Water Injection - Anybody Used it???

F

fiftyv8

Senior Member
I've been reading a little about water injection and see it was used during WWII and again in the late 60's and it would seem it is fashionable again now with the turbo and supercharger crowd.

Obviously the later crowd are driven by different needs to us Model A'ers, but has anybody employed it or considered water injection on their banger engines.

For folks like us it would seem there is an advantage in slightly increased HP, engine runs cooler, timing can be advanced more and a possibility of increased fuel economy, maybe a slight increase in compression and cleaner combustion chambers, not in any particular order of course...

The current crowd are seeking to run their engines cooler mostly caused by the huge HP modern engines can produce which then has heat as a by product, they are also adding 50% methanol or alcohol for what ever reasons.

Any way, I'd be interested to hear any thoughts or, we may even have an expert out there who could add more to this discussion.
 
Methanol (not ethanol) adds approximately 10% horse power but requires approximately 13 to 1 +compression to utilize it. Also it requires additional top lubricant to protect the valves. Also requires twice the volume of fuel. Can't see anything but problems putting it in a stock banger. Water injection also was utilized in high octane, high compression engines. It will however help clean combustion chambers. An old timer taught us the trick of pouring water down a warm engine carb at high rpm until it almost stalled and doing it several times. This knocked the rust off the valves and seats on a flathead that had sat for 20 years. After two tries it idled and ran well. Try at your own risk.
 
AHA ......[Also it requires additional top lubricant to protect the valves.]

Hmmmm ........ could this be one reason why they used MMO? LOL
 
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I had a beat up 51 Olds that smokes. One a month I gave her a coke bottle full of water. That cleaned up the valves and rings.

I flew B-50's for the Air Force. The 4360's had 6 minutes of water injection for added takeoff power. The water cooled the jugs some so more gas could be used. Several times I was very glad to have the extra boost.
 
Water injection was popular in racing two-cycle motorbike engines in the sixties. I never saw it make any difference to the finishing order!
 
the old flywheel engines(not all were hit and miss) often burned kerosene. the directions said to get the engine warmed up on gasolene then switch to kerosene and if there was a knocking sound you opened a valve to let a little water in until the knocking stopped. as i understand it the water raised the octane of the kerosene. a lot of older tractors also were set up to run on kero., but i don't know if they had the water injection feature.
 
The water didn't raise the octane any. Since water does not burn, it just cooled the combustion process enough to eliminate detonation.
 
I never flew the large radial engines like the 4360's like Clem Clement did so he is the expert here. But I recall learning about water injection used on the DC 7's. I think they were the CB17's. I went from 1820's in the DC3 directly to jets. So with a lot of technical knowledge missing, I did use a squirt bottle to inject water into the carb air intake of my fully warmed up and frisky RPM-ed Model A. I believe it helped. Some have said that I should not have done this, because they said that the cylinder pressure was too much. Kinda like detonation would be. I am not convinced that was correct in a non loaded model A engine at only a fast idle. So I will continue to do this unless some of you knowledgeable
persons explain why not to. It seems to me that if a leaking head gasket allowing water to enter the combustion chamber cleans carbon, that confirms to me the benefit of water injection as I did it.
I also think 40 Deluxe is correct. Water may have the effect like increasing the octane and may slow down the flame propagation as it also cools. I think it is an indirect consequent like octane increase but technically does not increase octane.
 
Back in the 1980's when gas prices increased markedly there was renewed interest in gas saving devices. The local technical college did some testing of water injection of carbureted engines and found that there was a slight increase in mileage per gallon with no noticeable loss in power and this was attributed to improved volumetric efficiency. The challenge was in metering the water injection at the optimum rate of flow per engine speed and load. Carburetors aren't designed to meter the input of both gas and water at the same time.
 
o.k. i had misunderstood the effect the water had in the old flywheel engines. the ones i have seen just had an adjustable needle to let some of the water from the cooling hopper be pulled in with the fuel/air mixture. i think kero. was cheaper in those days and so was a substitute for gasoline in the old engines and tractors. i've seen guys run engines on kero at the engine shows, boy they really stink.
 
My dad used to tell about plowing with a tractor running on kerosene (in the mid-'30's). After a few days of hard pulling the tractor would lose power due to carbon buildup on the valves, thus losing compression. The solution was to run the tractor on gasoline "until the valves healed up", as he put it. These engines had the exhaust manifold wrapped around the intake manifold to keep it good and hot to vaporize the kerosene better. Even then, a lot of raw unburned kerosene ended up in the oil. The oil pan had three petcocks, at different levels. After the tractor sat overnight, before starting in the morning you opened the top petcock and drained off the kero, then opened the middle petcock; if more kero came out, you drained that. If oil came out, you were good to go. The tractor was later converted to gasoline only. This involved a "cold manifold" (no exhaust heat) and popup pistons for more compression (gasoline was significantly higher octane). As I remember, the pistons came up almost a half inch above the block.
 
I had a Judson supercharger on a Volvo straight 4 cast iron engine. It boosted about 7PSI and the compression ratio was stock. I used water injection timed to a pressure switch, so it only came on near full throttle. It had an obvious positive effect on detonation. Because of the Judson, I was also running a MMO suction bottle. I wouldn't think it necessary on a normally aspirated car or Roots type charger. Just run at part throttle for the last mile to let everything dry out.

It does clean carbon.
 
Water is not compressible, so it raises compression pressure. Water will also absorb heat, so it has some combustion cooling effect. I have observed that water will do a good job of cleaning deposits from a combustion chamber.

Alcohol has more chemical energy than gasoline, but it requires more heat to combust it than gasoline.

Modern 87 octane gasoline enables the Model A & B engines to run with more spark advance, so I start with the factory advance timing. Then by iteration I the give the engine all of the advance it will take to avoid knocking under load in high gear.
 
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