318 MAX fuel economy builds?

[mpgmike]

I’ll have to say my 1987 E350 Ford van with the 460 bought new and has 49,890 miles. Replaced the intake gaskets back 17 years ago, ..., removed the pumps and egr tubes at the same time. Rebuilt carb 3 months ago (sat for two years without starting) runs great and never saw any coke...

First, you disabled the EGR, so it couldn't contribute to any coking. Second, this may add credence to possible excessive blow-by causing heavy oils in the PCV on Rat Bastid's Ford.

For the OP, what is your budget? If it were me, I'd start with a good tune-up and get a base line first. If I improve things, I want to quantify how much. My definition of a GOOD tune-up is good air & fuel filters, new PCV valve (and probably replace the PCV hose to the carb, and clean the PCV port in the carb), and brass terminal cap & matching rotor (Blue Streak or NAPA Belden are 2 examples). Next, I'd use solid core wires. Granatelli makes solid core 8 mm wires with an EMF suppressor ring that will work even on the latest computer controlled engines (like the LS & G3 Hemi which still uses ignition wires). Third, I personally would use non-resistor spark plugs from Brisk. Yes, NGK, Autolite, Champion and so forth make "non-resistor" spark plugs, but they still use a 1k ohm resistance (instead of the normal 10k ohms in normal resistor plugs). Brisk's Silver line has less than 6 ohms of resistance (their normal non-resistor plugs measured in at 220 ohms). Believe it or not, I'd clean the EGR passages and verify the diaphragm holds vacuum; test the thermo-valves (in the radiator?) to make sure they worked. EGR can actually help in some operating ranges. Then I'd drive it for awhile to get some numbers.

While in this phase, I'd try tweaking the ignition timing 2 degrees one way or the other to see if it gets better. If worse, go 4 degrees in the other direction (2 degrees the other way from baseline) and test again. If better, try 2 more degrees. This is also the phase to iron out carb, tranny, electrical, and other issues. Assuming nothing tragic rears its ugly head, I'd work on the next phase in about a month or 3.

 

[Hysteric]

Actually the coking was fuel that was being almost consumed in the plenum.

Can you explain how the fuel was being consumed. "Consumed" implies being burned if that was the case the engine would have detonated itself to death and yet its still ran right?

Consumption takes place in the cylinder not the manifold. Your claim doesn't add up.



Yeah read this even closer from Greg K.

Vacuum in an engine occurs at many places,including valve areas,ports, carb drillings, cylinders etc..an engine uses vacuum to lower the boiling points of fuel molecules which in turn assists cylinders to create a pressure on the crank.
Vaporisation is the key to making power,smooth power,a pressure curve that has some grunt to it.
When you modify an engine you are at risk of generally drastically reducing the cylinders ability to vaporise the mixture,especially at the lower rpm levels of the engines operation.When you have this condition occurring it forces you to calibrate the carby and ignition to a compromise which in turn decreases the cylinders ability of getting to full power quickly when you WOT the carby.
When you increase the manifold vacuum you raise the vaporisation of the fuel mixture prior to entering the cylinders, its important to realise the importance of this.When you have a greater amount of fuel mix that is vaporised before the entry of the cylinders you end up with a more homogenous mix in the cylinder prior to ignition time,its very important to understand the need for this.

I can post many many more quotes from both Greg and Bruce from the the 3 forums that they were kind enough to explain this stuff on. I have saved every statement Bruce and Greg made concerning Carbs and Engines. That's a lot of info to correlate into a cohesive understanding of how this stuff works.

This is what Greg K said concerning Bruce's Carb when they swapped if for a well tuned Holley. What did Bruce's Carb do to allow that I wonder.....

both are at WOT.
both venturis are on the same side of the engine.
with the holley the combustion on that side is upsetting the flow out of the holley booster.
on the smartcarby it is not.
with the smartcarby the combustion changed dramatically.

Did you read this?

30+ years ago I built a 360 using 318 cam, 318 open chamber heads (because the 302's weren't out yet), 318 intake & carb, and 318 exhaust manifolds. It was a 0.030" overbore using 1971 flat top pistons (no dish). As I recall, it ended up with a 10.8:1 static compression ratio. It was installed in a 1974 W-150 pick-up. It got 23-24 MPG HWY, and could pull a house on 87 octane fuel (quote from the truck owner).
3) Cylinder heads:
- Higher port velocities = higher efficiencies (BSFC). This has been extensively covered by the likes of David Vizard, Larry Widmer-TheOldOne, and numerous others. It isn't just port size, but eliminating dead zones where fuel can fall out of suspension.

Mike must have just gotten lucky with his engine not coking up.........Don't let the "higher" port velocities trigger you though.

Cant wait for "that's not what im saying" routine.......

 

[Rat Bastid]

Can you explain how the fuel was being consumed. "Consumed" implies being burned if that was the case the engine would have detonated itself to death and yet its still ran right?

Consumption takes place in the cylinder not the manifold. Your claim doesn't add up.



Yeah read this even closer from Greg K.



I can post many many more quotes from both Greg and Bruce from the the 3 forums that they were kind enough to explain this stuff on. I have saved every statement Bruce and Greg made concerning Carbs and Engines. That's a lot of info to correlate into a cohesive understanding of how this stuff works.

This is what Greg K said concerning Bruce's Carb when they swapped if for a well tuned Holley. What did Bruce's Carb do to allow that I wonder.....



Did you read this?



Mike must have just gotten lucky with his engine not coking up.........Don't let the "higher" port velocities trigger you though.

Cant wait for "that's not what im saying" routine.......

Give me a bit and I’ll read ALL your bullshit once again. What you don’t get is you live to tie a bunch of **** together that doesn’t go together.

For example, you LOVE to quote Shrinker (like above) where he says the engine is down on compression and to unfuck that deal he played with the carb.

I don’t usually do that. I fix THE issue. If you can select the proper cam timing and compression ratio then you don’t need to make the bullshit claims you do that you MUST aerosol the fuel out of the booster.

Ill read the rest later.

 

[Hysteric]

I don’t usually do that. I fix THE issue.

Both Larry Widmer and Bruce Robertson stated that they have managed to run 21-1 compression ratios In engines and Bruce said he'd managed to do it with pump fuel.

What issue were they fixing to be able to do that?

 

[Bewy]

Post #351. Non resistor plugs use a 1000 ohm resistor. Disagree with this. Have measured many non-res plugs over the years, NGK Champion, & measure close to zero.

 

[mpgmike]

Not sure why, but the NGK I tested showed around 9xx ohms. Furthermore, all their spec sheets show 1k ohms as well.

 

[Hysteric]

I Aim for 0.5 Ohms. I'll take a multimeter to the shop and test every plug. You would surprised how many plugs have less than ideal resistance.

 

[66fs]

So I'm looking into buying a long-distance capable daily driver. I have my eyes on a Dodge Diplomat and Chrysler 5th Avenue. Both have 318s and I thought it may be of my own interest to buy one as a daily as they are things I can work on instead of things I would need to take to a shop. In the case that I buy one or the other I would like to build the 318 for high fuel economy, I'm talking like 20+ mpg if possible. Anyone done this? Any input? Etc. Let's coffee-table talk daily stuff instead of high horsepower for once.

Should be doable without all the "theory". Main thing will be the carb, exhaust and ignition. Assuming both have a 2.45 rear, the first is a a good ignition. I run Taylor Spiro Core wires, platinum spark plugs, new cap, and new rotor. Convert to Chrysler electronic if you have any ignition problems. Play with timing to run as much advanced as the engine will allow. The best carbs for mpg are the 73?-75? BBD Carter with the adjustable rod hanger, Thermo-Quad, and the Quadra-Jet (318 and 360 trucks and vans). We could get 25 mpg with a factory 75 Cordoba 318 BBD and have gotten the same or better with the Thermo-quad. A good Quadra-Jet should be close to the Thermo-Quad. Use a Performance or Vacuum gage.

 

[Rat Bastid]

Both Larry Widmer and Bruce Robertson stated that they have managed to run 21-1 compression ratios In engines and Bruce said he'd managed to do it with pump fuel.

What issue were they fixing to be able to do that?

Im talking about the quote YOU posted and what Bruce was discussing.

As you love to do, you extrapolate things together so you can claim how smart you are.

Stay on topic for once.

 

[Hysteric]

Im talking about the quote YOU posted and what Bruce was discussing.

As you love to do, you extrapolate things together so you can claim how smart you are.

Stay on topic for once.

Here's more:

When you listen to a hotrod engine builder who restricts the compression to 185 for pump fuel you are listening to a builder who has poor homogenization. If the Homogenization is poor it means that there are larger distances between droplets which correlates into more heating of the air and less heating of the fuel. It’s the temperature of Oxygen that matters. Oxygen is the starter of combustion NOT the fuel. So when you have poor homogenization you have to reduce the compression pressure to avoid overheating the oxygen and causing it to react too fast and build a detonating pressure.

Hint, if you decrease droplet size you will increase vaporization at all points especially in the zones where its inhibited by the type of compression
That’s what carby sizing does too. The whole intake system is a vital part of the vaporization.

These cranking pressures can definitely be run however you have to have vaporization and homogenization to run them successfully.
Lots of people run higher octane fuel than what they really need to prevent detonation caused by lean burning at the early stages of the burn caused by lack of vaporization

This is one of my favourite's:

The vaporization level of the fuel at spark time affects the voltage needed to initiate current flow. its called the ionization voltage. the richer the environment is the less voltage needed for ionization. The richness of the environment is related to the homogenization and vaporization thats achieved prior to ignition its got nothing to do with the overall AFR. You can have a really rich 11:1AFR tune that is actually leaner than stoich around the plug at ignition time. That is a very common problem and its mainly caused by carburetor design and fuel separation in the ports and lack of compression pressure and time.

Imagine carb design causing an issue who could have possibly thought.

 

[Hysteric]

Should be doable without all the "theory"

Its all about vaporization which leads to combustion efficiency which leads to increased mileage. If you don't vaporize the mixture you don't burn it. More importantly improved vaporization leads to improved homogenization with increases the detonation resistance. If you do that you can run more compression.......Hmmm wonder what that might do for mileage.


Its not a theory its how it works.....

 

[Dartswinger70]

Stoichiometric ratio 14.7 :1 ? is dat wat ya mean...?

 

[Hysteric]

Stoichiometric ratio 14.7 :1 ? is dat wat ya mean...?

Yes. There is far more to detonation than just Octane ratings.

 

[Rat Bastid]

Here's more:







This is one of my favourite's:



Imagine carb design causing an issue who could have possibly thought.

I agree with ALL of the above. You also made one of my points. And that is not enough compression.

This place is the perfect example of not running enough compression and falling in love with compression numbers.

Nothing, not even a DEAD stocker should be built with less than a MEASURED 10:1 CR. Thats the MINIMUM.

And I agree that there are carbs that do a horrible job of atomization, or at least they aren’t correct for the job it’s been asked to do.

That doesn’t mean every carb needs an aerosol booster. Not every engine wants that.

 

[Hysteric]

I agree with ALL of the above.

I've been saying the same thing..........As Bruce stated its always about Vaporization and Homogenization

That doesn’t mean every carb needs an aerosol booster. Not every engine wants that.

Every engine will benefit from proper Vaporization and Homogenization.

 

[Rat Bastid]

I've been saying the same thing..........As Bruce stated its always about Vaporization and Homogenization



Every engine will benefit from proper Vaporization and Homogenization.

Damn dude. Take I’m agreeing with you for the win FFS.

The only thing I disagree with is YOUR interpretation of what atomization, vaporization and homogenization should look like.

IMO, it’s not a one size fits all proposition. You take a hot intake manifold and an aggressive booster and you WILL lose power.

Like reading a spark plug, you have to let the engine tell you what it wants.

 

[mgoblue9798]

Jesus. Enough with the back and forth BS already. Handle it in PM's if you must.

OP asked for ideas on how to achieve his goal of 20mpg with a 318 build.

If you don't have any helpful suggestions for him along those lines then just don't post in this thread.

 

[Dmopower]

Is there a stand alone spark control aftermarket unit for these engines? Something that advances spark just below ping? I remember 30 years ago Jacobs energy team made something. Are they still available?

 

[Rat Bastid]

Jesus. Enough with the back and forth BS already. Handle it in PM's if you must.

OP asked for ideas on how to achieve his goal of 20mpg with a 318 build.

If you don't have any helpful suggestions for him along those lines then just don't post in this thread.

I gave advice. You weren’t paying attention.

 

[Hysteric]

You take a hot intake manifold and an aggressive booster and you WILL lose power.

Something to think about:

We made a water heated intake manifold plenum where the fuel exited side draft carbys and impacted upon the water plate, The corrosion on the plate was high so the methanol was being vaporized effectively. The plenum volume was 8 times one cylinder, the carburetors were internally modified to decrease droplet size using my Smartcarby technology.
The purpose of the modifications we did was to decrease droplet size considerably thus decreasing vaporization time, that allowed high RPM. The limitation of the engines was vaporization not breathing.

You don't know unless you try.

 

[Hysteric]

Jesus. Enough with the back and forth BS already. Handle it in PM's if you must.

OP asked for ideas on how to achieve his goal of 20mpg with a 318 build.

If you don't have any helpful suggestions for him along those lines then just don't post in this thread.

The discussion is pertinent to the topic. If you think its as simple as just bolting parts together without understanding what they are actually doing to improve mileage then you are kidding yourself.

 

[Rat Bastid]

Something to think about:



You don't know unless you try.

If I had to use heat (speaking of the intake tract here) to aid in vaporizing the fuel I would much prefer to do it with coolant.

I ASSume that’s why Chrysler had some wildly popular water heated intake manifolds. In fact, I’m sure there were several of those types of manifolds made over the years.

IMO, exhaust heat is just not consistent enough to use to aid in vaporization. Coolant (heated coolant) would be much more consistent, although you wouldn’t get much help from it on cold starts until the engine temp came up.

 

[Dmopower]

If I had to use heat (speaking of the intake tract here) to aid in vaporizing the fuel I would much prefer to do it with coolant.

I ASSume that’s why Chrysler had some wildly popular water heated intake manifolds. In fact, I’m sure there were several of those types of manifolds made over the years.

IMO, exhaust heat is just not consistent enough to use to aid in vaporization. Coolant (heated coolant) would be much more consistent, although you wouldn’t get much help from it on cold starts until the engine temp came up.

IMO, exhaust heat is just not consistent enough to use to aid in vaporization. Coolant (heated coolant) would be much more consistent, although you wouldn’t get much help from it on cold starts until the engine temp came up.

Why not both?

 

[Rat Bastid]

IMO, exhaust heat is just not consistent enough to use to aid in vaporization. Coolant (heated coolant) would be much more consistent, although you wouldn’t get much help from it on cold starts until the engine temp came up.

Why not both?

I suppose you could use both (and someone probably did) but at some point you get the fuel vaporized too soon and that hurts power.

You have to find a balance between vaporization and what your booster delivers verses power output.

 

[Dmopower]

I suppose you could use both (and someone probably did) but at some point you get the fuel vaporized too soon and that hurts power.

You have to find a balance between vaporization and what your booster delivers verses power output.

So I'm learning on the fly here and I don't have an opinion as to which of you is correct or even if you are on the same paragraph of the same page.

But I have an idea about using both water and exhaust. I use Air-Aid 1" 4 hole spacer with threads. I'm taking it to the shop as soon as it gets here to have the perimeter center drilled 3/8" and tapped to run water through. I'm also taking a 1" 4 hole spacer with smooth ports that have the lines in the ports to catch the fuel as the book recommends. I'm taking the second spacer to the machine shop to have it drilled and tapped and I'm going to tap the heat cross overs on the manifold and run them through that spacer.

It will go like this. Manifold, Thin square hole gasket, 1" 4 hole regular spacer with scoured ports and exhaust going through it, 1/4" 4 hole insulated gasket, Air-Aid 4 hole spacer with water through it, 1/4" 4 hole insulated gasket, Carb.

The carb remains cooled enough by the coolant plate and thermo spacer, the fuel come from the carb and is thrown against the sides by the vortec. the threads act as fins and have more contact point for heat transfer. As this fuel spins down it comes into the spacer with exhaust in it and it's hotter. The fuel is tossed against the sides and falls into the groves which are super heated by the exhaust but below what I researched to be an issue. Thus creating a hotter and hotter mixture as it drops and the port wall conditions are there to take advantage of it.

Thoughts?

The heat from the exhaust will come on fast but it will not over heat the carb as the insulated gaskets and water in the top plate will dissipate the heat.

I been working on this idea and am in the process of building this and testing it out.

Thoughts?