Wishing all a Merry Christmas and a Happy New Year.
I own a 1948 1.5L car. Its been in the family since new. About a few months ago it developed a head gasket leak. I pulled the head and did the guides and valves. Head was faced. It had the compression plate (used to lower compression ratio) sandwiched between two copper gaskets. This plate is now removed.
The question I have is that should I punch out the blanks in the new copper gasket. Presently these are blocked off. There are corresponding water passages in the block and head. Even the compression plate has these holes. See the picture below. It shows the issue I am referring to. The gaskets I pulled out has someone punched out holes.
I don’t think the blocked holes are accidental. I suspect they were closed to increase the flow in the centre between cylinders 2 and 3 because the two exhaust ports from 2 and 3 are side by side in the centre. I also think that removing the blockages might cause unwanted deformation of the corrugations surrounding the holes opened.
On the 3 1/2 L engines there are three completely blanked-off holes like you indicate. There also are two holes not quite blanked off which have 3 mm holes in the centers. All of these blanked or partially-blanked holes are on water passages between block and head along the pushrod side and all the blocked or partially-blocked holes are between the pushrod openings (a part of the block and head which may need less cooling).
A guess on why this head gasket arises: perhaps the block and head design and testing stages had some uncertainty in thermal characteristics which could be resolved in development without needing to change casting designs. Various head gasket designs could give development needed without foundry changes.
Peter, Roger and Rob thank you all for such a quick reply.
I had a feeling that the blanked off holes had something to do with circulation but needed to be sure. The fact that some previous mechanic had punched these out on the old gaskets threw me off. The picture of the 3.5L block/gasket underlines this matter of circulation. Once again many thanks for all your input.
You are perhaps aware that your engine was also used in Standards and Triumph 1800s of the period, and I believe Ferguson tractor, but not TR2. You might check with people who know those cars for confirmation about the head gasket.
For your own records, you might make a 3D map of the water circulation in the head and block.
I have only one Triumph book in my library, but I looked through it to see what it had to say about engines going to SS and Jaguar.
Triumph had been pretty much destroyed by the Luftwaffe, so when Standard bought them all they got was the name.
Here’s the view from the other side of the fence, a quote from Standards MD Alick Dick.
“…before the war Standard had been supplying parts to SS. Standard had special engine tooling for the six-cylinder engines, and the overhead valve version of the four-cylinder engine, of which Lyons took all supplies. Immediately after the war Bill Lyons wanted to buy the tooling - he wanted to make all of his Jaguars in future - and John Black was willing to let him have that so that we could build a competitive car. We kept the four-cylinder tooling, but it just wasn’t viable without a new chassis and a new name. So that’s why we bought Triumph. Just because Bill Lyons made a sporting saloon, or a sports car, John Black was not going to let him get away with it.”
Thank you for your research. Indeed these engines trace their roots back to Standard. I have not been able to post any questions on the TR18/TR20 forum as it is open only to members. Gaining membership may require some form of payment I gather. Hence just for this one time question it seems a bit much. I have written to some other Mk IV specialists and waiting to hear from them.
Here is a picture of the TR18 block and gasket. As can be seen here the two holes are very much not blanked of. Most confusing. Anyhow research goes on.
Things to note: Firstly I’ve come across two versions of Corrujoint gasket. The good type has a corrugation around the periphery like the one in your previous photo but the one above does not and in my view is substandard. Secondly the blanked off holes re of reduced diameter so perhaps the one above was an interim design.
Here are some photos of a genuine Jaguar MK IV 1.5 litre gasket set, from my box of spares that came with my car prior to restoration. It is exactly the same as the gasket on my 1948 1.5 litre car when I took the engine apart, but I used a new one as this old part has a few dints in the copper work. It does confirm the correct holes, etc I believe for the required flows.
I was hoping the Service Manual would shed some light, but it doesn’t, just hints that something should be noted.
Parts catalogues also aren’t much help.
I suppose yours is a KB engine.
Deductive reasoning would suggest that they would not make a gasket with corrugated but unpunched holes without a reason.
I’m also curious about the egg-shaped piston holes. Is that the shape of the combustion chamber? Can you give us a pic of the head?
Correct part number for KB 1.5 litre engine is C1186, and that is what I ordered and used on my 1948. Here is a copy of the 1.5 litre Spares Catalogue:
Also aftermarket gasket parts are NOT the same, but I have found they often have extra holes to fit all the various Standard engines supplied in that era. They fit, but clearly the flows will be different, and this is one advertised on a popular marketing web-site (does not look correct to me)
Yes, and IIRC they (Triumph cars, not Triumph motorcycles, nor bicycles or underwear ) basically were bankrupth already before the war. Incidently they were neighbours at the old Foleshill industrial plant (with SS Cars, Standard Motor Company was elsewhere).
So Standard used the same block, crank, etc for their 1800cc IL4 on post-war Triumphs and it was originally their design. On the IL6 SS Cars had their own OHV cylinder head, designed in 1935 by none other than Harry Weslake, that’s what gave the engine the power needed. I do have a spare 4-cyl 1938 SS engine with some essential parts missing (crank, camshaft, all moving parts) with block, cyl head, sump, cam cover, valve train, etc. only for display.
These gaskets are for the Standard 1.5 litre engine. The Standards were still shipping side valve engines. It is only the Triumph 1.8 cars that used the Jaguar 1.5 litre engine.
Standards never used the OHV engines used in the Jaguars.
Yes. And now I am not sure, but I think SS used the sidevalve four, as it was, on the few 1 1/2 Litre SS Jaguars in 1936 and 1937 and in 1938 the SS Jaguar 1 1/2 Litre also got the OHV cylinder head that remained in production until 1949.
I have no idea if Standard / triumph used the same cylinder head as Jaguar after the war (1946-1949).
That might be. But these two engines (Jag and Triumph) look pretty similar with similar characteristics. One really has to dig deep to find out differences.
Peter’s knowledge is vast for the pre-war cars and he has pointed out the engines these gaskets belong to but I might add that they could be belonging to the pre 1936 side valve SS 2 cars.
@goodoldgrandad thank you so much for digging out this original old gasket. It is clear that indeed this original item has the two holes blanked off. So we can say that the gasket I have is not incorrect with the blanked holes.
) basically were bankrupth already before the war. Incidently they were neighbours at the old Foleshill industrial plant (with SS Cars, Standard Motor Company was elsewhere).