I’m just about to install the head with a Cometic TJP500 (.059" composite) from Terry’s. But I see the coolant holes are much smaller than the block/head/original gasket. What’s more they are different sizes left to right with no indication as to what is TOP. Can this be right? See below.
Whereas the uprated Cometic has the small coolant passage holes. SNG does note the larger holes are on the exhaust side, so they must aware of the small passages.
Unrelated but disturbing none the less, the Cometic die cutting quality is awful. There are ragged chunks looking to break free all over it. Additionally, the tiny holes don’t line up with the passages.
The two sizes of round coolant passage holes has been mentioned before, e.g.
I also recall discussions of the cooling efficacy of the deliberately smaller passages, but I can’t seem to find them in a search. Perhaps they were somewhere besides J-L.
The shape of the coolant passages doesn’t bother me at all: I’ve seen plenty of head gaskets that had round holes where oval passages were before: my complaint is not indicating which side of the gasket is top, and not lining the holes up with the extant passages.
A similar lack of attention to manufacturing cost me finishing the '86 Great Race.
Yes, I’m still bitter, and sensitive to PBS (Poorly Built Shit).
Simple measurements reveal the two small holes vs the OEM holes is an 80% reduction in area. Hard to believe this is OK. But I have a nice sheet metal punch So I can alter if need be. But REALLY?
Good point about misalignment. Doesn’t sound like Cometic. Is this their deluxe multi layer steel gasket?
Stating that the bigger passages are for the exhaust side is sufficient for installing the gasket. If you keep the front (timing chain opening) on the front, there is only one orientation that put the exhaust side on the exhaust side. No need to specify top.
I think I recall that the two sizes of smaller passages are intended to increase pressure and thereby reduce vapourization (cavitation) of coolant within the head passages, and thus its detrimental effect on cooling. IMHO from a memory loss sufferer.
I spent a long time on the phone with Cometic last week and they have NO inventory. Everything is now made to order with 3-4 week delivery. Sure sounds like a company who has moved their production somewhere else.
Edit: Also noticed no country of origin on the label. Another sign of someone moving production to a location they’re not sure of yet or ashamed of. The government penalty is less for a missing COO as opposed to the wrong COO.
The appearance of that gasket does not look like the quality of the Cometic gaskets I have seen in prior photos. Matter of fact, it bears a great deal of similarity to the craptastic part I got to “fix” the Auburn…
Hi Rick you could also try a Jaguar dealer if they still offer them. They were under the classic part division. both of my cars have them. The water hole seals are red and yes you will need to trim them as they are for the later XJ6 cars. Very nicely made.
I didn’t notice that. It comes shrink wrapped with Cometic instructions and a Cometic decal for your tool box. They must be outsourcing. I see Victor Reinz is part of Mahle Clevite and now owned by Dana. God only knows where anything is made anymore!
