have done any harm, Just get your mechanic to check the head and block with a straight edge between 3 and 4 to make sure. You might have an over heating problem in the block to to silting up of the waterways if the coolant wasn't changed every couple of years and there is some build up of corrosion.

Torque the head to 40 lb/ft, higher if you get some water / oil mixing. Then re torque after a few hundred miles.

Set the valve clearances to 12 thou as per the workshop manual, the 15 thou advice is not good as you will end up with a rattly engine, less performance and for no benefit!

[bmcecosse]

Once again - CJ trots out the old advice! But we know better now - follow the MG/Rover advice when unleaded fuel was introduced and use 15 thou on the exhausts at least. It doesn't rattle and you don't lose any performance and you do gain a little bit of extra protection against the gaps closing up due to valves running hotter than with the old leaded fuel. Skimming the head is a waste of time (and a LOT of money) if it doesn't need it. Check with straight edge and decide. The block is every bit as liable to be eroded as the head - driving on it was NOT a good idea - but understandable in the circs. And again - the later good advice from MG/Rover is to use 44 ft lbf on the nuts and I strongly advise to retighten after the first heat cycle and then to leave well alone.

[chickenjohn]

Once again BMC trots out the old bad advice!


But 15 thou will if anything make the situation worse with unleaded as the exhaust valve will be open for less time causing the hot exhaust gasses less time to get through the port. Thus increased pressure and more heat and possibillity of damage.

Best to stick to the original Morris Minor workshop manual advice and keep both to 12 thou.

And yes, BMC Ecosse, I have tried 15 thou exhaust and the engine top end DID rattle more and there was a drop in performance.

From cold to hot the clearances only close by 1 thou anyway so no benefit in opening the gap,

[bmcecosse]

I run mine at 18 thou actually - runs great and no rattles. You must have sensitive ears if you can hear any extra noise! some say there is actually an improvement in performance - due to the valve being 'snapped' off the seat by the rapidly rising slope of the cam - but I can't lay any claim to that one. Have you ever built a competition engine CJ - I wonder? The difference in 'time open' is absolutely miniscule - the point is to allow the hotter valve to expand without closing the gap when running hard. If you toddle about never over 50 mph - I guess it doesn't matter a jot.

[aupickup]

i jused to run mine at 15 thou and never had any problems

[IslipMinor]

Running the exhaust valve with slightly more clearance allows the valve to make contact with the exhaust seat for longer, allowing more time to conduct the heat away from the valve and into the seat/head. Very desirable when running unleaded fuel. If the valve gear is in good condition, I very much doubt that you will notice any increase in noise levels.

Not so necessary for inlet valves, as these are cooled by the incoming fuel/air mixture.

I believe that for a standard 948/1098, 0.012" for inlets and 0.015" for exhausts should be considered as the current standard settings.

[TFM150K]

I have just set all of my valve clearances at 15thou this evening and will let you know the results. Engine is bog-standard 1098 100000+ miles (probably) and not converted for leadfree, no additives used. Clearances had been 12thou before.

P.s. looking at the link above for the Payen Gaskets, although I have always considered them to be as good as you can get, £22.99 all-in seems a lot of money.....

[les]

I expect one of the results will be more clatter, and of course less valve opening. I've wondered why this option is adopted because as valve clearances are part of a service check, any closure of the original 12 thou gap can be rectified at that time. If anything, and that's doubtful, the only advantage of 15 thou is the gap will diminish a bit slower. I'm at a loss as to why my car, being set at 12 thou seems to run well and maintain that gap! 15 thou is only specified for certain camshafts.

[bmcecosse]

A copper gasket for a 998 Mini should be less than £10 at your local Autoparts place. A wipe of grease on each face (more discussion , I fear...) and it will be fine !

[kennatt]

mines set at 12 and been like that for the 25 years I've had it,engine must be wrecked by now I better look for a replacement

[bmcecosse]

Don't panic !! Just the exhaust valves and seats at risk - IF driven 'hard'. You're more likely to suffer coil failure....