460 is running rich on Edelbrock 1411

[viven44]

I guess I have no earthly idea of how ravenous these engines can be

I did recall this video I watched a while back but I didn't think much about it as I had figured these racing engines were a different animal altogether

I can totally see that the accelerator pump shot is nothing vs. what is actually flowing

https://www.youtube.com/watch?v=7Iq1B-2paCs

[ArdWrknTrk]

I have what might be considered a mild towing cam.
If I really romp on it I'm looking at 7-8 mpg

[viven44]

OK normally I'm a big fan of "if it ain't broke don't fix it" but it has been bugging me why the 78 Bronco doesn't take off from a stop like Big Blue 2WD with its 3.0 gears and 460, despite the fact that the 460 on the Bronco is healthier, has a double roller straight-up timing chain, and has 3.5 gears to boot.

Good news is I think I've solved my low-end part-throttle get up and go problem. Now it takes off like a 3.5 rear end should with a 460, I'd even say it takes off better than Big Blue 2WD! The difference is quite remarkable.

I had 15 mins this evening to go try 'one more thing'.

All I did was move the accelerator pump setting to the leanest position.... if my understanding is correct, by leaning out the pump shot I have less now and since the part-throttle response is better now, it would seem that I was bogging the engine with the bigger shot previously at every get up and go event....

The 'Richest' setting is called the "HotRod" setting in some of the online discussions and videos... I am wondering if that is misleading as correct A/F ratio is the top criteria. In my case the 'Richest' setting gave me the worst result.

[ArdWrknTrk]

I'm kinda surprised that you can't change the cam for a sooner -or later- shot, like a Holley....

Whatever...  I'm glad you seem to have it sussed now!  

[viven44]

I believe I understand more of it now...

I'm starting to think of it as my 460 having excellent vacuum on the stock cam -- the venturi is able to pull all the fuel it needs. Therefore the 'Hotrod' accelerator pump setting was causing a Rich condition. If a lumpy cam was involved, the venturi may not be as strong at idle so the 'HotRod' setting would help bring in more fuel...

I probably should try this on Big Blue 2WD as well

[ArdWrknTrk]

A lumpy "hotrod" cam has lots of overlap.
This bleeds compression at low rpm, and allows good filling at higher rpm, when the port velocity is high, and charge inertia is actually carrying unburned fuel into the exhaust headers.

This way you can get away with 14:1 static CR (or whatever) and still not see too much at lower rpm.
This is the sort of crap you need an MSD for, because nothing wants to light that charge with no dynamic compression

So it tries 3 times... below 3k rpm, but then stops giving multiple sparks, because the engine is now turning fast enough to where exhaust tuning and reversion are packing charge into the cylinder from both valves.

If you've never tuned an alcohol or nitro car this might seem weird, but that's how it works to make big power.

[viven44]

That’s very interesting!!! I’d watch someone else do that all day!!

And no I haven’t any interest in pushing things to their limits for fun on the track. I guess that’s the 3rd world in me

[ArdWrknTrk]

Plenty of people in the 3rd world seem to like blowing things up.  😉

I sure know I do!!!  

[viven44]

 

[viven44]

My parents are here now on vacation and they simply do not understand why I’m working on my cars “like a mechanic”. I asked them if they have never heard of people collecting cars where they live. According to them that is a hobby for the ‘Elite’ only… museum grade typically… so evidently hot rodding is not for the common man, sadly in the third world. You can probably see Where I get it from.

[ArdWrknTrk]

Tell them I send my welcome!  

I don't know how the weather is down in Tamil Nadu, but I see it's ferociously hot in Delhi.
Maybe early summer in Tejas is normal for them?

[viven44]

Thanks!

In Tamil Nadu, the peak summer is in April, May, but the temp alone isn't a good indication of how mad it is out there. Comparing temperatures alone the summers are no different from Texas. The Extreme Humidity over there is what kills it. I swear only the trees love it. They have a year around growing cycle. Exterior Paint on homes only lasts a few years before moss growth destroys it

[ArdWrknTrk]

So, it's very pleasant for them!  

I'm surprised that 3rd world countries aren't still using lead paint.
Nothing grows on that, and it lasts nearly forever.
(Let me tell you about the mercury anti-fouling paint I used to grind off the bottoms of boats -with nothing but a bandana tied over my face -).

[ArdWrknTrk]

Are your parents still in town?




One "barn fresh" 650 AVS in the box....  

[viven44]

Yes they are. They reminded me again today that I'm not a mechanic and should leave it to the professionals, ha ha.... my self-confidence this past month has been somewhat low...

And thanks for that Edelbrock 650 AVS!! Hope to put it to good use someday. You will need to send me your paypal or whatever else you prefer.

[ArdWrknTrk]

Drop it on!  😈
It works well enough on my truck.
Certainly much easier to tweak to perfection!

A 460 in a little Bronco should rip!

JBG and L&L started this mess, putting 385's in lightweight trucks with their conversion mounts, flywheels, headers and the like.

[viven44]

I shall endeavor to, my wife willing! I have exhausted just about all available resources (time) to fix what was broken....

And I am glad those guys started this mess. 7-8 city mpg (460) vs 10-11 city mpg (351m)..... its a wash. And as they say its all about the "smiles per gallon".

[ArdWrknTrk]

You have to really push hard to get 7!

Plowing snow or over 90 constantly.

[viven44]

Installed a different return spring for the "power enrichment" system. Since my vacuum reading was high the stock spring took too long and I definitely had a lean bog. I went to the 8" Spring and it is definitely doing a lot better



 

[85lebaront2]

There are also different step up rods (metering rods) with different diameters. Chrysler used a two stage piston that required a taller cover and longer jets so the rods wouldn't come out of the jets. The piston had a small spring that in conjunction with the nain spring would give an early "tip in" at a slightly richer mixture. Holley did the same, but had a 2 stage power valve to do it.

The older Carter carbs, the WCFB, WCD, WGD had a mechanical limiter on the metering rod system that prevented them from going too lean at higher throttle openings. The ThermoQuad OEM models had a similar system and like the older carbs had the metering rods linked together with a single piston.