Aluminium Cylinder Head Corrosion - 1974

[mole42]

In the Triumph "Service Information" for February 1974, item 98:

'A number of aluminium cylinder heads have been received in our Warranty Stores with the complaint of 'face corrosion'. These heads are from Stag and Dolomite vehicles, but the following remarks apply also to the Dolomite Sprint.

Examination of most heads has shown that corrosion is limited to the water pockets and does not affect the sealing area of the face as shown by the gasket outline.

Corrosion, except on the sealing area, is not detrimental in any way and heads that are returned for reasons of corrosion in areas other than the sealing zone will be returned and claims rejected.

Where the sealing face is corroded renew the head. Skimming or refacing aluminium heads, however slight, is not permissible (my emphasis)

Anti-freeze used in the cooling systems of the above models must only be to B.S.3152 specification as stated in the appropriate owners handbook. Corrosion can result from the use of anti-freeze not to this specification.'

[DJT]

I wonder how many heads were slung in the scrap bin when they could have been skimmed and returned to service?

[Robin Searle]

Dealing with a toxic mixture of steel, aluminum and antifreeze
In Triumph Stag engine heads.

Last year I experienced enough Triumph Stag engine problems to last a lifetime, resulting in the necessity of having to have my engine totally rebuilt. I had spent 18 months planning for a complete 12-day circumnavigation drive around Lake Superior by the Toronto Triumph Club, but a week before I was to lead the drive, my oil pressure dropped down to 3PSI. I was lucky to have a mechanic who owned a shop close by to where I live, Peter DeHaan of PD Engines Service and I coaxed the car to his shop. Peter diagnosed so many problems and recommended that he do a total rebuild.
I was lucky enough to have the opportunity of purchasing a ‘ rebuilt’ Stag engine from another Stag Club member and agreed to the price, then went to collect the engine and bring it back to Peters. With some assistance from me, my original engine was removed, and the replacement engine installed and was up and running 24 hours before the start of the marathon drive.
The morning of the start of the Lake drive we noticed some “missing” with the engine, but with all the ‘owner mechanics’ around a diagnosis could not be found. The engine managed to function, and we drove some 3,000 miles in total, Toronto back to Toronto.
My brother Ian with many years of British automotive experience came over and diagnosed that there was a problem with #5 and #7 cylinders. Peter meanwhile had been working on my original engine, where we replaced all 8 sleeves, complete replacement of all bearings, piston rings, total rebuild of crankshaft and camshafts. Both heads were completely machined and rebuilt with all new valves and the works.
Now we come to the real reason for me writing this article, Peter noticed that when he first fitted both heads and filled the engine with Evans Waterless Coolant, there was some oozing from the gasket on both sides. He removed both heads , took a good look and saw that there were many porous holes on the underside of each of the heads, especially where there was no corresponding inlet in the heads in two arrears for where the antifreeze exited the main block.
.



These are the porous holes that showed up in all three Stag engines and consistent with the use of antifreeze together with aluminum and steel combination.
He recalled that many years ago his father had come across this pitting phenomenon, but he had forgotten how the problem was solved. He spoke with the oldest member at the machine shop where he remembered that they used Permatex Gold Spray-A-Gasket and that it was still available.



When 3-4 coats of Permatex Gold Spray-A-Gasket is applied it will fill holes up to 3/1000 deep. Notice my finger print to show how thick the spray is prior to drying End of Part 1
DSCF1665-001.JPG

[Robin Searle]

Part 2 of Stag head porous holes.


Peter masked off the other arears of the heads then sprayed the porous areas several times [X4 in my case] where it was sucked up into the holes and will fill 3/1000 deep holes. Next, he sprayed the one side of the head gasket X3 that connects with the underside of the head then one coat on the opposite side that goes up against the block. Heads were replaced, and Evans coolant topped up, then engine was fired up and there were NO leaks or weeping seen.
Peter then took apart the engine that I had used whilst driving around Lake Superior and noticed was a mess it was, with some small parts missing and others fitted the wrong way around. The member who had sold me that engine mailed me a cheque to reimburse me the whole cost of my purchasing his engine, plus $500 to help pay for the labour. This was a fine gesture on his part and not something that I had expected, and then we discovered that he had yet another Stag engine that had been rebuilt in London Ontario, which also was a mess. On being stripped down Peter discovered that it required a replacement short block due to the movement of the sleeves. Needless to say that the ‘expert mechanic’ in London Ontario, is no longer in business.
The other two engines were completely rebuilt by Peter and the first thing he did was check all four heads when they were returned from the machine shop, guess what they all had the same problem that he had first noticed with my original engine

Here I will digress and refer you back to a previous article that I had written of why I changed over to Evans Waterless Coolant. Stags-Aluminum Engines-Corrosion. Antifreeze/Water vs. Waterless Coolants in the first pace.

The pitting that I found when I removed all the coolant hoses and the reason for my changing over to Evans Waterless Coolant engine.is in both photosattached
I had noticed much pitting around where the coolant hoses connect to the aluminum components on my engine and researched as to the cause and found a Jay Leno video of a similar problem that he had experienced with a Bugatti and all caused by the poor relationship between aluminum and antifreeze.
Now we all know what happens when you have drip from an eavestrough on a roof and you just totally ignore it what that drip does to the cement/driveway when it constantly drips down, it wears away the surface. Now with all that antifreeze/water combination exiting the block under pressure only to be prevented from flowing through the head because of no corresponding head inlets, then the scene is set up for the pitting in that area.
I remember when I first installed the Evans Waterless Coolant four years ago, we found a head leak issue, but we ‘overcame it’ by increasing the head torque, except now we know the real cause.
Over the past few years I have read on the various Stag forums about corrosion with Stag heads, but as I was not experiencing it at the time I did not do any follow up. Now we have discovered what the real cause of the problem is and how it can be fixed, when the heads are removed for any reason.

Robin Searle

[StagJonno]

Very interesting, Robin. Would you recommend, if the block is stripped, welding up the redundant holes in the coolant passages?

Jonno

Also, I wonder if the corrosion might have been caused by "old" coolant - eg when it's antcorrosion properties are spent?

[Robin Searle]

https://www.youtube.com/watch?reload=9&v=t7PykrgzWPQ

I would suggest to all those doubting Thomas out there that you take a look at the video that I have posted a link to above. This was the video that convinced me to change over from antifreeze to the Evans Waterless coolant AFTER I had discovered the effects on my aluminum pieces as shown in the two pictures.I posted above.

The clue was there when we first switched over to Evans, there were several leaks through the head gasket,but we "fixed" it by increasing the head torques to 65psi, only to discover it again after the my heads had been worked on and reassembled, that there again were the leaks. This in hindsight was the best thing to have happened as it was then we discovered what the real cause was 'porous holes' that allowed the coolant to leak out.

I can only speak to the age of my old coolant it was changed every TWO years and I used Prestone Antifreeze mixed to the correct ratio, but I go back to the fact three different engines and they all had the same problem and only discovered when the heads were removed. One interesting statistic and this could be just a coincidence but the corrosion on my heads were not quite as bad as on the other two engines, and I have not been using antifreeze for the past four years.The one other big advantage of switching to Evans is that it NEVER has to be changed and works from 350F to minus 40F.so no overheating or freezing. All of our tractor trailers here in NA run on Evans so that it does not matter where the trucks have to go extreme north -50C or extreme south where it hits 45C,same fluid is used.

As regards welding up the ends of the coolant passageways as they exit the block itself and where there is no corresponding entry into the head, I am not an expert but just thinking about it cannot think of any reason to rule it out. The Permatex fix would be the easiest route to go plus would not require the block to be resurfaced, as welding would.

Happy decision making!!.

Robin

[mole42]

Another item from the Triumph "Service Information" for March 1973, item 49:

'To avoid mistakes resulting from the omission of part numbers on 1972 and 1973 Stag cylinder head gaskets, both can be identified and correctly ordered by reference to the following information:

1972 Gasket - thickness 0.040 in (1.0 mm) approx
- the metal bridge-piece between the centre pair of cylinders is copper
- part number 214705

1973 Gasket - thickness is 0.055 in (1.4mm) approx.
- the bridge-piece as above is steel
- six slots for water transfer are added adjacent to the centre pair of cylinders
- part number 218981

Note: the 1973 gasket can be used to service all Stag engines.'

[Robin Searle]

All three Stag engines were rebuilt using the 1973 thick Gasket, but we are not sure what gaskets they previously had. combining a new thicker 1973 head gasket AND also doing the Permatex fix will make sure that all is fixed and will not cause any problems in future.
In Europe you do not 'enjoy' the extreme temperatures that we have here in NA, but you still do have the aluminum/steel and antifreeze problem and it is that which is the cause of the problem in the first place.

If Evans is used in your engine then it will necessitate you carrying a spare litre of Evans coolant in your trunk as you cannot top up if necessary with water, because that will screw up the Evans Coolant, but one advantage with it is that you can remove the rad cap whilst the engine is both hot AND running and you will not get scalded. I just keep a half full overflow bottle of Evans connected to the radiator and has worked like that for four years now.

Just reporting in !!

Robin

[Motorsport Micky]

Hi Robin,

Well I guess somebody has to be called "a Thomas" but I'm old enough and uncaring enough not to be bothered about name calling.
You have given a ringing endorsement for Evans waterless coolant, so I chased up reviews and opinions on the internet, (can be risky but you have to start somewhere). Check out this critique and see what you think

https://www.norosion.com/evanstest.htm

Now to declare I have had nothing to do and have no connection at all with Norosion or it's product, and have never used their product or the Evans coolant either, so my mind is as open as many a classic car owner can be. So I'm afraid I know a few more doubters who between them know quite a bit about engines, antifreeze (ones a Emeritus professor) and cover across a couple of continents..
https://www.tr-register.co.uk/forums...less-coolant/&

Please also review this website here of the Evans product
http://www.oilem.com/potential-issue...gine-coolants/
and give your reaction to what is claimed. I can say that there are rolling roads who won't accept a car with Evans coolant because in their environment of restricted cooling (mostly inside premises) they say the Evans allows the engines, and especially cylinder heads to run very hot, which with cars often on the limit of cooling capacity can cause problems never mind the increased risk of fire.
Thanks for reporting in ! I await your comments.

Micky

[trunt]

+1 Micky

I have always gone the other way, as little anti-freeze as possible with some extra inhibitors to help.. My cars never freeze, why protect down to minus whatever degrees?

I looked up the No-Rosion and they have another product HyperKhuhl that is interesting, it says it has "extra protection for aluminium" but still contains the same inhibitors.. I may try that..

[mole42]

I’m using 50/50 Bluecol/Distilled water. Not for the low-temperature benefits but for the anti-corrosion properties of genuine Bluecol. I am aware that the heat transfer capability of the mixture is compromised but it has worked effectively for 25,000+ miles. I recently fitted a hotter thermostat which nicely brings the gauge up to ‘N’. It’s very rare that I need to use the electric fan.

[davidf]

I’m using 50/50 Bluecol/Distilled water. Not for the low-temperature benefits but for the anti-corrosion properties of genuine Bluecol. I am aware that the heat transfer capability of the mixture is compromised but it has worked effectively for 25,000+ miles. I recently fitted a hotter thermostat which nicely brings the gauge up to ‘N’. It’s very rare that I need to use the electric fan.

I have used the same since building a new engine - about 80000 miles up to last time I had the heads off, and still no head corrosion.

Sorry, missed one point - I use tap water, not distilled.

[Robin Searle]

I read all of the links and their comments, one thought that has occurred to me how much of a difference is there between European antifreeze and that used here in NA? Four years ago the Toronto Triumph Car Club crossed over into the US on a stinking hot day and we were 30-40 minutes in a line up,my Stag was the only one of the Triumphs TR3-TR8 s that did not overheat, with many bellowing steam.My needle stayed a fraction of an inch above the N all of the time.

Response from Evans below:

“Thank you for the opportunity to relay our side of the debate here.

Glycol is slippery. As I said to the technical director in the American Flat Track Series, any fluid is slippery on the track. What’s important is keeping the fluid off the track in the first place. Our coolant does not build vapor pressure, so it doesn’t boil out when it gets hot like antifreeze or water. Our coolant is legal in flat track and some road race motorcycles series. I road raced motorcycles with waterless coolant for 15 years without incident. I wouldn’t ask anyone to do something that I haven’t done myself.

All glycol based coolants are combustible, this includes water-based antifreeze. The “flash point” is the same for waterless and water-based coolants, go ahead and google “gylycol fire”. Flash point does not mean that it will spontaneously ignite, there must be a flame source present. The auto-ignition temperature is significantly higher, somewhere up above 700F. Again, this behavior is common with water-based antifreeze as well.

The heat transfer of waterless coolant is a little less than with water-based antifreeze just as water is a better conductor of heat than antifreeze. A cooling system is “air side limited”, however, which means that the heat transfer between metal and liquid is insignificant compared to the heat transfer between metal and air at the radiator. The radiator efficiency is based on the temperature difference between the radiator metal and the air temperature. The greater that temperature difference, the better the transfer efficiency. Runaway temperatures are a problem with water-based antifreeze, not waterless coolant because when the water boils to vapor inside the engine virtually all cooling capacity is lost. The metal temperatures will spike by hundreds of degrees creating the detonation-causing hot spots and head warping that is associated with overheating. If our coolant temperatures rise above normal, it doesn’t vaporize and the liquid to metal contact is not lost. With a higher coolant temperature, the radiator efficiency improves because of the larger difference between metal and air temperatures; the system will reach equilibrium rather than spiking.

Octane is needed to delay detonation of the fuel mixture. A lower octane can actually be used with our coolant because hot spots are not formed.

The viscosity of our coolant at operating temperature is very close to that of antifreeze, again, not an issue.

Like radial tires and disc brakes, not everybody will accept a new technology at the start; we are offering an advancement in engine cooling and everyone needs to make their own decisions.

John Light -Evans Powersports Coolant Director”

[DJT]

Robin, you are obviously convinced about Evans Coolant, and good luck with it. I have read just as many negative reports about it and having used 30% Glycol mixtures all my motoring life (nigh on 50 years) including over 100,000 miles of Stag driving, I am not about to change now. It takes me about an hour every 2 years to drain, flush and refill the Stag cooling system with quality Glycol/tap water mix and costs less than £20. The Stags I’ve owned don’t overheat, running below midway on the temp gauge in the hottest weather the UK can throw at us. I’ve stripped both the engines I’ve had and corrosion of the head surfaces hasn’t been a problem.

[Motorsport Micky]

Robin,

Thanks for exposing the differences between the Evans Coolant and our normal Glycol anti freeze as recommended by the factory and used by Triumph Stag owners for the last 45 years. I'm sure all members of the forum will wish you well with your continued use of the Evans product, and your future results with it will be of interest to many.

Just a point but if you compare the answer of John Light of Evans Coolant given in response to the last link of the Oilem site you'll see that is word for word to the response published by them in 2014, so unless you've copy pasted that in then all Evans these days are doing is giving a long term corporate response to owners legitimate concerns, pity they are not valued more than that.

Micky