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Painting inner face of water jacket


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Hi Folks,

what are the pro's and con's of painting the internal surfaces of the 4 pot water jacket and external surface of the liners.

 

Will this stop/reduce rusting?

Is there a benefit.?

What is the best paint/process for the job

 

I've not done this in the past but 'm sure somebody has.

 

Roger

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The risk would be that the paint comes off at a later stage, & blocks up the waterways.

I would say better to clean out the block as much as possible, then always use a high concentration of antifreeze with corrosion inhibitor.

& maybe flush out every couple of years ?

 

Bob.

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Roger,

 

These 4 pot engines have lasted 50 years in bare metal, how long do you plan on living ?

 

I understand that the liners can be coated in a ceramic which then prevents any rust build up on them, but as for coating inside the block as Bob says I would consider it risky to coat the water jacket with any substance which may come off afterwards ( midway through your annual Scottish tour ? ) and cause a build up or blockage in the narrow parts of the water passages in and around the block.

 

Also whatever substance is used it must at least have the same heat transference properties as the bare metal...hmmmm and of course not cause any "nipping" in the critical area which is the waist of the liner at the FO8 joins which will cause localised overheating and piston picking up. Also there is lots of discussion on the "Hotrod" and drag racing websites on the benefits of inner surface block painting in the main crankcase to help the transference of oil back into the sump via "slippy" walls and some extra hp to be found this way rather than the standard castings on engines, and there is a big difference of opinion about the loss of heat transfer through the engine walls by painting (even in substances that are supposed not to hinder it ).

 

I'm quite happy to build these 4 pots " as nature intended"

 

Mick Richards

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To get the maximum cooling effect, the coolant needs to come into contact with the metal, so I would have thought that putting a skin onto the surface of the metal would reduce the effectiveness of the coolant, and we know that keeping the 4-pot engine at the right temperature is not that easy in warm weather. It's possible that modern fuels are partly to blame, but there's no easy way round that!

 

Why not use Forlife or Evans' Waterless coolant?

The late Dr Michael Bingley always used Forlife and told me on numerous occasions that the bare metal inside the block of his TR6 was completely rust-free. Of course, the splendidly eccentric and precise Mike died before Evans' product came on the market, so I cannot guess what he would have said about that!

 

Ian Cornish

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I didn't consider the waterless coolant, TR cars have run very well before this stuff was invented, for 50+ years, with stuff that falls freely from the skies, why change things, there are better things to chuck money at surely.

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Hi Ian,

I've now binned the internal paint job idea. I will have to investigate the Forlife coolant. Where is it available.

 

Roger

I got some from the MGOC website Roger. Demon Tweeks do it also.

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Hi Pete,

indeed the engines have certainly battled against modern coolants quite well but as this engine is completely rust free I was thinking if it was possible to keep it that way.

We all know that the rusty particles gather round the back of #4 pot for a chin wag and a fag so I was attempting to banish their presence altogether.

 

I think the Forlife coolant is the way to go as it is not overly expensive, unlike the Evans coolant. And if the late Dr.Bingley recommended to them who could argue against that.

 

Roger

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In the 1940s and 1950s, folk would use water (no anti-freeze) as coolant during the warmer months, then put in anti-freeze for the winter, repeating this regime annually. Corrosion would occur inside the block, but was not noticed because our cars were pretty new at that time. After ten or more years of this, it was not uncommon to open the drain cock on the side of the block and see not a trickle - in fact, we discovered that my brother's TR3 had had its drain cock open all the time, but no coolant had leaked out!

 

Most of us will have treated the chassis and bodywork with Waxoyl (or similar product) in order to stop the rot, so it strikes me as foolish not to try and preserve the inside of the engine as well.

 

Ian Cornish

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Suspect (don't know) modern coolants are doing a pretty good job of reducing corrosion as well as galvanic problems.

However nothing wrong with Roger doing the guinea pig bit for us.

I'd go for one with metallic bits in it like the copper/zinc primer paints. Ideal would be one that is black. In physics they told us that it absorbs more heat.

Not going to try it in my donk (too late now anyway) but quite happy for Roger to blaze the trail.

(Loved the 'chin wag and a fag' bit!!)

Edited by littlejim
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Hi LJ,

thank you for allowing me to be reckless (normal state) but it's not my engine.

 

I've been mulling over the idea and I think I may have my wires crossed. It's not the water jacket that gets painted (or perhaps it is) but the crankcase area where the oil is.

Can't see any point in painting the inside pf a TRactor engine.

 

Roger (confused of Middlesex)

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Elsewhere on the forum, I have seen a recomendation to use "central heating" type cleaner / de-scaler to clean out the waterworks of an installed engine, which seems like a good idea.

Why not take this a step further, & add "central heating" type corrosion inhibitor i.e. Fernox or similar.

I have had this in my central heating system for many years, & whenever I have to drain it (for maintenance / modification purposes) the water always comes out clean, slightly pink due to the inhibitor, with no brown / black bits, also most of my radiators are pre 1980's, & are still working fine.

Will be tempted to try this the next time I have to drain the TR.

 

Bob.

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Hi Bob,

yes, I also spotted that post somewhere.

in theory Fernox should cause no problems to a TRactor engine as it uses all the materials found in a H/H system.

Although C/H water comes out clean you often find that there is often a black deposit in the bottoms of the rads - it tends to be loose and free flowing.

 

Roger

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I put Fernox in my heating. It gradually removed corrosion. Fine.

 

Then all the rad-valves that had scale around the operating shafts that was sealing them started to seep.

OK so I re-packed the stuffing glands and all was good.

 

So you might expect leaks to appear. I'll let you guess where they might be.

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Fernox contents:

www.fernox.com/files/Safetydatasheets/English/24004_CH-3_Eng.pdf‎

Triethanolamine will buffer pH but is also a surfactant, so it should shift sludge well, even if it finds leaks. Seems to me to be good to clean out sludgy rubbish.

Benzotrialzole is a corrosion inhibitor active on copper. So I think Rogers c/h black stuff might be a copper sulphide.

The molybdate is also a corrosion inhibitor particualrly good at bimetallic corrosion inhibition: http://en.wikipedia.org/wiki/Sodium_molybdate

 

Its quite possible ethylene glycol antifreezes use same inhibitors: their MSDS data sheets may reveal all.

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Interesting back and forth.

My 2 pennyworth:

The black stuff in c/h radiators is black iron oxide.

So far as paint is concerned black is advantageous in increasing radiant efficiency, but inside the engine we are talking conduction. So the question comes down to would ~50 microns (2 thou in old money) or so of paint be better than a clean metal to water interface or a coating of rust?

Off hand I don't know what the thermal conductivity of a metal filled paint is but an electronic grade silver filled epoxy (optimised for conductivity) is typically about 5W/metre/K. This is going to be better than any paint, I would guess by as much as x4.
Steel varies according to type but will be between say 20 for stainless steel and about 40 for carbon steel

Solid Alumina (a ceramic) is about 30.
And rust is about 0.6 w/m/K

So a quick mental sum indicates that if the rust grew to about 10-15 microns thick it would be as insulative as the best possible paint and then progressively worse.

So the answer to Roger's original question is likely to be:

In the longer term paint is better than rust, but nothing is best of all.

 

Conclusion: avoid rust for highest thermal efficiency, but without experimental verification it's impossible to say if there is actually any significant/measurable differences in use. Probably the volume and temp of water flow is much more significant. In this respect keep in mind anyway most of us drive around with a bit of rust and no problems.

Probably this is really more about longevity/preservation of the engine than a thermal matter, if that is a concern the water free coolants are probably a better route to go.

 

Mike

Edited by MikeF
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There is only one kind of paint worth thinking about and its POR.

 

We used this on mild-steel parts that should have been made in stainless but were wrong.

We could have emade them but tried POR instead.

 

These were cycled from -40 to +70 every hour, every day, for 2-years inside an environmental test chamber.

When you do this the entire area is covered with ice, water and vapour in cyclic fashion because we did not use dry air.

 

This paint did not come off. BUT these were small parts and you could prepare the surface very completely.

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  • 6 years later...

I've been trying to put another engine together for a couple of years and things are finally moving again. The block was acid dipped 3 years ago and then left :ph34r: I was told at the time that the liners would "just fall out mate when its dipped"....they didn't and now I have retrieved the block I find its full of **** in the water jacket. I have sealed up all the holes in the outer faces of the block, cleaned the figure of 8 seal faces and bolted covers over these along with the block to head face and intend having it blasted.

Someone said why don't you paint it out and so I have been looking into this and it doesn't seem to be a good idea, i get that now but my round about question is...

when it comes back from the blasters what could I use to stop it rusting whilst it sits waiting for 

A. to be built

B. I get round to fitting it and running it up

I thought perhaps a spray out with WD40??

 

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That sounds like a possible solution, you may have to re-apply periodically.

Bob.

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Spray with thin oil or spray on grease and the wrap in cling film.

Stuart.

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  • 2 weeks later...

sorry, been away....gosh I needed that!

Thanks both, I think I'll spray it out with WD40 when I pick it up on monday afternoon and take it straight round to Pete who's going to put the short engine together for me.

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