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Triumph TR6 - hardened valve seats in all US spec TR6s?

I have a 74.5 TR6 which was purchased a few months ago. I have no idea if the car has hardened valve seats, and hence don't know if I should be using a lead substitute in my gas? I know this is a retrofit that is done on cars designed for leaded gas use, but I thought I read somewhere that all US spec (carb) TR6s were built with hardened valve seats in preparation of using unleaded gas.
Anyone know otherwise? should I be using a lead substitute? Is there an easy way to check if hardened valve seats have been inserted?
Many thanks,
Austin Brown
Austin Brown

Hi Austin,
Welcome to the TR6 world...
As per the owner's manual of my '75 it states to use a fuel with a min octane rating of 91 ie regular fuel ( but I think reg is actully rated about 80 or so )whilst the Bentley driver's handbook / shop manual says to use a min of 100. I myself typically run 90 - 94. I would assume your's will be happy with something around there.
Charlie Ballard

Hi Austin

I always used the lead substitute and then read an article which I can't find that suggested the difference in milage obtained was negligable with the standard valve seats. Additive or no.

None of the original engines had hardened valve seats.

Very few have been modified that I have seen and seem to be none the worse for wear.

Bill Brayford

I have a spare '75 US cylinder head and it does not have hardened inserts, before I changed it to a PI spec head with hardened seats I ran for 3000+ miles on unleaded and suffered no valve recession.
R. Algie

It is my understanding that hardened valve seats are only needed if your engine operates in a high load condition for a long time. ie pulling a heavy trailer a long distance or if you run in the Daytona 500. Is this not correct?

I am a new owner. I am curious to know.
How many of you have run your car with unlead? for how long?


Paddy, I run my 71 on unleaded. There have been some articles on this. Generally, it isn't worth fixing until you do a valve job.

JL Bryan

So it sounds like there is no need to use a lead substitute OR to have hardened valve seats put in, so long as the car is used for regular driving conditions only? Does everyone tend to use premium gas? I normally opt for the middle grade becasue I cant bring myself to pay near $1/liter. Is this safe or should I put in the highest octane I can find?
many thanks for the responses above.
Austin Brown

With the low compression head I use the lower octane and I have the timing advanced with no ping. You will actually lose power with a higher octane due to slower burn with high octane. The higher compression engines need higher octane. By the way those off the shelf octane boosters are misleading. When they say they increase octane 4 points they mean .4 octane. ie 93 octane now becomes 93.4 octane.

In my opinion, use the best gas you can get reliably from the same source and adjust your timing to avoid ping/knock/detonation. I use the same brand as much as possible. Since I'm in southeastern Wisconsin I can only get the reformulated gas specified by the state in response to US-EPA sanctions for Milwaukee.

This fuel is as expensive as almost anywhere in the US. While in Honolulu a couple of years ago I was surprised to see prices less than Wisconsin!

I get good results from 92 octane at $2.129 (today). I run 87 octane in my Buick ($1.969) Midgrade here is 89 octane at $2.049. As the cost of gas is so high (to me) anyway what difference does $.08 per gallon really make?

Apologies to those of you paying even more... but I think we all agree that the joy of driving a TR is worth it.

Charlie Smith
EC Smith


Tetrathyl lead is apparently available - I see adds for it in the back of "Grassroots Motorsports" and "Classic Motorsports" magazines.

When I need higher octane, like in my other "interests", I buy racing fuel and mix to get the ratio I need.


Tim Brand

Charlie Just came back from topping up the beast.
$ .774 per liter x 3.785 = $2.93 /US gal. in Canuck bucks x .73 = $2.14 US per gal. for 87 regular. We are parked right here in the middle of the oil/gas fields and we pay more. Don't get the guys in eastern Canada going! You're gettin a deal. Did someone say something about election! Brian
B. Towne

I seem to recall reading in one of the old Moss "newspaper" mailers that the valve seats from '73 on were induction hardened. I don't think I have the issue any more - at least 8 years or so old.

I can't attest to the correctness of the claim, and it wouldn't be as hard as the inserts, either. Plus, my machinest said don't bother with inserts on the inlet valves.

Brent B

Hi All

As for hardened seats.

The first of the unleaded gases are 1976 vintage. England and Europe and the rest of the world long after that. There was quite a lot of griping about offshore cars even in Canada taking jobs away from American auto-builders. Many are built in Canada. So governments set out some pretty silly restrictions. Likley due to prodding by Union and corporate lobbiests like those bumper over riders on the 6 etc. to try and stem the flow. I can't see them using a more expensive item hardened valve seats in 73 though for something not developed till 76?

Heres some interesting reading on it and it also gives an idea of what is being pumped into the air instead.

Lead is not a good thing. But unfortunately the brains forcing its removal and replacing it with other problem chemicals. Ingested way too much lead to think clearly.

As for the EPA I am not sure of its worldwide clout. But here in Canada and US it has huge funding mostly from gas taxes with little control because it is the politically correct thing to do? That means they do whatever they damn well please!

I questioned a young Chemistry Grad. and he pointed out that for his Doctorate he can get full funding to identify pollutants and polluters from the EPA. Does the EPA fund research into the solutions? No! There mandate is a to seek out and identify?

This type of organisation has no place in our society in 2004. It didn't work in Salem or the McCarthy erra. Mr. Nader killed the corvair and drove a Volvo? I have owned both, and the Corvair was a much safer car in that erra. Old Volvos had a roll center about the same as a 40 Ford? A virtual pig.

But Ralph made the bucks and got the whole watch dog theme rolling. If you think your safer in your Volvo than your TR6 up against an 18 wheeler hauling steel? You likley graduated with a degree in environmental studies?

Now we have vast numbers of environmental students graduating because they could not make the cuts for engineering or much else. Mom told them there way to smart to be a tradesman and actually do something of value. So they work for our tax dollar giving no solutions of any value but have the right to fine me if I don't comply with the rules they set out. Hell any teenager knows anyone over 40 is an idiot why waste big money educating them in environmental studies? Just give them a ticket book.

Self interest groups EPA and others seeking government funding only with our well being in mind of course? Yah right. Have just about destroyed creditable society and politics. The Witch hunters of Salem/McCarthy/ Nader had limited scope. No answers either just burn them because I say its so. Now with the global society and stupid politicians lookout for the new hunters.

My opinion only.
Don't blame me for the rant Brian mentioned elections and politicians...:)

Bill Brayford

Speaking of unleaded gas, as I can remember in 1974 all Amaco gas was unleaded. Can't remember when they started. But it carried unleaded at least for a few years before that. They have also mentioned that fact on their TV ad back then preaching their enviromental correctness.
EPA may not be a efficient agency, hardly any .gov is. But the law has its merits. Because big corporation did a lot more damage then a bum agency. I have seen a lot of fouled landscape in the third world, and I truely glad that we have some protection here. Even though it is not perfect.
When I revisited London in 1980, after we ran the unleaded for a few years here. I still remember that stink in my eyes from the exhaust. What a difference it made.


Bill B.--You must be smoldering still from your Parliament's Royal Assent to the new Canadian Environmental Protection Act back in '99. Flow restrictions on gas dispensing nozzles to reduce exposure to benzene? In time, you too will enjoy the benefits of a US-style EPA program.

Now, if we could just do something about the fossil power plants and their unmanaged air pollutants.

Rick O.
Rick Orthen

Hey Paddy I looked for that and Amaco it seems sold unleaded back in the 50s. Yes the EPA in 1973 called for a choice of unleaded fuel by 1974. I still doubt England complied with hardened valve seats?

Paddy and Rick don't get me wrong. The EPA is a realy good concept badly executed. Unfortunateley they do not have the clout to get to the real poluters on either side of the boarder. Canada produces much of the East Coasts grid Hydro as seen last summer. Canada says the US is not holding up there end of the deal and vise versa. A couple of friends that work in nuclear energy say that its getting better?

In Canada Rick much of it is more political than realistic. At corporate level many real targets are US corporations that provide many jobs. They always seem to be missed. And then split back to the states leaving the mess? We have 3 sights that require cleanup in our own city of 100k all Us corporations that just left. Thats pretty universal for business. Our current Prime Minister would have been better suited doing business in the slave trade if you look at his corporate activitys.

Back to car reality.
Instead we have a lot of foolishness. One example is headers epa certified for use in all 50 states will get you a $400.00 fine here. But if you contest the fine in court it will be thrown out??? If you call about anything complex to the EPA types here your given a 1-800 California to call. Neat eh.

I am against the concept of a group that equates to... You know something needs fixing. Taking your complaint to the agency that seems to be set up to resolve the situation. And being told yes we have determined there is a problem. OH Good! So what do I do? Don't know. Here's your bill.

Realy look at it. I personaly am too old to be amazed by smoke and mirrors!

Bill Brayford

Hi Bill,
If Amaco sold unleaded since the 50s, I guess it will be all right for our stock TR to use it.
IMHO most of those special spirit are snake oil anyway. Spend the money on lattes will at least keep you awake.


Good point Paddy

Bill Brayford

This thread was discussed between 23/06/2004 and 30/06/2004

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