|12-06-2012 08:30 AM|
Ok well, that gives me some ideas to start with, thanks for all the posts guys, very helpful. I should be able to put a wrench to it this weekend. Maybe I can figure out a way to get a timing light on her too.
|12-05-2012 11:39 PM|
|12-05-2012 10:02 PM|
Cobalt- Yes, I'm mindful about fuel pressure. I have a pump that only puts out 6 psi and a gauge on the fuel rail, so I'm pretty confident there.
Fbrid- Yeah I was thinking along those lines too, and although I have more tuning to do it does seem as though the difference between idle in park and idle in drive is vast. I guess that would point to a difference in timing at those two points. Lousy part is my balancer is hidden by the stupid long water pump so I really can't get a good idea about the timing. I set it at 12 and have been going by degrees of distributor movement, where 1=2. I'll look into the timing, but I'm not sure if I could even get it to start without a lot of kickback at 24 degrees initial. Seems like a lot.
|12-05-2012 10:01 PM|
|cobalt327||If you want to check to see if the PV is open during idle, turn the idle mixture screws all the way in (count the turns so you can return them after the test). Then start the engine. If the engine won't idle, the power valve is not open.|
|12-05-2012 09:03 PM|
If the fuel pressure is too high for the needle and seat, the bowls can overfill after the engine is shut off while there's still pressure in the fuel line. If this is happening you should be able to run the engine, shut it off, then wait a few minutes until it starts to seep before remove the sight plugs to see if the fuel level has risen a lot. If you have side hung float bowls connected w/the balance tube, removing just one plug will tell the story.
This doesn't necessarily mean the fuel pressure is too high, just that it may be too high for the needle and seat/float the way things sit. The float might be heavy or the N&S assembly worn or has a spec of dirt, etc. fouling it.
See what that tells you, if anything. If that's not it we'll keep trying.
|12-05-2012 05:58 PM|
|RWENUTS||I had the same choke problem on a 3310 on a built 350. I pulled the choke assembly apart and ground the cam that the high idle screw is adjusted on to so that I got more rpm with less choke. Basically made the curve flatter. You might need to experiment a bit.|
|12-05-2012 03:38 PM|
Perculation or boiling the gas in the carb in the middle of december is very unlikely. It is also not that common of an issue. I have only seen two cars that had that issue in my life of hotrodding. Cant imagine that is the problem here since the engone is cold and wont stay running without the choke for 20 minutes.
More of a problem with super high compression engines that have to idle for a long time. Usally a little air under the hood cleans them right up.
That being said spacer wont hurt.
|12-05-2012 03:26 PM|
Had the same type issues with my big pontiqc and edelbrock carb. Manual choke and auto. Once it was running but still cold it was real touchy to find the right place for the choke to sit. In out on off it was never happy in one spot for more than a minute or two.
Finally called edelbrock and they said its normal and offered a new linkage that would give me better control. I decided to buy electric choke it worked like a charm and never needed to touch it again. Just got the kit plugged it it and weverything worked. From the first turn of the key. Also noticed choke would be working for several minutes after the engine was warmed up. And always adjusting a lot more than i wanted to try to do while i was driving or sitting in the drive waiting for it to warm up.
After the electric choke i could start the car and run back in the house and wait til the rpm went down and new it was warmed up and have heat. Before i had to sit and baby the car or floor it out the drive way to keep it running in gear. It was also annoying in summer with the manual choke.
Get the electric kit and be done. You will be happy you did.
Fix the fuel leak asap. Small problems can get much bigger if not corrected right away.
Dont screw up the tune of your warm carb if it runs right. You can try some more timing but you will be taking it back out come summer. Best to reslove the issue not the symtoms.
|12-05-2012 03:03 PM|
Thanks for the comprehensive reply. I'm not entirely sold on the percolation issue, especially since I get the problem even only running a couple minutes. That said, I certainly do have an insulator I could install and it costs me nothing to at least try it!
I run ported vacuum advance, and have an adjustable can. You never know exactly how much you're getting from that thing, but I set it just under where it was pinging before I took everything apart. Yes, I am running a thermostat too.
Initial timing I have about 14 degrees. I'm hesitant to add more than that, but I guess I could try. My mechanical is limited to I believe 22 or 24 additional degrees (Moroso HEI replacement).
So I'll try adding in a couple of degrees, insulate my carb and give it more fast idle. As I'm driving it really does come alive and I like where its set now. I have to get it down to the strip and play with timing to see where the power is at.
|12-05-2012 11:19 AM|
Agree also on using an insulator of some sort, but don't unnecessarily lower the float level. This will delay actuation of the various carb circuits.
Be sure the idle mixture screws are adjusted to give the highest idle speed or highest vacuum reading, w/the engine fully warmed up- like after a 15 minute drive.
As for the choke, you need to readjust the fast idle screw so it'll raise the idle more w/o needing to close the choke more. This will keep the engine from loading up from too much choke and will hopefully allow it to go into gear w/o stalling. BUT, there's also a possibility that it's just going to take longer to warm up. You are using a thermostat, right? No 'stat makes the warm up take a lot longer than it should.
Another thing that can help cold drive-off is to give it enough initial timing. If you add initial you'll need to take out some mechanical advance to compensate, otherwise the total timing will be too high.
If you're using ported vacuum for the vacuum advance, switching it to manifold vacuum (and resetting the idle speed and idle mixture screws) can help. In this case the initial and total timing does not need to be changed.
If you're not using a vacuum advance, you should seriously consider using it.
|12-05-2012 10:24 AM|
Holley 4160 (3310-S) continuing issues
Here is INSTALLATION, TUNING, AND ADJUSTMENT Manual from Holley. http://www.holley.com/data/Products/...9934-3rev2.pdf Some solutions for fuel leaks after the engine is shutdown. This is usually caused by percolation. This is when the engine is shut off and the engine temperature rises it causes the fuel to boil in the bowl and leak out of the boosters. There are a couple of things you can do to cure this one is make sure the fuel level is not too high. You can also lower the fuel level about 1/8" below the sight plug hole and this will cure it sometimes. The heat from the engine will rise into the carburetor sometimes and will cause the fuel to boil. Installing a phenolic heat spacer between the carburetor and the intake or a heat shield can cure this. These parts will prevent heat from getting to the carburetor and boiling the fuel. To fix your choke you can replace the manual choke with this electric choke conversion kit.Holley Performance Products Choke Conversion Kit*45-223.
|12-05-2012 08:30 AM|
Holley 4160 (3310-S) continuing issues
I've had a couple of issues with my Holley for quite some time now, and have really just now gotten around to addressing them. Being that its cold out this way, I'd like to be able to use my (Manual) choke, but it's never given me anything but grief. At a certain point it the linkage travel, it will raise idle and and keep me from having to feather the motor, but it will still die if I try to put it in gear. Any more travel and the motor just loads up, lots of black smoke and chokes itself out. So my only solution is to sit there feathering the thing for probably a good 5-10 minutes until it wants to run.
I have a relatively big cam, 280h comps in a 383. I wonder if I'm dropping so much vacuum that the power valve is dumping during choke? I just rebuilt the carb, so everything is nice and fresh. Really didn't even need it, but this problem has preceded the rebuild.
The other minor issue is that there is a tiny fuel leak which I think is coming from the rear bowl. It doesn't leak while the car is running, but after its off and sits for 30 min to an hour, a very small pool of gas builds up on the passenger side intake, right under the choke linkage. The leak is so slight its almost impossible to trace. The carb gasket is moist only from the point of the leak or so to the back of the carb, not on the front, which makes me think it must be coming from the rear bowl.
Any ideas are appreciated, thanks guys.