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Topic Review (Newest First)
05-14-2009 07:23 PM
bubbahotep
Quote:
Originally Posted by cobalt327
Glad you're on the right path.

Just don't forget that by changing the rear blades, there may be need to readjust the idle mixture screws. They should be adjusted first, then the curb idle speed screw after.
I believe I did that. I turned em in with my current settings until I almost got a stall, then backed out 1/4 turn and then a little bit more as someone had suggested (both sides). Highest vacuum I could get. From there I corrected my idle rpm with the IDLE SPEED screw and left the secondaries alone

Again, thanks a lot for the help to everyone with an opinion or suggestion. Im sure its not perfect but it was SURE as hell way way wrongly adjusted when I made the post looking at the spark plugs. At least I have a good starting point for finer tuning.
05-14-2009 06:56 PM
cobalt327 Glad you're on the right path.

Just don't forget that by changing the rear blades, there may be need to readjust the idle mixture screws. They should be adjusted first, then the curb idle speed screw after.
05-14-2009 05:01 PM
ericnova72 The difference is that the secondary just has a constant discharge idle feed, where as the front is adjustable with the mixture needle screws and this is what the carb is intended to idle on. I wouldn't worry about having adjustable rear idle mixture, sounds like you have it where it needs to be now, it just needed the correct balance.
05-14-2009 03:34 PM
bubbahotep The results:

I backed off the secondary opening as suggest and raised the IDLE SPEED screw to compensate. Surprisingly it gave me a cleaner 800rpm idle and Im quite happy. I pulled the carb off to see how the openings looked

I have .040 (roughly) opening on that opening which is still somewhat square and I no longer have that larger round pinhole exposed which ISNT supposed to be exposed anyway (from my original pics)

If I did try to put in more secondary opening then rpm goes up but I get a choppy idle. If I leave the secondary as it is, and I increase the IDLE SPEED instead (opening the primary side) I get the same increase in rpm but totally smooth (as someone suggested). Is that because the primary is also dumping more gas along with the air whereas the secondary is air only? Why such a difference between opening either of the 2 sides?

Would those profrom adjustable secondary metering blocks give me more adjustable results? Or other brand? This carb has no secondary metering block as I mistakenly thought it did. While Im very happy with the results at this point I wouldnt mind screwing with even more crap and adding bells and whistles
05-14-2009 12:34 PM
cobalt327
Quote:
Originally Posted by bubbahotep
Oops, I'm wrong. Just looked at a photo and the rear bowl is straight to the main body. My error. I could have sworn I had 2, dreaming I guess

1 block
No biggie- this just makes it a bit of a beach to tune the 2'ndary jetting.

There are different 2'ndary plates available, you can modify the existing plate w/a pin vice (tiny twist drill bits w/a holder)- and there are ways (if needed) to convert to a 4150-style so as to have removable jets like the primary side.

In most cases, these 3310's are good carbs out of the box, requiring mainly primary jetting and accelerator pump tuning to bring them in real good.

You can cross the bridge in regards to 2'ndary jetting when (and if) the time comes, IMO.
05-14-2009 12:25 PM
bubbahotep Oops, I'm wrong. Just looked at a photo and the rear bowl is straight to the main body. My error. I could have sworn I had 2, dreaming I guess

1 block
05-14-2009 12:14 PM
cobalt327
Quote:
Originally Posted by bubbahotep
2 blocks on mine. Front side has the idle mix screws, rear has nothing. Correct?
4150- you are absolutely correct!
05-14-2009 12:13 PM
bubbahotep 2 blocks on mine. Front side has the idle mix screws, rear has nothing. Correct?
05-14-2009 11:28 AM
cobalt327 3310's can be either a 4150 or 4160- difference is (mainly) in whether there's a metering "block" for the 2'ndary side or a metering "plate".

A metering block-equipped 3310 (4150-style) will have the same size metering block in the back as it has in the front. This is located between the float bowl and the body of the carb, a metering block is about 3/4" thick, give or take.

I would be replacing that 15-year-old power valve, if it were me. It doesn't need to leak to be bad- once they're gas-soaked than allowed to dry out, they can become stiff and less responsive to manifold vacuum than it should be.
05-14-2009 10:19 AM
bubbahotep Bogie, carb is a 3310 which is a 4150 holley I think? Vac secondaries , 750cfm, no choke mechanism but the choke plate is there, on an automatic 2004r. The only thing ever changed was the power valves about 15 years ago. Everything else is stock holley. The powervalves I understood you tested them by trying to stall the car with turning idle screws way in. Stall means valves are good. They should not affect idle anyway I thought?

Jets are stock and I don't know what they are offhand

I have no off idle stumble, no dead spot. It just seems a bit choppy to me at 1000rpm idle when I used to be at 800 and not as choppy (even though I had the plates too far open). I'll be checking my plugs tonight
05-13-2009 07:31 PM
oldbogie
Quote:
Originally Posted by bubbahotep
lol, this is CRAZY. Too much air from the back? I have a bent screw driver that lets me turn the secondary adjustment screw while running. I know that if I back-off on the secondary opening my idle drops....so then I should increase on the IDLE SPEED screw to compensate?

Im going to try it again tomorrow but first Im pulling every spark plug to make sure they're not fouled. I have such a nice rpm now except for the damn stumble I can feel.
I gotta git outa here, but have some to say. Meanwhile, how about getting the specific numbers off that Holley, they don't all work the same way on the idle system, looks like we need to figure out exactly what this beast is.

Bogie
05-13-2009 07:21 PM
cobalt327
Quote:
Originally Posted by bubbahotep
I know that if I back-off on the secondary opening my idle drops....so then I should increase on the IDLE SPEED screw to compensate?
I would first use the idle mixture screws to compensate for the 2'ndary being tightened up. Only then use the idle speed screw.

Your idle mixture screws should have a larger range of adjustment than you've described, but that's neither here nor there at this point.

Adjust the 2'ndary blades tighter, then idle mixture screws, then idle speed- if needed. See where that leaves you.

After you get the idle where it's stable, work on the accelerator pump adjustments if the stumble is right off idle.
05-13-2009 07:04 PM
bubbahotep
Quote:
Originally Posted by ericnova72
Sounds to me like maybe you have opened the back up too much and shut the front down too far, don't get too hung up on having a "perfectly square" T-slot opening on the front, just reasonably close to square is good. You may be pulling too much through the rear T-slot now.
lol, this is CRAZY. Too much air from the back? I have a bent screw driver that lets me turn the secondary adjustment screw while running. I know that if I back-off on the secondary opening my idle drops....so then I should increase on the IDLE SPEED screw to compensate?

Im going to try it again tomorrow but first Im pulling every spark plug to make sure they're not fouled. I have such a nice rpm now except for the damn stumble I can feel.
05-13-2009 06:42 PM
ericnova72 Sounds to me like maybe you have opened the back up too much and shut the front down too far, don't get too hung up on having a "perfectly square" T-slot opening on the front, just reasonably close to square is good. You may be pulling too much through the rear T-slot now.
05-13-2009 03:22 PM
bubbahotep Heres an update and opinions would be appreciated:

I bought a holley book which confirms everything posted here. Still, I have a minor issue if you read:

1) Got my IDLE SPEED screw almost down to zero. Its maybe 1/4 turn now and under the carb is "square"

2) My idle MIXTURE screws are about 1 turn out each. Any farther in the car begins to stall, farther out does nothing

3) I have the SECONDARIES opened just slightly. Maybe the thickness of 2 pieces of paper opening. Very very small

Car idles at 1000 rpm with this setup, BUT, to me it feels like its not a clean idle. Its almost feels like a fouled plug (these are litterallly 2 weeks old). Revving the engine the car seems ok, no backfire no roughness.

If I grab the secondary rod (to open them more) I can get the car to go into any rpm I want. 3000 rpm is possible. So I'll assume I DONT want to mess with the secondary adjustment anymore

The Holley book I got says that sometimes you ALSO need to drill the holes in the plates but it doesnt say what might indicate I need to do so.

I raised my idle timing from 18 to 30' for ZERO affect. The car didnt seem to idle any better.

Is it possible I also need a hole or 2 in the plates for more air?

Right now Im at 1000 rpm idle but a bit rocky. Even with my setup I know this car can idle smooth at 800rpm even with the k-klack k-klack of the engine.
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