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MG TD TF 1500 - Hardening the engine

In one of the University Motors videos, Mr. Twist talked for a little about the issue of non-leaded gas and its effect on the engine, and what can be done, in terms of 'hardened valves and vale seats'.

Exactly what work is necessary to bring a 1951 XPAG engine up to where it could run safely on modern gasolines?

G M Baker

Mr. GM,
there is not a clear black and white answer for your question. You can find a lot of material in the archive here in the BBS.
Anyway, I drove my 1953 TD without hardened valves and seats. But I'm prepared, I have just modified a spare Head, which I have found in Ebay.
I used an Unlead conversion Kit (Ebay# 370233959006)from NTG Motor Service in Ipswich, Suffolk, England, which containes Stainless Steel Valves (Inlet & Exhaust, Manganese Silicon Bronze Valve Guides and Hardened Valve Seat Inserts for the Exaust Valve.
I have machined the Head carefully and shrunk the ring in the prepared groove. It's a simple task if you have the right Mashinery availaible. After facing the head he is now ready for installation. But I will not do it yet. I'll still stay with the original head but in case of trouble I can change over.
Cheers,
Guenter



Guenter

I don't have the equipment to do the work myself but have a great machine shop guy who I trust absolutely to do such work. But is this "unleaded" kit all that is needed or are there other issues to look at?

Geoff
G M Baker

Geoff,

Gunter is right. There is a wealth of information in the Archives on the subject. Not everyone agrees that putting in hardened seats is needed for an engine that has run leaded fuel as the lead is still on the seats and is cushioning the valves. However, on my rebuild I had my head done with hardened seats and bronze valve guides. Other issues with unleaded fuel is compatibility with the fuel system rubber parts, but with today's parts that tends to not be an issue anymore.

dave
Dave Braun

Geoff - Guenter is correct, hardened seats, bronze guides and stellite exhaust valves are really all that is needed, with the hardened seats being the only thing that is absolutely required. That said, I have been running our TD on unleaded fuel with an standard head and have not experienced any problems. Unless you are racing or driving at 70+ mph on the freeways several hours every day, there is no real need to make a special effort to install the upgrades. My philosophy is to wait until it is necessary to overhaul the head and have the work done at that time if it is needed. Cheers - Dave
David DuBois

I agree with Dave,,
If you are building a car mainly for Sunday drives and a few car local shows, and moderate speeds, the stock head will be fine. But if you are planning on long trips, with many hours on the road, and some higher speeds, IMHO, you should look at using the hardend seats and valves. There is another item that would be helpful, and that is a "TOP OILER" They add a mist/drip of oil,usually Marvel Mystery Oil, to the intake manifold to help cool things down a bit.
I have heard of a very few instances of incorrectly installed hardend seats popping out of the head causing considerable damage. I say again, INCORRECTLY installed,,,,

SPW
Steve Wincze

Another option, whose merits are sometimes debated, is the addition of a lead substitute to the fuel. The closest thing to an impartial test of lead substitutes was performed by "The Federation of British Historic Vehicle Clubs."

http://club.triumph.org.uk/links/leadfree.html

I have an unmodified head and use Red Line Lead Substitute on the assumption that it cannot hurt and may help. If work is needed on engine internals in the future, I will likely take that opportunity to do the head modifications described by Guenter (a.k.a. The Dave DuBois Strategy)

Larry
Larry Shoer

Our local engine expert ( he rebuilds all sorts of british race cars) has seen no problems with heads without inserts on street T, A , B , and other cars)

Most valve seat burning problems arise because of the timing, he says.

My TF 1500 which is stage 3 tuned (9.5 compression ratio, etc) has been running on unleaded since it's introduction in the US. The only conversion being Stellite exhaust valves 20 years ago. On a rebuild two years ago due to a lost freeze plug while driving at about 60 MPH for an unknown time, the head showed no valve seat recession or burning. This was after about 16000 miles on US unleaded fuel.

Use some sort lead substitute if it makes you feel better, but don't go overboard with all the hardened seats, bronze valve guides, etc that the unleaded conversion advocates say. ( Is it marketing????)
Don Harmer


Read these:

http://www.sbintl.com/tech6.html
http://www.sbintl.com/tech7.html

Then leave it alone until such time as the head needs to be rebuilt. I've built a lot of engines, never installed any hardened seats in an engine that didn't already have serious recession = very few, never had a problem.

And Geoff-
Please email me re the bike, as asked in the thread where you posted the pic!

FRM
FR Millmore

Dropped into the machine shop today and they were just seating the valves....
The old ones looked good and that is with 25,000 miles(that I have put on it) on unleaded fuel...
Figured while it was apart it didn't hurt to do all I could to it....



gblawson(gordon)

FRM, I sent you an email re the bike... must have gotten lost in your spam filters... I'll resend

Thx all for the info, not looking to do any work on it now, just wanted to understand the options.

Geoff
G M Baker

Agree to a point with all the above. How much do they charge for doing the valves for no lead? At my shop it adds almost 1/2 again the cost of a standard valve job.

My old head had 15,000 when the engine failed (not do to head issues). I had the head gone over prior to putting it on the new engine. Shop said everything was fine. they did clean it up but the valves were fine. They said there was no indication of any issues related to running without lead.

My TD does not get a lot of miles. Figure the valves did fine on unleaded for 15,000, I will not put that on for some time. so why add the extra cost.
Bruce-C

I'm being charged in the $450 range for the machining... I provided the stems and valves and springs...they did the decking, seats and work....
That makes the whole head work a bit pricey... all the bits and pieces were close to $500
gblawson(gordon)

Mr GM Baker:
I am a "snowbird" living in Tucson for 5-6 months of the year escaping the cold in Calgary Alberta.
I got my head "hardened" in Phoenix last winter and they did a wonderful job. Contact me at rod-murray@hotmail.com and we can discuss it:)
Best Regards
Rod Murray (now in warm sunny AZ) :)
Rod Murray

FMR is right on-if you have good compression and it is running well, leave it alone. Something else is likely to break (crankshaft, headgasket) before you have valve seat recession issues. Drive and enjoy. George
George Butz

Rod, I've sent you an email. George - as I said, I'm just researching, I've got no rebuild plans. I'll be using additives for the foreseeable future...

Geoff
G M Baker

This thread was discussed between 19/11/2009 and 21/11/2009

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.