End of saga. I took my MGB back in for the smog test today, it passed. How
did I get it to pass?
I went to a leaner jet in the Weber DGV, adjusted the valves, replaced the
vacuum advance (actually installed a spare dizzy), moved the vacuum supply
from the intake to the carb, put on a new dizzy cap, rotor and points,
leaned the idle adjustment screw all the way, and timed the engine.
It actually failed the first time I was there today, but I asked the guy
what his recommendation would be, and if I could do it right there. He
suggested retarding the timing a "hair" (which would make the idle fall off)
and then adjusting the idle up. I retarded the timing about 3 degrees and
increased the idle to 1200 rpm. Oh yeah, and paid another $15.00. Then it
passed.
I don't have the results of the test with me but I am just glad it passed.
I want to thank all the "listers" that helped with this.
Larry Hoy, Denver, CO USA
1970 MGB Daily Driver ~ 1967 MGB Vintage Racer ~ 1969 MGB Undergoing V8
conversion
http://home.cwix.com/~larryhoy@cwix.com/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> -----Original Message-----
> From: owner-mgs@autox.team.net [mailto:owner-mgs@autox.team.net]On
> Behalf Of Larry Hoy
> Sent: Saturday, July 10, 1999 4:44 PM
> To: MG List
> Subject: 1970 MGB Smog
>
>
> I took my 1970 MGB for an emissions test.
>
> It passed CO and failed HC
>
> At idle CO was 4.96, and at 2500rpm it was 2.67, limit is 5.5
>
> At Idle HC was 2000, and at 2500rpm it was 2000, limit is 1000
>
> I have a Weber downdraft carb; and a 25D distributor, with points. No air
> pump.
>
> I did nothing before the test (like tune up, etc)
>
> I now plan a tune up.
>
> My question is about the vacuum advance unit. I don't think it
> is working.
> I removed the distributor and sucked and blew on the vacuum advance, no
> movement. I noticed an air sound coming from where the flange
> [the one the
> hose slips over] and the vacuum advance unit join, I assume that's bad. I
> also noticed oil coming out of the vacuum advance unit. Any comments?
>
> Maybe a little education on HC and CO emissions might be in order, any
> experts out there?
>
> Thanks in advance.
>
> Larry Hoy
> http://home.cwix.com/~larryhoy@cwix.com/
>
>
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