So the 318 is running! No magnum heads, just mid 80’s heads with a quick lapping of the valves.

For a refresher, it’s a stock motor freshened up. New rings, bearings, etc.
New Comp Cam XE250H (.432/.444 lift; 206/212 duration @ .050)
Edelbrock 1406 (600 CFM) carb.

I am very happy with how it drives. It pulls a lot harder at WOT, it sounds more mellow (yet doesn’t seem like it’s fighting itself). It still warms up quickly under driving conditions due to the lean carb (I will change jets soon) and 190 degree thermostat, but it seems to be doing ok so far. There is a small surge at steady RPM’s while driving though, but you have to look for it to really notice it.

So now, I have a question about the poor idling quality.

It runs great in Park or Neutral, but when I put it in gear, it runs rough or dies. Sometimes the RPM’s will drop and it will sputter for a bit then die.

15 lbs of vacuum at idle. In gear it drops to 12 lbs. It holds steady until it sputters and dies. In “Park” the needle doesn’t even move. The initial timing is 16 degrees BTDC, and I am unsure of total at this time because my damper is not marked. It does increase with engine RPM though, I made sure of that.

I also noticed the PCV valve was making noise, almost like a quiet tin can rattle or something. When I pinch the line or plug it off, the sound goes away. I tried 3 different valves until I put the original one back on.

Another thing I noticed: I disconnected the PCV line so it was just sucking air. It is a constant sucking, no pulsing noted.

However, the RPM’s increased quite a bit. I turned the throttle screw down and it seemed to run better at idle. I put it in gear and it didn’t die as quickly. It ran much better.

The idle screws are turned 1-1/2 turns out. This seems to be where it likes it the best right now.

So….I have another 1406 carb I can try running to see if the carb is the problem.

I know my carb is jetted lean, but this should have nothing to do with the idle problem. I sprayed out the idle screw holes with carb cleaner, but I didn’t see much change.

Any ideas where to start here?

Thanks guys!

Eightlitermopar

Also, I have considered the vacuum leak thing, but why would it run BETTER when I create a vacuum leak by disconnecting the PCV line?

hmm....

Adjust the idle mixture screws while in gear.

thanks for the replies...I won't be able to mess with it much for the next several days, but I'll keep you guys posted.

I don't have a tach right now, but I can get one so I can have some better answers.

This car was due for saftey/emissions back in April, so I'm just hoping to get it running right before I get pulled over by the cops!

eightlitermopar

The PCV valve is supposed to close at high vacuum, like at idle.

Opening that port to atmosphere leans down the mixture.

On a normal carb, the starting point for idle mixture adjustment is 1 1/2 turns out from lightly seated.

You are in Salt Lake City, Temple Square is 4320 feet elevation. (On a Holley carb I'd jet down four sizes.) That means your A/F ratio is going to be rich with a sea level carb. You could probably run the Edelbrock electric choke carb as out of the box, as it is set up lean from the factory. If you are setting idle mixture, you will probably go in 1/4 turn or so from the starting point.

Have you set your idle rpm first, then set idle mixture, then reset idle rpm, then reset idle mixture? It has to happen a few times.

If you have to pass emissions, you won't be able to run too much initial advance, at least I haven't been able to.

R.

Put the carb back to stock factory settings. Surging at cruise is lean. With 16 degrees initial and a stock distributor WOT is way over advanced,don't spend time at WOT unless you get the mech advance fixed.

Those 1406's are definitely way lean out of the box. Mine was so lean that it had me chasing a ghost, thinking that my fuel smelling car was rich, when it was actually way lean. If you take a look at this, http://vb.foureyedpride.com/archive/index.php/t-74438.html , he makes some interesting points that others tried and had success with, and it made sense to me, so I tried it. Boy what a difference. Basically it says that since the 1405 & 1406 are the same carb, other than one being manual and one being elec choke, that you should just use the 1405 tuning chart and calibration kit. The 1405 is factory performance tuned and the 1406 is economy tuned (read LEAN). IIRC 1 step Rich on the 1406's economy chart was still 2 steps lean on the 1405'a performance chart. It worked wonders for my car's time.

roe

ROE, the OP lives in Utah and the elevation is 4300 feet above mean sea level, something like that.

SO, the 1406 is lean out of the box AT SEA LEVEL. At 4300 feet it should actually be pretty close to right on, as it came out of the box.

R.

So I took a couple of minutes this afternoon to poke around on the car. It is currently 100 degrees under my carport, so my time was limited.

Anyway, I checked the fuel pump. Rock solid 7 lbs at idle or revved. I changed the fuel filter. The old one has no restriction, but I changed it just to eliminate options.

However, when I did this rebuild, I didn't pay much attention to the distributor. At the time, I just took it out, cleaned it up on the outside and put it back.

The cap and rotor are about a year old. It is a stock 44 year old unit with a pertronix ignitor kit put in. This was installed before I bought the car.

Today I noticed that the inside of the distributor has a lot of surface rust! I sprayed some WD40 on it and fired it up. It doesn't want to die at idle any more, but it lugs down like it is trying.

I haven't actually driven it yet, but I think I may have found my can of worms.

Could corroded distributor internals cause the problems like I was experiencing? Anyone else have similiar experiences with something like this?

Thanks!

eightlitermopar

P.S. Oh, and I do plan on turning down the intial timing as well.

Here is a picture. Do you think this could be the source of my problem?

eightlitermopar

Another picture of it disassembled.

I found this in the bottom of the distributor. What is it? Is it important?


I have very little experience with distributors....so this is all new to me.

Is that a leg of the triangle "snap ring"

2 things to check,

1. make sure your distributor bushing is good. the plastic gets hard and then cracks and breaks. i usually replace them with an aluminum pc. this stops the end play of the distributor and needs to be snug to only allow a few .002-.003 of movement.

2. rust where your seeing isn't critical. sure it would look nice shiny, but is the pertronix moving freely with the vacuum can? is the gap of the reluctor changing as the engine surges? make sure the gap is about .006-.008

3 make sure your weights can move freely and are not getting bound up. i always clean these and grease the pins so i now they move. on the pins you want to use a lithium grease not something heavy like wheel bearing grease.

Thanks for the replies. I took it apart and the mentioned stuff looks good. There was some rust everywhere and I suspect something was binding or not working right.

I gave a good dose of wd40 to everything and reassembled. It seems to idle better.

I set my inital timing at 2 degrees advanced. (I know stock is TDC), but I have never ran it this low since I have owned it. I'll use it as a starting point. It does not die at idle anymore....yet.

Today was 104 degrees when I got off work, so I didn't drive anywhere. Simple start and adjust.

Tomorrow morning I am planning a drive before the sun comes up. Keep your fingers crossed!

So the drive went great. No problems. No full throttle knocking or pinging.

The motor warms up quick and stays steady (thanks to the new aluminum radiator).

The motor is not a powerhouse, but it has consistant power and pulls hard without surging or cutting out (like before).

I got home and pulled it up on the ramps (to let it cool, then I have a rattling exhaust to adjust).

Pulling up the ramps I had it half throttle just to get it up the ramps! LOW POWER!

So, I took the distributor off and apart once again. I dug out a spare 318 points distributor and stole the triangle "snap ring".

My theory is that this missing part has been causing me grief.

Anyway, The snap ring is restored to where it should be and I have reset the initial timing to 6 degrees advanced (for high altitude driving). After all this trouble, I think I may have cured my problem.

Now I might be able to drive this thing this summer!

eightlitermopar