Differences in Headdesign 1275

[MMT1968]

As the head came off the damage came to light. The head gasket had blown between #2 and #3 as expected. But the head suffered a serious damage at the rim between the two combustion chambers withsome eroded material. We now try to find out if it’s possible and practical to Laser weld that. If not the head is scrap unfortunately.

Chris

[philthehill]

Bad luck.
Before you do anything check that head for flatness especially in the area where it has been damaged as it is showing signs of having been blowing before total failure.

[MMT1968]

Surely we‘ll check that.

[ndevans]

Deleted

[ndevans]

This is the one from Minspares described as OEM





So far so good.

Looks very similar to the one I have. I didn't use it in the end after hearing bad things about composite gaskets.
Is it possible to prepare them for use by putting them in the oven for a few minutes, then soaking in hot water before fitting?

[svenedin]

As the head came off the damage came to light. The head gasket had blown between #2 and #3 as expected. But the head suffered a serious damage at the rim between the two combustion chambers withsome eroded material. We now try to find out if it’s possible and practical to Laser weld that. If not the head is scrap unfortunately.

Chris

Sorry to hear about your cylinder head troubles. Are there signs of erosion between 1 and 2 as well? Much less than between 3 and 4.

Stephen

[MMT1968]

As far as I know no. But I have not seen the head myself but just the pics.

Chris

[panky]

Looks very similar to the one I have. I didn't use it in the end after hearing bad things about composite gaskets.
Is it possible to prepare them for use by putting them in the oven for a few minutes, then soaking in hot water before fitting?

I don't think that would work as it would cool down very quickly when put in place.

Sorry about the thread hi-jack.

[MMT1968]

Hi,
An update:

I guess we found the problem causing the recurrent damages to the head gasket.
The head has been pressure tested and showed significant leakages at two brass plugs in the water channels.
I think that some steam through these leakages has weakened the head gasket which led to the short time it lasted. I had three gasket failures almost every 500 miles with no prior signs of overheating. Maybe the difference in temperature is also causedby this.

Any further ideas welcome.

Chris

[MMT1968]

An update that might be interesting.

The workshop that had done the rolling road tests has measured the temperature in several different BMC-A engines that were not transversal mounted. In all Midgets and Morris they tested as well as in the MG-A and -B even if these got different and bigger engines the temperatures were quite similar in difference between front and back end. In all cars they measured a difference of 15 to 20°C regardless if the heater was switched on or not. I guess that’s more than interesting as it could be a reason for head gasket failures mainly on cylinder 3.

Chris

[Bill_qaz]

That looks a lot of erosion of the head face for 500 miles, I would respectfully suggest the head face has been already compromised when the previous gasket(s) were fitted.

[MMT1968]

No, the head surface had been planed as well as the corresponding block surface. That erosion at the head was 2,5mm deep, at the block 0,12mm deep.
The main problem are the two marked dowels. The one in the middle shows brownly changes at the central edge and towards cylinder 3. My interpretation is: at this point was a waterleakage heading towards the combustion chamber of #3 with rusty water. That means corrosion in the seat of the dowel. That water spray getting into the combustion chamber #3 must have increased the temperature in there significantly leading to that damage of the head.

The head can be repaired by laser welding of that erosion and fitting new dowels but the estimated cost for that job are exeeding the value of the head. As I‘m not convinced that this head would be reliable in the future I bought a new head instead of having the damaged obe repaired.

Chris

[Bill_qaz]

Good decision, hope it resolves your reoccurring issue

[MMT1968]

Another update:

I found a specialized welding workshop that Laser welded the described erosion in the head. They did a good jobfor quite a small amount of 30€. Now the head will get three new dowels in the water Channels to solve the leakage. After that I‘ll have it pressure tested, then we will see if it works. Fingers crossed

Chris