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MG TD TF 1500 - Hardened Valve Seats

I finally got sufficiently organized here in Tucson so that I can look after some machining, locally, I need to have done on an XPAG TF head that I bought from a chap in BC from this list.
I have the bronze guildes and the stellite valves are coming and what I now need is the hardened valve seats to go in the head; however, it seems that the young chap that i was talking to, at Moss, didn't know where I might find any hardened valve seats.This was yesterday (Friday) so I tried the numbers at Abingdon Spares but the phones kept ringing with no answer?? So my question to you folks is, Where would the Hardened Valve Seats be available?

Thanks in advance for the help!
Rod Murray 1954 TF
Rod Murray

Did you ask your machine shop? I believe they are hardened steel and are ground to fit?

Rod, ABS is only open 5 days a week.
Jim Merz

My machinist furnished mine - I think most shops do.

Good luck!
James Budrow

Many of us have found that you don't need the hardened valve seats.
Our local expert, Bob Wagner, has been rebuilding MG's for racing for years and has yet to used valve seats. "A waste of time and money"!

He has rebuilt two TF XPEG engines for me without hardened seats and they are performing fine. Just be sure not to run too lean.

The need for hardened seats in an iron head is a myth!

Don Harmer

Rod - Have your machinist check the valve seats for excessive recession. If they don't show any recession, there is no need to put any new seat, hardened or otherwise, in. just keep driving the car until the valves start receding into the head and then put the hardened seats in. We had nearly 80,000 miles on the engine in our TD before I blew it up (not due to valve problems) and there was no sign of the valves receding into the head at that point. Cheers - Dave
David DuBois

To Rod Murray -- We have had a tremendus ice storm here in New Hampshire. It was much worse up in Walpole where Abingdon Spares is. Don't dispare, when the electricity and phones are restored Abingdon will answer their phone.

R. K. Jeffers

Have to Ditto Dave. My engine had 25,000 when it blew and the head look almost like new. This head never has run on leaded gas. Because the head on my new engine was shaved down to very low levels, I just used the one from my original engine. I did have my machinist check it over. he did put in new rocker bushings, but otherwise did nothing to the head.

If I was to put TF valves in, i would just have to have the openings increased?

Don Harmer,

I'm sorry to be so diametrically opposed to your view, but I have incontrovertible evidence to the contrary.

About 5 years ago, I ran into a gal who lives near Kingston, ON and she was asking me about hardened seats for her TF. I counselled her to have them put in, but her machine shop advised not to, and that running the super grade of fuel would have the effect of not needing hardened seats.

Id love to know where these myths come from!

Last spring she called me to tell me that she had lost compression, and upon inspection of the head, ALL exhaust valve seats were badly burned away.

I keep in touch with her; and another $700 later she had hardened seats that she got from Abingdon, put into her cyl. head and she is now monitoring compression, and all seems well.

Please dont blame it on Canadian fuel. She told me that she gets most of her gas in Alexandria Bay, NY.

Gord Clark
Rockburn, Qu.

Gordon A. Clark

I know there are a lot or reasons for burning valves... I had a couple in my '60 MGA coupe (in '65) and two valve jobs on my '68 Mini (in '69)... don't know what caused them then, but I have put more miles on the TD then on either of those cars....and no loss of compression or problems of any kind ... I would think I would have burned them by now? If one is redoing the head for other reasons it wouldn't hurt to put more modern metal in the seats...but I wouldn't run out and pull a head to just 'do it'!

Anything that interferes with valve cooling or creates extra heat in the valve or head can lead to premature valve failure. A buildup of deposits on the valve face and seat can have an insulating effect that slows cooling and makes the valve run hot. So too can poor contact between the valve and seat if the seat is too narrow, nonconcentric or off-square. If deposits build up in one spot or flake off in another, it can allow leaks that create hot spots on the valve and result in "channeling" (grooves eroded or burned into the valve).
Cooling problems in the engine itself can lead to valve sticking and burning if the operating temperature gets too high. Low coolant, a defective thermostat, a weak water pump, a radiator obstruction, a defective cooling fan or fan switch, etc. can all make an engine run hot. This, in turn, makes the valve stems swell which may cause them to gall or stick in their guides if there is not enough clearance. If the valve sticks open, it can burn or be destroyed if it smacks the piston.
Valves can also run hot because of elevated combustion temperatures. Factors such as retarded ignition timing, lean fuel mixtures (often due to vacuum leaks), detonation (from too much compression or low octane fuel) or preignition (from hot spots caused by deposits in the combustion chamber or too hot a spark plug) can all play a role here. Likewise, exhaust restrictions can make the valves run hot.

gordon, after reading your post, i am not sure what you are telling me in regard to the hardened seat issue. which myth are you refering to? i would offer that if you are pro hardened seats, one example is not incontrovertible proof. (i have a notor that only ran on leaded fuel and ALL seats were recessed.) i go with the majority on this post, my personal experience, and the articles i have read..i am in the "lead was added as an antiknock compound not a valve lubricant" group. perhaps that is what you are sayng as well. regards, tom
tom peterson


The myth to which I refer is that (current) premium fuel is a substitute for lead.

Before I did my own seats, I used to add a lead additive which frankly, over the life of the ownership, is probably less expensive. I just got tired of going through the procedure.

The original lead was a simple compound - tetra-ethyl lead and was indeed, as you have noted, used as an anti-knock element, but over the years, its lubricating qualities became noted, and it evolved into something quite a bit more complex than simple tetra-ethyl lead, and lubrication became a marketing pitch of the TE lead compound.

Colin Stafford has a chemical background and can probably shed a little more light on this.

I too know several chaps who have had no trouble w/o the seat mods, but my point is ... why take the chance?

Gord Clark
Rockburn, Qu.
Gordon A. Clark


after reading the comments here, I was of mixed opinion, as to whether to put the hardened valve seats in; however, thought that they probably couldn't hurt, so yesterday I rephoned Abingdon (they had been hit hard by the ice storm)and found that they do not provide hardened valve seats and they gave me the Abindon's owners (Bob..nice chap!) phone number to talk to him about them. He basically agreed with the concensus here that he has NEVER seen the need for them in any of the many British cars he has had, including 2 "T's" with iron heads. Thus I will check the recession and only put them in if they need it because of this recession!
Thanks, to you all, for your input!
Rod Murray
Rod Murray

I would suggest that if your are interested in the "chemistry" of Tetra Ethyl Lead (TEL) you should go to the Wikipedia web site and search for Ethyl Corporation and click on the history, and under the Tetraethyl lead paragraph, click on the highlighted ling, "tetraethyl lead"
I think it has most of the infromation a layman would need.
colin stafford

I believe that another way to ensure that exhaust valves get burnt is to have insuficient valve clearance. One needs to be carefull, because there are at least 3 different clearances specified on various TD valve covers. During the production run different cams were used. Also 2 different head castings. The only sure way to know what cam is in your engine is to fit it with a degree wheel and measure the durations.
Steve Tobias

One way of burning the valves I can attest to is using the wrong needles in the carb. Burned a set of valves a few months after getting my TD back in 74. PO had changed the needles and at that time, I did not think to check them.

One thing to note during this discussion-seat erosion is actually a different issue than burned valves. Erosion can occur without the valve burning-the seat area simply begins to gradually disappear and the valve sinks further and further into the head. The seat to valve contact patch is naturally affected,but compression loss most often occurs when the clearance between the stem tip and the rocker becomes non-existant. Compression can sometimes be regained by readjusting the valve clearance. Good clue to upcoming problem is a valve that is continually gets tight-seat going away or valve stretching. Continuing to operate an engine with tight valves will of course burn the valves - so the two issues can go hand in hand. Have had a wide variety engines in the shop with the problem-no real rhyme or reason to it. Some, like Dave D's show no ill effects;while recently we had a 65 Mustang with less than 10,000 miles on rebuild with every exhaust seat gone. Also it was run on premium fuel w/lead additive every tankful.Sound familiar,Gord? Last week had an 01 Ranger with 2 seats gone-engine supposed to run on no lead fuels. Anyway,hard seats,properly installed,can be a good investment-but not a neccesity in all cases. Proper attention to valve clearance,low coolant temps,and avoiding very lean fuel mixtures are all good suggestions for prolonging seat life. Sorry for the long rant-trying to be clear on what is happening on so many engines these days. Dan
Dan Craig

Rod: D&W Machining can do it here in Calgary. They did both my high compression (Shaved) and stock head for me a couple of years ago.
J.W. Herbert

This thread was discussed between 13/12/2008 and 21/12/2008

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