Water cooled heads...can you oil cool them instead?

[fran9r]

Right. Air cooled engine.

To which I want to put a water cooled head. Yes, I know thats a fucking stupid idea. Stick with it...

The questions is, what would I need to do to make it work? Can I replace the water in the head for oil, taking a seperate feed/return and an electric pump? If I fed it through a cooler, would that be enough?

[Egg on Leggs]

Why would you want to use oil, water has better heat transfer qualities and is lighter.

[CMSMJ1]

the head gasket would go all the time as the cooler head would not expand as much as the warmer block...

[Andy J]

Just use an early GSXR engine and theyve done the job for you.

Air cooled barrels and an oil cooled head, twin oil pumps and all the difficult stuff worked out for you!

[Andy J]

Why would you want to use oil, water has better heat transfer qualities and is lighter.

But you need an extra pump to move the coolant around and a big radiator so the weight you save by using water is negated by this.

However, watercooling gives more control over engine temps. It also adds a sound deadening layer to the engine which in these Euro controlled days is a factor. The main reason the Suzuki stopped producing the very successful GSXR/Bandit engine was emissions and noise,the technology itself was fine for bikes over 20yrs after the engine was first thought of.

[Superdunc]

Oil is lighter than water volume for volume.

Head Gaskets won't be a problem.

Water will cool more efficiently. (one correct fact so far in this thread.)

You will not always need a pump if you use water, you can use the thermo syphon effect.

Plenty of people have done it, Porsche on some 911 variants, and plenty of 2t race bikes. You end up with a cooler combustion chamber, so you can run higher compression ratios, and/or ignition advance before detionation becomes an issue.

All aircooled engines rely on oil to cool them, Suzuki took the concept further than most though.

[fran9r]

Just use an early GSXR engine and theyve done the job for you.

Air cooled barrels and an oil cooled head, twin oil pumps and all the difficult stuff worked out for you!

Tell me more...where are the pumps located in the system, and is the oil cooled before or after going round the head?

[fran9r]

Plenty of people have done it, Porsche on some 911 variants, and plenty of 2t race bikes. You end up with a cooler combustion chamber, so you can run higher compression ratios, and/or ignition advance before detionation becomes an issue.

Excellent...do you mean an oil or water cooled head on an air cooled engine? If so, would you have any links or pointers?

[banoffee]

Tell me more...where are the pumps located in the system, and is the oil cooled before or after going round the head?

[Superdunc]

Excellent...do you mean an oil or water cooled head on an air cooled engine? If so, would you have any links or pointers?

Not something I've researched, but I did see a 50cc Maico GP bike a few months back. It had an air cooled head, which the fins had been machined down on , though not completely, and then had a fabricated aluminium water jacket welded around it.

A thermo-syphon system works because hot water is less dense than cooler water. The water in the head heats up and rises out of the top of the water jacket, replaced by the cooler water from the rad which wants to sink to the bottom of the system. Many cars relied on this system right up untill the early sixties.

[fran9r]

I might be being thick, but I can't see the cooler.

[fran9r]

Not something I've researched, but I did see a 50cc Maico GP bike a few months back. It had an air cooled head, which the fins had been machined down on , though not completely, and then had a fabricated aluminium water jacket welded around it.

A thermo-syphon system works because hot water is less dense than cooler water. The water in the head heats up and rises out of the top of the water jacket, replaced by the cooler water from the rad which wants to sink to the bottom of the system. Many cars relied on this system right up untill the early sixties.

Sounds interesting...

I'm trying to use a water cooled head on an old air cooled engine. For looks, I don't want a water radiator and fan, but I'm thinking I could hide an (usually smaller, without a fan) oil cooler, maybe under the engine, or somewhere.

As the head is water cooled, I was thinking get some 'fins' cut to make it look (to a casual observer at least) like an air cooled head, but hiding all the double overhead cam and a million valves of a modern engine.

Simples. Ahem.

[Superdunc]

Sounds interesting...

I'm trying to use a water cooled head on an old air cooled engine. For looks, I don't want a water radiator and fan, but I'm thinking I could hide an (usually smaller, without a fan) oil cooler, maybe under the engine, or somewhere.

As the head is water cooled, I was thinking get some 'fins' cut to make it look (to a casual observer at least) like an air cooled head, but hiding all the double overhead cam and a million valves of a modern engine.

Simples. Ahem.

Sounds very interesting. What engine, and what cylinder head are you using?

[banoffee]

oops

did another quick bing...

(smaller engine but same principle)

[fran9r]

Cool thanks banoffee.

[Egg on Leggs]

Oil is lighter than water volume for volume.

Clumsy me, I know that water is heavier, it was a reference to the system. You would need more oil than water for a given unit of cooling and with it being more viscous it would need larger hoses to thermo syphon or a more energy absorbing pump due to it's greater viscosity.

[fran9r]

Sounds very interesting. What engine, and what cylinder head are you using?

Well, bearing in mind I said it was a fucking stupid idea...

I have a 1950s Sunbeam S7/8 engine, that has a poor head -it was originally designed as a crossflow, them became a victim of penny pinching, and ended up with the intake/exhaust on the same side, poor design and 24bhp from it's 500cc.

I've looked at a few options, but the closest match I've seen is a TRX/TDM head (100mm spacing really, the Yam's head is 98mm). Note -this is from online data, I need to check one out. The bore is much bigger, but if I can make a new liner and use the Yam pistons, that would provide just under 800cc. I still need to consider if it would work from a crank and cam firing point of view, but so far that is my loose plan. It's not about max bhp, it's about making the old girl a bit peppier. The 'beam revs to 6500, which maybe could go more....the Yam makes 65bhp at those revs...If I can get 45/50 brake and a ton topend I'll be a happy man.

So, from the Suzuki diagram, it does look as though putting oil round the Yam head maybe a goer?

[spacemonkey]

Cool thanks banoffee.

Sweet! How about getting your fins cut out and putting the head on a slotting machine. Put some slots in the water jacket make your fins so they'll fit the slot and I'm sure Loctite will have a fancy adhesive that will do the job and seal the whole thing up. You could fill the cavity with anything that conducts heat well. That would give you an air cooled head with minimal hassle. Maybe water, what about the sodium that theyu often fill exhaust valve stems with? Does anyone know if that is practical?

[Superdunc]

Well, bearing in mind I said it was a fucking stupid idea...

I have a 1950s Sunbeam S7/8 engine, that has a poor head -it was originally designed as a crossflow, them became a victim of penny pinching, and ended up with the intake/exhaust on the same side, poor design and 24bhp from it's 500cc.

I've looked at a few options, but the closest match I've seen is a TRX/TDM head (100mm spacing really, the Yam's head is 98mm). Note -this is from online data, I need to check one out. The bore is much bigger, but if I can make a new liner and use the Yam pistons, that would provide just under 800cc. I still need to consider if it would work from a crank and cam firing point of view, but so far that is my loose plan. It's not about max bhp, it's about making the old girl a bit peppier. The 'beam revs to 6500, which maybe could go more....the Yam makes 65bhp at those revs...If I can get 45/50 brake and a ton topend I'll be a happy man.

So, from the Suzuki diagram, it does look as though putting oil round the Yam head maybe a goer?

Like your thinking. What about using a modernish aircooled cylinder head, Yamaha XS650 for example, or half a gsx1100 head.

[fran9r]

Like your thinking. What about using a modernish aircooled cylinder head, Yamaha XS650 for example, or half a gsx1100 head.

If the cylinder spacing is not 100mm, or very close, then it creates it's own problems. Both the above have much less than that. The GSX has a central camchain -the spacing between cylinders 2-3 is about right (because it's wide because of the camchain drive), but the sunbeam cam drive is on the end. I could get the head lined up somewhere, but then not be able to turn the cams...I seem to remember the XS camchain is central too, although thats a problem with it being a twin. The TRX is the only one I've seen that looks possible.

The pan head would have been cool though -is uses 3 cogs, so I was hoping is would have a kinda gear driven cams sound. Sadly, the cam bearing is where I need to take the drive. Oh well.

[fran9r]

Sweet! How about getting your fins cut out and putting the head on a slotting machine. Put some slots in the water jacket make your fins so they'll fit the slot and I'm sure Loctite will have a fancy adhesive that will do the job and seal the whole thing up. You could fill the cavity with anything that conducts heat well. That would give you an air cooled head with minimal hassle. Maybe water, what about the sodium that theyu often fill exhaust valve stems with? Does anyone know if that is practical?

Now that sounds cool (no pun intended). Anyone? Go on, someone...

[Superdunc]

How about a pair of xr250 cylinder heads, you can space the combustion chambers exactly as you want. Cam drive for the rear head will require some thought though.

[fran9r]

How about a pair of xr250 cylinder heads, you can space the combustion chambers exactly as you want. Cam drive for the rear head will require some thought though.

I'm not saying no by any means, but 19bhp at over 8000 rpm would mean upping the revs, and also the potential is a lot less. Still a possibility, and I think the cam drive could be overcome, but I wonder if the work with something like a TRX would be more beneficial?

[Superdunc]

I'm not saying no by any means, but 19bhp at over 8000 rpm would mean upping the revs, and also the potential is a lot less. Still a possibility, and I think the cam drive could be overcome, but I wonder if the work with something like a TRX would be more beneficial?

Go for xr400 or xr600 heads if you want bigger valves. Trail bike engines are tuned for a good torque spread so you should be able to get them to work well at lower revs.. You can play about with the cam timing to get it to better suit . my old xr600 had 56bhp!

[fran9r]

Go for xr400 or xr600 heads if you want bigger valves. Trail bike engines are tuned for a good torque spread so you should be able to get them to work well at lower revs.. You can play about with the cam timing to get it to better suit . my old xr600 had 56bhp!

In a couple of ways it may be easier to do that -cylinder spacing, air cooled, and cam timing (cylinder to cylinder) are all changable.

But, I would really prefer to have a DOHC layout, so I'd still prefer the TRX/TDM.

[lorenzo]

A gsxr1100 head was ruled out due to the cam chain placement, but surely, if you're only using 2 of the cylinders, then you've got the choice of either the middle two for a central chain, or a left or right pair for a side mounted chain?

Your problem with the TRX head, as opposed to an earlier TDM one, will be the cam timing as they're 270deg cranks on the later tdms and all trx's.

[fran9r]

A gsxr1100 head was ruled out due to the cam chain placement, but surely, if you're only using 2 of the cylinders, then you've got the choice of either the middle two for a central chain, or a left or right pair for a side mounted chain?

Your problem with the TRX head, as opposed to an earlier TDM one, will be the cam timing as they're 270deg cranks on the later tdms and all trx's.

I think I mentioned about crank timing...anyone happen to know if the early TDM is a 180 or 360 crank?

Your right on the cam chain drive and cylinders...but I want the drive off the end, and around 100mm spacing between cylinders. Thats not common, less so with DOHC.

[CMSMJ1]

I think I mentioned about crank timing...anyone happen to know if the early TDM is a 180 or 360 crank?

Your right on the cam chain drive and cylinders...but I want the drive off the end, and around 100mm spacing between cylinders. Thats not common, less so with DOHC.

TDM are 270 degree I think...

[fran9r]

TDM are 270 degree I think...

Apparently earlier ones are 360. Game back on.

[CMSMJ1]

Cool - do it!