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mints53

Head Gasket failure?

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Some advice is needed. The last couple of times I have been out in my 4A (about a 20 mile run) I got back and found foam coming out of the expansion bottle with some coolant loss when checked after it had cooled down. Other than that there are no other symptoms - overheating, foam in the oil etc. A worrying sign of possible head gasket problems I thought. I bought a test kit - the type with the fluid that changes colour and have just done a test that shows clearly the presence of combustion products in the radiator.

So how likely is it that I will get away with just a head gasket job, possibly skimming the head. Naturally I'd refurb the head at the same time. I am concerned about disturbing the liners are there any special measures I need to take? Also when I have done this job on other cars I get the head dipped to clean it up, is this OK on a TR head?  Should I also fit new valves and springs or is it best to stick with what Triumph fitted given the questionable quality of some modern replacement parts.

I'm expecting a battle to remove the head any tips to help this would be appreciated

Of course everything depends on what I find when I get the head off

Thanks for any advice before I start this job.

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Hi Mints,

            once the head is unbolted do NOT rotate the crank until the liners are held down tight.

many moons ago I found that the front stud on the exhaust manifold was screwed in so far it was  clamped against the head stud and wouldn't shift.

If the existing valve clean up then use them.  Stick with the standard valve springs unless you are thinking of racing etc.

There is an Ali core plug on top of the head that may not like an acid dip.

 

Roger 

 

Edited by RogerH

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Just change the gasket, as Roger says don't turn the engine while the head is off. Skimming the head is optional and stripping/rebuilding the head also optional....  Beware mission creep.. that's why I say just do the gasket and then get the car ready for spring...

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STOP.

If not too late, before you remove the head, try re-torquing it down, I was getting pressurisation of the cooling system 2 years ago, & suspected the head gasket was leaking.

I re- torqued the head, & got a surprising amount of extra turns on all stud nuts. It cured the problem.

Bob.

Edited by Lebro
smellin mistook

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If you have exhaust gases in the cooling water, it may be the sign of a cracked head (ask me how I know :angry:).

Get the head pressure tested before any other work. If cracked, they can sometimes be repaired.

To remove the head, if it sticks use wooden wedges, not steel!

Mike

PS You might try a bottle of K Seal before pulling the head. It sometimes cures the problem. M.

Edited by mike3md
More thoughts

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27 minutes ago, Lebro said:

STOP.

If not too late, before you remove the head, try re-torquing it down, I was getting pressurisation of the cooling system 2 years ago, & suspected the head gasket was leaking.

I re- torqued the head, & got a surprising amount of extra turs on all stud nuts. It cured the problem.

Bob.

+1 Bob had just the same a couple of months back, re torque and fine again.

Paul

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29 minutes ago, Lebro said:

STOP.

If not too late, before you remove the head, try re-torquing it down, I was getting pressurisation of the cooling system 2 years ago, & suspected the head gasket was leaking.

I re- torqued the head, & got a surprising amount of extra turs on all stud nuts. It cured the problem.

Bob.

+1   good spot - do the easy stuff first

 

Roger.

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I also had a similar problem on my 3a. New studs and nuts enabling me to torque to 110 lbs sorted it out. 

Good luck,

Tim

 

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Thanks for the replies I must say I am pleased that there maybe a fix not involving taking the head off. I don't have a lot of time at  the moment and was hoping to be driving the car across for a trip to France in March. I'll let the  Forum know how I get on.

 

Mints 53

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It looks like I am going to have to pull the head off. I've tried the retorqueing process and retested with similar results. This is what I did

Drained the coolant

Went over the head nuts starting from the inside and working out, backing off about 1/8 turn and pulling down to 105lbft. There might have been some additional movement but it was small

Refill with fresh coolant and retest.

Can anyone see a flaw in my method?

The next question is what does the forum recommend for a head gasket.

Thanks

 

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I suggest this is a good time to do a compression test to see what is going on in each cylinder.

 

The next stage is remove the head and visually inspect what is going on.

 

What could be the problem is that a build up of sludge around No4 jacket has become cemented leading to overheating and HGF.

 

Do not worry about unseating the liners as if the problem is cemented sludge you are going to need to remove the liners the chip out the cementation and clear the water jacket. It is also a good opportunity to replace the piston rings and while you are about it the big ends.

 

The job is simple and straightforward as you can do it all with the engine in situ, all it needs is a bit of spare time to do it:-)

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Hi mints53 ~

Some time ago when I rebuilt the engine on my 3A this is what I found ~ puzzle find the block drain hole!

Tom.

DSCF0225 - Copy.JPG

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Hi all

I've taken the head off now and taken it to be checked, just had the bad news, it's cracked and been scrapped. I haven't seen it myself so don't know where the crack is but is there any experience out there of a possible repair?

I'm currently also looking into alternatives, either a second hand good one (anyone got one for sale?) or one of the new ones that Moss sell ( does anyone have experience of these?)

All suggestions are welcome

Mints53

 

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Hi Mints,

            have you got a name and where are you based.

If you want to try and get a used head start another thread asking for one. That will attract possible donors to you.

I have a New steel Moss head (3 years now) and it works very well. The only issue is that they use uprated valve springs.

I would suggest removing them and fitting your old softer springs - unless you plan to go racing etc.

 

Roger

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Who has decided the head is scrap ? where have you taken it too ? TR specialist ? other classic garage ? Please forward a photo of the head and the crack, will you accept a price of a pint for your scrap head ?

Mick Richards

PS: these engines just don't blow head gaskets unless badly put together, I should check the height of the liners over the block surface, measure around each liner in 4 positions and make a note on a little map, then we'll talk.

Edited by Motorsport Mickey

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9 minutes ago, iain said:

I’ll offer two pints! 

:-)

Iain

 

By now you should have started to get the idea that we may be sceptical the head is scrap. We do see an occasional one but courage mon brave, lets see what you've got.

Mick Richards

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Mints,

Before condemning the head have a look at www.fraserbrowneng.co.uk. Four years ago they made a great job of welding a crack in my cylinder head, which otherwise would have been scrap. 

Tim

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Hi All:

Thanks for all your replies. The head has been condemned by a TR specialist, I've not used them before but have no reason to doubt their verdict. I'm picking it up tomorrow and will have a good look when I get it back, I'll certainly be investigating a repair in the first instance indeed, Fraser Brown Engineering will probably be my first port of call.

I've checked the liner heights and they look pretty good to me, although I've only used a straight edge and feeler gauge, I am measuring about 0.0035 ( a tight 4 thou and loose 3 thou) all round and across all  4 cylinders. How does that sound?

It's good to know there is at least a solution with a new one from Moss although at considerable cost. I have even been looking at their aluminium ones, having done my back in lifting the old one off, a lighter version looks attractive.

Thanks again.

Mints 53

 

 

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0.003 - 0.004" all around is good.  As mentioned before do not move the crank unless all the liners are held down.

 

The Ali head should be good but the racing boys don't like them I understand. I have a steel head and it works well.

 

Roger

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Moss has sold over 700 of the reproduction TR4A cylinder heads - an amazing number and a figure which gives one great confidence.

How many of the 4-pot TRs would be off the road by now had this project not taken off?  Definitely one of the greatest initiatives in helping to preserve the marque, and we have to thank Pete Buckles, Pete Cox and the Spares Development Fund for this.

Ian Cornish

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3 minutes ago, ianc said:

Moss has sold over 700 of the reproduction TR4A cylinder heads - an amazing number and a figure which gives one great confidence.

How many of the 4-pot TRs would be off the road by now had this project not taken off?  Definitely one of the greatest initiatives in helping to preserve the marque, and we have to thank Pete Buckles, Pete Cox and the Spares Development Fund for this.

Ian Cornish

^ +1 and the SDF still exists doing great work for all TR owners, but how many current TR owners know that the SDF has "got their back" with the cylinder head design and production along with other projects, it's only reward being cars that may have been scrapped continuing to run. Thanks to all the TR owners who voluntarily "dibbed in" with their monies, an early example of "crowdfunding".

Mick Richards

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