My 318 dyno results

[AJ/FormS]

So I haven't been able to get the idle quality where I want. I did try the Holley Ultra Street Avenger 670, but it didn't improve anything so I'm back to the Holley Street Avenger 570.

Cold starts during winter time are terrible. I also get hesitation driving around at low RPM all the way until the thermostat opens and the engine is up the temperature. I'm thinking I need to increase the idle feed restrictor?

Anyways, when I built this engine the Whiplash camshaft was chosen for being used with the OEM 302 cylinder heads, which I later found out were cracked. Since I know have the Edelbrock Performer RPM cylinder heads and I'm unhappy with the idle quality, I'm considering replacing the camshaft. What do you guys think about the Lunati Voodoo 20200710?

Hang on Olei
What are the specs on that cam, I found two whiplash cams, and neither of them have the advertised specs listed.
Ok I went to the Hughes site; it appears you may have the 1326 cam, with 213/226, or who knows cam, and it may be on a 109 LSa who knows.
But if it is a 213/226/109 cam and if you installed it at plus 5 or at 104, then if I gross that roller up by 53 degrees for typical roller acceleration ramps, then I get
advertised numbers of 266/280/109, and an ICA of 57*. Now, that will get you a Dcr of 8.2@165psi and a VP of 135, and that is a nice place for an aluminum headed teener to be.
So we know the engine design is fine

But here's the deal; with the effective starter gear of 2.94x2.74x12/31=6.24 is really taxing your combo. I didn't see the Stall-spec on your XTM, so,I went to the Hughes site and found that the XTM has a design stall of 2500 to 2700.
So;Your problem isn't carb nor cam, nor stall.
Yes you can get rid of that cam, but that Voodoo ain't the answer either. And
Yes you can put 3.55s in there, but that ain't the answer either with 31s. That will only increase your starter gear to 3.55x2.74x12/15.5=7.53 normalized to a 24" tire. Your combo is begging for a starter closer to 10/1...... and that would take 4.30s at a minimum. 4.3x2.74x12/15.5=9.12 normalized.

IMO your problem is strictly in the tune, and specifically in the T-port sync.and pump-shot. That cam has just 55* of overlap, so you may be trying too hard to hear the lope;check this out;
AJ's guide to Transfer Port Synchronization

Additionally, you probably have a reason to be running just 9.5Scr,with aluminum heads, but that is holding back your low rpm performance, a bit.
Just for kicks, I ran the Wallace at 10.5Scr and got a Dcr of 8.79@181psi, and that would really wake your combo up, to the tune of VP=144.That's a 7% improvement. This would allow you to run a bit more cam without a penalty in low rpm performance, but not the Voodoo you listed; that is a retro-fit roller for an LA block. 180psi might sound like a lot, but I run that in my combo ....on 87E10 gas. I have run more. Other guys are running 200 and a bit more, but not in a pick-up truck with 2.94s,lol.

 

[olei]

The advertised stall rating for my converter is 1800. I've estimated the DCR to be right at the edge for 91 octane pump gas, I can't remember exactly though. Might have been 8.7.

The thing is, already as the car is now, I think it drives nicely (hey, I drove this car for several years with a 125HP 3.9 V6 before the engine swap). It's the idle, cold starts and hesitations when cold that annoys me the most. And normally, at any condition, if I just blip the throttle the engine will stall. I think it might be to lean at the idle circuit, but it's hard to tell with the valve overlap. Smells rich at the tail pipe, and the AFR gauge goes crazy lean.

What cam would work with my setup?

 

[Mattax]

Have you tried messing with the choke?
Choke set ups are tricky.
Some of the newer carbs don't have operating choke pull offs either. Check that connection - its probably internal on that carb, and if it works, the adjustment.

 

[olei]

I have checked the choke, it "works". Only the working time of the choke is adjustable.

 

[AJ/FormS]

comments in the quote

The advertised stall rating for my converter is 1800. I've estimated the DCR to be right at the edge for 91 octane pump gas, I can't remember exactly though. Might have been 8.7.

The thing is, already as the car is now, I think it drives nicely (hey, I drove this car for several years with a 125HP 3.9 V6 before the engine swap). It's the idle, cold starts and hesitations when cold that annoys me the most. And normally, at any condition, if I just blip the throttle the engine will stall. I think it might be to lean at the idle circuit, but it's hard to tell with the valve overlap. Smells rich at the tail pipe, and the AFR gauge goes crazy lean.

What cam would work with my setup?

View attachment 1715151719

Oh that's even a smaller cam and so a higher pressure, I like it!
But a worse stall.
But hang on, this ain't all bad. In fact it's very good.

With this new information, I am fully convinced that your issue is in the tune, namely the T-port sync and the vacuum advance. You are describing symptoms that can be directly linked to the throttle being too far closed at idle.All of them!
So do the T-port sync, and hook up the Vacuum advance to the sparkport. Don't be afraid to reduce the idle timing to 14 or 12 or even 10.
Then I highly recommend a two-stage advance curve; very fast up to 2800 or so, then slowing down to be all in at no sooner than 3400.
And the fast idle speed, on the second highest step,(the kicked down to step), should be fast enough that the vacuum advance is all in.

Your idle stink
may be because you have cranked out the mixture screws in an effort to cover the hesitation. What you need to do is increase the throttle opening to uncover and engage the transfers, and so be able to lean out the idle mixture screws. Of course this will increase the idle speed, and the proper way to reduce it is to decrease the timing.
This will solve you stalling with slammed-shut throttle valves, because now the engine will be able to draw in some fuel from the transfers, the way the factory designed it to.
This will also help solve your raw fuel smell in your exhaust, because with the backed off mixture screws, it is no longer so fat.
This will eliminate your tip-in hesitation. Just remember to sync your pumpshot to the new idle throttle setting.
This should provide a better mixture for the engine when on choke, but the working vacuum advance will make the biggest improvement.
>Those aluminum heads suck a tremendous amount of heat out of the engine, making the engine think it is always cold, and she feels really cold when an iron headed engine would think it's just a little cold. So when the ambient temp is cold, the choke will be really really important, and it starts with the vacuum advance bringing in a lot of timing, to start the fire really really early. I have a 22* can on mine and the engine often wants more.
So at 1500rpm my warm-up rpm, my engine is seeing 14+4+22=40*. To that I occasionally add 8* via my dash-mounted, dial-back, timing device. So that would then total 48*; and it's not too much. Then I don't let her warm up for long, but within 2 or three minutes I am moving, and 3 more gets me on the hiway. Then as I'm cruising along with my foot steady on the pedal,at 60 mph, with the timing now 14+10+22+8=54,I can feel the heads come up to temp, by the surge in speed, as the car increases in mph without throttle input. That's when I take the extra 8* out. This can take 3 to 5, to even 8 miles, depending on the ambient temp.
In an effort to combat the heat loss in the chambers, I run a minimum water temp of 205*F.
>Now,If the exhaust burns your eyes,
then you may have the additional problem of the engine sucking air,most probably from the secondaries not being fully closed, but could be other.
If you cannot get the idle speed down, with the secondaries fully closed but not sticking, and the T-port sync properly set, and the idle timing reduced to about 12*, and the PCV properly functioning; THEN, go look for a vacuum leak, and be sure to check for a leak into the valley, as well.
>Ignore the AFR under 1800rpm; it lies with that cam.
Also, once the beast is running properly, put a vacuum gauge on the manifold and slowly rev the engine up. Watch the gauge. The vacuum should slowly and steadily rise to a peak value and then just hang there for a while.This should happen below 3000rpm and the peak I would expect to be at about 2000with that cam. The lowest rpm that it peaks at, is the first rpm that the air going into the engine, is finally all going in the right direction,namely down! into the cylinders. I would consider that to be the LOWEST stall rating.
>Now let's go play the numbers.
This cam is listed at 208/214/107+5 and grossing it up to advertised, I get about
260/268/107,and that will get you an ICA of 52*. OK and plugging those into the Wallace calculator, I get a DCR of 8.23@166psi with a VP of 137 and that is awesome for a 318. So again, the engine is right on. And this is why your 1800TC is making you happy with that pitiful starter gear.
Read about VP here
V/P Index Calculation
But what Hughes has done with the 102 install is send a bunch of exhaust back into the plenum at low idle, to make it sound fierce,lol; and that is perhaps making your tuning difficult. This, IMO gimmick, also reduces your power extraction time, leaving plenty of energy in the exhaust, to make a nice high-pressure pop out the tailpipe. And of course, there may be plenty of unburned gas in that exhaust.
______________________________________________________________

If I had that cam, I would re-time it to in at 105/106. That would reduce your Dcr to 8.1@162psi and drop the VP to 131. So that's a loss of lowspeed performance of 4.5%. To cover that, I would increase the cylinder pressure with the thinnest headgasket I could find, while keeping the Q to no less than .030. The difference from the popular .039 gasket to the .028 is about 2.5cc, and that would restore the VP to 136.But the pressure would be increased to 168psi, sweet.
What this would do is; open the exhaust a few degrees later, sucking some energy out of the exhaust and putting it into the crank. So the slightly later opening intake valve will see less exhaust travel into the intake. This will decrease the rough idle slightly, and simultaneously clean up the exhaust some.
This will have the added benefit of a smoother more stable idle when the engine is cold and especially on choke.And the longer extraction period will help in the fuel-mileage department
And finally,I would get a 2800TC and stick some 3.91s in there at least, or if hiway comfort is a concern then 3.73s;65=2630@zero-slip. .....................................But that is what I would do.

done,I think,lol

 

[Mattax]

I have checked the choke, it "works". Only the working time of the choke is adjustable.

by 'Works', you mean it closes when cold and eventually opens when warmed up?
You probably understand, that's not good enough - especially in a cold climate.
It may have an internal vacuum actuated pull off. Unless someone here has one apart, you'll have to determine this yourself. What it does is as soon as the engine starts, the choke will open a bit more. The older Holleys from the 60s and 70s have this, as do factory carbs. Newer stuff its maybe yes often no.

 

[olei]

With this new information, I am fully convinced that your issue is in the tune, namely the T-port sync and the vacuum advance.

I have tried adjusting the transfer slot, and I believe I'm having it pretty much squared right now. The secondary throttle blades are barely open.
I have ported vacuum advance. Initial timing timing is 26 degrees IIRC (32 degrees total).
Idle mixture screws doesn't seem to be responsive, at least when looking at the vacuum.

Btw, how come I can't run a retro fit camshaft?

 

[olei]

by 'Works', you mean it closes when cold and eventually opens when warmed up?
You probably understand, that's not good enough - especially in a cold climate.
It may have an internal vacuum actuated pull off. Unless someone here has one apart, you'll have to determine this yourself. What it does is as soon as the engine starts, the choke will open a bit more. The older Holleys from the 60s and 70s have this, as do factory carbs. Newer stuff its maybe yes often no.

Yes, it closes when I touch the throttle before starting. The adjustment on the choke is only for how long you want it to stay on. It does have a vacuum actuated pull off that opens the choke butterfly a tiny bit, which is not adjustable. I guess I could try tweaking the rods for the choke butterfly.

 

[Mattax]

It does have a vacuum actuated pull off that opens the choke butterfly a tiny bit, which is not adjustable. I guess I could try tweaking the rods for the choke butterfly.

That's it. Some sort of mechanical rod or notched plate determines the amount of position difference from non-running to running.
You say its great when warmed up - so thats why I'm focused on the choke during cold running.

although I bet AJ will say something is not correct if the throttle mix screws are having no effect once warmed up.
If you can turn them in until they just close and still no effect - I too going to say that something is not quite right.

 

[rumblefish360]

AJ is prepping a book, please stand by...

 

[olei]

That's it. Some sort of mechanical rod or notched plate determines the amount of position difference from non-running to running.
You say its great when warmed up - so thats why I'm focused on the choke during cold running.

although I bet AJ will say something is not correct if the throttle mix screws are having no effect once warmed up.
If you can turn them in until they just close and still no effect - I too going to say that something is not quite right.

It runs good when warmed up, yes. It also idles, but still weak.

 

[Mattax]

IMO that's alot of initial timing with that combo. 14 - 16, maybe 18* BTDC, around 700 - 800 rpm. Then it will run stronger at idle with a somewhat richer mixture, something in the 12- 13.5 AFR range, but you can just use vacuum in gear as an indicator.

 

[AJ/FormS]

I have checked the choke, it "works". Only the working time of the choke is adjustable.

That's not exactly true Olei
You also have an adjustment on how far the choke opens right after start-up. This is called the vacuum break. To change it, you have to bend the link-rod.
The trick is to have the choke set so that after it starts, you don't have to do anything for about a half a minute. Then as the rpm begins to rise, you tap the pedal to allow the fast idle cam to drop down a step or two. Then you can drive away.
If you have to keep slapping the pedal to keep it running, then you may have several problems, chief of which is probably insufficient timing, due to a non-working vacuum advance; and second would be the vacuum-break adjustment. Now you only have a few seconds at start-up to get that vacuum break set-right, so don't be discouraged if it takes a half a dozen attempts, or more.
And of course, when the engine is stone-cold, that choke has to be completely closed. Part way won't do it.Almost closed won't do it. It has to be completely closed, and the secondaries also have to be completely closed.
During the first few revolutions, the engine will be attempting to start on the fuel you pumped in there, by the pedal. And it will be trying to get air from wherever it can,namely; the PCV, around the perimeter of the choke-blade, past the secondary valves,and from the float bowl, through every orifice that is open, like the MJs, the PV,the low-speed circuits, and the bleeds; every orifice under that closed choke will be gushing gas, except the accelerator pump.
>As soon as the engine fires, and even slightly before, manifold vacuum will begin tugging on the choke pull-off. And that will reduce the pull on all those bleeding fuel ports. As the engine catches, the choke blade opens to whatever you have adjusted it to, and if you got it right, the engine will begin to slowly rev up.
If you got it too far open, the engine will begin to run out of fuel, and slow down, causing you to slap the pedal to keep it running. This will then kick down the fast idle cam, and now yer stuck there babysitting the thing. If it stalls, a couple of shots from the accelerator pump and it will start right up, only to repeat this crap.
If you got it to far closed, then engine will very-soon begin to slowdown, and you will again have to help it stay running. But the fast idle cam will at least still be there for you. A very rich engine takes a long,long, time to warm up. If it stalls, it will be very difficult to restart.
If you get it just right, the engine will catch, and begin to slowly rev up as the engine warms up. In about a minute you will find the rpm objectionable and you will tap it down. Then it will run just nicely for another period of time, which is governed by the choke spring, and that you have the power to adjust for your local temperature, and to match the characteristics of your engine.
>With aluminum heads,during the time that the engine is on the tapped-down fast-idle step, it is very important to have a working VA kicking in a bunch of timing. Without it, the fire doesn't get going until the pistons are way down the bore, and the engine barely has enough power to idle, much less take being put into gear.
Now, you have set the idle timing to 20* which is about half of what it wants. And I have no idea of what your timing might be at the warm-up idle-speed, But The VA, together with the centrifugal,have to kick in the rest.
>After the T-port sync has been set, you may find the idle-timing down at say 12*. Well this is gonna make big trouble on the choke system. Now it will be more important than ever, to have a good working VA, AND THE BIGGEST ONE YOU CAN FIND,usually about 22*. And that is also why I recommended the 2-stage timing curve.
If you can't get the VA to work off the sparkport, while the engine is on the fast idle, you will have to hook it directly to manifold vacuum. This may introduce a new set of issues, namely a too-fast idlespeed. But those are usually easier to overcome than a crappy warm-up period due to insufficient timing.
> Once you have the idle timing set, you will have to revisit your power-timing.

Oh CheezeWhiz , I'm late to the party,lol.

 

[AJ/FormS]

That small cam does not want additional air from the secondaries. Close 'em up tight, but not sticking. The PCV will be sufficient.
The thing is; at low rpm that early opening intake valve (assuming you got the cam install right), is allowing a very large amount of exhaust back up into the intake manifold, and that is why your idle vacuum is so low. It may be too low to keep your PV system shut off. That would explain why your mixture screws are unresponsive, and it might explain your raw-gas smell out the tailpipe.
If you have the T-port sync set right, and the idle-timing around 12 to 16, then it should be easily possible to stall the engine by closing one or both mixture screws. If it doesn't stall, you have to ask;"where is the engine getting it's fuel?" The square transfers should not be enough, even with an excessively high float level. So you gotta look at the PV system.

 

[toolmanmike]

I see you are running a Edelbrock RPM intake. Is it a Air Gap?

 

[toolmanmike]

Also Aj, That carb does not have a primary choke pull off, just a electric heated choke coil.

 

[AJ/FormS]

Also Aj, That carb does not have a primary choke pull off, just a electric heated choke coil.

Do you mean that if you take the black cover off,and the separator plate out, that there is not a piston in there with a connector link internal to the device?
If that's true, then that is the wrong carb for Norway,lol.

Also if it's true, then to the OP; I'm sorry man, I messed up, and I have never seen a carb like that. And IMO, if I couldn't convert it to some type of pull-off, I would get rid of it.A carb has to have a choke pull-off of some type.

 

[toolmanmike]

Do you mean that if you take the black cover off,and the separator plate out, that there is not a piston in there with a connector link internal to the device?
If that's true, then that is the wrong carb for Norway,lol.

Also if it's true, then to the OP; I'm sorry man, I messed up, and I have never seen a carb like that. And IMO, if I couldn't convert it to some type of pull-off, I would get rid of it.A carb has to have a choke pull-off of some type.

Here's a link to the manual.. Choke adjustment is on page 7..http://documents.holley.com/199r10487-1rev6.pdf

 

[Mattax]

I saw that too, but Olei said he saw the choke open further upon firing.

Might be internal - as shown in Fig 15.
http://documents.holley.com/199r8378rev.pdf
OTH, there no spec listed for Choke qualifying - assuming the list number Olie has is 80570. In that case, maybe all he saw was the action of the manifold vacuum on the choke blade itself.

http://documents.holley.com/199r10015-1rev1.pdf

 

[fishy68]

Even though that is pretty much a baby cam it has a fair amount of overlap due to the 107* centerline. It calls for a much higher stall converter than you have and a stall converter in the neighborhood of 2500-2800 rpm would help by not loading the engine as much when you shift into gear. Another thing you might try is installing a block heater (or 2 since your in a cold climate). I installed one in mine and love it. If I am going to drive it the next day I plug it in the night before and when I go out in the morning I hit the key and it fires right up and will idle on it's own and I have a whole lot more cam in mine than you do. Best $25 I spent on it IMO

 

[olei]

Holy moly! Thank you guys!

OK, let's see... Let me add a few things.

- I can stall the engine if I turn the idle mixture screws all the way in, but it doesn't make any difference on the vacuum at something around 1.5 - 3 turns out.
- The carb has got a pull off, but it is not adjustable (but yes, I can bend the rods)! When I touch the throttle the choke butterfly closes completely, and when I start the engine it opens up to about 3/8" gap.
- I already run the thin head gaskets.
- Another example of the hesitation I get at cold engine. Let's say I finally move up to speed in 2nd gear, barely touching the throttle. it does the 2-3 shift it stumbles, even though I'm keeping the throttle rock steady (barely open).
- At cruise speed (warm engine) I'm getting 16:1 AFR.
- Idle vacuum in gear is 13" (and I thought that was pretty good?).
- Hughes Engines stated that the 318 Whiplash roller camshaft can be used with OEM stall speed (but hey, they have also removed it from the catalogue).
- IIRC, I closed the secondaries and opened them back up 1/4" turn.
- I run the Wagner PCV valve in fixed orifice mode.

How come I should lower initial timing? From my understanding it should have as much as it can take, without having starter issues when hot? Increased initial timing makes it stronger? I would think less initial timing would make it worse?

 

[Mattax]

- I can stall the engine if I turn the idle mixture screws all the way in, but it doesn't make any difference on the vacuum at something around 1.5 - 3 turns out.

The only question is whether they provide adjustment. It doesn't matter whether the adjustment range is 1/4 to 1 turn out, or 1.5 to 3 turns out. These needle valves are the last restriction in the circuit. The lack of noticible effect after opening them up more than 1.5 turns could be due the amount of fuel mix available (restrictions upstream and amount diverted through transfer slots), or that a richer mix isn't providing any more power.

- The carb has got a pull off, but it is not adjustable (but yes, I can bend the rods)! When I touch the throttle the choke butterfly closes completely, and when I start the engine it opens up to about 3/8" gap.

If it has an internal pull-off (choke qualifier) the adjustment is under the choke cap as shown in fig. 15. Even if it is physically there, it may not be connected to a vacuum passage. All things worth verifying.

- Another example of the hesitation I get at cold engine. Let's say I finally move up to speed in 2nd gear, barely touching the throttle. it does the 2-3 shift it stumbles, even though I'm keeping the throttle rock steady (barely open).

Yes. A cold engine needs to be richer throughout most of the power band.

- At cruise speed (warm engine) I'm getting 16:1 AFR.

That seems a little high for a radical but if running good, then that's fine.

- Idle vacuum in gear is 13" (and I thought that was pretty good?).

For your cam, seems about right. What's the rpm? 800 or 1200 is big difference.

- I run the Wagner PCV valve in fixed orifice mode.

With 13"Hg at idle, I'd think you could use it in normal load mode, but deal with that later. My recollection is the Wagner allows some adjustment of the air bypass. So the nice thing is you can use this feature to help adjust the throttle blade positions if needed. ( Say for example its idling at 1200 rpm and the timing is already down to 14"Hg or so)

How come I should lower initial timing? From my understanding it should have as much as it can take, without having starter issues when hot? Increased initial timing makes it stronger? I would think less initial timing would make it worse?

The purpose of timing is to develop maximum pressures as the piston is going down - maximizing force on the crank arm around 20 degrees after top provides the most leverage.
Yes we have all observed the engine runs faster with more timing. But its not more powerful. When load is put on it, rpm drops alot.
The starter should not be the determinant of the proper timing at idle. That's OK for racers who have no interest or easy means of adjustment because of what they are doing and the very radical cams etc.
Timing should match the combustion conditions which vary with piston speed, fuel density and load.
For a stronger idle, try something in the range of 14 - 18* BTDC at 650-850 rpm, and AFR mix from 12.5 to 14 AFR. There's no exact number since your engine is different than the next guys this has to be systematically tested 'till you get it as close as you want. But the range of what will work has been pretty well established. You can look at the pre-emissions factory engines to see these numbers are in the ballpark for an engine with somewhat hot cam.

 

[olei]

The only question is whether they provide adjustment. It doesn't matter whether the adjustment range is 1/4 to 1 turn out, or 1.5 to 3 turns out. These needle valves are the last restriction in the circuit. The lack of noticible effect after opening them up more than 1.5 turns could be due the amount of fuel mix available (restrictions upstream and amount diverted through transfer slots), or that a richer mix isn't providing any more power.
If it has an internal pull-off (choke qualifier) the adjustment is under the choke cap as shown in fig. 15. Even if it is physically there, it may not be connected to a vacuum passage. All things worth verifying.
I have read other guys needing to open up the idle feed restrictor to get them to run properly, that's why I was planning on trying the same since I also see kinda lean cruise AFR (16:1).
It does have the internal pull-off, and it is connected to a vacuum passage. I will take a look at this again, since it's been a while.


Yes. A cold engine needs to be richer throughout most of the power band.
That seems a little high for a radical but if running good, then that's fine.
For your cam, seems about right. What's the rpm? 800 or 1200 is big difference.
With 13"Hg at idle, I'd think you could use it in normal load mode, but deal with that later. My recollection is the Wagner allows some adjustment of the air bypass. So the nice thing is you can use this feature to help adjust the throttle blade positions if needed. ( Say for example its idling at 1200 rpm and the timing is already down to 14"Hg or so)
IIRC, I'm at 1000RPM in park and get about 150RPM drop into gear. I have planned to try set it up in normal mode later on when everything else is setup right.


The purpose of timing is to develop maximum pressures as the piston is going down - maximizing force on the crank arm around 20 degrees after top provides the most leverage.
Yes we have all observed the engine runs faster with more timing. But its not more powerful. When load is put on it, rpm drops alot.
The starter should not be the determinant of the proper timing at idle. That's OK for racers who have no interest or easy means of adjustment because of what they are doing and the very radical cams etc.
Timing should match the combustion conditions which vary with piston speed, fuel density and load.
For a stronger idle, try something in the range of 14 - 18* BTDC at 650-850 rpm, and AFR mix from 12.5 to 14 AFR. There's no exact number since your engine is different than the next guys this has to be systematically tested 'till you get it as close as you want. But the range of what will work has been pretty well established. You can look at the pre-emissions factory engines to see these numbers are in the ballpark for an engine with somewhat hot cam
Oh man, I have been too hung up seing other people with tight LSAs (longer duration though) even running locked out timing. I will try to lower initial timing! Would RPM drop be the correct indication to look for? Adjust initial for the least RPM drop into gear?
AFR on idle is hard to read, due to the valve overlap.

Thanks! Replies in quote.

 

[Mattax]

Thanks! Replies in quote.

I have read other guys needing to open up the idle feed restrictor to get them to run properly, that's why I was planning on trying the same since I also see kinda lean cruise AFR (16:1).

Is there a problem? Don't get too wrapped up in the numbers. An engine can cruise lean, how lean depends on the load and the engine. Use the number as reference, so when you hit limits you know what they are.

Tests for problems
One test for IFR (and IAB) recommended by Mike Urich is to very slowly open the throttle from idle. If there it any miss or hesitation, its too lean. That requires a sensitive ear and some experience. I prefer same concept but driving. Very slowly increase the throttle from a stop to note if there are any dead spots or hesitations. Slow opening minimizes contribution and effect from the acceleration pump.

IFR changes can be sensitive, and when those restrictions are in the high position, they are less predictible. If you do anything here, start by placing them in the submerged position.

Last but not least. As you increase the throttle from light cruising to part power, the AFR should get leaner and power should increase. Approaching full thottle it should then get richer (power valve opening) and continue to increase in power.
-> If you are doing this from local roads, 30-50 mph, the carb will be transitioning from idle circuit to main circuit to main circuit with power valve opening.
-> If you do this from high speed roads, 65 mph, even at cruise, the carb will be mostly on the main circuit.
In between, it is too hard for me to guess as it will vary from combination to combination.

Changes to the idle air bleeds are a fine tune. In theory effect the top of the off-idle more than the idle. I find they effect both idle and off idle. A thin wires in them (run down to the aircleaner gasket so they don't move) is a handy way to experiment with restricting them slightly.)

IIRC, I'm at 1000RPM in park and get about 150RPM drop into gear. I have planned to try set it up in normal mode later on when everything else is setup right.
I was in a similar situation with my previous 340, using Comp Cams 280 HE cam.
Now with a slightly more radical cam, I can get it to idle in gear around 750 rpm. 800-850 in Neutral. Gets better as the engine gets warmer. (no choke right now)
As I learned , the correct timing makes a big diference.

Oh man, I have been too hung up seing other people with tight LSAs (longer duration though) even running locked out timing. I will try to lower initial timing! Would RPM drop be the correct indication to look for? Adjust initial for the least RPM drop into gear?
Yes that's a good way-
AFR on idle is hard to read, due to the valve overlap.
Yes, and its hard to know how accurate it is because the WBO2 interprets the Oxygen as AFR based on assumptions about how combustion occured. We can move timing around or other variables and sometimes it looks like AFR changed, but its not true. We know if the engine speed & load stayed the same, then with a carb - the AFR supplied stayed the same.

 

[olei]

After the T-port sync has been set, you may find the idle-timing down at say 12*. Well this is gonna make big trouble on the choke system. Now it will be more important than ever, to have a good working VA, AND THE BIGGEST ONE YOU CAN FIND,usually about 22*. And that is also why I recommended the 2-stage timing curve.
If you can't get the VA to work off the sparkport, while the engine is on the fast idle, you will have to hook it directly to manifold vacuum.

How come you want me to take out initial timing, but add VA? I can't see it making any difference in the end?
Also, wouldn't connecting it to my manifold vacuum just make my idle quality worse, due to my lumpy idle (making timing jump up and down?).

I see you are running a Edelbrock RPM intake. Is it a Air Gap?

It's not the air gap.