Dan,
If I interpret you question marks correctly, it sounds like you have found
the vacuum leak - - through the PCV valve (no guts??). Maybe the DPO took
the guts out so it could keep up with the excessive blowby (I'm assuming
four stars worth of pissed off is excessive). If the vacuum is 11 inches
of mercury (not lbs), this is pretty low and would explain a rough idle.
This vacuum level could be normal for a really big cam. If it is 11 psig
(not normally measured in these units), then this corresponds to 22 inches
of mercury which is very good. Below about 16-18 inches is where the idle
goes from smooth to lopy. You should hook up the vacuum gauge again and
advance the ignition until you get the maximum vacuum, then readjust the
idle screws. Set them both equal (1.5 turns to start) and adjust both equal
amounts until you get the best idle, then open each one up a tad - - just
before the idle gets perceptibly rougher. Recheck the spark advance again -
- just enough advance to get the best vacuum, not more. Get a timing light
and measure what the advance is, both at idle and at about 3000 rpm, or
wherever the maximum advance occurs. This can vary a lot and what is best
depends on the characteristics of the motor. Typically, for 289 Windsor
heads, between 12-16 degrees initial advance and between 32-36 degrees
total and all in by 2500-3000 rpms. (I'm assuming a mechanical advance on
the distributor which is much simpler to adjust.)
OK, so now you've done all of this and either a) it runs really bitchin
(not likely) or b) it runs better, but still not great (more likely). In
any case, get a proper PCV valve and at least maybe you won't burn exhaust
valves from running too lean on one or two cylinders. Then, maybe get a
breather cap with a vent hose fitting and run a hose to the air cleaner.
Now, one way or the other, the blow by will have to go through the motor,
but at least this way it won't cause you idle to be so rough and possibly
damage your engine. Assuming the latter scenario, I would check compression
on all eight cylinders; what is it, and are they each within +/- 5 psig or
so. You can get tricky and do leak down tests to determine if it's valves
or rings/guides. Based on what you've described, you are probably going to
have to start saving up for a major overhaul in the not-to-distant future.
I hope not, but the bad signs are there.
Hope this adds something useful to what others have contributed.
Good luck,
Bob
At 07:55 PM 9/16/98 -0400, Alicia wrote:
>thank you all for the info on adj and things to look for. wired choke and
>adjusted cold now i have to let cool to see if it works right. with engine
>up to temp i started to adjust screws to about 1 1/2 turns. still runs
>about the same. so i started looking for vac. leaks. now when i bought the
>car, dpo said that engine had been camed and raced buy his dpo, so rough
>idle didn't bother me.( i also bought the car not running)
>on heat block under carb, vac hose go's to pcv valve in valve cover, i
>pulled this hose and hooked vac gauge there. start engine smooth idle that
>i never had before?? pulled out pcv valve no gutts? but now i get oil smoke
>blowing out oil fill cap, not a lot but enough to **** me off. also there
>was about 11 lbs of vac. on gauge. so what do i do now? any suggestions?
>thanks disappointed dan
>
>Alicia & Dan
>Windsor, NY
>
>B9471431
>B395017486LRX
>B395006486LRX
>
Robert L. Palmer
Dept. of AMES, Univ. of Calif., San Diego
rpalmer@ames.ucsd.edu
rpalmer@cts.com
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