Cylinder head gasket

[David Morris]

Hi Dave,

The washers under the head stud nuts should all be steel. Just a point to remember about washers and the heads, I am sure that you have realised, but the washers under the long studs on the heads that hold down the rocker shaft should be quite a small diameter. If you fit wider washers here, they are very likely to clamp up the adjacent rockers. It easily done and I speak from experience! Also, you will find that the washers under the lower head studs also need to be quite a small diameter, as they fit into recesses. These head nuts along the bottom edge fit into these recesses and this makes it difficult to get a socket fit them properly when tightening down. Most of us have a socket in our tool kits that has been ground-down to fit into the recesses. I believe JCS stock special longer head nuts, that cures this problem. Sounds like a good idea for a future Christmas present?

I have never tried tightening down the head without a gasket, which sounds a good idea to check the gap. I wonder if it was even all around? Did you check this? We have found that, with the blocks being at least 55 years old, they warp and get distorted, especially if they have been welded at some point in their lives. They are delicate lumps and don't suffer any heavy-handiness!

Now that you mention it, I do remember working on an engine where someone had sacrificed an old copper gasket and peeled away a single thickness of just the copper foil section of the lower part of the gasket, about 1.5" up from the bottom edge, just short of the cylinders but the full width, to give a sort of additional mini-gasket that was then added to the proper gasket and presumably gives a better 'nip' along the lower edge, when this was used to pack-out the lower section. It sounds a bit drastic, but I wonder if this might help you? Your measurements all around the gap might indicate whether this is worth trying?

Hope this helps,

David

[alexander]

Thanks Keith for the link very interesting reading and will add to my Jowett knowledge.
David thanks for the idea re shim gasket, I'll get some new steel washers and pull the head down again first and check the joint again. Then if still .008" I'll have a go at the shim.

Dave

[alexander]

Hi Everyone
Update on head gasket problem, made a shim to go on the lower edge of the gasket and followed the instructions for fitting the gasket.
I knew the water pump bearing was shot so as the water was out I thought I'd recon it, well not the easy job I thought. I ended up needing new shaft ,bushes, seals, bearing and impeller, thanks to JCS all replaced.
Got the water pump back on today and had coolant dripping from the weep hole in the front cover, does the seals need to run in on the impeller or do I need to check the seal.
The head gasket seems better re water but now there is an oil leak from the gasket. Also oil must be getting into the cylinder as the car is burning oil. Compression and oil pressure is good.
With lots of time to kill at the moment I'll strip head down again and have another go.
Dave

[Keith Clements]

A few issues here. Leaking water pump is fairly common after fitting new seals. The setting of the load on each seal is critical. Others should advise. Sometimes the leak stops after a hundred miles of running.
Is there smoke out of the exhaust pipe?
What is the oil consumption per 1000 miles?
Oil on plugs?
Endoscope might help.

[David Morris]

Hi Alexander,

Good news that you are making progress. On the question of water pumps, there are two colleagues in the club who are much more knowledgeable than me and, I am sure, can advise. Try giving either John Airey or Drummond Black for advice on setting the pumps. I watched John rebuild one recently and the thickness of the gasket, part no. 50853 and numbered 332 in the parts list, is critical to giving the right pre-load to the seals. John often has to add extra gaskets to avoid giving the new seals from JCS too much loading. I believe the seals are sourced from India, as they fit the ubiquitous Hindustani taxis they use there, derived from an old BMC design?

Keith is right that, with new seals, they do take a while to settle-in and can leak initially. Glad that you have good oil pressure and compression. What type of oil are you using? Sometimes, if using a thin oil, it can lead to excessive consumption/leaks? You need SAE 30 or similar, preferably not a modern oil, but one designed and formulated for classic cars. I get my SAE 30 from Rye Oil in Kent. Free delivery too!

All the best,

David

[alexander]

A little history of the car. I bought the car last June, it had stood for two years due to ill health of owner.
A lot of work had been done to the car, rewire, new brakes respray and engine rebuild.
I was told the engine would need to be run in and on inspection there was no smoke from the exhaust.
The oil pressure is 70 on start up and when hot 50 on tick over. Compression good.
Over the last few months I've reworked all the things that you would do to a car that's been stood, the last thing being the water leak from the head and water pump.
Yesterday I could smell oil burning and the head had an oil leak but no water leak.
Checked down the cylinders with a cotton bud and no oil on 2&4 but slight oil on 1&3(the side of the head gasket problem)
Today no smell of oil burning still have oil leak from head, checked torque ok , number one inlet tappet needs slight adjustment. Both plugs in 1&3 showing no sign of oil and no oil on the cotton bud.
Lots of condensation from tail pipe and worse when I blip, the car has only been started in the garage as I have not driven on road yet so that could be the reason.
Good news is the water pump has stopped leaking.
So I think my next step is to revisit the head gasket and try to fix the oil leak and hope the water leak does not come back.
Thanks for suggestion
Dave

[Keith Clements]

Is the oil dropping onto exhaust manifold?
Check oil return gallery from rocker cover is not blocked. Run a coat hanger type wire down it. A leaking head gasket may have rusted a bore which might polish up with a bit more running in.

[alexander]

Hi Keith and David
I should have thought of oil on exhaust, the day I had the burning oil smell there was oil on the exhaust, next day I cleaned the bottom of head and the exhaust with "upol" degreaser hence no smell of burning oil. That was another of my senior moments do I feel daft or what.
Will check the oil return as I redo the head gasket.
Thanks
Dave

[alexander]

I thought I had better give an update. The burning oil was due to a worn rocker shaft and no oil seal . Giving a build up of oil in the rocker cover that was to high to return in the normal way. Changing the rocker shaft and putting back correctly has solved the problem, no more oil burning smell.
Thanks again for all inputs