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MG Midget and Sprite Technical - Water in Oil from where? Engine refurb

Hi,

I am refurbing a 1275 engine. The car and engine is recently purchased, Sep 20.

I'm told the engine had a new head gasket fitted quite recently before I purchased the car. The seller had taken the car as trade in, he didn't know much about it. When he took the car in he was given the old head gasket, which was burnt out between the two middle pistons, (my plan was alwyas to strip the engine).

When I drained the oil, it was very grey, which I took to mean water in the oil. I'm not sure if this was becasue the engine had not been used for extended periods and condensation not been burnt off (it also had an oil coller fitted) or water had leaked in.

Now I have the head off I have taken some pictures of the head gasket and the underside of the head. As you can see pretty coaked up, and the head gasket is already marked between the two middle cylinders.

Im not sure the head gasket should look this bad already.Any idea what would cause the water in the oil as I can't see it coming in from here?






BruceBurrowes

I'm not sure with the grey in the oil, AFAIK usually condensation sends the oil milky colour or yogurt on the underside of the oil filler cap if bad.

I wonder if grey might have been some additive to stop a leak or something else.

You could syphon a sample out and leave it in a small glass jar and see if and how it might settle out or put a few drops on white tissue paper and see what you get.

The head gasket doesn't look good to me, look on the head and block in that area for scarring. There appears to be a soot bridge between 2 and 3 on the head so possibly from there but you'd also need to check the block there too and see how the underside of the gasket is.

Also a couple of the small holes on the right in the block/gasket photo appear to have something in them.

Others with expertise (excludes me) will hopefully be along.

Nigel Atkins

Gasket blowing between cylinders 2 and 3 is a fairly common version of HGF. Worth checking the head with a straight edge and check the block too. Especially check for the area immediately around the studs which can get pulled up.
Reputedly, some people have reinforced the gasket on that narrow strip between those cylinder by laying a short length of copper wire on top of the gasket before putting the head on. Not tried it myself!

That said, a mistake often made is to overdo the head stud tightening. This crushes the fire rings to the point that the pressure of the clamped head is spread over the whole gasket area, instead of being concentrated on the fire rings where it should be, to be most effective. Tighten to the correct torque settings and don't be tempted to "add a bit for good luck"! And be sure to use a good quality Payen gasket.
GuyW

Doesn’t look too bad but definitely something fishy going on between 2 and 3. First thing you need to do is check the head and block are perfectly flat. Easy with the head as you can just send it away and have it skimmed (the minimum required for it to be flat) and I’d definitely recommend you have that done.

The block will just have to be checked if it is in the car which is best done by removing the studs and using a decent straight edge, strong light and feeler gauges. Obviously this is after you have cleaned it all perfectly - without letting any of the crud fall down the holes!! Hopefully it will be ok or unfortunately it will need to be stripped and skimmed like the head.

The head gasket that has been used doesn’t look like a good one which probably didn’t help. Definitely get a good quality one like Payen as Guy mentions. I think the BK450 is the one to go for, try Minispares as the website will point you in the right direction.

As well as all that I’d check that all the studs, nuts and washers are the same and in good condition.

Not seen exhaust valves like that before, they appear to have dimples in the centre.

Just had a thought, do you know whether they changed the oil after the head gasket was replaced?
John Payne

Yes Payen BK450 is the recommended gasket, but that was the gasket than went on mine recently and in the same place.

Got mine from Mini Spares at a very good price even allowing for their more costly P&P.

You'd hope they'd given the engine a good and thorough clean/oil change and perhaps good thorough coolant change or clean and change - but for whatever reason perhaps only the head gasket was changed and bo other work.
Nigel Atkins

As others have said...Can the mating surface of the head be acceptably flattened off by using sheets of wet and dry on a flat surface? - pane of glass usually. I second Payen gasket from Minispares, clean mating surfaces, correct head torque (in the correct order) for sure.

I assume it goes between 2 and 3 as the (hotter) exhaust valves are close together. You may also want to check out the cooling system, the mix - as if it runs lean it will run hot especially at the exhaust valves - and the cooling channels in the vicinity.
Oggers

I wouldn't use glass as a reference surface for that purpose because it's not necessarily flat and it can flex even with thick pieces so you would need a flat surface to support it on. Small pieces may look flat but in larger area it can appear wavy and even have defects. My mother's large centre bay double glazed window panel had to be replaced twice due to defects in the glass causing noticeable optical distortion. I would take it to an engine or decent machine shop to be tested if you don't have access to a suitable straight edge. I've seen a useful rule of thumb recently that the head should be flat to with 0.001" x the number of cylinders so 0.004" for this, anyone know if a WSM spec is available.
David Billington

I've seen them silver gaskets with the little reinforcing plates between the bores before, they really are crap
If you get a brand new one and roll the firing rings back between 2-3 and pull the plate out there's no gasket material under it right in the centre where it needs it most ,It's a wonder they don't blow in the packet before you put them on
I've also seen them blow between 1-2 and 3-4 out at the ends of the plates--they are really dodgey cheap nasty gaskets, and I'd imagine the owner went for cheap so probably didn't flush the oil out either--grey oil is dirty black oil with water init
Surfacing a head with wet/dry on glass is a bit scarey, glass isn't that straight,do it properly and get it skimmed, either ground or with a multi tip diamond cutter is best

Bruce, if you want to eliminate the risk of this happening again the only way is to get the head skimmed and (I can feel the knives coming out already) In your first pic. in the centre of the block between 2-3, on the pushrod side there is the coolant hole that you can see, on the other side of the centre (non pushrod side) there is also a similar hole but covered by the blank gasket, you can see the outline of it on the gasket, If you get a drill about 1/8" and drill dead centre of that mark in the gasket and then use the gasket as a templet to drill a matching hole in the head and your new gasket, this will give a bit of coolant circulatation around this hotspot--It's probably the hottest part of the head with these two cylinders the closest together and having the exhaust valves on these cylinders together and feeding into one port--It just needs this little steam hole to let any trapped air/steam out and to keep a bit of circulation going there
IF I remember correctly the Payen gasket already has a large hole there so only needs the head drilling with a little 1/8" hole dead centre of the hole already in the gasket, I'm pretty sure the block already has the hole but if it doesn't you've got your 1/8" drill ready to make it happen there as well---well worth doing

willy
William Revit

I have found that providing the mating surfaces are dead flat and the correct head tightening procedure is followed then the standard HG is fine. I run a 10.50 CR albeit with an 11 stud head.
Bob Beaumont

I do think that it is important NOT to overtighten. Slightly counter-intuitive as one would expect the tighter the better. But overtightening crushes the fire rings which is where the sealing takes place. Crushing the rings distorts them, spreading the load over a wider area (so reducing the contact pressure) and prvents them from adapting to any slight irregularities in the machined surfaces.
GuyW

I recently built a half engine for someone leaving them to fit the head and refit in the car. They fitted a Payen HG and torqued before going off to bed. Going back to the engine in the morning the sump had water in it. Phoning Payen revealed a known fault and advice to fit, torque, heat cycle, and retorque in succession. To date the second HG has held.


Alan Anstead

In general yes, and don't forget to retorque even if they say not needed on the pack--we all know they always move, unless you're going for a decent mls gasket ,then it can be tweeked right up initially and left alone
William Revit

The Payen gasket I got had a sticker on the covering (forget the exact details) saying something about not putting the coolant in until the engine was to be run otherwise it could get into the gasket. I thought it was advice from Mini Spares.

The label had nothing about torquing or retorquing, luckily this was done.

(I like the photo)
Nigel Atkins

Alan's little engine stand is rather cool.
And I have the same one-handed Irwin clamps. They're brilliant.

Off topic... As you were...
Greybeard

Wonder when the baking tray went back back to the oven.
Nigel Atkins

The problem for us folks out in the sticks is that a decent machinist is many miles away - even if such folk exist any more! I seem to recall my last foray into a head skim would have also cost 300 quid! I have no doubt that a head skim is the right way to go, but I have successfully flattened off old bike cylinder heads using wet and dry, and the gasket was suitably thick to take up any residual imperfections. Wholly agree with Guy/Alan that torque settings/procedure are most important.
Oggers

I'd be interested to see the other side of the gasket.
Maybe it's just my screen but I think I see signs of water passing #2 fire ring.
Regarding the grey colour of the oil, I would not normally associate that with water.
I do remember seeing oil that was a weird, shiny grey colour when I did an oil change on a Capri. It turned out the owner had used an additive. Molyslip or Slick50 or something like that, I don't remember exactly. Well it was 40 years ago!
Usually water makes the familiar yellowish snot under the filler cap as Nigel says, and yellowish streaks in the oil, but I guess it's possible.
It's likely that the head will need a skim I think because it seems to have been slapped together with cheap parts, so I would not be confident that it was even checked properly at the time. But you might be lucky. It's certainly in sore need of a good clean anyway.

Is it just me or does anyone else suspect that gasket is upside down?
Greybeard

I wonder earlier if the grey might be an additive, perhaps even some sort of oil stop-leak.

Also a couple of the small holes on the right in the block/gasket photo appear to have something in them, what's that about, perhaps that is the gasket wrong way up?


Nigel Atkins

I noticed that the last Payen gasket I bought about 18 months ago seemed to be of lesser quality than ones from a few years back.

Didn’t have any problems with it and it was a long time after building it before I ran it. I can’t remember when I put the coolant in though.

One thing I tend to do now is not only clean the head and block surfaces but degrease them with thinners. I also only take the gasket out of the packet until I’m just about to fit it and make sure my hands/gloves are clean first. The slightly sticky covering attracts dust and dirt and can’t be cleaned off.

I’ll add that nothing I’ve tried yet stops my head gasket needing replacement every 2 or 3 years but at least I’m getting good at doing them! Mine only seem to blow at the outer edges with traces of coolant seen down the distributor side of the block or a couple of times from the front/back of 1 or 4. I’m still running standard 9 studs so I’m planning to get some ARP’s this time and then drill for 11 studs next time the engine is out.
John Payne

Oggers £300 for a head skim?!!!

Down in the south west I paid £70 for a skim of my 1500 head, including a pressure test. And then we’re happy to do the job with the valves still on the head.

Refitted with a Payen gasket and the top half of the engine doesn't leak. The bottom half is still a little incontinent though.
Chris Madge

Chris

If I recall right it was somewhere in Aberdeen - which is for sure rip-off central. For sure it would have been cheaper elsewhere, but as elsewhere was Glasgow - some 2 hours away....
Oggers

300-70 for a skim crikey
I pay $40 here including a magnaflux and a pres. test if it has valves init so around 20 of your pounds
William Revit

If I remember rightly it was 70 quid when I got one done in Glasgow for an Opel diesel a couple of years ago, but that included cleaning up the valve seats.
I noticed in the nick of time that they forgot to radius the sharp edges, but that only took twenty minutes.
The owner bought the top end gasket set himself, a brand I'd never heard of called Elring I think.
Must have got something right, the little van is still chugging around okay.
Good point about leaving the gasket in the packet until you need it though. My dad was always insistent about that too.

By the way, has anyone here used the Cometic gaskets that Prop loved so much? I've never seen one to my knowledge.
(Asking for a friend obvs; I'll have his GT6 engine to do sometime soonish).
Greybeard

The grey oil could be the result of using Graphogen when rebuilding. I have used this black paste to coat bearing surfaces when rebuilding an engine and give some lubrication on initial start-up. It mixes freely with the oil but does turn it slightly greyish.

Oggers, there is an excellent machine shop in Dundee. I've not used them yet but they get good reviews from folk who have.
http://www.agra-eng.co.uk/services/classic-and-vintage-engineering
Mike Howlett

Nobody any ideas or suggestions as to what's across the couple of the small holes on the right (at cylinders 2 and 3) in the block/gasket photo?
Nigel Atkins

Cheers Mike. That could come in very useful. I have yet to find a decent machine shop in Aberdeen - which is odd considering the oil industry presence. I think there is also a spot near Blairgowrie.
Oggers

Greybeard
I have used Cometic gaskets. They were used as it was necessary to reduce the CR to suit the camshafts being fitted ( A.C.Dodd R.T. Spec recommended 9.2 - 9.5 CR )
The engines had previously had the CR raised by head skimming.
Their other, claimed, advantage is that they can be made to order to give a specific bore capacity. They are advertised as being suitable for use five times.

In the past Minispares sold a very good HG made in Aus. It was supplied in a cellophane wrapper that was removed on fitting. The gasket was coated with a sticky sustance. I have these on both my 948 and 1275 engines. Alas NLA I was led to believe the Aus Co went bust.
Alan
Alan Anstead

That'd be a Monotorque Alan--Sticky gasket for sure, about the only composite gasket made that didn't need a retorque
They were a fairly good gasket made by ACL here, but when ACL got itself in bother they stopped making them--Then when ACL started up again they didn't do them again

Grey
I'm a real Cometic fan, used them for years on the chev racer, but there again there are a few different types, but if you mean the mls steel gasket then yes it's a ripper-BUT the head needs to be dead straight and finely machined, they come with a coating on them to stop coolant and oil creeping around on them but I'm naughty and give them a light spray of coppercote -just to seal em up--i told Prop to do it on his but he slightly overdid it, when he sent a pic it was like a swimming pool and he also was the unluckyest guy on the planet and got a gasket that had one of the rivets in the misformed and jacked his head up
2nd go with the rivet removed and a lot less copper and he was away
I ordered a custom one for the elan years ago with 85mm bore and 80 though thickness--from the US and it was here in 5 days, can't beat that for service
I've had the head off since and just cleaned the gasket up and recoated it and it's still on there. probably done around 70000klm now on that gasket

Nigel
It looks like some sort of clear stuff--probably oozed out of the crappy gasket, when them gaskets come new they have like a silver couting on them so probably that trying to escape down the hole
William Revit

Oggers, if you just need a head skimmed there used to be a place down near Union Square/ the Petrofac building that skimmed and rebuilt heads.

It wasn't exactly a high-tech opperation, but they did the job at a good price when my old Rover 25 had a melt down!

That was something like ten years ago now though...

Edit: scrap that! Looks to now be a place called "Geany Motors", a used car garage.
Malcolm

Bruce, and others,
now I've enlarged the image I can see what looks like fibrous around other holes, probably from the gasket(?), orange arrow highlights a snag looking piece.

But the red arrow is to what looks like a more stiff or formed piece, possibly a hole ring reinforce piece, (metal/rubber?). Certainly doesn't look right to me.

The gasket has '8 - 2008F' on it if that means anything to anyone.

Do the drilled dimples on the exhaust valves mean anything?



Nigel Atkins

Anyone bought a Payen BK450 head gasket recently? Was about to order one plus some ARP head studs but there seems to be a national shortage of them! None of the usual suspects have them in stock and even the main suppliers don’t seem to have them.

Looks like I might have to hang fire with my precautionary gasket change, I’ve got an AF470 (similar but has different oil feed seal) but I carry that as a spare so don’t really want to use it. Maybe it’s time I looked at alternatives like Cometic.
John Payne

John,
you'd make a great storeman!

How many HGF do you get that requires you to carry a spare head gasket, don't you have a large fleet of vehicles that use that gasket or racing requirement.

A mate sent me a photo recently of a MASC article and as far as I could see it was just more or less the text from the Mini Spares site about the gaskets they sell and was very confusing (and perhaps contradictory) about which gasket to use and just suggested different customers had different preferences, except the bit about -
"For performance engines and 8 port alloy heads where you should not have the rocker feed sealing ring which can cause problems, use the original TAM1521 with 3.3cc compressed volume or GEG300 with 3.4cc compressed volume or composite type C-AHT189".

Previously with a quick look I couldn't find Payen in the UK and just got one of their suppliers.




Nigel Atkins

Nigel
The Masc article I took from the Minispares website as I was finding it difficult to write something every month for the Mascot magazine.

John
Following the problem with the Payen, that I mentioned above, a BGA part Number CH5318 is giving service at present although the recipient advises that only 300 miles have been put on the engine due to current restrictions.
It was obtained from Jayar Car Parts.

You may find that Autodoc have Payen in stock
Alan
Alan Anstead

Cheers Alan. Autodoc list them but out of stock. I think it's that time of year where all the pre season engine builds are being done - or of course could be a Brexit/Covid issue.

But I think I might have found one on ebay after doing a general search for any Mini head gasket. It's the full head set DK450 but has the BK450 in it. Anyway, I've ordered it so hopefully should be sorted.

Nigel, I would make a terrible 'blanket stacker' I'm afraid - the RAF term for storeman!

Only get HGF every couple of years but I'm doing a precautionary gasket change and upgrade of studs this year. I guess I've put at least 6 on this engine in 15 years but not much else, it's been pretty reliable - it's got to go bang sometime soon though!

John Payne

John

Have you tried F. W. Thornton in Telford?

http://www.fwthornton.co.uk/gaskets

According to their gaskets web page, they carry a comprehensive stock of Payen gaskets.

Although I've never actually used them, I know that they have a reputation for having all sorts of vintage stuff in stock, especially pistons.

Might be worth a phone call at the very least.

Cheers

Colin
C Mee

Alan,
no problem, I'd no idea who'd done the piece as I only got a photo of a page as we were corresponding on the Payen problem you mentioned, I meant the information from Mini Spares was confusing and perhaps contradictory as I'd previously studied the info Mini Spares have on the gaskets they sell (well attempted) before ordering my hg a few months ago.

I thought about order the AF470 (as I was going round in circles chasing GUG702560) but when I saw the "special black sealing ring" I decided to avoid it having had to remove the engine for the sake of a rubber seal ring already only months before.

I thought the label on the gasket about coolant was by Mini Spares, it certainly didn't suggest it was a fix for a manufacturing fault but we both thought it was strange.

Imagine my 'joy' when I discovered the gasket that had blown was already a BK470.
Nigel Atkins

John P - I bought a couple of BK450 from Somerford Minis last December - looks like I had the last ones as they also show as on back order now. I note that mine cost just over a tenner each and the current listed price is more than double !
David Smith

"Only get HGF every couple of years but I'm doing a precautionary gasket change and upgrade of studs this year. I guess I've put at least 6 on this engine in 15 years but not much else, it's been pretty reliable -----" .

Hgf every couple of years? Something wrong there if hg failing so often.

anamnesis

Not much wrong anamnesis, they only tend to weep coolant at the sides, I get tell tale lines of dried coolant down the side of the block. The only thing I’d say could help is that it’s a while since the block was skimmed plus I am using standard 9 (and 50 year old!) studs whereas most competition cars use 11 stud and usually they are ARP ones. When you imagine those 9 studs are holding the head on to an engine with nearly 11:1 compression and loads more power and revs it’s not surprising they go occasionally. Plus the time when it tends to do its most of its work is often in the heat of a midsummer day! One day when I rebuild it next I’ll have both faces skimmed and perhaps change to a Cometic gasket.

Cheers David, yes virtually everywhere they are on back order. Just ordered a full head set from Minimine on eBay so hopefully sorted. If you search BK450 on eBay you’ll see a couple for sale at daft prices like £75!
John Payne

I've only treated my car to a new head gasket once in the last 20 years/ 92k, and that was when I changed to a different head.
Otherwise, I have re-used the head gaskets a couple of times. Seems ok if they are not showing signs of damage and if they are not overtightened. But I am not racing, although CR is 10.5.

But I do need a new one now as there is a bit of an oil weep at the front left hand corner where the oil gallery is. I've ignored it for long enough!

I have had 2 blown HG on Spridgets, but they were both on a 1500.
GuyW

MED Engineering list the BK450/470 and it seems they are available ?

R.
richard b

Ah right, I didn't take note that you were racing it John Payne.

On the 11 stud vs 9, the front is lower torque; 25lbs I recall ?? I've never been convinced it does much. I snapped a tap in that stud hole, and couldn't get it out. Decided to leave both those extra studs out. Still no hgf as a result.

My engine is high comp too. Cooper s pistons 30+, and a skimmed fast road head. Like Guy I hadn't done a hg change for over 20 years, until I rebuilt the engine.

But then again, although I thrash it, I don't race it.
anamnesis

Cheers Richard, hadn’t thought about trying MED.

My Mk1 midget with a new tweaked 1275 in it has a BK450, I’m not expecting to have to change that one - ever hopefully!

Didn’t realise it was possible to reuse them Guy, if I’d have known that you could have had all my old ones!
I suppose it’s the force of the head pulling down on them that seals, not the initial crushing. I reuse the ones on my old motorbikes but they are solid copper and you can re anneal them.

One thing I’ve noticed about the 11 stud kits is that the ones on sale now are all studs. Someone correct me if I’m wrong but I thought the two extra ones used to be long bolts? I can see why studs would be better though. They still say 25lbs as you point out Ana.

Anyway, cheers for all the excellent knowledge/help/pointers as usual!
John Payne

John

The front one is a shoulderd bolt the rear one is a stud. The front bolt is 5/16 unc whereas the other studs are 3/8 unc. TBA I have not (to date!) ever had a HGF on my 1275 engine. I assume the change to ARP is about quality of replacement parts. In the 1980's I had my race engines prepared by Longman and they still had the factory 11 stud layout. Running 11.75 CR and split Webers, I did not have a HGF although I seemed to go through rocker shafts but thats another story!!
Bob Beaumont

As said below, only the front is a bolt -- (as original, not kits), -- and the rear is a stud, tightened to the same torque as the other studs.
anamnesis

Well I've never had one go either, and that includes a FJ screamer with over 12/1 CR. I rebuild with Wellseal and always chamfer the threads in the block.I re torque too,although with BK450 it's generally considered unnecessary.
f pollock

This thread was discussed between 01/01/2021 and 16/01/2021

MG Midget and Sprite Technical index

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