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Triumph TR6 - Removing emission control gear

Hello,

I have a 1974 1/2 TR6 and I'm planning to remove all of the pollution control gear as it is in a jumble and I'd rather do without it.

I've come across a few discussion threads on this on a few TR boards but Ineed something with photos (I'm very much a newbie to Triumphs.)

Any guidance would be greatly appreciated.

Thanks,
Steve
S O'Reilly

Hi Steve

If you have a 74.5 car, I think that means no air pump. I have a '75 car, and the air pump came off along with the air injection manifold, which was rusted through and not easily replaced. That was a decent amount of weight saved, and tidied up the engine bay a lot. The air injection system, as far as I can tell, simply pumps air into the exhaust manifold to reduce the concentration of gases measured as part of emissions testing. No actual reduction in the gas produced, just diluted with air. I have no issues removing this system as I don;t see any actual benefit.

There is also an EGR (exhaust gas recirculation) system which takes some of the exhaust gas and passes it back to the inlet manifold. I think the idea is to take any unburned fuel and give it another pass through the cylinders. I believe it only happens at idle. I am not really sure this is very helpful either - the odds that your EGR valve is actually working at this point are fairly slim anyway. This system is simply removed - there should be a short pipe from the top of the cylinder hear to a small metal "mushroom" - this is the EGR valve. From the valve it then has a short (maybe 8 inches total) pipe through one right angle to the inlet manifold. Remove the connections at the inlet manifold and at the cylinder head and it is gone. Now, finding plugs to fill the spaces is another matter. I don't recall the threads involved, but they aren't something you will pick up at Home Depot. I bought the pair of plugs from a chap on ebay who sold them at the time - this was maybe 8 years ago, and I doubt he is still in the TR6 EGR plug business, but might be worth a search. There is, as I recall, a connection from one of the carbs to the EGR valve to trigger it to open - take that off and plug the carb connection. Hey presto, EGR system gone.

The remaining emissions stuff is aimed at returning fuel vapours to the fuel tank, rather than just venting to atmosphere. I don't see any harm in this, and it is not enough hoses/tubes etc. to justify getting rid of it, in my opinion at least.

The remaining hoses/pipes are probably worth keeping. I am not sure when the vacuum advance on the distributor turned into a vacuum retard, certainly by 1975, but maybe on the 74.5 cars too. I didn't like the retard function, so when I had the distributor rebuilt (by Jeff at Advance - highly recommended!) he changed it to a vacuum advance, so the thin tube connecting to the carbs is still in place on my car. If you just want to disable the vacuum retard you can remove that tube. That would eliminate the flame traps and their brackets as well.

I hope that makes sense. If you haven't already done so, I suggest you download or take a look at the roadster factory parts catalogues (www.the-roadster-factory.com and click on catalogues > TR6 > vol 1 blue and vol 2 green. They have great detailed drawings of all the parts and have been invaluable in my work on my car.

Cheers
Alistair
A Hewitt

Hi Steve:
I have a '76 from which I removed all the pollution gear when I rebuilt my spare engine. Where are you in Nfld? You can come and look at my setup if you're close. I'm in Paradise.
Cheers,
Bob
Bob Evans

This is irrelevant to Steve's objective but Alistair mentions that the injection air diluted the exhaust gas. While this was also the case, the real purpose of the air injection was to help finish combustion by adding more air to the exhaust. The oxygen in the air would react with the hot gases and further break down unreacted hydrocarbons to water and carbon dioxide and convert carbon monoxide to carbon dioxide and probably also had some influence on the nitrogen oxides produced. But the air pump did rob the engine of power.
Michael Petryschuk

Michael

I stand corrected! I figured that there was probably some additional function, as simply diluting the measured gases must surely have been seen as cheating the system!

I never tried my engine with the air pump after rebuilding, but I did have the air pump initially operating, albeit through a rusted out air injection manifold, and I then removed the pump and all the pipework to the exhaust manifold. before the engine rebuild I was running on 4, sometimes 5 cylinders, so power was well down, and I felt no difference from removing the air pump. I guess what i am trying to say is that unless you are doing some sort of time trials, I don't think it is worth removing the air pump simply for power gains.

Alistair
A Hewitt

I would agree Alistair - probably not a hill of beans different unless you are looking for performance and not cruising although it is something else to break and maintain. My 69 only has the PCV system (which I have bypassed) and the funky carburettor actuated timing retard valve for when the car is at idle. This valve only mad an appearance in the 69 model I believe,

And as mentioned by Alistair - the TRF templates were a Godsend for the kind work Steve is attempting. Saved me a few times.
Michael Petryschuk

Thanks guys, very helpful.

Bob, I'm over in Southlands and would love to stop by sometime to see your set-up.

Let me know when is good for you,
Steve
S O'Reilly

Steve:
Just about any evening or the weekend is good. E-mail should be showing unlinked on this comment. You can e-mail & we'll hook up by phone.
Bob
Bob Evans

Steve's hooked boys. Turns out he bought his 6 from a friend of a relative of mine but the really cool thing is that it belonged to another friend of mine who bought it when it was a couple of years old in the mid '70's and I was a passenger in it and also drove it once. Friend had it in storage for 30+ years and finally sold it to the guy Steve bought it from; he restored it and sold it to Steve. Can't wait to get over to Steve's and see it again after all these years. That's the great thing about this forum - you just never know what's going to come your way.
Cheers,
Bob
P.S. Back then my buddy had white walls on it :(
Bob Evans

Excellent
Another convert. Welcome to the club Steve

It is a small world and these cars are full of history and stories. Bob's connection to Steve's car is just another great example.

I have been fortunate with my car as my father bought the car from the original owner in 1977. When I visited Sarnia in September with the car I invited the original owner over to see the car for the first time in probably 30 years. He was quite pleased to see it and tell some stories about it.

He actually picked up the car in England while on vacation with his wife in April 1969 and drove it for 6 weeks. Part of the reason was he could ship the car as a used car and avoid a number of duty fees and taxes.
Michael Petryschuk

Thanks guys, and yes, I am definitely hooked :-)

Looking forward to next summer and getting this beautiful car on the road.

Steve
S O'Reilly

A small world indeed. I live in a small town outside of Regina, and one day in 1993 a neighbour stopped by to pick up his kid who was playing with my son, and noticed my TR which was stripped to bare metal at the time (I had turned 40 and needed a red sports car: my wife wouldn'nt let me buy one so I was repainting the green one I already had). He was telling me how he had bought one new in '69 and driven it on many long trips including Mexico and when it was basically worn out he had given it to his brother in law who finished driving it into the ground. When I told him I bought it in 1977 from a guy named Dennis who was selling it for parts, it became clear that this had been his car. Its been to more places than I have.

Alas, the snow appears to have arrived for the season so it is now hibernating in the corner of my shop.

A. J. Koschinsky

I know what you mean by those wives Tony

I have another 69 "parts" car that I want to restore but my wife said not until we get new floors and carpet for the house. Guess what happened this week. New kitchen floor, new hall floor, new carpet for the living and family room. Car restoration here I come.
Michael Petryschuk

This thread was discussed between 24/10/2014 and 14/11/2014

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