Completely removing emissions from a 74 B?

I did quite a few searches but didn't come across the answers I am looking for here.

I'm reworking a friend's 74 B and as I'm really only familiar with the mark 1 cars, I'm not sure what I can remove of the carbon system and the evaporative tank.

He long since did away with the air pump and components on the intake manifold. I have some questions about the following:

1. Can the evaporative tank be removed from the trunk and the hole to the gas tank capped? Does this screw up the venting of the tank? Can you overcome this with a different type of gas cap?

2. Anti-run-on valve and carbon canister: can they be pulled as well? If so, what to do with the two wires that run to the valve? Also, what about the venting of the HIF carbs that runs to the carbon canister? Can you remove that as well and cap them, or just run a hose from carb to carb?

Any tips and answers would be much appreciated! Now, back to garage to keep stripping this baby down for a repaint! ;)

Leave the canisters, they don't hurt a thing.

Left the carbon canister on mine. I like the looks. I think it also helps with overflow of gas, fumes, etc. The rail etc. I removed. Got some plugs on Ebay from someone to plug the holes in the block left from removing the old equipment. I think the trunk can is still there, too. Mine's a '74. Good year.

Do not remove the evaporative loss system - there is no reason to do so.

To completely remove the emission controls from a 1974 (18V) you will have to:

1) Remove air pump and associated plumbing.
2) Remove the injectors in the head. This normally requires removal of the head although some claim that screw extractors will pull them out from the top.
3) Change the pistons.
4) Change the camshaft.
5) Change the needles in the carburetors
6) Change the distributor curve
7) Change to the double row timing chain and sprockets (to correct camshaft timing)

You'll want to simply remove the air pump and plug the ports in the head. Don't need to worry about any of the cannisters. :)

Maury. Leaving the cannister, trunk catch can and anti run on valve in place and operation does make sense. The later cars didn't have any problems with overfilling the fuel tank and the anti run on valve does prevent dieseling which can happen with the later HIF carbs.

The side cover and float bowl venting system is effective and not very conspicous, so I'd leave it alone.

In answer to your question. Yes, you can cap all the tank vent lines, then just drill a hole in the cap.

Vent the carburetor fuel bowls to the ground, the same way the early cars were.

Fold back, insulate and tape the anti run on valve wiring. You can also replace the oil pressure switch junction fitting with one from an early car which doesn't have the port.

Again. I wouldn't recomend it. The stock setup isn't that ugly and difficult to take care of.

kelvin

Can you tell me why I shouldn't remove the evaporative loss system? And the car's been running for years without the air pump, injection rail and the ports are plugged, and none of that internal work was done to the engine. Why would all of that be necessary to just plugging the air ports in the head?


Anyway, I'm trying clean up the engine bay and covert the washer system from that hanging bag to the earlier washer bottle that mounts where the carbon canister is located. Hence my need to remove it.

Also want to clean up the trunk and would like to get that can out of there.

The washer bottle can be mounted to the back side of the radiator panel. The mounting holes for the bracket are probably already there. I know they were on my '74.

Maury. The reason for advising not removing the evaporative loss system is simply because it doesn't affect the engine's performance at all, and it does route fuel vapors and also overfilled fuel tank excess fuel effectively. The added bonus is an operable anti run on feature, that with some engines is really helpful.

I've been in the clean up camp too, and took all the stuff off my first 1973 MGB. Then had to deal with dieseling when I put bad fuel in the tank and also fuel running out of the filler cap when I overfilled the tank on a hot day.

My current 1970 MGB, has the cannister intact, but everything else (air pump etc) stripped off it.

It's not a big deal, you can go either way, but personally I'd look for another place for the washer fluid rather than screwing with a system that works quite well.

If all the stuff is in poor condition and would have to be renewed, then that's a different story.

Kelvin; thanks for that, that's what I was looking for. Gave me a great how-to on how to do it as well as telling me why I shouldn't. ;)

Paul: Thanks, I had forgotten that! My old 69 was set up that way as well.