smog while running in rebuild, or wait?
 

I need to have a smog test before my car can be registered after 1.5 years of non-op (83 SC, 155k miles). I just got it back together after taking it down to the crank and refreshing worn stuff. Passed easily last time (when I purchased it). Now it has 964 cams but is otherwise stock (cat w/ O2 sensor).

I'm more or less following the break-in procedure in Wayne's engine rebuild book. So far I've driven only 15 miles. It runs great.

So can I get it smogged soon, or should I wait until things are broken in more? Will Red Line engine break in additive affect any smog readings adversely?

Also, should I get a CO meter and set up the mixture prior to getting the car smogged, or should I assume because it runs well the mixture is at least in the neighborhood?

Thanks!

Find a shop that will understand your situation, and that does re-testing for free should it not pass.
-C

No, you should drive the car under varying loads and throttle openings for at least several hundred miles before thinking about a smog test. You should do an oil change the day before the test and drive the car for at least 10 miles to heat up the oil. You will need to reset the mixture after a rebuild. You should learn to set up the mixture with a dwell meter and the timing to find the best compromise for smogging the car and/or road performance. They are usually two different settings, especially if you want the best cold start drivability.

My inclination is to drive it for a couple hundred, ditch the oil and additive, then take the long way to the test. As for the mix, can I set that with just a dwell? (I understand the dwell is at least part of the setup for lambda. I need to read up on cis....)

I tested my 930 engine only after about 150 miles or less, can't remember for sure, it was right away. Not sure it the na cars are the same as turbo but I adjusted co and idle lean just to make it easier to pass and it did easily. Then readjust afr back to normal so it runs and starts normal.
I didn't even have a cat.
All the horror stories had me squirming big time. No problem. I have an afr gauge though which helps. Good luck.

Thanks, that's comforting! Thinking now when the time comes I may run down to the shop and have them use their gas analyzer, then recheck the ignition timing and idle. Then do it again after the test. In the meantime, I need to drive it for a bit...

Thing about the 964 cams is that mileage drops 5 mpg or so from SC cams. Where do them HC's go? Do they all get burned efficiently?

You may have to utilize some tricks.

Talking out my you-know-what here but maybe a morsel or two worth considering...

Use a gas that burns quick - no premium or midgrade

Retard timing a touch

front of cat at idle on some recent cars I tested (Harbor Freight laser thermometer) was 250-ish. Rev it to 3000 rpm's for ten seconds and the temp was 400+. Stays hot for quite a while. Will help the scrubbing reaction.

Everything working / no vacuum leaks / usual due diligence.

CO dialed in a little lean with dwell meter or a real exhaust sniffer.

I like what Freeborn suggests. Find the wrench that has some compassion.