Head Gasket - why should it keep blowing?

[traveller83]

When I bought my 1967 traveller last year, the engine was replaced with a recon - which has taken me a good 12,000 miles so far without too much trouble... EXCEPT... the head gasket has just gone for the third time!

I have taken it to a local garage on the first two occasions and they skimmed the head (only on the second occasion), but I'm tiring of this quarterly ritual!

How difficult is it to replace the gasket? I'm assuming all the other associated gaskets require replacing as well?

In the event the block is (must be) distorted, should both surfaces have been skimmed?

It always goes between the two rear valves which I know is an accepted 'hotspot', but there must be something that can be done? I rarely do long motorway journeys so don't regularly exert the engine to a great extent...

Any advice or tips most welcome!

[MikeHA4]

I'm hoping to get a Traveller, failing that then a saloon. I would like it to do 100miles on a motorway. Not every month mind. I would think that if the lubrication is working properly and engine temperature maintained with adequate cooling to all parts this should be OK! Seeing as old B series diesels are running for perhaps 8 hours non-stop in the leisure market during the summer.

OHV engines aren't difficult to change the head gasket with the right spanners/sockets and leverage. The head has to be undone and done up bit-by-bit in the right order, to spread the load. When it is replaced, valve gaps need re-setting.

I do wonder about your comment of the block face being true also. I've personally not had either a head or block skimmed, only gasket replacements. Someone else will be along to improve on these thoughts I'm sure..

[Alec]

Hello Traveller83,

there is something wrong, head gaskets shouldn't need to be replaced that often.

I assume you mean it goes between two cylinders, not valves? In answer your question, it is quite easy to change a Minor cylinder head gasket, just a few hand tools but worth getting a torque wrench to put it back. Get a workshop manual as the first step.

I think with the history I would be looking for a crack where the gasket is blowing, and as the head has been skimmed it should be easy to see? It is possible that there is a block problem but that is very rare. The other and again rare situation is if someone in the past has 'modified' the cylinder head and ground away the combustion chamber beyond the gasket edge. Again easy to check with the head off. I would have thought that the garage would have done that the second time. It looks as if they just assumed that the head was warped, which is not common on cast iron heads.

Alec

[kittyfell]

If the engine was run with the gasket blowing, then there is every chance the block and/or head has been eroded in that area. Easy to check once the head is off, in fact both head and block should be checked with a straight edge (12" steel rule) to see if there is any distortion or erosion. Any decent garage would have done this when changing the head gasket previously........ Unfortunately any distortion in the block means engine out and complete strip-down before machining the top face, and then possibly machining the piston crowns too. I have to wonder who did the 'reconditioning' on your engine?
Changing the gasket is dead easy, and although everyone now will say use a torque wrench, for many many years (and many gaskets) I have managed with just a normal socket set and some judgment on the tightening process. Basically you tighten in order from the center outwards pulling them up evenly and then finally pulling them to the point where you can just feel the stud 'yielding'. Important then to reset the valve gaps, run the engine up to temperature and then re-tighten the nuts and finally re-set the gaps. Perhaps your 'garage' didn't bother to do this before? These A series engines should run 'for ever' without blowing the gasket. PM sent with more information.

[MikeHA4]

Thank you for your thoughts on the longevity of the cast iron block/head and the gasket. I was beginning to feel concerned about my belief in these engines! In our family, people that have had blown head gaskets and one, a connecting rod through a block side were all Ford engines. I had a 1300 Mk2 escort estate automatic once, sold it on. It wasn't that old or high mileage. I heard later, it had blown the head gasket and had a cracked head..

[billlobban]

Surely the garage would have checked the block and head especially after the second time it failed. If they didnt then they shouldnt be in business and I would dump them straightaway. DIY gasket change it easy but I would suggest you use the slightly more expensive but better 'copper' head gasket. If youve never done it before that means you probably dont have the level of skill kittyfell is talking about so I would beg or borrow a torque wrench.
Done properly you should never have to change the gasket

[MikeHA4]

I agree with that. I haven't used/seen less than a copper-clad gasket.. Don't say you can get recycled cardboard ones with tinplate rim on the holes...

[billlobban]

Don't say you can get recycled cardboard ones with tinplate rim on the holes...

I'm afraid so BM (and I presume everyone else) sell the 'standard' gasket for £3.50 an enormous saving on the £4.50 for the 'copper' version

[kittyfell]

Every Pound saved is a Pound to spend on something else!

[charlie_morris_minor]

never assume anything..

i once had a midget over heat on me.. for the next two or three months after being repaired it went back and forwards to the garage ( it was under warranty ) as it was losing water all the time and overheating. Eventually he farmed the work out to an MG place to look at.. they fixed it first time.. er the head was warped from the original overheating and he had not thought to check it was still true.. I hate to think what it cost him in time and effort not to fix

[bmcecosse]

The standard gasket is perfectly ok on a standard engine. That will NOT be the problem. The gaskets have either not been fitted correctly/not enough care taken/not torqued down sufficiently/not re-tightened after the first heat cycle - or there is something fundamentally wrong with block or head. Who supplied the reconditioned engine - and did you complain to them when it initially blew the gasket ? How many miles had it run at that point ?