Building an engine without a head...

[digger]

I think bmw's last f1 engines the cylinder head and crankcase were a single piece

p85 engine from page 12

https://8000vueltas.com/wp-content/uplo ... ngines.pdf

[Shaner]

Couldn't you I crease the compression to insane levels??

[Newold1]

Actually referred to as monoblock engines.
Check out this website.

www.steyr-motors.com

[PackardV8]

Couldn't you I crease the compression to insane levels??

Yes, no head gasket failure at higher compression ratios was one reason for the monoblock. Define "insane". The Offys on alcohol ran 14:1 for 500 miles, sometimes. The inherent Offy problem has always been a 270" 4-cylinder is trying to shake itself apart every revolution. When the stroke was shortened to the 255", the vibration problem got less bad. The monoblock design loved turbo boost and by the time the turbos were downsized to 160"- 170" with the same architecture, they were almost reliable while making three times the horsepower.

Considering "insane" compression ratios, diesels run hundreds of thousands of miles with insane compression ratios, but they're built heavier to withstand the forces. Second reason for the monoblock is more strength and less weight.

[rebelyell]

https://www.ebay.com/itm/Vintage-60s-We ... 0543080649

https://www.ebay.com/itm/Vintage-Very-R ... 0595466086

Chrysler/West Bend Two-Cycle (no valvetrain, just ports)
Aluminum Monobloc crankcase+cylinder+head casting
chromed bore (self-peeling)

had a pair on a POS kart in sixties

[peejay]

Casting the head and block as a unit was quite common in the early days. Several of the Harry Miller designs done by Leo Goosen, including what became known as the Offenhauser, were done this way.

Just imagine the difficulty of achieving a precision valve seat when working up through a small diameter cylinder (the Miller 91" straight-eight has a 2.200" bore diameter) and at 45-degrees. There's literally no line of sight; it had to be done by feel.

If the bore is that small and the valves are at a 45 degree angle, how do you get the VALVES in and out?

[pdq67]

Offy's, airplanes, old motorcycles. Common pre-war.
Most recent one I can think of is a honda "5 horse" little 160cc guy.
split diagonal crankcase, one cam lobe runs both valves, 25lbs total, very interesting.

modok,

Would you please post back a link to this little engine.

Fascinating to me!

pdq67

[pdq67]

Back again, btw, Rolls Royse used to lap their blocks and heads and didn't use head gaskets if not mistaken?

pdq67

[modok]

Honda gc160
found some pics here
https://www.brandnewengines.com/GC160-JY5.aspx

[enginenut2]

Outboard Marine Corporation (OMC) in the late 50's owned Evinrude , Johnson, Cushman, lawn boy, and other. They brought out a Cushman Eagle scooter with a new 9 HP ohv engine. The engine had a removable Cyl with integral head and they made a 2cyl opposed version for their "Truckster". Thousands of these were in use by the postal dept, police depts. and grounds keeping people. These engines were expensive but very durable with pressure oiling , inserted steel rods, press fit pins and small valves to limit output. Valve work was done up through the bore and the cyls had cast in sleeves. Many of the old (pre 1930) engines had head and block cast together but most had the valves serviced through a removable cage or plug. The engine people usually refer to these engines as "jughead" engines and they can be found up to 6" bore or more.

[SchmidtMotorWorks]

Casting the head and block as a unit was quite common in the early days. Several of the Harry Miller designs done by Leo Goosen, including what became known as the Offenhauser, were done this way.

Just imagine the difficulty of achieving a precision valve seat when working up through a small diameter cylinder (the Miller 91" straight-eight has a 2.200" bore diameter) and at 45-degrees. There's literally no line of sight; it had to be done by feel.

If the bore is that small and the valves are at a 45 degree angle, how do you get the VALVES in and out?

The ports are super low, the short side makes almost a u-turn; so the valves can be very short.