Brinell Test Failure. Options??

[geodon]

The MGTC I'm restoring has a racing history. It was running with an period Laystall-Lucas aluminium head. Damn rare & dated 15/10/1953.

The engine works I took it to for testing took one look at the indentations made by the flat washers under the mounting bolts & declared "It's been cooked & the metal has gone soft". A Brinell (hardness) test proved it. If I used it I'd get repeated head gasket failures.

I've heard rumours of treatments to re-harden aluminium but surely they would have known about them?

Does anyone have insights?

 

[schlitzaugen]

They may know but may not be available in Oz. Ask them.

If no go, I would try looking overseas if head is so rare. Impossible to not find someone in the UK who can do it.

 

[PeterT]

It's a bit messy as they're quenched to room temp and then precipitation (age) hardened at 165º for 24 hrs. Heating up for the quench will soften the valve seats. Thus it will cost a few dollars in heat treatment time and rebuilding, but if it's rare then worth doing. I'd imagine there are still heat treatment places around, or not too far from Geelong.

 

[jaahn]

hi I guess google is the answer. These may help.
From Autosport Dec 1952
The Laystall Engineering Co. Ltd. have made available a special head, designed ab inito in high-compression form. It incorporates the larger valves and stronger springs normally supplied for ” Stage II ” tune, and these are included in the price of £48. It is cast in RR 50 aluminium alloy, which not only eases all the heat-flow problems, but saves 16 lbs. of weight. The main feature, however, is the scientific proportioning of the ports and head shape, which greatly increases the air flow. The technical side of the project is the work of John Lucas, who has put the speed into many of our fastest engines.
So that is the alloy which may help to decide the details of the heat treatment. Here is an old spec sheet and initial casting heat treatment description. Does not include hardening process.

I would think that some places in the UK would know what to do.
Good luck jaahn

 

[Andrew Watkins]

The MGTC I'm restoring has a racing history. It was running with an period Laystall-Lucas aluminium head. Damn rare & dated 15/10/1953.

The engine works I took it to for testing took one look at the indentations made by the flat washers under the mounting bolts & declared "It's been cooked & the metal has gone soft". A Brinell (hardness) test proved it. If I used it I'd get repeated head gasket failures.

I've heard rumours of treatments to re-harden aluminium but surely they would have known about them?

Does anyone have insights?

Try Oppy Head Treatment
23 Grosvenor St
Abbotsford
Vic
94288039

I was going down this path with Dauph Gordini head a few years ago and explored it with them. They were helpful and talked sense, but I ended up finding another head, so can‘t report on their performance

Good luck

Andrew

 

[driven]

UK seems the go. Appears these guys can make a new one

MG T-Type Cylinder Heads | XPAG Engineering-XPAG Engineering

We have been refurbishing, converting and manufacturing cylinder heads for many years now and we are confident that we can meet any requirement you may have regarding the T-Type cylinder head.

www.xpagengineering.co.uk

 

[geodon]

Thanks to all who responded.

The depth of knowledge here never fails to impress me

I've been communicating with George Edney the founder of XPAG Engineering in the UK. He actually bought the moulds from Laystall when they stopped making heads. An amazing guy. Still races a 120bhp Lester MG & has been selected to compete at the Goodwood Revival soon. He's 80yo!

Anyway, he can supply an complete original steel head reco'd with oversize valves & bronze guides landed here for ~$1400. He claims with a race cam (which I already have) the power output will be close to what a new $4000+ ally head produces.

The pragmatist in me says this is the way to go but not before I check out Andrew's contact.

 

[PeterT]

It will cost $1000+ to have the head repaired/reco'd after heat treatment.

 

[RINGER]

I've just finished a retro moded light 15. Having redone some aspects more than once, I have again re-learned trying to do things on the cheap usually works out dearer than taking a proven, but what appears a more expensive route.
In the scheme of things $1500 is peanuts.

 

[Kenfuego]

OK while I did study metallurgy as an apprentice, my gut feeling was that aluminium as a soft and stable head should be desirable when tightening the head down and compressing the head gasket. But against that thought is also the knowledge that after bushfires burn historic vehicles, the consensus is that the heat effected components are not suitable for reuse because of the changes wrought by high uncontrolled heat.

Still I wonder at the decision to virtually scrap your "valuable and rare" head.

I am no expert on metallurgy, stressing and de-stressing of such equipment. Curious though....

Ken

 

[Aln]

For another opinion on the re-hardening your aluminium head try this group in many capital cities in Australia. I had a BMW E30 M3 head done by the Brisbane group many years ago. Yes, all the valve guides and seats will need to be replaced which will add to the costs, as Peter T said, $1000 would get you on your way with the head restoration after the treatment. The actual treatment process was not very expensive as I recall.

https://hta-global.com/products-services/treatments/

 

[PeterT]

I am no expert on metallurgy, stressing and de-stressing of such equipment. Curious though....

I teach this stuff. The idea is to heat to a temperature high enough to create a single phase material (soft). If you let it cool slowly from B, like in a bush fire etc., it remains soft because the resultant structure has very little Cu in solid solution (0.2% Cu). If you quench from B, then all of the 4% Cu is retained in solid solution. However, it is not in equilibrium at room temp. For this reason, you store aircraft rivets in the fridge until ready for use.

Re-heating slightly for a short period of time, will allow precipitates to form at the grain boundaries, which impede dislocations and further strengthens the alloy. There is a sweet spot of time vrs temp to obtain maximum strength. Thus the term age hardening.

An aircraft rivet would be line A. Cylinder head line C.