DeTomaso Mailing List: February 1997, Message #50
     



From: MikeLDrew@aol.com

Subject: Tips to pass Smog checks

Date: Fri, 7 Feb 1997 08:35:00 -0500 (EST)



If you have a vintage machine and want to pass your smog check, here are

some tips:



To pass smog, I do the following;



Make sure the mechanical advance doesn't come on too fast, e.g about 30

degrees total at about 4,000 RPM with about 8 degrees initial timing.

Make sure the vacuum advance doesn't come on too fast, usually a few washers

under the spring (if the vacuum bellows is made this way) or a stronger

spring. Worst case, just plug the vacuum line during the smog test. Too

much vacuum advance will kill your chances. No vacuum advance also reduces

fuel economy and aggravates overheating tendancies.

Set the initial spark timing at 6 to 8 degrees

Get the main jets fairly lean, just short of lean/light throttle surge.

Set it this way after getting the advance curve fixed, not before.

New Plugs. Set the gap at about 0.048" (Yeeessss, I know, that's more

than the 0.032 spec.). A bigger gap helps combustion, but don't overdo

it or you get mis-firing. If you have a REAL ignition system, you can

go to 0.060" But a CD ignition sometimes aggravates smog behavior, even

with MSD; they don't like lean fuel mixtures.

Set the idle jets lean ... just before roughness starts (again, after

the advance curve amd timing is set).

Set the idle RPM as high as the spec allows.

Go drive it on the freeway for awhile to blow the carbon out of the chambers.

Go straight to the smog checkout place from the freeway.



If the engine is really tired, you've had it. there is nothing you can

do to salvage it ... it's a gross polluter. It's gotta be overhauled.



After I do all this (and pass, of course), I set the idle RPM back where

it belongs, and enrichen the idle screws about a quarter turn. Maybe set

the static ignition timing to 10 or 12 degrees.  The vehicle should run

fine, but it won't have the snap it has with a more agressive tune-up.

But the gas mileage is respectable this way. And, it runs OK on the street

and it won't pollute much either.



As a reference, my '67 Shelby GT350 passed just fine last August under

the real smog II environment. The engine had ~ 2,000 miles on it and was

tuned as stated above. The only critique of its smog check was my main

jets were a tad lean. Cam by Elgin, 270 degrees intake and 260 degress

exhaust at .050 lift. Not a race cam, but not a mild street cam either.

More agressive than the stock HiPo cam. Otherwise a stock 289 HiPo. No

air injectors (a Texas Car) against the CA air injector smog check

specification

(they don't give you any credit for out-of-state cars).



If this isn't enough evidence, my Jensen-Healey track car also passed

... with Webers on it! Last September it did this. SMOG II again. I won't

leave it that way for the track, of course.



My 65 352 FE engined truck passed this way too, way back when when '65s

required it.



Hope this helps.



Don Wollesen



| Distributed by the norcal-saac mailing list. Send submissions |

|    to norcal-saac@norcal-saac.org, subscribe/unsubscribe      |

|    admin requests to norcal-saac-request@norcal-saac.org.     |