Riz, Steve,

         Just a thought. With the addition of the pcv to the triple carbs, you might want to close down the idle circuits and shut off the end carbs at idle all together. All three plus the PCV working is a lot of air. It would be a lot easier to work with one (center) carb because the velocity of the idle air and fuel will be higher. I didn't see a mention of which distributor you're running, but following Steve's instructions on a later distributor (not a Loadamatic) will help you a bunch. you might need to dig up a Crane adjustable advance can and limit the mechanical advance so you can use 12 degrees or so initial, without the vacuum hooked up.

     Another issue will be the tendancy for the engine to "hunt" with straight vacuum. As the rpm drops, the advance drops, causing the engine to drop more RPM. then it will pick up etc.

Frank/Rebop

Bristol, In ( by Elkhart) 

Riz - Are you running the Mallory distributor (p/n 3738701)? Their info says that the "standard" (01) ignition set-up is 24° at the crank - so your outfit would probably be OK with 12°-14° for an initial setting at idle. That would be 36°-38° total. Mallory has an advance curve kit (p/n 29015) that will let you tune the curve - and quite a booklet about how to do it. You should probably shoot to get it all in by 2500-2700 rpm. The directions for the curve kit are on the Mallory site and worth looking at regardless.

Frank is right - there are some specific things to know about the trips - I haven't ever worked through a set before and don't have all of the straight skinny. But....there are several threads on this forum that have dealt with all sorts of issues with the elimination of the end carb idles - use and non-use of power valves, etc. So do a bit of digging around.

Where are you taking the vacuum for your PCV - it interests me that it rattles. That would indcate you have fairly low vacuum at idle - which you shouldn't.

 
 Steve Metzger       Tucson, Arizona

Steve,



Awesome info that is the distributor I am using. I will have to research that part number. Might be quite a journey. Quite honestly I have never really gotten into changing the advance curves a whole lot, but I think you may be right. I did have to add to the timing to work with the new trans. I will wager I have too much initial and idle timing, which could explain the hard starts and poor idle quality under load.



I do have the idle circuits and pvs blocked on the otters on the 3x. I also upped the jets on them 4 sizes to 56 to compensate for the lack of PV.



The PCV is dumped back into the rear of the valley pan. I had to add a new 90 deg port and bend some aluminum pipe to work with the new manifold. The rattling is the valve itself running back and forth. I bugged me for a while, and thought I had something spinster going on. But there are no real vacuum leaks, I also though I could have baleen losing it through the bottom end, but the engine has absolutely zero smoke, and no signs of leaks or leaks out the bottom.



Kinda bugs me that you are worried about it I just chocked it up to new set up differences and dismissed it. What are you thinking?

Mike Rizzo

1963 F100 "Rudy"

Daniel Island, SC

An observation most modern engines have a sealed crankase. The dipstick and oil filler are sealed, air tight. Is it possible excess air is coming in through the oil filler breather and dipstick? I was going to seal these openings on mine.

I had the same problem initially with my PCV-rattling like crazy at idle.There are a couple of issues when dealing with different PCV valves.The size of the orifice and the spring pressure which works against engine vacuum to open the valve.At idle the valve should be closed or close to it allowing minimal air to enter the carb.Different valves have different spring strength keeping the valve open.The 4 cylinder PCV has smaller orifice and I guess a lighter spring so it is held closed at idle.The 302 valve was opening and closing rapidly at idle causing inconsistent mixture and the rattling noise.Changed to the 4 cylinder one and problem solved. 

  

I am thinking I have partial issues of all the above. In addition to a small exhaust leak. I am going to have some quality time in the garage this week while we are getting all of this unseasonably warm weather. Figure I will start with the timing and idle and see if that helps the vac. Then on to checking vac at idle and maybe digging more into the PCV.

Mike Rizzo

1963 F100 "Rudy"

Daniel Island, SC

I had the same idea, since that air is unfiltered/dirty. But, crankcase pressure at high revs always pushes the dipstick out of the tube a bit, and too much restriction on the breather/filler usually causes oil pumping.

6 VOLTS/POS. GRD. NW INDIANA

There were "sealed up" systems on several vehicles I've owned - where the PCV is taking "suction" air through the valve from the valve cover - and the sump intake "breather" is getting its air from inside the air filter housing. At lower rev's the PCV is sort of "sipping" air out of the crankcase - but if you get on the engine really hard and fast - and blow-by overpowers that volume by some amount then the "overflow" gets taken directly into the carb.

 
 Steve Metzger       Tucson, Arizona

Ok played a little with the timing and got it set at 12 deg. Helped the idle but it still acts like a vacuum leak someplace. The PCV is still rattling. It starts up but needs some throttle play until warmed up. I am working on rerouting the choke cable so that is pretty normal. But after warm up it still is hard to start. I am running out of places to look for a vacuum leak. I have a new vac modulator on the trans so that should be ok. Very little vacuum pulled from the engine. Just PCV and trans. So I am thinking that if the PCV went bad or as mentioned is opening too light to go there first. The only other thing I can think of is an internal carb leak and quite honestly I am tired of tearing them down.



What do you guys think go for the PCV first at least to eliminate that and then move on, seems like the cheapest fix. I had a little déjà vu when one mentioned that the engine is acting like running on the PCV alone. Granted I have 3 carb openings but it does act like it could run just on the PCV alone.

Mike Rizzo

1963 F100 "Rudy"

Daniel Island, SC

Riz - Seems to me you ought to just start plugging things until you find the culprit!

Bagging the two end carbs - plug the PVC line - that sort of thing should begin to sort things out. I had an old four barrel carb I bought one time that pulled lots of air through the (very) loose butterfly shafts. 

 
 Steve Metzger       Tucson, Arizona