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MG MGB Technical - Emission Test

Coming up on that time again! 80MGB, Illinois. "Just" passed last time; comfortable pass margin the time before and complete initial failure the time before that. The less the preparation, the better the score!

Should I request the high speed portion of the test be performed with the overdrive IN?

Besides reinstalling the converter and airpump, I prefer not to spend a lot of "tuning" time out in the cold.

Apologies for not supplying specific previous results. Maybe I'm getting too old/lazy to deserve British cars?

Jerry
Jerry White

Don't use the OD. Not too familiar with Illinois smog checks - in California they're rolling on the dyno at something like 25mph, and I can't imagine that any state would have a rolling road test at such a high speed that you'd need the OD on. But even if they do roll it at freeway speeds (not likely) so long as you're running original Stromberg carb you probably want the OD off - the Strombergs usually mix OK at 2500-3500 rpm, but anywhere near idle things aren't so stable.

Double check that the choke is not malfunctioning, and check the mixture if you have the facility to do so.

Naturally, you want to change your oil, check your air filter on both the carb and the air pump, make sure the pump is crankin' out air and the cat is good and hot, and have the car fully warmed up before testing.

A properly tuned 77-80 MGB in good tune with working cat and air pump should be able to turn in surprisingly low numbers - at 2500 mine turned in 5 ppm HC and 0.00% CO. It has also once been pegged as a rolling Superfund site - minor stuff, you know, one misadjusted valve or whatnot, can throw a Stromberg so far off it's kinda scary. But if you get it running smoothly on all 4 with no sputtering or missing, and the cat and air pump are OK, you'll do just fine.

Best of luck on it!

-sam
Sam

Thanks, Sam. I appreciate the tips, and also the reassurance. The dyno test here approaches highway speed, and I just wondered if the lower OD rpms could make a difference. Apparently that would be the least of the problems - if there are any.
Thanks again.
Jerry
Jerry

Jerry,

Interesting that Illinois requires a rolling test for your car, as I doubt rolling tests were required when your car was new, were they? I would think that as Sam suggests a mechanically sound late model "B" with all of the components in place should perform very well.

Do you have a program in Illinois for classic, or antique cars? Here in Delaware we have an antique tag program that requires a single safety and emmissions test. If passed it eliminates future testing, only an annual fee is required. We are limited to the requirements set by our insurance companies.

Regards, and good luck with your test,

L.C. '74 B/GT
Larry C.

Thanks, Larry, for the good wishes.
8-9 years ago when I got the car, emission testing was done with a tach pickup on the hood and revving the motor to various "speeds" indicated on a monitor and holding until the technician said stop, then going on to the next "speed" (if nothing had fallen off or was boiling). Exhaust gasses were analyzed to meet specs -- specs an MG couldn't meet when new, and I learned an MG had never passed, at least at that location. Then things got more uniform.

Illinois testing is in the Chicago and maybe other metropolitan areas only. Borders are zip codes, not counties or towns.

Later it got more sophisticated. Newer cars are tested with OBCII readings, but older ones 67-95 or so require dyno testing at speed. A large fan is wheeled into position in front of the car to cool it. Only the techs, not the owners, drive the cars now and one can only wonder how that came about!

There is, of course, a cursory visual inspection and the MG gas cap (simple, stock and original) always requires the tech to contact a supervisor and they both look at it, look at a book, then put it back on. I've never asked.

We have a test-exempt 25 years or more Antique Auto plate, but it's somewhat restrictive i.e., car shows, parades, test drives, etc. Frequently abused I'm sure.

All said, I suppose the test is necessary, and the testing realistic. Now was that the red or the yellow bottle of Heet.....

jerry
Jerry White

Jerry,
I had my '77 B tested a couple of weeks ago. It was not put on the rollers, just the tailpipe sniffer. Passed OK. A couple of more tips, clean or replace your spark plugs, fill up with Amoco (BP) premium, adjust your idle to about 950 RPM. If you are going to fail it will usually be at low RPM's. I am not sure but have heard that you cannot be over 1,000 RPM's for idle. I passed on the low speeds so they never went any further. Also, you can ask to sit in the passenger seat now during the test. Good Luck!
Mike Crowley

Thank you, Mike.
Now that you mention it, I had another car tested a couple months ago, and it tested so fast they may not have used the high speed test on it either, but it seemed like they were cross country touring in the car ahead of mine, and the owner was really getting upset.

Last year they tested both high and low speeds on the cars I had tested (not the MG).
A technician there said the faster it tests, the better the results.

I have declined being a passenger in the test since this became an option. Pretended cool indifference; maybe whistling in the graveyard? Probably less stressful. For both of us.
Jerry

This thread was discussed between 05/10/2004 and 13/10/2004

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