Ethanol Laced Modern Gasoline -Carburetor and FI fuel meter temperatures

[Michael G.]

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

An update to my earlier posts here: today I went for a 30 mile ride in my 63 L84, burning 110 race fuel, in 92 degree ambient, after making the alterations to my fuel lines more permanent. I insulated all the way from under the battery tray to the fuel bowl inlet (with the fuel pump left uninsulated). At the end of the 30 miles the idle was stable at 750 RPM. I turned the car off and let it sit with the hood closed for 15 minutes. It then restarted it easily and the idle was still stable at 750. I then drove 30 miles home and opened the hood. I can't measure much else with the new insulation, but the fuel bowl measured 133 degrees.

The car ran VERY well the whole time, even better than normal at 72 ambient. I'd say the changes are very effective.

My tank is about empty, so I may try a tank of 90 octane no-ethanol fuel, to see the result on performance and fuel bowl temp..

[Duke W.]

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

... a 15 degree drop. Actually, you should try some E10 and see if there are any driveabililty or hot start problems.

Duke

[John M.]

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

65 FI sitting running 1000 rpm 1/2hr in driveway, first time it rolled on it's own since 2010. The engine was not rebuilt, just cleaned up inside and out, minor head rework, rebuit FI, etc. 100 octane avgas (!)

Temp ouside 81
Fueline at frame 135
fuel pump, fuel filter 118
Fuel bowl(?) 125
Copper tubes under plenum 125
fuel injectors, front 130, rear 140

fill tank 140
therm housing 153
top hose 146
Top of radiator 172
bott hose 118
bypass hose 161
temp gage boss 146
Temp gage in car 180
The car would have idled all day at 180, NO Leaks!!

Parked with hood down 10 minutes
Gasline, pump, filter, doghouse 120
therm housing 169
rear injector 146, front 142
copper under plenum 140
water pump 187
bypass 180

That's it, except the damn thing sounds great.

[Steven S.]

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

Duke here are my numbers. I have a '63 with a replacement 66 block. Bored 40 over, 300hp with a 350 hp cam. Electronic distributor - no vacuum advance to carb. Intake, exhaust and carb are all '63 with AFB carb with spacer. Drove 30 minutes in stop and go traffic never over 40 MPH. Heat soak for 5 minutes for second readings. Using pump 87 with up to 10% ethanol.

Ambient temp 92 F
Temp gauge 190 estimate (to right of zero in 180)/ 215?
Termo housing - 205/222
Fuel line from pump to carb. 187/210
Frame rail to pump 186/185
Front of Carb 156//163
Rear of Carb 191/168
Fuel filter 174/171

[Duke W.]

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

Are you saying that you have a '63 cast iron manifold with the phenolic spacer and metal heat shield under the AFB?

On AFBs the sides of the carb down low should be shot with the IR gun, which is the bottom of the fuel bowls.

Your temperatures are very high. Are you having any driveability or hot start problems?

Are your carb temperatures correctly reported? I am suspicious of a 35 degree difference at the two points of the carburetor.

Duke

[Steven S.]

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

Yes to first question.
Shot carb in front and back, not side. Numbers are correct, no driving issues at all.

[Steven S.]

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

No driving issues at all. Temps list are what I got. Shot front of carb, not sides. Answer to your first question is yes.

[Clem Z.]

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

to get a good reading with a IR gun you need a flat black surface so you should paint each surface flat black to get a true reading

[Michael M.]

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

Hi guys,

Duke, you were looking for L79 numbers. Here are mine. After a 45 minute drive idling at 800 rpm. / 5 minutes after shutdown. Air temp 92 degrees.

Temp Gauge 210/215
Thermo hous. 187/198
Fuel line @ frame 158/161
Rubber line 174/148
Fuel pump 163/153
Chrome line@ inlet 181/208
Chrome @ bend 164/199
Bowl front 143/149
Bowl rear 159/156
Intake below gasket 203/208

It's a stock 327/350, stock aluminum intake, thin fiber gasket, stock 3367 list carb, newly rebuilt. N40, side exhaust, stock exhaust manifolds. Heat riser functioning properly. FWIW, 93 octane pump gas, no additives. I wasn't sure where everyone measured the fuel line so I measured the bend at the top (in the air, coolest spot) and just before the carb inlet. At the bottom it was same as the fuel pump. FYI, the exhaust manifolds were 310 drivers side, 288 pass side after 5 min. Carb temps drivers side. A hot one in NY!

Mike

[Duke W.]

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

Thanks for the data. I don't understand what you mean by "exhaust intakes". Can you be more specific regarding what area this is.

Getting a temperature reading on the manifolds is a good idea. Shoot the outboard surface of the "crotch" where the two branchs from the front and rear merge. With full time vacuum advance and the correct range of total idle timing, they should be no more than about 500F.

Did you have any driveability problems during the drive or while idling after the drive?

One thing I'm seeing is higher rear bowl temperatures on Holleys. This makes sense since there is very little fuel flowing through them. Even with the heating prior to entering the carb, fuel flow through the front bowl has a cooling effect.

Duke

[Michael M.]

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

Sorry Duke, it must be "brain-lock" something akin to vapor lock. It has to be the heat. I meant the exhaust manifolds. Actually, I shot them at exactly that spot. It was the hottest spot on the manifolds at the time (5 minutes after shutdown). Next time out I'll shoot them while it's running to see what I get. BTW, I left the hood open for the 5 minutes. Maybe I'll do it again with the hood closed, if it makes a difference to your study.

As far as driveability, it was the usual with this car. It runs better as it gets warmer. It really likes the heat. It idled nicely with no stumbles and drove the same way. It is an L79, so it sounds a bit "lumpy?" but the engine doesn't rock or wiggle or anything at idle and it holds pretty steady at 800 on the dash tach, which is a bit fidgety anyway. I don't really know what cam/pistons/other internals are in it, it's at 75,000 miles and It looks original inside. I had the intake and oil pan off at the same time and it certainly doesn't look new, but you never know.

I did notice that the drivers side runs hotter than the passenger side, even with the carb. The numbers were lower on the passenger side for the bowls as well as the exhaust manifolds. The intake was the same 203/208 on both sides, just under the carb gasket.

I'm looking forward to a serious tune-up. I printed your notes from the convention and along with the service manual, etc.. I'm looking to make it run as good as I possibly can. I'll let you know how I make out. I'm glad they posted it and sorry I missed it.

Mike

[Stuart F.]

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

Duke;

Before I forget it, your point about trying E10 is well taken. My original purpose for experimenting with easy modifications to control the hot soak percolation was to find a way to live with E10. I believe I have reached that goal, but fortunately along the way Michael Hanson gave me the heads up on where and how to find sources for non-Ethanol fuel. The registry showed one station about 17 miles from me that was supposed to have 92 octane non-E gas. Well, by the time I was ready for a refill, I traveled there only to find their product was 90 octane. The proprietor told me his supplier had resently changed (lowered) the octane and he would not be able to get the better fuel anymore. I expect that the same thing will happen to the 90 octane too in the not to distant future, and I will be forced back to E10 anyway. A lot of boat owners (his main clientele) will be very unhappy, but then their votes don't add up.

When it happens, I'm ready. If they force us to E-85, well, then we're all in trouble and our vintage cars will only be of value to museums - 10 cents on the dollar.

You've been getting some interesting data.

Stu Fox

[Duke W.]

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

Stu - there's no way a vintage car or even a modern car that was not designed to use ethanol up to 85 percent will run on E85. There has been a move toward E15, but there is a lot of pushback. I think EPA approved E15 as optional, but I don't think the wholesale or retail industry is going buying in.

Michael - given your high recorded temperatures, I'm surprised you're not having percolation-like driveability problems. What part of the country do you live in and what fuel are you using? Are you getting any detonation?

Measure the head gasket thickness at the corners of the head-block interface. If it is .018" it's likely that the heads have never been off since Fllint bolted them on.

The best time to shoot the manifolds with the IR gun is after a few minutes of idling following a good drive. They rapidly cool at engine shutdown, but if they are no more than about 500F after a few minutes of idling following a good drive, your idle mixture and spark advance are in the ballpark.

For the approximate five minute heat soak after shutdown, the hood should be fully closed - just like it would be if you made a stop for gas or a cup of Starbucks.

Duke

[Michael M.]

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

Duke,

I live in New York, on long Island. It was hot but not really humid today, around 92 when I left. I usually fill the vette up with Sunoco 93 octane, which I did before my drive today at a station in Huntington, NY. Today there was a 46 foot cigarette on a trailer and they were filling up as well. The owner said that it's the only place he buys gas for his boat. It had triple 575 HP big blocks, so I guess he doesn't go too far. As far as I know, it's not non-ethanol gas.

The drive was about half stop and go and some longer runs with speeds up to 65, but most of the longer runs were between 35 and 50 mph. All right around sea level on the north shore. The temps didn't get that high until I stopped and let it idle. It ran around 180-190 on my temp gauge while driving. I rarely have a stall on take-off, but usually only when it's real hot. It's always run better as the temp gets to around 180-190, especially in cool weather, although it takes some time to get it up that high. I think I'm running a 160 degree thermostat. In hot weather it's wide open anyway. I should probably swap it out for a 180 in winter. It idles great and I've never had any detonation. I've had some long drives on one of the parkways in bumper to bumper traffic in really hot weather last summer and it never detonated or stalled, but I did feather the throttle a little a couple of times when I felt it stalling, but it cooled down nice and ran well once the road opened up again. Without AC it's not that much fun to drive in really hot weather anyway. It gets pretty hot inside unless you're on the highway and moving pretty good. If it's cloudy I take the top down and it's better. I definitely drive it more often when it's cooler. I had the carb rebuilt and restored last year.

When you ask about detonation, do you mean a backfire through the tailpipe or do you mean knocking and pinging (my GMC truck knocks and pings when I don't use premium gas)? It backfires occasionally. Less so since I replaced the intake gasket last summer (it was leaking oil). I may have changed the timing some when I replaced the distributor.

Mike

[Duke W.]

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

Detonation is pinging/knocking,

Duke