I have always wondered if a water cooled engine can be made with the cylinder and head integral like you see on many air-cooled engines. I was curious if one could machine coolant passages through the side of the cylinder and then through the head. I am sure screw in “plugs” would have to be used in the head to block of passages required for such machining through the head.
Would such a design be possible? IF possible, would it simply be too costly or limit the cooling capacity of the engine? I figured it might benefit from not having a head gasket, maybe allowing for hotter and more efficient running? OHV operation has been done on the air-cooled version via pushrods, timing chains, and belts. Has such an engine ever been made in the water cooled variety? I figure the benefits (if possible) might not be balanced out by the costs.
Google Bugatti (the antique ones from the 1930s) - they did that. I think there have been others. But it limits the ability to make complex valve geometries. I’m not familiar with the aircooled engines you’re talking about - which ones? Two stroke? No valves to worry about there.
Interesting. Apparently the advantages of this design were no longer a concern when better materials for head gaskets/bolts came along. I am sure it could be better in certain circumstances but in the ordinary car engine, the cost and other disadvantages would be a major drawback. I can understand the valve servicing being a major issue.
I seem to recall having an engine of this design in an old riding mower a while back. It was OHV with pushrods. The thing lost power in a blaze of smoke one day and I started to take it apart after realizing it had NO compression. Well I too the valve cover off and one of the valves was missing. The retainer had failed, allowing the entire valve to go inside the cylinder. I looked down the cylinder through the spark plug hole with a light while turning the engine over by hand and could see a hole in the piston. I scraped the engine and seem to recall the head/cylinder bolts being really long as they had to pass through the cylinder to get to the block. The pushrods had a gallery machined into the side of the cylinder where the cooling fins were located.
I think it was a Briggs or Kohler engine. I honestly didn’t pay much attention once I saw the hole in the piston as I saw it as scrap metal from that point on. It wasn’t worth messing with.
I think it would be very possible and could actually be less expensive to manufacture if the manufacturing engineers were open to new ideas. It would need to be made from aluminum and the top of the engine would be stamped in layers and then pressed together to “weld” them together. The valves could be screw in assemblies like some on Honda’s and Mitsubushi’s in the late 70’s.
Every 2 stroke/cycle I’ve have since the early 70’s has had separate removable cylinder heads. Having a non removable head just seems like a step backwards to me. Say you strip out a spark plug hole. I know you could possibly “Heli-Coil” it. But I’d much rather be able to take the head off to do it.
It definitely sounds like the advantages to this design were negated once more reliable head gaskets came along. Yes, it might be more reliable but also WAY more of a pain to deal with if service in the head area is required.
I can also imagine the manufacturing costs being A LOT higher. It seems simpler to have a separate head assembly.
I too am with meanjoe on this one.
Having spent a good many years of my life up to my elbows in design and manufacture of stuff, I’m having a hard time envisioning how it could reduce costs. If it could, my guess is that monoblocks would be ubiquitous.
Also with all the focus on fuel efficiency and emissions, I can’t see this design winning out from what I have read about the monoblock design over the last day. This is also one of the reasons many engines are interference. The non-interference designs with valve reliefs in the pistons do not produce as clean emissions as those without.
Here’s another rather unusual engine used by a lot of WWI airplanes, the Gnome Monosoupape Type N Rotary featuring integral cylinder heads and a single valve which did both intake and exhaust duty and was opened not by a pushrod, but a pullrod.
@“the same mountainbike”, how is the RR W engine different from the VW W engine used in the Bugatti Veyron W16 (first engine on list)? VW also used the W engine design in the Bentley, Audi, and VW Phaeton.
