Posted By : John Davies,
16-Jul-2006, 10:10am
Chris,
I bow to your superior knowledge, but as you own a 1200 Herald........
To remove all doubt, here is a pic of a used, six cylinder head gasket.
If you look at one, Colin, you will see that it is symmetrical in one axis - you can turn it end for end. That doesn't matter on a
non-recessed block, but it does on the recessed. That's why there is a tab on the rear edge of the recessed. Here it has almost all
broken off, probably from me trying to reach gear box cover screw anchors or something behind it. It also means that there are two
holes for the single head oilway, which is confusing.
I've marked the five holes in the head that communicate with the head water jacket, but have no corresponding waterways in the block,
so are not perforated in the gasket.
Not sure what you mean by "one large waterway on the edge paralell to the stud". The two elongated ways either end are the major ones.
The long holes parallel to the long side are, of course, for the push rod galleries.
IMHO, you need to check that you have the correct gasket, fit that, run the engine until it has heated right through. let it cool down,
re-torque the head nuts - and drive away. Another re-torque in 100 miles or so.
Any more probs and suspect a non-flat head or block face.
John
Just found out why my head gasket blew on the maiden voyage... anyone identify the head / block pattern?
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Posted By : Colin
Lindsay, 16-Jul-2006, 10:51am
I'm aware there are three heads: Mk1, Mk 2 and late Mk3 domed piston, which is the one I was originally supplied before having it
replaced. The block is a MK2 block. The photo here illustrates what I mean - there seem to be a lot of waterways with no
corresponding hole in the opposite face, or certainly not in the gasket anyway - there are a lot of small brown circles on the
gasket where water has been lying against the gasket face; even the perforated holes aren't accurate to the size of the waterway
(the large one to the right in this photo, not the long oilway, John!). What I need to know is: is it meant to be this way, or are
there waterways meant to be straight through for coolant flow? Of course I dumped all my old gaskets to prevent the temptation of
reusing one someday so can't compare with the copper type. I find it very strange that the water doesn't go anywhere but just sits
against the gasket in a dead end. When the engine was started after the head had been fitted, it ran for fifty miles with no
problems - normal temperature - until the car was turned off, then we had a major blow up in the expansion bottle; a lot of
bubbling and a four foot fountain of water...I retorqued the head and only one nut required minor tightening, but after fourteen
miles - same problem, turn engine off and stand well back. I'm not going to rebuild everything until I'm sure it's 100% correct.
All opinions and advice are very definitely welcome!
Colin
Just found out why my head gasket blew on the maiden voyage... anyone identify the head / block pattern?
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Posted By : Lindsay
Dearing, 16-Jul-2006, 12:00pm
In the light of this thread I went and checked my stripped down late Mk3 recessed block and head and compared the old gasket
with the waterways. The brown circles shown in the gasket photo are present on mine also and are caused by the head having
waterways at those points but NO corresponding ones on the block! I also have a Vitesse Mk2 non recessed block and the waterway
holes are identical to the later Mk3!! So why have the heads got these holes and blocks do not? The late Vitesse and early
Mk2/3 GT6 has TR5 type cylinder heads whilst the later Mk3's has Triumph 2000. Could this be the reason I wonder? Maybe it was
too expensive to change the engine cores. I doubt we will ever know when Triumph costings come into play.
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Posted By : Philip
Brammer, 16-Jul-2006, 12:45pm
I'm wondering if the 'blind' waterways are a part of the block casting process. There are similar 'blind' waterways on the
1500 block.
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Posted By : Chris
Taylor, 16-Jul-2006, 12:58pm
The blocks and head castings will be very similar or the same. There is no reason to be different between models, except
for head "thickness" for variations in compression ratio. Indeed the domed head pistons were to enable the same head to be
used with both 2 litre and 2.5 litre engines. The only block that WAS different in the internal coring was the 1600 which
had water all the way around the all bores, 2 litre having bores "siamesed" so no water actually gets fully between 1 and
2, 3 and 4 etc. Not sure this actually changed the gasket details significantly as I believe you can fit the 2l Mk1 gasket
to a 1600, and this was recommended for the 1720cc "conversions" that John Kipping produced at one time (to use up supplies
of herald 1200 standard sized pistons if I recall!). This was to prevent excessively high compression ratio, the copper Mk1
gasket being a little thicker than the 1600 pressed tin one.
In order to cast a head with lots of holes "inside" it is necessary to put cores (around which the molten metal flows) in
from the outside. Some of these were attached to the rest of the mould via specific holes, subsequently blocked off with
core plugs, (hence the name!) others seem to have gone in from the head/block face. If they are not needed for COOLANT
through flow into and out of the head, then they are dead ends. It is no surprise to me that the relevant gasket has no
holes in it to match.
Since you are going to need one anyway, I suggest you get a new headgasket (Stanpart or Paynes or other original supplier
if at all possible) and have a good look at the hole patterns. As long as there is a hole in the gasket that lines up
reaonably well where there are corresponding holes in BOTH block and head faces, then all should be well. Your gasket looks
to me like a cheapo accessory shop item, though I can't see the whole picture. The original Mk1 gasket was copper, but
while I thought that was the case for the Mk2, I've never actually had a mk2 engine apart.
Is there any evidence from the gasket as to exactly where the gasket has blown? Probably into a combustion chamber for the
coolant system to have become as pressurised as the water fountain indicates.
Also worth checking both block face and head for flatness. A warped block is unusual, a head less so but more easily fixed!
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Posted By : Colin Lindsay, 16-Jul-2006, 02:27pm
Chic Doig will be pleased, it was one of his Payen gaskets...
There are no marks on the block, head face or gasket indicating where the leak was, which is annoying as I'd like to
find it and so determine the cure!!
Colin
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Posted By : Chris Taylor, 16-Jul-2006, 04:45pm
Oops, there are times when one might wish to remain anonymous on this messageboard! I did say it LOOKED
like......... shows how jolly good these aftermarket reproductions are (rapidly backtracking!!!!!)
Not wishing to insult your considerable Triumph experience, but I presume this gasket was NOT one with a tab at the
rear for a recessed bore block? Can't say I can see it in the photos, but one of the earlier posters suggested it
was. (That said, I would have expected that to seal the combustion chambers but leak water and oil
everywhere!).
Although it is just possible you have a flawed or porous head, my first line of checking would be to take out the
studs and check the block and head faces for flatness.
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Posted By : Kevin Rochfort, 16-Jul-2006, 04:58pm
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Posted By : David Rumens, 16-Jul-2006, 06:43pm
What prefix is on the engine and what number is on the head?
Mk11 heads have a number of 517528 on the front carb side of the head, near the water pump. The engine should
have a prefix of either HC (Mk11 Vitesse or KC (Mk11 GT6). And Mk111 GT6 KE up to 10,000 after 10,000 a
diifferent block, head and domed pistons were used.
So if your head is 517528 and your engine is either HC or KC or KE less than 10,001 then you require a Vitesse
Mk11 head gasket.
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Posted By : Chris Povey, 21-Jul-2006, 12:43pm
Hi Colin,
The problem you describe (water fountain on turning off engine) sounds very much like there has was a big
air - lock in the cooling system. I uesd to run a couple of cars with Ford V6 engines where airlocks were a
considerable problem after refilling the cooling system. The symptoms of having an airlock were exactly as
you have - much gurgling and high pressures in the cooling system. I believe this is caused by water coming
into contact with areas of the engine/head castings which have been uncooled due the airlock. This water
instantly boiles causing the almost explosive expulsion of coolant.
Can you actually see a failure on your head gasket? Was there water in the oil or vice versa?
It seems unlikely that the head gasket you had was incorrect for your engine.
Good luck with a solution.
Chris
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Posted By : Colin Lindsay, 21-Jul-2006, 08:52pm
Thanks to all who have contributed - it's very handy to be able to think out loud and bounce ideas off
other enthusiasts to see what arises. I've obtained a head gasket for the Vitesse Mk2, but still can't
see any problem in the old gasket or evidence of warping on the head, nor oil in the water. I'm
intrigued by the idea of the water air-lock, the water was coming out of the block tap when opened and
the heater was working but you never know and it's something I'll bear in mind when refitting and
refilling the system.
I've had suggestions of sealing the gasket using Wellseal or Gasketworks type sealers but I reckon the
gasket should stand on its' own without needing assistance if everything's as it should be. I'll try
once more before throwing heavy things about and retiring to somewhere where Triumphs are only a
pleasant dream. (or go back to driving my Herald which hasn't let me down yet... except for the wiring
loom... and the bodywork....and the holey hood...)
Colin
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Posted By : Leon Guyot, 22-Jul-2006, 01:39am
Triumphs are pretty much a pleasant dream here in Southern Oregon.
Almost never see one, except my Vitesse, and Dennis Barr's Herald, under restoration.
I know there are a couple of people in the neighbourhood with Triumphs, TR3 & TR250, and a
Spitfire and a 'V8 Coupé' which I have never seen about 40 miles south, that's about
it.
There are a handful of MGs and Jaguars around here, and a few original Minis, as well as 2 Austin
Healey 3000's, oh and a Riley Elf...
Not counting modern Range Rovers, Jaguars and the odd Bentley/RR, that's about the lot.
Best Regards
Léon
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Posted By : Steve Cureton, 22-Jul-2006, 09:09am
Returning to the comment about a fountain of water, I had a similar experience on a non-Triumph
last year which turned out to be a failed head gasket - coincidence maybe? The fountain wasn't
as dramatic sounding as yours but it was enough to make me jump back when the erruption began!
It also only happened when the engine was switched off which I put down to the fact there was
no longer enough water to circulate thereby creating hot spots followed an instant boiling as
the water flowed to it's natural height when the pump stopped turning.
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Posted By : Colin Lindsay, 22-Jul-2006,
03:43pm
Just in the middle of refitting it all together, making sure it's all flat and scrupulously
clean, and a quick exploration of the waterways with a high pressure hose and an air gun
reveals yet another hidden stash of gritty bits - this is even after I took nearly half a
pound of crud out of the waterways before fitting the 'recon' unleaded head last year. I
had to stand the block on the end with the pump apertures facing down on a rubber mat and
belt the hell out of the head with a rubber mallet - and this all fell out....
Really reinforces my faith in certain Triumph traders....
So: it may have been blocked waterways after all, but time will tell.....
Colin
Just found out why my head gasket blew on the maiden voyage... anyone identify the head /
block pattern?
