Moparts

holley 3310 tuning/ adjustments?

Posted By: jensenguy

holley 3310 tuning/ adjustments? - 08/15/09 06:56 PM

I was hoping there was someone on here that could help me out roughly tuning my carb. Its a holley 3310-4, on my 440 that I just got broken-in recently. The engine runs ok, but it seems like it could be smoother, and the exhaust is making my eyes water.

Now Ive never done anything with this carb before, it was unbolted from the engine when I rebuilt it, and bolted back on to it when I was done. Im suprised its running as good as it is.

Im a complete newbie when it comes to carburetors, I know where the idle screw is and thats about it. So does anyone have any quick and easy tips to improve the mixture?

thanks a lot!
Posted By: YO7_A66

Re: holley 3310 tuning/ adjustments? - 08/15/09 07:07 PM

Before you start with the carb, can you tell us what the initial timing (at idle) and what is the total timing?

Carb Basics: Do you have a vacuum gage?
Does the car have a tach?
Try spraying starter fluid or carb cleaner around the intake/carb base to see if there are any vacuum leaks. If the idle rpms change, fix the leaks before tuning the carb.

The above are just some basic things to check before digging into the carb adjustments. Once everything is ready, then we can help you out with the carb tuning.
Posted By: jensenguy

Re: holley 3310 tuning/ adjustments? - 08/15/09 07:13 PM

Quote:

Before you start with the carb, can you tell us what the initial timing (at idle) and what is the total timing?

Carb Basics: Do you have a vacuum gage?
Does the car have a tach?



Well Ive got the initial timing set a 10 btdc. As far as total timing goes, I really dont know, I cant really check that with just the stock timing mark tab can I? Also Im reluctant to change the timing too far from where I am, I had a ton of trouble starting the engine at first (for break-in) and Ive finally found the sweet spot that starts and runs quickly.

I do have a tach, but Ill have to do some searching for a vacuum gauge.
Posted By: D_C

Re: holley 3310 tuning/ adjustments? - 08/15/09 07:38 PM

Holley.com has a great tech section complete with YouTube videos.

Holley Tech Service

Holley TV website

Make sure you check out the "Common Questions" and "Tech Library" topics.

There are some important "Basics" you should learn and understand and they are really not all that difficult:

* Importance of Correct Fuel-Level Adjustment
* Power-Valve Selection
* Accelerator-Pump - Lever-Adjustment, Squirter-Size, cam
* Idle Circuit Mixture & Secondary Idle Set-Screw Adjustment

Posted By: RapidRobert

Re: holley 3310 tuning/ adjustments? - 08/15/09 07:52 PM

Quote:

As far as total timing goes, I really dont know, I cant really check that with just the stock timing mark tab can I? Also Im reluctant to change the timing too far from where I am,

yes dont change the timing till you find out where it is at now(for your baseline). Get a timing tape or measure/mark the dampener(.0632683" is (1) degree) so 2&1/4 would be 35.5 degrees(which'd be a nice conservative total(checked wo vac adv).
Posted By: jensenguy

Re: holley 3310 tuning/ adjustments? - 08/15/09 08:28 PM

Quote:

Quote:

As far as total timing goes, I really dont know, I cant really check that with just the stock timing mark tab can I? Also Im reluctant to change the timing too far from where I am,

yes dont change the timing till you find out where it is at now(for your baseline). Get a timing tape or measure/mark the dampener(.0632683" is (1) degree) so 2&1/4 would be 35.5 degrees(which'd be a nice conservative total(checked wo vac adv).



ok, I made a mark on my dampner as you suggested at 2 1/4". It looks like Im getting there, or very close to it at least. Probably 2500 - 3000 rpm, Im not sure I dont have a second person here right now.

So Im thinking my timing is at least close to where i need to be.
Posted By: SomeCarGuy

Re: holley 3310 tuning/ adjustments? - 08/15/09 08:43 PM

Can you find out and post jetting and PV numbers? that will help.
Posted By: RapidRobert

Re: holley 3310 tuning/ adjustments? - 08/15/09 08:54 PM

what cam? At idle how much vacuum & what idle speed, & (as mentioned) what PV & 1st (& easy to do) is to check your float levels.
Posted By: JimG

Re: holley 3310 tuning/ adjustments? - 08/15/09 08:55 PM

That's good that total timing is right.

You didn't mention the cam in the engine. If it's an aftermarket cam with more-than-stock valve overlap, you might need a lot more than 10* initial timing...like 15 to 18.

If that's the case, you might have the curb idle screw cranked too far open, exposing too much of the transition slot, causing the rich condition you describe.

Flip the carb over and take a look at the relationship between the t-slots and the throttle plates. The plates should expose enough of the t-slot that it looks like a square. Any more and it must be fixed, either by giving he engine more timing or other methods.

Attached picture 5419507-rightwithgraphics.JPG
Posted By: RapidRobert

Re: holley 3310 tuning/ adjustments? - 08/15/09 09:01 PM

Quote:


You didn't mention the cam in the engine. If it's an aftermarket cam with more-than-stock valve overlap, you might need a lot more than 10* initial timing...like 15 to 18.
If that's the case, you might have the curb idle screw cranked too far open, exposing too much of the transition slot, causing the rich condition you describe.

this is what we've been missing. thank you Jimmy
Posted By: JimG

Re: holley 3310 tuning/ adjustments? - 08/15/09 09:08 PM

Quote:

Quote:


You didn't mention the cam in the engine. If it's an aftermarket cam with more-than-stock valve overlap, you might need a lot more than 10* initial timing...like 15 to 18.
If that's the case, you might have the curb idle screw cranked too far open, exposing too much of the transition slot, causing the rich condition you describe.

this is what we've been missing. thank you Jimmy



Robert:

'twern't nothin'!

If that is indeed an issue on the OP's car, I'll post the pics of my distributor slots that I shortened using JB Weld...which, by the way, are still holding up just fine.

Did I ever thank you for making me paranoid that they were gonna just fall out?
Posted By: RapidRobert

Re: holley 3310 tuning/ adjustments? - 08/15/09 09:14 PM

Quote:

Robert: 'twern't nothin'!
Did I ever thank you for making me paranoid that they were gonna just fall out?

(1) Jim you are too humble (2) no you never got around to taking care of that & I will add that I dissassembled one yesterday & the JB weld had crumbled so I expect you to start having problems any day now
Posted By: jensenguy

Re: holley 3310 tuning/ adjustments? - 08/15/09 09:14 PM

Quote:

what cam? At idle how much vacuum & what idle speed, & (as mentioned) what PV & 1st (& easy to do) is to check your float levels.



Its got the Lunati Voodoo 60303 226/234 dur., .494/.513 lift. I was running the stock cam before the rebuild, and it was running pretty good with the carb setup the way it is still. I'll have to get a vacuum gauge for tomorrow, Im without one right now. Its idling around 7-800 rpm in park. Power valve, who knows, but I'd rather not take anything apart before lasting all my other options.

Ill start working on figuring out my float levels and go from there. Thanks guys!

Also should I try bumping my initial up to 15 or so and see what happens?
Posted By: RapidRobert

Re: holley 3310 tuning/ adjustments? - 08/15/09 09:17 PM

Quote:

Also should I try bumping my initial up to 15 or so and see what happens?

yes then slow your idle speed
Posted By: JimG

Re: holley 3310 tuning/ adjustments? - 08/15/09 09:19 PM

Quote:

Quote:

Also should I try bumping my initial up to 15 or so and see what happens?

yes then slow your idle speed



But don't hammer on it with the timing bumped up. If the engine likes the timing advanced (and I bet it does) you'll need to limit the mechanical advance to compensate.

Do you have any JB Weld?

Jim
Posted By: Sinitro

Re: holley 3310 tuning/ adjustments? - 08/15/09 09:39 PM

Before punting..

Post back some of the specs..
Vacuum @ Idle.

The Holley is super EZ to tune but it all starts with making sure no leaks, adequate inital (12 degrees) timing, and high enough vacuum (>10 inches). Then next going inside the Holley for possible revs for the power valve, nozzles and jets. Seems like the idle speed is a little low..
But do it a step @ a time, post back and we can help you more..

Just my $0.015..
Posted By: jensenguy

Re: holley 3310 tuning/ adjustments? - 08/15/09 09:47 PM

Quote:

Quote:

Quote:

Also should I try bumping my initial up to 15 or so and see what happens?

yes then slow your idle speed



But don't hammer on it with the timing bumped up. If the engine likes the timing advanced (and I bet it does) you'll need to limit the mechanical advance to compensate.

Do you have any JB Weld?

Jim



Well it definitely likes 15 degrees initial. Exhaust seemed to get a little cleaner, but still not right. So from what im putting together, if I leave my initial at 15 without modifying my distributor Ill have too much total timing? Is that right?
Posted By: jensenguy

Re: holley 3310 tuning/ adjustments? - 08/15/09 09:51 PM

Another thing,

I was trying to check my float levels, when I open the sights the back one is dry, but the front one has fuel running out. That means the float level on that one is too high correct? But the thing that got me, when I loosen the adjusting screw on either the front or the back, I get fuel running (almost spraying) out from under the adjusting screw. Should it do that?
Posted By: RapidRobert

Re: holley 3310 tuning/ adjustments? - 08/15/09 09:52 PM

Quote:

So from what im putting together, if I leave my initial at 15 without modifying my distributor Ill have too much total timing? Is that right?

yes you'll have to have your shop weld up the slots (there's a chart in the archives)
Posted By: JimG

Re: holley 3310 tuning/ adjustments? - 08/15/09 10:02 PM

Quote:

Quote:

So from what im putting together, if I leave my initial at 15 without modifying my distributor Ill have too much total timing? Is that right?

yes you'll have to have your shop weld up the slots (there's a chart in the archives)



Archives, schmarkives!



Mopar Distributor Advance Slots

dist. degrees X 2 + initial= total


dist. degrees / slot size
6.............. .340
7............... .355
8............... .375
9............... .390
10.............. .405
11.5 ........... .420
12.............. .435
13.............. .445
14.............. .460
15.............. .475
16.............. .490
17.............. .505
18.............. .520
Posted By: JimG

Re: holley 3310 tuning/ adjustments? - 08/15/09 10:04 PM

Quote:

Another thing,

...But the thing that got me, when I loosen the adjusting screw on either the front or the back, I get fuel running (almost spraying) out from under the adjusting screw. Should it do that?



Yes. It's under pressure when the engine is running (assuming a mechanical fuel pump).

J

ETA it will also have residual pressure after you shut the engine off.
Posted By: D_C

Re: holley 3310 tuning/ adjustments? - 08/15/09 10:19 PM

Quote:

Another thing,

I was trying to check my float levels, when I open the sights the back one is dry, but the front one has fuel running out. That means the float level on that one is too high correct?



Yes. You need to lower the float so it shuts the needle-valve off sooner.

Quote:

But the thing that got me, when I loosen the adjusting screw on either the front or the back, I get fuel running (almost spraying) out from under the adjusting screw. Should it do that?



Yes, that is normal but can be minimized by keeping the screw, screwed down, as you adjust the nut (so it's a two-hand operation,) wide-screwdriver and 5/8-inch wrench.

Of course, the needle-seat screw and nut gaskets do wear out too, eventually.
Posted By: sthemi

Re: holley 3310 tuning/ adjustments? - 08/16/09 05:03 PM

I just had the same problem with my 3310, two hands one with the big screwdriver and the other with an open end wrench..
work slowly and keep the screw a bit snug to keep gas from going all over..
It took a couple of minutes for the engine to clean up after I had the float set properly.
Posted By: jensenguy

Re: holley 3310 tuning/ adjustments? - 08/18/09 12:08 AM

OK, im back with some more numbers.

First off I did manage to get my floats adjusted, I had to turn the front adjuster about 3/4 of a turn in to get fuel to stop running out of the sight. It doesnt seem like that really changed anything yet though.

Im now at 15 degrees of initial timing, pulling about 11 inches of vacuum at 850rpm. Is that what I should be seeing with the bigger cam?

So whats my next step?
Posted By: JimG

Re: holley 3310 tuning/ adjustments? - 08/18/09 11:49 AM

IIRC, you went from 10 degrees to 15 degrees initial timing and stopped there? To truly know where the "sweet spot" is, you must go too far, then back off (approach "dead nuts" from both directions so you'll know you're there). Bump the timing up some more until it quits producing more idle vacuum/smoother idle/better throttle response or until the hot engine kicks back against the starter when you try to restart it. Then and only then will you know the initial timing is optimized. My guess is 18 - 20 degrees will be about right, but there's no way to know without trying it.

After that you'll have to disassemble the distributor and (not JB ) weld up the advance slots and file them to the correct length to get the total advance back down to 36-38 degrees. If you haven't already done so, you might want to think anout recurving the distributor with a lighter spring at that point. The engine is in a Jensen, and they're fairly light cars, yes?

If you're interested in using the vacuum advance, you'll work on that next. Tuning it consists of adjusting the level of vacuum required to actuate the vacuum advance mechanism (easy) and possibly limiting the degrees of vacuum advance, based on what your engine will tolerate (not quite as easy). You'll find that the opinions of Moparts members regarding vacuum advance varies widely, with some swearing by it and some swearing at it.

Assuming the rest of the ignition system passes muster, then it's back to the carb.

Post back with your results.

Jim
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