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Just bought a Triumph GT6.... and I think I need a new head gasket :( (inc. pics!)


HeebieGeebie
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Hi all!

Just bought myself an early 30th Birthday present, a beautiful GT6 MkII (see pics below). I picked it up last Wednesday on my friends trailer.

This is my first foray into classic car ownership so I'm going in blind!

2 years or so ago, the engine was swapped for a 2500 'MM' engine with triple webers and the car has been used for track days a few times a year but appears to have been well maintained (Although for this reason It wouldn't surprise me if my suspicions noted in the title of this post are correct). I would also like to take it on track at some point, but will mostly use it for weekend drives and attending car shows & meets.

Anyway, today I took the car out for the first time in my ownership for about half an hour. She drove beautifully, except there were a couple of short occasions where there seemed to be excessive smoke out the exhaust and the smell of burning oil, the rest of the time the exhaust looked lovely and clear.

I never experienced this on the short pre-purchase test drive.

So I left the car to cool down for a couple of hours in my garage and checked the oil level, it had decreased a small but noticeable amount since my pre-drive check.

I also looked under the oil cap to find what looks to be the dreaded 'mayo'. I wiped some off before thinking that I should take a photo, so there was more on the cap than what you can see in the photo's.

I never saw any mayo when I checked the oil cap pre-purchase, it did look a bit suspiciously too clean though, but the seller was a decent chap and I have no reason to suspect he was hiding anything.

So, I would really appreciate your thoughts, do you think my suspicions are correct and I need a new head gasket?

Also, my car has a rather 'interesting' looking valve cover breather setup and oil catch can, i plan to remove and inspect this to ensure it's not blocked. As I believe this could put gaskets under excessive pressure, am I right in thinking that?

Thanks in advance for your help!!

 

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That does look like emulsified oil.

The good news is the head gasket is relatively easy and cheap to change on one of these cars if doing yourself.

The factory workshop manual will give you a step by step guide with drawings. The parts book is also good with exploded views of the parts.

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Thanks for your quick reply!! Took it for a test drive last Saturday before purchase, let it run for a few minutes before taking it out for maybe 10 mins or so. Not sure how long it had been standing before that. Then just took it out for the first time today for around 30 mins. Last service was recent, the oil on the dipstick looks almost fresh out of the bottle, very clear. The coolant is blue and no signs of oil in it. I'll have a read through the workshop manual, I would like to attempt this job myself if it's required, first time I've done it though.

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Its a good sign the oil is clear and the water is blue. Keep a close check on the levels. If its been standing there could have been condensation in the rockercover. A few more drives should sort that out. As long as the temperature is ok and no big long plumes of smoke come along you should be fine. White smoke water, grey black rich mix , blue oil. Get some more miles in and smile, where abouts are you. If you can get along to a local meet they will be able to advise and have a good look at your car, looks great.

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6 hours ago, HeebieGeebie said:

I hope you're right! I'm in Chichester, so very much looking forward to getting over to Goodwood as often as i can to chill in the paddock and maybe take her round the track.

Welcome. Good choice of car, I know of an almost identical one, same Royal blue with Revs fitted. And good to see somebody else who plans to do some trackdays. Sadly the TSSC does not get involved with trackdays/motorsport, but other Triumph clubs do (mainly the TR Register, and they invite CT to attend) I have done a dozen or so over the last few years, including Goodwood, Castle Combe, Donnington, Blyton, Brands Hatch and Silverstone. Drop me a message if you wish to know more.

Back to your mayo issue. These engines can breathe and it looks like your catch tank vents to the atmosphere, somewhere down by the chassis. That may not be enough, especially with the 1/2 internal breather pipe . I have seen 6 cylinder racers using 32mm (same as GT6 rad hose) for a breather to atmosphere. That is a little extreme, but speaking to the chap it is what worked after trying smaller. The other way is to feed the breather into the inlet manifolds via a PCV valve which will help suck fumes from the engine breather and hopefully keep the engine from getting positive crankcase  pressure (which will help stop the engine leaking oil) I have a halfway system, feeding my breathers into a catchtank, and from there into my airfilter so any fumes don't get into the car, and it helps with a little vacuum.

As to the cause of the mayo, your main question, it could just be the oil has not got hot enough for long enough to evaporate any moisture. I see you have an oil cooler fitted (I can see the pipework) but I can't see an oil thermostat. A thermostat is ESSENTIAL as it allows the oil to operate at the correct temp. No thermostat, the oil will stay far too cold, and that could be causing your issue. 

BTW I am just along the coast in Hove, not far at all.

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agree mayo on the filler is just the easiest point to be cooled and any condensation/moisture  in the oil will deposit on the cap 

if it had a tin cover it would be all over  the inside  alloy holds the heat  but the cap is cooled  easier

never think hair cream /mayo is head gasket related its short runs that make it 

a HG will if failed allow many 1000s psi combustion pressures into the water jacket and you get cooling loss and over flows 

the coolant jacket is only a few psi but that may creep coolant into a bore when standing  there is a vast difference in head gasket pressures as to what goes where and when if it has a sealing problem 

unless its some catastrophic failure ( were there is no guessing ) its highly unusual to get  coolant in oil or oil in coolant 

i agree the breather is too small   thats due to the small spout on the alloy covers  breathing needs to be easy no a long route of small hose 

take Clives idea and make it larger bore as a start 

rules on classics  do homework and always tackle the easy cheap fix first before you tackle the many  mis guided Myths 

that are all too frequent wallet emptiers 

Pete

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Hi, a cylinder compression test would be useful and its probably worth buying a gauge if you havent got one or can easily borrow one. The readings should all be roughly the same but the value will depend on the condition of the engine and if the head has been skimmed.

In fact when buying an expensive older car, and if the seller will allow it, I would always recommend doing a compression test as its so easy and gives added confidence👍

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Totally Agree with the foregoing. My experience of the "6"s` Is back to the the ownership of a Vitesse in the 80`s. But all Engines of this era had a tendency to make "Mayo" under cold/cool conditions. We always recomended a good "Italian Tune". Go get it really hot, Good excuse for some "fun"!. Clives advice. re; Oil Cooler thermostat is well worth checking. Overcooling lubricant is  as bad as overheating it, It should run at optimium temperature. Go and enjoy, just keep an eye on it for a while.

Pete

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Hi HeebieGeebie

Welcome into the world of classics and congrats on the purchase of a nice looking car. I have a 69 White 19 Mk2, also on Revolutions.

Unusual to see a white chassis on a blue car, would be interesting to know why.

Advice given so far is spot on and I would also suggest you use the car a bit under various conditions and monitor the situation. Is the engine consuming any coolant. A mark on the overflow bottle would allow you to monitor. An oil cooler without a thermostat might be a contributory factor, but possibly not overly significant at this time of year.

Obviously with the triple Webbers, performance was a previous priority and catch cans are not unusual for track focused cars. I don't think you mentioned whether there is any significant accumulation of oil in tank and whether there is any evidence of mayonnaise there. I have a small catch can on my GT6 which the standard PCV breathes (pulls) through. photo attached. It collects a small amount of oil but nothing significant and I think the inlet (and the environment) is all the better for it.

I see that there is a tapping on the centre inlet manifold that could be used for the PCV.

When I was researching catch cans previously I recall that a naturally vented can does need to have quite large pipework to be effective as others have said. I think a filter on the outlet is also sometimes used.

Ian

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HG,

Mayonnaise is often seen if a car is run from cold, especially in cold weather, due to condensation of the water vapour in blowby gases on cold engine parts like the rocker cover.

But you said, I think that you saw this after half an hour's driving, so the engine should be thorughly warmed and the rocker cover too.      So real!    You may like to use one of the services (EG Wix) that analyse your engine oil, fo all sorts of wear and contaminants.

On hot oil smells, you don't say if you have oil drips on the floor.   It is difficult to totally seal a Triumph engine, and in use ssome can drip onto the exhaust pipe, causing smell and sometimes smoke.

Nice car!  Goodwood may get you hooked - try an Autosolo event, or Hill climb, as an intro to competiton?

John

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7 hours ago, clive said:

BTW I am just along the coast in Hove, not far at all.

Welcome. I am the other way in Emsworth, with a compression tester you are welcome to borrow. 

As an aside, had the first let down in 15 years yesterday with fuel pouring out of the air filter.  Fortunately not far from home and response from Peter James breakdown first class, but arriving home on an AA trailer disheartening on a Sunday afternoon when you live on a main road.  Carb stripping in progress which stymies sailing!

Dick

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Welcome, that's a good looking GT6.

As has been said, these engines are heavy breathers and without vacuum scavenging via the original PCV, they need a big atmospheric breather.

There's more info here

TR6 related but relevant. I wouldn't be too worried about the mayo. Try driving the car, check the condition and levels of oil and water, then only change the head gasket if there is an obvious problem.

Nigel

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Wow, thanks all for your replies, i'll try to respond to some of your comments:

Clive - You're right I don't have an oil thermostat, can you recommend one? Also, you're catch can setup sounds like the one in Ian's picture, I think I'm going to try to replicate that setup. I might do a little experiment and measure the pressure in the valve cover before and after, see if it makes a difference. If the valve cover already maxes out at atmospheric pressure I might just leave the current setup, but get rid of that copper pipe  (😄) and relocate the catch can somewhere closer, I'm not hugely keen on the idea of running back into the intake for fear of dirty valves.

Johny / Dick - I think the first thing on my to do list now is to do a compression test. The previous owner had apparently done one a year or so ago and wrote down the readings, they were all pretty close around 125-130psi which I think is OK?. However, something I just realised is that the dipstick was held down with a spring, I guess it had been popping out, i.e. there is pressure in the crank case, this is a bit concerning and i want to check compression before doing anything else. Dick, I may take you up on that offer of the compression tester! (Unlucky on the breakdown by the way!)

PeteH - I think the "italian tune" is the second item on my to do list haha

Ian Foster - Regarding the white chassis, i'm not sure but I have some pictures of the restoration that was done back in 2006 and i'll have a look and see if there are any clues or whether the guy just liked the idea of a white chassis. Regarding coolant, my overflow bottle is virtually empty <50ml in there, not sure if that's a good or bad thing - the coolant in the radiator is full to near the top. And finally, regarding catch can, i meant to empty it tonight and see how much was in there but I didn't get round to it. Will have a look tomorrow.

JohnD - I will look to get an oil anaylsis done after a few miles of usage for sure, good idea! No obvious oil leaks, but i can smell it so i'm sure there is some seepage somewhere, to be expected i guess.

Thanks all for your replies that has really helped alleviate my fears regarding head gasket but intensified my fears about poor compression haha 😄

Also, can anyone point me in the direction of where I can buy a replacement oil cap (as shown in picture in the first post), I can't seem to find one with that 'female' design?

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whats the problem with the existing cap ??  and you are lucky the std alloy cover normally fouls a GT6 bonnet  so hows this been solved ???

and a thought on oil smells   whats in the sump, maybe a oil change for a known brand 20/50 will help

some oils  whiff  when hot  and do check the baulkhead has no open unplugged/ broken grommet   holes lurking 

and well fitting pedal box gaiters    and the heater plenum to bonnet seal works 

 

Pete

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9 hours ago, HeebieGeebie said:

Wow, thanks all for your replies, i'll try to respond to some of your comments:

Clive - You're right I don't have an oil thermostat, can you recommend one? Also, you're catch can setup sounds like the one in Ian's picture, I think I'm going to try to replicate that setup. I might do a little experiment and measure the pressure in the valve cover before and after, see if it makes a difference. If the valve cover already maxes out at atmospheric pressure I might just leave the current setup, but get rid of that copper pipe  (😄) and relocate the catch can somewhere closer, I'm not hugely keen on the idea of running back into the intake for fear of dirty valves.

 

 

Ian Foster - Regarding the white chassis, i'm not sure but I have some pictures of the restoration that was done back in 2006 and i'll have a look and see if there are any clues or whether the guy just liked the idea of a white chassis. Regarding coolant, my overflow bottle is virtually empty <50ml in there, not sure if that's a good or bad thing - the coolant in the radiator is full to near the top. And finally, regarding catch can, i meant to empty it tonight and see how much was in there but I didn't get round to it. Will have a look tomorrow.

 

Mocal make an inline oil thermostat. They are a proper manufacturer, buy with confidence. like this

https://www.ebay.co.uk/itm/401376608743?hash=item5d73e901e7:g:cj4AAOSwCXBdzBku

White for a chassis (and other structural steel) make seeing cracks easy, so te builder may have decided it was a good idea, making inspections easy.

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The coolant overflow bottle sounds a bit low as the end of the pipe must always be kept immersed because its a syphon (keep mine 1/3 - 1/2 full).

A clear hose is a big advantage because you can easily check that its always full of coolant and working correctly to allow liquid and not air to be sucked back into the radiator when it cools. Consequently whenever you remove the rad cap it should be full to the cap top seal with coolant - no air what so ever. Obviously when you do this the pipe will drain into the bottle but after the next run it should be full again...

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HG,

Do you realise that the rocker cover is not original?   It's a cast alloy version of the OE pressed steel, so  you might look at suppliers of the alloy version to find a cap.

 

On the mayonnaise.   You said in your original post that the car had only been used occasionally.     I wonder if that was for short runs, or even just being started in the garage, a favourite way to 'maintain' a car in storage, that IMHO just wears out the bearings and drains the battery.   And also adds water to the sump oil, from combustion and normal blow by.      Regular use, running the car on the road for hours, heats the engine thoroughly and evaporates that water.       If your DPO's practice has allowed water to accumulate, that might be the sorce of the water.        USE THE CAR!      That will get rid of this water, and the mayonnaise might disappear!

John

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11 hours ago, HeebieGeebie said:

Regarding coolant, my overflow bottle is virtually empty <50ml in there, not sure if that's a good or bad thing - the coolant in the radiator is full to near the top. And finally, regarding catch can, i meant to empty it tonight and see how much was in there but I didn't get round to it.

HG

I have my radiator overflow bottle half full when cold and the level rises to just below the shoulder when fully hot. A couple of marks on the bottle allow the level to be monitored.

It will be interesting to see whether your catch can has any internal structure to promote condensation of oil vapours and filtration of the expelled air. 

If the catch can is working properly, what is being drawn back into the engine should be clean and therefore shouldn't make the valves dirty.

This is a useful link which gives some technical background and comment on typically available units. I fabricated some 'internals' into a plain (but quite nicely made) 'cheepie' can.

The original oil filler cap has a steel wool filter element in it, which I assume is to filter air drawn in to compensate for the slight vacuum created by the PCV.

Ian

 

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