What part of the fastener area is the coolant leaking from? Could be there are some wet head bolts (into the water jacket, on purpose or accidentally) that require thread sealant. In cast iron, ordinary teflon pipe thread compound works fine.

Copper head gaskets are great for sealing combustion which makes them a good choice for race engines, especially boosted, but can be weepy and seepy with oil and coolant in road use. One factor is surface finish -- with cast iron should be around 50 to 60 ra and must be very flat and straight, .002" in every direction as copper has relatively little crush.

With a copper gasket, if there are sensitive water or oil passages through the head gasket plane you may well have to use a sealant. There are aerosol gasket sealers designed to use with copper or steel gaskets, or in desperation cases you can apply a *thin* coating of silicone RTV to the critical areas. Open a fresh tube (for best consistency) smooth it on, then use the rest of the tube for standard things. A small silk-screen roller works slick.

There is nothing wrong with a composition gasket if it is manufactured and installed properly. It's the popular choice for standard stock road rebuilds due to its forgiving nature. Retorquing the head fasteners may well fix it, even if they have already had their initial retorquing. The MLS gasket is probably the best all-around choice but if nobody makes one for your application (which I am guessing is the case) you are out of luck there.

Raceworks LLC in Los Angleles specializes in making copper head gaskets and they are way into vintage racing with British junk, should be able to fix you right up.

What part of the fastener area is the coolant leaking from?

Coolant is "wicking" up two head studs....seen collecting or maybe even migrating up through the two head stud nuts?? and on top of the flat washers...nah... must be getting blown up there from under the washer or even from the head to block interface below, so something will have to be done fairly soon (head off) to prevent corrosion in that area.

Thanks to both of you...something to follow up after Easter Bathurst

Hmmm the head is off...and some high tensile head bolts are on order (maybe ARP)...its possible that the bolts were stretching...time will tell!!

Good call on the head studs/bolts, most likely too.

My Alfetta would show coolant whenever I retensioned the head and took the head nuts off first to put some neversieze on the threads. Have some copper washers under the nuts.

In Oz theres a number of gasket makers who will do the job for you but I'm here and can't remember their names - ask Serco in Brisbane http://www.serco.com.au/

Here are some other things that you might consider.

1 As mentioned earlier, copper head gaskets do a fine job of sealing the cylinder, but water and oil passages are another thing. The late Chuck Daigh taught me this little trick. Coat the block deck surface with a spray on layer of Hylomar (or other sealant). Then take a bobbin of ordinary sewing thread and lay an "0-ring" of thread around each water and oil passage. Spray both sides of the copper head gasket with Hylomar, let it sit for 10 minutes before installing. Torque as specified.

I watched Chuck rebuilt one of the Desmodromic valve engines from the Scarab GP car a couple of years ago. This engine used NO head gasket at all (head directly on block), only hylomar and sewing thread. Sure did run nice and LOUD too.

The two most common copper types used for head gaskets as C101 and C110. C101 is by far the best (also the most costly). It is described as being 99.9 pure copper. It has good ductility and heat transfer, both admirable qualities for a head gasket. It is available in various thicknesses, but for head gaskets the 0.032 and 0.040 thicknesses would seem ideal, as they would retain good squish characteristics. C110 copper (roofing copper) and has a slightly higher level of other elements. It is not quite as ductile, but is somewhat higher tensile strength. In a pinch it can be a good alternative.

Copper head gaskets MUST of course be prepared before use. If the gasket was made using a laser or water jet cutter, then ALL of the edges must be deburred first. Then, you MUST make sure that it is in an annealed state (really quite floppy and in bent does NOT return to the original shape). If you are unsure, heat the gasket with an oxy-acetelyne torch with a large "rosebud" tip until it reaches the minimum annealing temperature of 700 deg Fahrenheit. The easy way to do this is to turn on the acetelyne only (black soot) and coat both sides of the copper head gasket with this soot. Then add oxygen and with the rosebud tip heat evenly until the soot burns off completely. This is the magic temperature. Then quench in cool water. The quenching will prevent unnecessary surface oxidation. Once the head gasket is cool, place it in a smooth surface (granite surface plate is ideal) and clean the surface LIGHTLY with the finest 3M abrasive "pot scrubber" you can buy (green color is good). This slight etching will give a good grip for the Hylomar surface spray.

2. On head studs I ALWAYS put them in with a small amount of Permatex #2 sealer. Apply some to the threads and then rolls the threads of two studs together to work the material into the root of the threads. the problem lies in the fact that if the studs go into the water jacket space, then once the engine heats up the system will develop perhaps 10-15 PSI of pressure. Without sealant this water will spiral through the threads in the block, then throught the threads at the top end of the stud, into the rocker galley and drain back into the sump.

I ran across this on small bore Fiat motors, where the center head bolt hole is used to carry oil to the head (for the rocker arms assembly). Of course while the engine was running, there was never a problem as the oil pressure would overcome the water pressure. However after the race, upon turning off the engine, the oil pressure would disappear and the water pressure would remain. Come back 2-3 hours later and check the dipstick, and there would be 1-2 litres of water in the oil. Small block Chevrolet V8s had the same problem when converted to studs. You do not know how many times I pulled the head only to find out the head gasket looked PERFECT, before I discovered the real culprit.

3. With respect to studs, and similarly for bolts, they should be designed with a necked down section, so that the smallest diameter of the stud/bolt shank is less than the root diameter of the threads. Secondly all studs/bolts should be tightened so that they achieve a specified stretch, usually 0.005-0.006 inch. Bigger is not always better. More torque is not always better either, as you could simply be lifting the deck of the block and making things worse. A stud/bolt must stretch this small amount to achieve clamping force.

The problem with older bolts/studs is that as there is not record of the original length, there is not way of accurately checking if the stud/bolt is still elastic, or whether it has become "plastic" in nature. I measure and record the new length of all stud/bolts that are critical to engine performance (head, rods, mains, flywheel, pressure plate). Then when the engine is disassembled the next time I can measure the length of the bolt and see if it has returned to its original length. If the stud/bolt does not return to within 0.001 of the original length, then it should be replaced. Once a stud/bolt goes into the plastic phase, it will never have clamping force and thus will lose torque.

I use these little techniques on the Fiat/Abarth engines that I prepare, some running as much as 13.8:1 compression (over 10:1 dynamic compression) and have never lost a head gasket. Other's experience may vary, but it is probably a good starting point.

Sorry for the long-winded answer, but I hate it when I read good suggestions, but no hints about impementation.

Regards,
Paul

Well I thought it was fascinating, thanks.

You quoted my post but I didn't offer any suggestions good or bad!

My Alfa would pass water because the studs go down all the way through the water jackets down to the bottom of the block (bloody long studs) and the head nuts were below the radiators top level so theres no way to seal them other than the mentioned copper washer under the head nut.

The worlds best head gasket sealant is clear silicone window sealant, coat ya head gasket lightly either side and plonk it on wet - including copper gaskets. Nothing better for sealing exhaust manifolds either except if there is lambda sensor because the silicone fumes from the edges of the silicone burning will kill them.

The thread trick is an ancient one, dating back to the invention of the wrench more or less. Nothing magic about it, how it works is simple... the thread prevents the sealant from being squeezed from the sealing surfaces unevenly, creating voids... which happens because the surfaces are uneven. The thread ensures that the minimum sealant thickness at any point will be equal to the thread's compressed diameter. However, with quality pieces and proper surface preparation, you can use the sealer alone and put the thread back in the sewing basket. You will find many applications over the last 25-30 years that are manufactured just that way. (Known in the industry as "gasketless sealing" or more accurately, "form-in-place gasket.") But there are cases where the surfaces are never going to be truly right, the vertically split crankcases on vintage British motorcycle engines being a good example, and here the thread method is proven effective -- if a bit messy and inelegant.

High-precision equipment (laboratory vacuum pumps, extreme pressure hydraulic systems, etc) often employs dry assembly with no gaskets or sealant of any kind. This demonstrates that good sealing is not really about gasket and sealer tricks but the quality of the surfaces being joined. As a practical matter with automotive-type stuff, there are three things to watch: Flatness, surface finish, and fastener bores... the last being frequently overlooked. In applications where two cast and machined components are joined with a paper gasket, if the surfaces are right you can install the gasket with a thin coat of wheel bearing grease on both sides to hold the gasket in position. It won't leak in a thousand years, and the next person to service it will thank you for the easy disassembly and zero cleanup time. But the surfaces have to be right. If the surfaces are not right, there are any number of goops and tricks that may seal it up. Or maybe not. I am not a fan of goops, sprays, etc. but that's just me.

Head gaskets are a subject unto themselves. In applications where modern composite or MLS gaskets are available, I don't know why anyone would bother with anything else. Likewise with wet head bolts. Use a good thread sealant and you are good to go. One thing I have seen folks struggle with on SBC and BBC, which employ wet head bolts: Sealer is used on the bolts and yet they still weep. That is often a good indication (BBC especially) that the block is cracked in the thread roots. At some previous time the bolts leaked and someone decided they needed tightening.

Can you post photos of the block, head, gasket, bolts? I am 100 percent certain you can fix it in one try.

One of the few times in my working life I have taken a job with pay for someone else (I wanted a rest inbetween running my own things) was restoring 50/60/70's British bikes. I have never used the thread method although I have heard of it and exclusively used by brand "Three Bond 1104" and before used "Yamabond" from the 70's which I believe is the same product on for any case joints.

Thinking about the job and mentioning a Workmate that was killed on Mt Glorious a few years ago in the water/methonal thread I looked up their website and shocked to find the picture of all of us is still there, only about 15 years old (I think). 2 or so years great fun restoring them but sadly had to move on to make real money again. 2nd from the left is me. The site should be updated, 2 of my ex workmates in the pic are dead and old Fred has long retired.

http://www.britishmotorcycle.com.au/britishmotorcycle.html - click on "About Us"

http://www.britishmotorcycle.com.au/

Thanks fellas Just catching up with a bunch of things after a computer rebuild and change of ISP.

Oh! Memories! Just look at all that space in which to wield a spanner! I have very little experience of working on anything remotely 'modern' apart from some '80's Touring Car stuff, but seeing that open-plan engine bay brought back memories of standing inside the bay of my Lotus Cortina and lowering the short-motor into place, one foot on each chassis rail, praying that my frozen, oily hands wouldn't slip on the newly-painted block...

We got hold of a 2 litre Volvo piston and checked it against the MGC unit. Everything was basically the same except the crown was about a mm below the standard pistons. Not a problem if you are shaving heads and decking blocks to achieve a particular compression ratio for racing (I suppose).

Ohhh dear....hope you had safety boots on might make a good cartoon Tony

Safety boots? They're for girls...Aaaaargh! Ooooh! Bugger!

and so did the owner of this particular MGC

Unfortunately, the head is in for a skim just in case some warping is in evidence...I suggested a more scientific approach but pure science and conjecture don't get a vehicle back on the road!!

Again, many many thanks for all the advice

Thanks McGuire...thats one area I was pushing when we were collectively scratching our heads...I was saying (for instance) maybe its a cracked head (above the head gasket) but the thing had been crack tested during machining and overhaul. Some thread sealer might definately be applied this time around!!

Front End Overhaul commences...

Does anyone know the trick for freeing up this shaft after forty years in its bushings??



as can be seen...WD40 has been applied and will continue to be for a few days....then it might be time to try the snap freezing spray!! (some reluctance to use a persuader because the parts are diecast)

Brembo replacement rotors are about 2mm too big in diam...does anyone know if the small amount of rotor to caliper clearance will cope with the "Austin Healey" (Brembo in this case) replacement rotors?

FWIW: Rotors were stamped 11 02A AA and were 12.7mm thick (current original rotors are 11.7mm)

Does anyone know what the minimum thickness is?? (no, its not mentioned in the workshop manual)

Which parts are diecast, Mick?

I wouldn't think anything in that lot is...

The C is back on the road with serviced king pins and and other replaceable components and still with its 40 year old upper bushes undisturbed....new AH Disk rotors work superbly without any caliper interference problems :-)

Never use silastic on a head gasket. NEVER.No good gasket will seal with that stuff. Ok on most other things, not intakes or fuel systems.
A lot of engines have the head bolts tapped into the water jackets. Use GM head stud sealer and no more problem. But do not retorque or the threads will leak.Loctite is ok on head studs as a sealer but I would not recomend it for headbolts.
Permatex non hardening is ok in a retorque situation but do it soon after the engine is initially started as it still does harden eventually, and is messy to clean up the bolts and threads when the head is off again.
On the MG C I think they have head studs so just seal the studs. Or as a short term bodge some radiator stop leak will work too, but the bolts/studs and threads will still rust.

I think its already been mentioned but my Brother is an engineer and we rebuilt several B series Motors in the late 1960's,1620 & 1798 Motors bored out to 1844cc using flat tops and shaved heads(so it was a reasonable compression ratio,9 point something IIRC) and never had a problem with Head Gaskets. We used copper and my Brother always coated both sides with wheel bearing grease,i don't know if its a old wife's tale or not but it seemed to work.

That seems totally against the grain. The first thing you do with a headgasket is make certain that everything is clean and oil and grease free. About the only thing that maybe should be used is hylomar, or maybe shellac [head stud sealer] and that is on old style composite gaskets. Do not use on modern teflon coated ones.

Yeah,my Brother said it was a 1960's thing,chemicals in the clay(or something like that) helped seal everything but probaly a Furphy,most likely didn't do anything but it didn't do any harm either,the grease squeezed into the water passages came out thru the top of the radiator once the motor was started. We may have been lucky but i remember the Datsun Rally engine we built running for nearly 50k with no water after splitting the radiator on a particular rough Mountain track inland from Batesman Bay.(spectator in a Datsun 1600 gave us his radiator and we finished the Rally with no Engine damage).
Anyway straying OT but just a thought from the past as all engine builders have their favourite tricks and secrets.

Those would have been copper and/or steel gaskets with compressible material between the sheets, I'm sure...

Very different to the stuff you get today.

The bad news for today is that one heads stud is again "wicking" up coolant...damn!! What are you supposed to do? Machine annulus and drop in copper O Rings...or what!!

No, that's a bit drastic...

Stick a Hemi 6 into it. It does mean, however, that you have to beef up the rear axles and put in lighter front springs.

If a properly sealed head stud continues to weep, that generally means the block is cracked through the thread roots in the stud bore.

I really hope thats not the case Magoo...however, before the head was decked as insurance and the whole lot extra carefully put back together...it had been wicking up that same stud AFAIR

"Stop-Leak" in the radiator water? It is not as if this engine is an irreplaceable historic classic.

I would suggest you go to you local Repco or what ever and get some ""Sealwell " T5101 coolant system sealant and cleaner made by JDM industries in Eltham ,Vic.....A lot of the engine /head shops use it ....I have used it on vehicles with similar issues and it has rectified the problem

Cheers

Lynds

The sealwell cubes work really well and do not seem to clog radiators.The the crux of the matter is why, has it a cracked thread in the block as Mac suggests or just not enough sealant?
Is the engine studs or bolts? If it is a blind hole it may have split, or a hole drilled into the water jacket will weep if not enough sealant was used.
Or how good are the headgaskets, are they old stock from somewhere? The may be the problem leaking to the bolt then climbing up. Is it weeping out the side too, that style of engine often does. The sealwell will probably fix that.
I have found that old stock composition headgaskets will often leak water, badly. I guess the core material goes off [and probably not the good old asbestos!!] and is not water tight anymore. Also if a headstud sealer was used and it was retorqued that may well be the trouble.
This is a more common problem than most people realise.A lot of engines have headbolts rust in, and then break whentrying to undo them. I have had to throw away an engine, the bolts broke and I could not get the head off, that included having the head on the block and tackle holding the weight of the front of the car for a weekend. This seems to happen a lot on 90s engines, and torqu to yeild bolts seem to do it regularly. Though normally you can still butcher the head off.

Here is the sequence of items that I would check and do.

1. If there are hollow dowels around any of the studs, to locate the head, I would make sure that the recess in the head is deep enough to accept the height of the dowel above the head deck (plus head gasket).
2. Chase all threads with a thread chaser (preferably not a tap, as a tap will remove additional material and thereby cause an inferior thread fit), and clean threads with brake cleaner and compressed air.
3. Apply Permatex #2 to the threads of the stud on the end that goes in the block. My preferred method is to work the sealer into the threads by rolling the threads of two studs together, thus forcing the sealant into the root of the threads. This also ensures that there is less excess material that has to be cleaned up later.
4. Install studs and tighten only sufficiently to provide a good thread-to-thread seat (about 3-4 ft/lb).
5. Take clean, dry, grease free headgasket (whatever type you want to use) and spray both sides with Hylomar Blue spray sealer. Let the gasket sit for 15 minutes before placing on head.
6. Apply thread lubricant (ARP or some equivalent to the threads, both sides of washer and underside of nut.

Torque to specification.

I have used this technique for years and have not had a problem. I developed this technique when I had trouble with head studs on a Chevrolet V8.

I'd add an "Inspect for cracks" step. Cracks emanating from openings in the deck - especially threaded holes - are extremely common. Even a simple procedure like a spray-pack dye check is better than nothing.

The theory about the cracked block might be true where the stud screws into the water jacket (e.g. Holden), or where it might be close to the water jacket and the block cracks. MGC head studs are nowhere near the water jacket, relatively speaking, and the head and block were checked for cracks when the motor was rebuilt, i.e. when it leaked from several studs. I am confident there are no cracks, but water under pressure finds its way into all sorts of places. When water finds its way into cracks, it boils intensely and expels water from the radiator excessively. That is not happening.

If the stud is not in a wet bore, we really need to ask where the coolant is coming from that is supposedly wicking up the threads.

The head gasket must be tracking water from the water gallerys to the headstud. As I said in a prior post old stock gaskets often leak. In some respects things are not made as they used to be. Try a different brand/style f gasket. A lot have manufacture date on thepackaging these days which may help. But that style of engine is probably a bit short on for choice.
Another point how good is the tension wrech you are assembling with? Also use moly on the thread and on the headstud washer it will help, a lot, to get true tension. And failing that maybe tension it 10lb more though not ideal. And probably etorque as soon as it gets warm.
Or as Ray says install a Hemi!! or a 4litre Ford.

Hey Magoo!! supposedly???? I know what green coolant looks like fella

Ohhhh Magoo...youv'e done it again!!

Yeah Lee...you are probably on the money....unfortunately the assembly has been done first by a well respected engine reco company and then by a knowledegeable amateur who is very well aware of the perils of after-market parts these days...we sourced the best head gasket available....the secret weapon is still to be tried, an original competition head gasket...but...we are getting tired of whipping the head off!!!

I assume so. I am only asking where the coolant can be coming from if the stud bore is blind. Either the bore is no longer blind, hmm, or something is pushing coolant up the stud bore. It's possible that coolant is leaking across the gasket and then up the stud, but not terribly likely -- it should also be leaking out the side of the head/block junction or into a cylinder as well. Takes a rather comprehensive gasket failure and there should be more symptoms.

But in better news, by far the more usual case: the coolant is not wicking up the stud and out, more like it's leaking from some external source, then being blown back by the fan and airflow and hanging on the stud and nut. That's far more common than coolant leaking out of a blind hole. And definitely worth checking out completely before tearing off the cylinder head one more time. Me, I would clean and dry the engine and compartment thoroughly and park the car on white butcher paper, then install a cooling system pressure tester and keep it pumped to the max. And wait. I'm not a big fan of it could be this or it could be that.

Have you got a drawing showing a section through the point where the stud screws into the block?

Only scan read this thread so maybe somebody has suggested this already but I would be dye penning the bolt hole in the cylinder head - I agree with Magoo if the head gasket had failed there ought to be more signs of leaks at the head / block junction so more likely is a cracked cylinder head.

One other thing do not assume the surfaces are flat, CHECK. As a HQ engine sealer I have seen most forms of bad machining with both heads and blocks totally out of square, in other words one end or side 10, 20, 50 thou lower than the other and on one occasion a freshly milled head was low in one corner. How I do not know but it was. Also with studs if it is not machined fairly square with the studs it will not clamp very well as you are tring to bend the studs. Bolts are little more forgiving in that scenario.
And some of this maching was done by top shops, good equipment but obviously bad operators.
I have seen a head in a headmill that was supported in only 3 corners and I watched it hammer/ chatter everytime the cut got near that corner.

Huh??? Mr Cutaway himself, himself asking that question I thought you chaps had X-Ray vision

Seriously, I suppose the workshop manua; may be worth a look in this regard....Thanks.

Thanks to all once again for all the GREAT suggestions...very much appreciated

Magoo...I'd say something is pushing coolant up the stud, of course the stud hole may not now be blind, but you would think that would have been detected on several previous head off investigations. Fan is well shrouded and focussed....unlikely that its being blown up and collecting...it pools and stays around the head nut/washer (about the third back on the right, the one behind the posted stud).

Rachael...dye penning the bolt hole in the cylinder head might be something to do,,,however, other studs have leaked previously...so I still suspect head to gasket interface problems is the cause

Lee...ohhhhh just great THANKS for that little gem What's the world coming too!!!

Hey Lynds...go to the top of the class....MGCC Motokhana today....about a 30 Km run out to it....Sealwell " T5101 coolant system sealant and cleaner made by JDM industries in Eltham ,Vic.....used before the run....no wicking throughout the Khana and run out to the venue...a small pinhole in the radiator also stopped Might be the cure

Hey ...Thats good to hear...I use it on most head or engine rebuilds after giving cooling system a good clean /flush out ....minimum cost and is a bit of insurance....
Would also suggest that next time you have to take head off .take those old head studs and nuts and replace with new ones as some of the old BMC studs were a bit marginal at best...and if I read correctly head has been offf several times to many

Cheers

Lynds

That stuff is quite good, a lot of engine reconditioners crumble a cube in the block before they fit the welch plugs. It fixes minor leaks in racecar radiators too. Which reminds me I have one that needs a cube!!

Yeah...fingers crossed...and the studs are "new", replaced when the problem first started just in case the old ones were stretched or elastic! Cheers to All.