Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

[Rob M.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Duke,

Here are some more numbers for you. Ambient temp +/- 68-70 and the numbers are at shut down and 5 minutes after. I used an IR gun from Harbor Freight (can't comment on accuracy, but seems to work fine). 1966, 327/300 4spd. with no mods.

Temp gauge: 175/180
Thermostat housing: 174/163
Fuel line from pump to carb: 166/170
Frame rail to pump: 118/112
front of carb: 150/145
Rear of carb: 160/155

Shooting the the carb near the mixture screw resulted in higher temps - mid 170's as I recall. But, I didn't write them down.

[Duke W.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Thanks for the data, Rob.

To all who submit temp data - shoot the carb bowls low - below the fuel level, which will give the best estimate of actual fuel temperature.

Right now I'm particularly interested in seeing some data for the early AFB configured 300 HP engine to see if that thermal spacer keeps the fuel bowls cooler. Correct me if I'm wrong, but my understanding is that the '66-'67 300HP engines had the Holley bolted directed to the manifold.

Duke

[Rob M.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Duke,

My Holley has a gasket and a metal baffle between intake and carb.

[Donald O.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Before I undertake my temp readings with my IFR gun, I'd like to hear some advice on how best to use it so as to get the most accurate readings. Mine has a MAX/MIN button to display same when held for one (1) second. The reason I ask is that I have noticed it will hunt a lot if I let it (trigger in), specially on manifold spots - both intake Water Manifold, and Exhaust Crossover, as well as Exhaust Manifolds. My Laser dot is some 8 degrees off actual measuring spot which one has to allow for as well. I bought mine at a "Sun and Fun" flyin in Lakeland, FL a number of years back and have replaced the battery at least once - so it may not be the latest tech.

Stu Fox

Stu,
As you just noted, using an IR hand held is the LEAST accurate way of measuring temps. Even if someone here decides to use thermocouples and a data acquisition system, most of the J and K types are only accurate to + 1.5*C. One really needs to be using a system pf PRTs (these are accurate to 2 decimal places) and measure both the gasoline in the pipes and bowl as well as the pipes and exterior of the bowls.
About 75% of the engines we test have a minimum of 48 thermocouples and we just finished a development program where this engine had 96 plus 4 sets of PRTs.

Don't get me wrong about using a hand held IR gun, they do have their uses: like getting a quick temp on a cooling hose or an exhaust manifold. Any other use is just a waste of T & M as they are not a calibrate-able (sp) temp monitor.

Don

[Clem Z.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Stu,
As you just noted, using an IR hand held is the LEAST accurate way of measuring temps. Even if someone here decides to use thermocouples and a data acquisition system, most of the J and K types are only accurate to + 1.5*C. One really needs to be using a system pf PRTs (these are accurate to 2 decimal places) and measure both the gasoline in the pipes and bowl as well as the pipes and exterior of the bowls.
About 75% of the engines we test have a minimum of 48 thermocouples and we just finished a development program where this engine had 96 plus 4 sets of PRTs.

Don't get me wrong about using a hand held IR gun, they do have their uses: like getting a quick temp on a cooling hose or an exhaust manifold. Any other use is just a waste of T & M as they are not a calibrate-able (sp) temp monitor.

Don

i also understnd they have a pretty large area they look at as it is not a pin point measuring device

[Duke W.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Stu,
About 75% of the engines we test have a minimum of 48 thermocouples and we just finished a development program where this engine had 96 plus 4 sets of PRTs.

Don't get me wrong about using a hand held IR gun, they do have their uses: like getting a quick temp on a cooling hose or an exhaust manifold. Any other use is just a waste of T & M as they are not a calibrate-able (sp) temp monitor.

Don

Who is the "we" you refer to? ...perhaps an organization that has the resources to conduct this project to a greater degree of accuracy? Would you care to volunteer to install 96 thermocouples on a dozen different vintage Corvette engine configurations to provide more accurate data?

In the meantime, I continue to request data as previously requested and as posted by several individuals - thank-you for your support! Read your IR gun instructions and be as accurate as you can be. I don't need temperature data to two decimal places accuracy.

Further, I request a second time that we keep this thread ON TOPIC! If you want to debate the efficacy or accuracy of this project, please start another thread.

Duke

[Donald O.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Who is the "we" you refer to? ...perhaps an organization that has the resources to conduct this project to a greater degree of accuracy? Would you care to volunteer to install 96 thermocouples on a dozen different vintage Corvette engine configurations to provide more accurate data?

In the meantime, I continue to request data as previously requested and as posted by several individuals - thank-you for your support! Read your IR gun instructions and be as accurate as you can be. I don't need temperature data to two decimal places accuracy.

Further, I request a second time that we keep this thread ON TOPIC! If you want to debate the efficacy or accuracy of this project, please start another thread.

Duke

OK, I'll install them, YOU BUY THEM.
You want data and you don't care if it is accurate?

Oh, and the "we" I referred to is a world class technological leader in engine technology and testing and development for ALL vehicle and engine OE manufacturers. When we provide data to our clients, its accurate, repeatable and certifiable.

To me this is ON TOPIC whether you agree or not. So just what IS your topic? Provide solution to problems that 90% don't have? Trying to get 40-50 tear old engines and their technology to perform at today's standards? And based on what....4 to 6 persons responses with highly suspect data?

[Clem Z.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

seems to me the answer to this question is that someone that is having this problem switch to 100% race gas for a couple of tank fulls to see if the problem is still there and if the problem goes away the 10% ethanol is the problem.

[Stuart F.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Duke;

FWIW, here is my test data. I ran the tests twice yesterday morning beginning @ 1130 hrs following rides of 20 minutes, and then later 30 minutes. There was a fair amount of traffic so I was only able to do a couple of short WOT to generate some additional heat:

Test Conditions:

- Ambient temp @ 93*+ and Humidity @ 44, light winds N/NE @ 10 to 12 mph. The first data upon return w/engine @ idle, hood open, filter removed. The second data after shut down (hot soak) w/filter installed, hood closed 5 to 10 minutes.

Engine Temp Gauge 175* 180*

Engine @ Thermostat Hse 175* 146* (Robertshaw type repro)

Fuel Line @ Frame 128* 125*

Fuel Pump 142* 140*

Fuel Line - Pump to Filter 162* 150*

Fuel Filter 139* 140*

Filter Hose to Carb 149* 141*

Carb (Choke Side) 133* 138*

Carb (Pump Side) 122* 130*

Carb (Back) 126* 141*

Carb (Front) 128* 140*

Additional Data:

Water Manifold (Drv Side) 161* 175*

Water Manifold (Pass Side) 162* 179* (@ temp sensor)

Radiator Inlet (top) 166* 133*

Radiator Outlet (bottom) 136* 138*

Water Tank 180* 143*

Man Ex Crossover (Drv side) 193* 170*

Man Ex Crossover (Pass side) 188* 154*

Notes: - Heat riser valve operational, full open during first test @ Idle
- Fuel: 90 octane "Non-Ethanol" w/Max Lead 2000 additive
- Full Ignition Shielding in place
- Pertronics electronic ignition conversion w/matching coil & full 12VDC input (Ballast By-passed)
- B28 (236) VAC w/Dyna-Flyte Plate
- corrected 12* initial, 38* total mech advance
- Champion J8 plugs (Inst 2002 w/10k)
- Lectric Limited "dated" plug wires (Inst 1998)
- Carter 3721SB (Replacement) carb w/phenolic spacer sandwiched btwn gaskets (main jetting same as 3461S)
- Electric Choke w/manifold mounted thermal sensor control

You probably won't consider my data useful for your purposes, but my changes from stock were done to deal with the ambient conditions here in Florida using (if need be) 10% Ethanol Laced fuel. The 3721SB on my engine now has the richer .037" idle/low speed jetting, plus the .104" primary jets w/std metering rods (.060" x .069") and transition springs. It is the best combo I have found to date. I would like to set up my 3461S to match, but I'd have to modify the primary clusters which would be permanent and I'm not ready to do that yet as it is too valuable.

This way of testing may not be Rocket Science (using a hand held IFR gun), but I bought it at an EAA convention - so if it is accurate enough for the flyboys, it should be good enough for my 49 year old engine, which BTW has never been apart.

I have a bunch of photos of my "Cool Mods" if any one is interested, I could post - perhaps in another thread.

Thanks for your patience.

Stu Fox

[Duke W.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Thanks for the comprehensive data set. You don't need any WOT time. The worse case is slogging around in low speed traffic.

It's my understanding that you have a rubber hose between the filter and carb inlet rather than the OE steel line. Is that correct?

Duke

[Stuart F.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Duke;

Yes, I use a 3/8" fuel hose from the filter to the carb for two reasons; 1) the added 7/16" gasket and spacer stack under the carb makes a stock steel line connection impractical (it can be done, but I didn't want to bend the filter and bracket), 2) my intent was to isolate the carb from the heat conducted through the steel lines, i.e. the hot air tube to the choke and the fuel line.

My desire to do some WOT runs was to generate more heat in the oil. The effect, I believe, would be to create more longer lasting heat in the engine (heat soak) and therefore a longer cool down time.

Stu Fox

[Duke W.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Thanks, now I need a 340 HP without the added insulator and also looking for L-79 data.

Highest oil temperatures in normal use are typically seen in heavy stop-and-go driving in hot weather. A few short WOT runs won't do much to heat the oil because of the cooling affect of speed. The way to get the oil really hot is hot-lapping a race track in hot weather.

Duke

[Stuart F.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Duke;

The reason I went after solving the problem with the fuel was that, in a hot soak condition, I could look into the carb and see the fuel bubbling out of the primary clusters. It was so bad that I had to change the oil three times, and my local Advance Auto Parts store would not accept my drain oil because it reeked of gas (not good). At that time, I was running a factory stock carburetion system (single base gasket, steel fuel lines and hot air choke) and a 160* thermostat.

My notes from then, with the tests I ran with my IFR gun, showed carb temperatures during hot soak (while dripping gas) to be 168* on the choke side, and 163* on the pump side. The thermostat housing was running 168* to 170*, and the water manifold temps were 180* (driver's side), and 175* (passenger side, at temp sensor). This was after about a 20 mile run at highway speeds (70 to 80 mph, and a few WOT), and a good 15+ minute hot soak in my garage. I don't know if this would be of any value to your data, but was the base line from which I compared my later modifications.

I hope you can get another stock 340 hp to provide some data. If I looked back through the archives far enough I could probably find a lot of my complaint threads based on my "stinky garage". Even after I thought I had the situation under control, I started to have a lot of fumes again when I was trying to sort out my 3461S carb. Then, I found those pesky little Vapor Vents on it which I have plugged. That seems to have corrected that for now.

Stu Fox

[George J.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

OK, I'll install them, YOU BUY THEM.
You want data and you don't care if it is accurate?

Oh, and the "we" I referred to is a world class technological leader in engine technology and testing and development for ALL vehicle and engine OE manufacturers. When we provide data to our clients, its accurate, repeatable and certifiable.

To me this is ON TOPIC whether you agree or not. So just what IS your topic? Provide solution to problems that 90% don't have? Trying to get 40-50 tear old engines and their technology to perform at today's standards? And based on what....4 to 6 persons responses with highly suspect data?

Correct me if I'm wrong, but if the components of the engine that are in contact with the fuel are at a temperature above which the ethanol laced fuel "boils" then there may be a problem with the ethanol laced fuels. If none of those components are above that temperature, then the fuel can't be "boiling". I would think that the methods here would be good enough to come to a conclusion about this, at least.

George

[Duke W.]

Re: Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

Duke;

The reason I went after solving the problem with the fuel was that, in a hot soak condition, I could look into the carb and see the fuel bubbling out of the primary clusters. It was so bad that I had to change the oil three times, and my local Advance Auto Parts store would not accept my drain oil because it reeked of gas (not good). At that time, I was running a factory stock carburetion system (single base gasket, steel fuel lines and hot air choke) and a 160* thermostat.

My notes from then, with the tests I ran with my IFR gun, showed carb temperatures during hot soak (while dripping gas) to be 168* on the choke side, and 163* on the pump side. The thermostat housing was running 168* to 170*, and the water manifold temps were 180* (driver's side), and 175* (passenger side, at temp sensor). This was after about a 20 mile run at highway speeds (70 to 80 mph, and a few WOT), and a good 15+ minute hot soak in my garage. I don't know if this would be of any value to your data, but was the base line from which I compared my later modifications.

I hope you can get another stock 340 hp to provide some data. If I looked back through the archives far enough I could probably find a lot of my complaint threads based on my "stinky garage". Even after I thought I had the situation under control, I started to have a lot of fumes again when I was trying to sort out my 3461S carb. Then, I found those pesky little Vapor Vents on it which I have plugged. That seems to have corrected that for now.

Stu Fox

You did a very good job insulating the carb from heat as you appear to have gone from the highest bowl temperatures in this data set to the lowest - a drop of over 30 degrees. In fact, I think if you ran some E10 the percolation problem will not be any worse than with the straight gasoline you are running now.

Are you willing to give E10 a try?

The problem is that the distillation curve of E10 flattens out in the 20 to 40 percent range. The straight summer blend gasoline distillation curve is fairly linear and rising from the 20 to 70 percent points. The summer blend E10 curve in the 40-50 percent range is like a winter blend straight gasoline, and the mid point is about 170 degrees versus about 200 for straight summer gasoline. The maximum 50 percent point for 100LL avgas from ASTM D910 is 105C, which is about 221F, so avgas has less tendecy to percolate than any mogas.

This is the source of the percolation problems that many owners are reporting with E10, and the cure is to reduce the amount of heat the fuel picks up from the fuel pump inlet pipe to the carb bowl. Hopefully, this can be done on most engine configurations without deviating too much from OE appearance, but it may take more.

I'm working on a graph that compares the distillation curves of typical summer straight premium gasoline, typical summer blend premium E10, and 100LL avgas. The differences in the distillation curves are obvious and dramatic.

Duke