Air-Cooling a Water-Cooled Engine

[FElony]

Yes, it's a Monkey Talk kinda topic!!

Let's say you can devise a pump that can push air into the water inlets at the front of the block at approximately the same pressure that the water pump produces. Remove "freeze" plugs, thermostat/housing, hoses, radiator, fan. Maybe put air exits at rear of manifold? Using ambient air instead of hot water, can the engine achieve homogeneous thermal dispersion (<--monkey) at some point in a range that allows for reliable operation?

The scenario is this: There is a local drag venue that runs 200 feet on dirt, and allows everything from your daily driver to thingies with zoomies and paddles in back. Two lane staging, long but moves quickly due to short duration runs. Stage, then full throttle for 4 seconds or so, then back to idle. Intent: reduction of weight from the nose of the vehicle to aid traction in dirt. Horsepower: approx 350-450.

Team Avian will argue for the possibility. Team Aquarian will say that nothing beats a gusher pusher.

[Rory428]

FElony, are you eating those brownies being sold by a guy at the park with dreadlocks again?

[Heo]

I have actualy seen something like that on a Model-T Engine. there you have water in
on the side of the block. They had put a funnel on the water inlet pipe and modified
the fan bracket so the fan was blowing in to the funnel If it worked i dont know
the engine wasn´t seized up atleast

[jayb]

There has to be a way to evaluate that engineering-wise, but I don't know how to do it.  I suppose it would boil down to (pun intended) how well the heat transfers to the air, as opposed to a liquid coolant...

[FElony]

There has to be a way to evaluate that engineering-wise, but I don't know how to do it.  I suppose it would boil down to (pun intended) how well the heat transfers to the air, as opposed to a liquid coolant...

Pulling the hood off any car improves engine temps, no?

[machoneman]

Why not just run water in the engine, no pump, belts, pulleys, etc?

As others did then and now, we ran our Boss 302 injected gas FED with just head/block water, no other circulation system nor radiator. Run time from warm-up, burnout, staging and a mid 10 second run must have been 2-3 minutes. Petcocks on both sides let the now pretty hot water out in seconds. A quick cool-down, more tap-temp water loaded in through screw-off tops to the Enderle injector intake top water fills at the front and we were ready for another run.

Keep in mind the entire water jacket system in almost any V-8 can't even be 5-6 quarts @7.7 lb.s gallon = 12 lb.s or so. Even an FE can't hold but say 6 quarts or about that 12lbs. max. We'd fire the engine dry for about 1 minute after a teardown but that was only to ascertain the copper head gaskets w/aluminum paint sealed up. Be sure if you go this route to add topside water exits lines (think: small diameter F.I. SS lines) at the engine's back to allow hot water to escape below the chassis.   

[thatdarncat]

I don't have any real answers backed up by engineering studies or math or anything, but it's not unusual for a few drag race classes to run without a traditional cooling system at all. Especially examples like you mentioned that are short duration, and often if they are alcohol fueled. The race cars will be towed to the starting line though, so under your example it would have to be determined if that was allowed by the rules. But just running without a cooling system isn't treading any new ground, I'd guess any experienced engine builder who has done that combo could spec what was needed. 

I would question the premise though, if just to save weight, for that short of a run the liquid cooling system needed is pretty small. A tiny radiator, a couple gallons of water, and a small electric pump is all that is needed, maybe a small fan. Small, light aluminum/plastic radiators are available at any pick-a-part salvage yard on the cheap if a budget is important. Your example of possibly coming up with some kind of air pump would most likely add back in the weight saved over a liquid cooling system.

Would the rules allow an air cooled engine? Why re-engineer the engine if someone has already done the work for you. I've seen people build some really light dragsters with snowmobile engines for example. Just throwing it out there, lots of possibilities, but what is or isn't allowed by the rules is the first hurtle. 

[Rory428]

Why not just run water in the engine, no pump, belts, pulleys, etc?

As others did then and now, we ran our Boss 302 injected gas FED with just head/block water, no other circulation system nor radiator. Run time from warm-up, burnout, staging and a mid 10 second run must have been 2-3 minutes. Petcocks on both sides let the now pretty hot water out in seconds. A quick cool-down, more tap-temp water loaded in through screw-off tops to the Enderle injector intake top water fills at the front and we were ready for another run.

Where were racing this dragster? Back in the early 70s, there was a front engine dragster at Mission Raceway IN BC Canada with a stack FI Boss 302 with Hi Port heads. That you?

[FElony]

Why not just run water in the engine, no pump, belts, pulleys, etc?

As others did then and now, we ran our Boss 302 injected gas FED with just head/block water, no other circulation system nor radiator. Run time from warm-up, burnout, staging and a mid 10 second run must have been 2-3 minutes. Petcocks on both sides let the now pretty hot water out in seconds. A quick cool-down, more tap-temp water loaded in through screw-off tops to the Enderle injector intake top water fills at the front and we were ready for another run.

Keep in mind the entire water jacket system in almost any V-8 can't even be 5-6 quarts @7.7 lb.s gallon = 12 lb.s or so. Even an FE can't hold but say 6 quarts or about that 12lbs. max. We'd fire the engine dry for about 1 minute after a teardown but that was only to ascertain the copper head gaskets w/aluminum paint sealed up. Be sure if you go this route to add topside water exits lines (think: small diameter F.I. SS lines) at the engine's back to allow hot water to escape below the chassis.

Staging lane times could reach 15 minutes later in the evening when it gets busier. Nowhere to dump hot water. Keep in mind that we get into triple digits here, so coming off the trailer the block is already warm.

Anyone put a cyl head temp gauge on their engine?

[FElony]

I don't have any real answers backed up by engineering studies or math or anything, but it's not unusual for a few drag race classes to run without a traditional cooling system at all. Especially examples like you mentioned that are short duration, and often if they are alcohol fueled. The race cars will be towed to the starting line though, so under your example it would have to be determined if that was allowed by the rules. But just running without a cooling system isn't treading any new ground, I'd guess any experienced engine builder who has done that combo could spec what was needed. 

I would question the premise though, if just to save weight, for that short of a run the liquid cooling system needed is pretty small. A tiny radiator, a couple gallons of water, and a small electric pump is all that is needed, maybe a small fan. Small, light aluminum/plastic radiators are available at any pick-a-part salvage yard on the cheap if a budget is important. Your example of possibly coming up with some kind of air pump would most likely add back in the weight saved over a liquid cooling system.

Would the rules allow an air cooled engine? Why re-engineer the engine if someone has already done the work for you. I've seen people build some really light dragsters with snowmobile engines for example. Just throwing it out there, lots of possibilities, but what is or isn't allowed by the rules is the first hurtle.

The reason a small water system wouldn't work is wait time at idle over 100 degrees ambient. No real rules there. Mostly meant as a fun thing, so you'll see ATV's and 2-wheeled stuff and what not. No tech inspection.

[plovett]

I think air is much much less dense than water.  That would be the primary problem.  For a given volume you will have so many less molecules to transfer the heat to.  The most efficient way to transfer heat is by having your coolant go through a phase change.  Generally that means using your heat to boil a liquid.  It takes heat energy to increase the temperature of a liquid, but when the liquid goes through a phase change, to a gas, then a whole bunch of energy is transferred.  It's not easy though because then you have both liquid and gas in the same system.  Shit, sorry for rambling, but long story short I don't think so on using air.  Heck, even "air cooled" engines are partially oil cooled. 

JMO,

paulie

[plovett]

A constant loss cooling system might work.  I'm not sure if I have the terminology right, but what I mean is that you have liquid coolant in your engine, but it's not a closed system.  The coolant boils off and is lost/vented to the atmosphere.  You would have a coolant reservoir just big enough to run as long as you need it to.  Maybe you could time so the coolant was basically gone by the time you need to hit the gas.   

If traction is the goal, why not put most of the cooling system and coolant in the rear of the vehicle?  Much easier than trying to reengineer an entire cooling system. 

JMO,

paulie

[thatdarncat]

The reason a small water system wouldn't work is wait time at idle over 100 degrees ambient. No real rules there. Mostly meant as a fun thing, so you'll see ATV's and 2-wheeled stuff and what not. No tech inspection.

Since I don't have direct knowledge of this event, that still leaves lots of questions...

Are all these vehicles running in the same class?

With no rules and no tech...Build a pair of tube frame rails with the nastiest snowmobile or motorcycle engine you can find, skip everything else. It's your butt on the line so up to you if you feel the need for something like safety. If you're set on using a cast iron block check into using alcohol for fuel, engine runs much cooler. Used alcohol circle track carbs are easy to find. Can you tow a good sized water tank up to the starting line with you? then unhook it before making the run? Then you could get by with just the water in the block. Hook it back up after the run and circulate until the next run. They make quick connect liquid fittings. 

[machoneman]

Nope! Only raced here in the Midwest at Union Grove, WI and Rockford Dragway in Rockford, IL.

Why not just run water in the engine, no pump, belts, pulleys, etc?

As others did then and now, we ran our Boss 302 injected gas FED with just head/block water, no other circulation system nor radiator. Run time from warm-up, burnout, staging and a mid 10 second run must have been 2-3 minutes. Petcocks on both sides let the now pretty hot water out in seconds. A quick cool-down, more tap-temp water loaded in through screw-off tops to the Enderle injector intake top water fills at the front and we were ready for another run.

Where were racing this dragster? Back in the early 70s, there was a front engine dragster at Mission Raceway IN BC Canada with a stack FI Boss 302 with Hi Port heads. That you?

[Drew Pojedinec]

Alcohol for fuel
Evans for coolant.