US Mk1 Fed. fuel tank

[sujitroy]

I'm having my original Mk1 Fed tank boiled out and sealed. Here is a photo of it. Notice the 4 vent pipes at each corner. It has a drain plug at the bottom. The vapors from the tank go into another smaller tank.
Sujit

[SaskStag]

I capped those off and converted to UK set up. The emissions paraphenalia was half gone anyway. I used Por15 on the outside after it was professionally cleaned inside and sealed after decaying mouse fluids ate through the tank....urghhh
I expect you're keeping it federal?

[trunt]

Not sure what testing you need in California but if you need to keep emissions I would consider changing it to mk2 type, much simpler. I don’t think you would need the anti Run on valve, mine seems fine without it.

Terry

[sujitroy]

I have my mk1 set up intact and anything older than '75 in California is exempt from any sort of testing.

[trunt]

OK

That’s a surprise, here in Delaware we have emissions testing from 1968 on. Though due to COVID mine was not tested so I have 2 more years until I need to get it tested. However they only check exhaust emissions, the venting etc is not covered.

[Registrar]

Dear All,

As far as I am aware the venting was introduced to conform to the US regulations which existed prior to 1970 - but the regulations are not easy to trace and California was different to the other states. It was certainly and deliberately introduced to all US destined cars and was trialled on the US prototypes. It isn't about venting as such but about containing fuel vapours and not either venting them to atmosphere or allowing them to infiltrate the cabin of the car . They are fed through the small overflow tank and a piping system to the engine bay where they are captured in the charcoal canister(s). They are then gradually released into the carbs for 'burning' through the cylinders. Whether current regs do the same thing, or whether the original regs are now enforced on older cars, I do not know If it wasn't tested in Delaware I would suggest that this part of the testing system has been forgotten or that simple visual inspection to check the carbon canister is all that they remember to do nowadays.

Peter

[trunt]

Correct, it’s all through the carbon canister, both fumes and air intake to replace used fuel. they even vent the carb fuel reservoir to the canister when engine is stopped, when it’s running it’s vented to the air filter box where it’s sucked in to the carb inlet, that way no fumes escape.

Yes, The regs in force in the original build year are always used.


Delaware doesn't look for anything really, just test the exhaust emissions at idle. Which makes me think that the venting part was CA only. Sometime after 1973 (no more federal stags) they start testing at 2500 rpm or something like that and later they pressure tested the fuel cap. (Maybe the whole system as well?) Been through all of those over my 30 odd years here.. Nowadays with my modern cars it’s simple, they plug in, if there are no fault codes and engine light is off - it’s a pass!

Terry

[Registrar]

Dear Terry,

As I have said, the safety and emission regulations are not easy to trace but I did start to explain what I can understand in the November magazine.

One of these issues is the crankcase venting - through the small pipe on the top of the right hand cam cover. I bet nobody ever checks this nowadays but it was part of the US regulations for all new cars since the mid sixties. Much of the US regs were actually enacted in the 1970 Clean Air Act Amendments but were not enforced until the 1972 model year (as it was too late to change the 1971 model specs when the Act was passed) - Hence Stag had different compression ration for the 1972 model year but all 1970 and 1971 cars had the same basic engine as those in the UK. Hence, if you have a 1970 or1971 car you can pop the 146HP engine components in and use the car as it was designed to be used. The fact that all the US spec cars had the fuel tank venting arrangments and carbon canisters suggests strongly to me that this was already part of the US regulations when the car came out in 1970. Of course, what garages bother to check nowadays if there are no fault codes to look at, is rather up to them but, being in the States, you would be better placed to know - however, probably best not to dig too deeply into this sort of thing.

Best wishes

Peter

[trunt]

OK I don't see the magazine,

There's also the probability that Triumph built a "50 state" car, and some of the emissions equipment was required by CA only, not the other 49 states. As you say Its very difficult to find the regs other than the exhaust emissions requirements. In any case how the heck is an inspector going to determine what is supposed to be fitted on a car they see once every blue moon?

In most states the big changes of that period came in 1973 and 1975. The strange thing is that CA does not test pre-75 cars but Delaware does! LOL, Maybe due to a large Hotrod lobby in CA?

[Registrar]

Dear Terry

I think that you are probably right in querying how an inspector could be expected to know exactly what equipment was fitted on the myriad of different car models from fifty years ago. The easy one to check is the emissions as every car has an exhaust system and you just stick your thing up there and read off. Job done. It is those that are by far the most important nowadays anyway.

The big changes were for the 1972 model year - which is when the 1970 Amendments kicked in (and when Stag changed its USA engines to lower compression ratio and less power) - and 1975 when the next phase of the regulations were phased in - it is no real surprise that Triumph dropped Stag in the States at the end of 1973 as, despite what they said, they would have had difficulty in dealing with the 1975 model year emissions regs (for cars being built in the second half of 1974 for release into the States in October 1975) and there was a tightening up on body safety - hence all the rubber bumpers which suddenly appeared. Whether the rear petrol tank on the Stag would have passed the rear end shunt tests I am not sure. Notably, the E-type V12 was also withdrawn before the 1975 model year. What is not generally known is that in 1972 (I think that it was 1972 from memory) BL sent out two Marinas, an E-type and a Stag for the 50,000 mile emission tests round the roads of Warwickshire. These were all equipped with catalytic converters and were the subject of BL claims that they had solved the USA emissions problems. Although there was notable publicity for the send off - nothing seems to have been published about the results. Draw your own conclusions.

Peter