TheSamba.com :: View topic

Tue Jul 26, 2016 4:46 pm

You shouldn't be using your idle mixture to fix a decel problem. Set your idle by the LBI procedure and then fix what's causing the popping (timing, exhaust leak, etc)

Wed Jul 27, 2016 6:47 am

Do what I do. Just start from scratch. Unbolt exhaust check your gaskets. Put in the metal gaskets. And re tighten. Then try again. Make LiL changes at a time. I bet it's an exhaust leak if u have paper gaskets

Wed Jul 27, 2016 8:52 am

Exhaust leak is not the issue, there is more fuel getting in at idle than I think there should be and I need to figure out why. Not a huge issue, car runs great otherwise, just idles at 12:1 AFR.

Stan

Wed Jul 27, 2016 9:02 am

I have seen a few motors(not ACVW motors, but motors) that will not idle easily at AFR's leaner than 12's and possibly 13's. To get them there, you will need to add air and even some timing advance. And maybe even up the idle RPM a bit.

Wed Jul 27, 2016 9:12 am

So, with 54 idles I had it idling in 13s, but I had idle screws turned in a bit and timing down to like 2. Progression holes were still closed I believe. I actually like it better the way it is now, and idle is lower -- just the 12AFR.

Stan

Wed Jul 27, 2016 11:30 am

Idle feel can be as subjective as what oil to run....if you are happy with your cars idle, stick with it.

On mine I was noticing that I was getting sooty at the exhaust tip, so I turned in the idle mixture screws to lean it out some. I run with the air screws closed, and just double checked the balance with the snail gauge, all is good and idle only varies with ambient air temps.

I need to get a new sensor for my WB to actually know where things are falling, but I am pleased with current running conditions and will pretty much leave things as they are.

Wed Jul 27, 2016 11:48 am

I wonder if it's time to try backing out air bypass screws a bit.

Stan

Thu Jul 28, 2016 6:36 pm

stan_tichomirov wrote: I wonder if it's time to try backing out air bypass screws a bit.

Not an especially easy thing to do, as those screws are in close quarters the the side of the engine compartment. And then you'll need to be able to adjust them for balance. I closed mine for all of these reasons, until I possibly add "Weber Windows" in the future.

Thu Jul 28, 2016 6:50 pm

I have tall manifolds now. But deck lid hits the passenger side air cleaner top and it causes lid to misalign. And I'm too much OCD to leave it like that.

Question is if I put in regular height manifolds will I have to retune again?? Will it run richer or leaner?

Thu Jul 28, 2016 7:52 pm

Non-offset ones? You could use standoffs to move the lid back.

Stan

Fri Jul 29, 2016 8:20 am

Yes they are straight manifolds. And that was my dilemma. Bottom of deck lid is propped for summer cooking. But now that I have motor tuned correctly I assume it will run cool enough that I can close lid again. Main reason I propped lid was because I have a convertible. And it blocks air when top is down. But now it should be ok right?

Fri Jul 29, 2016 10:01 am

Depends on year. Early vert with doghouse will need more air. Late vert with doghouse should be fine.

Tue Aug 02, 2016 9:02 am

Well still working on things. Here is where I am at now. Engine is 2316 type IV, 200 HP & 200 ftlb torque, distributor is a Unilite with mechanical advance only. Timing set at 900 RPM idle 8 deg. Idle jets .50, mains at 145 and AC at 240.

Runs pretty well with slight hesitation at around 2000 RPM. My concern is that when I cruise in 4th gear I read high 13 to low 14 on the LM2. If I could get that down to low 13 I think I'd be set. Any thoughts on the A/F ratios at cruise? Is high 13 and low 14 problematic?

Tue Aug 02, 2016 9:27 am

Try a 52.5 idle and reset LBI.

Tue Aug 02, 2016 9:54 am

I ran with .52 idle jets. It brings everything down (3rd gear 3000 rpm etc.) from high 12 and low 13's to high 11 and low 12's. It does bring the 4th gear cruise at 3000 to 3500 to low 12's rather than the high 13 low 14's I get with the .50.

Am I better to stay with the .52 and richer burn all around than the .50 idle where everything is high 12 low 13's but highway cruise is high 13 and low 14?

Tue Aug 02, 2016 10:13 am

offhand I'd say your air jets are too big, and you are double metering fuel in the 2500-3k range from progression and main. Try to go back to 200 air and 52.5 idle, and see how it behaves.

Tue Aug 02, 2016 1:33 pm

I went with the large AC to try and get the mains in sooner so that while cruising on the hwy at 3000 & 3500 I would get out of the low 14 and high 13 to low and mid 13. That was my hope but didn't get me there.

Is high 13 and low 14 a bad place to cruise at steady speed on highway? Just worried about heat.

Tue Aug 02, 2016 1:37 pm

That's a stupid question, because it means you haven't read this thread.

Tue Aug 02, 2016 3:27 pm

Well, from what I have read some opinions are that light load cruise at the high 13 and low 14 is ok. The idle is suggested to be low 14 when set-up for LBI. I suspect from what I've read that low 14 under load would be a bad pace to be. I suspect low 14 is also not preferred in my situation but thought I'd ask anyway.

Tue Aug 02, 2016 3:30 pm

As stated 20x in this thread, centrifugal only engines should be 12.8-13.2:1 for everything but idle, which is normally best at mid 13s.

I can't tell you how frustrating it is repeating the same thing over and over because people are either too lazy, or are reading it but absorbing zero.