Ultimate head/cylinder sealing???, cylinders that "screw" into heads??? Options

[Mueller]

so I've been researching the different methods of getting that "perfect" seal between the cylinder and the head:

lapping of both surfaces,
use of a metal O-ring (common on watercooled cars, not much material on an aircooled cylinder),
copper head gasket,
"fire seal" as used on 935's,
and
Jakes use of a carbon seal

what else am I missing?

non-stock motor such as high compression and or
turbocharged

[maf914]

For some of its turbo racing engines I believe I read that Porsche welded the heads to the cylinders. Leakproof! I'd have to do a bit of digging to find out for which cars they did this.

Mike

[SpecialK]

Kinda like the Cox 049 engines used for little control line airplanes... yeah, and have the cylinders screw into the block and do away with head bolts all together. ..Might be a little tricky keeping the deck height equal. (IMG:style_emoticons/default/idea.gif)

[machina]

Kinda like the Cox 049 engines used for little control line airplanes... yeah, and have the cylinders screw into the block and do away with head bolts all together. ..Might be a little tricky keeping the deck height equal. (IMG:style_emoticons/default/idea.gif)

I remember those cox engines.

You could adjust the deck height with shims no problem, but I do remember those suckers always loosening up and flying off.

Didn't have a torque wrench when I was 12, but I bet jake did.

dr

[Mueller]

oh yea, i was going to post the welded heads....in fact i have seen heads with the cylinders "built-in"....hard to do a valve job unless you have some special equipment...

i'd want something that could easily be taken apart in the future.....the threads could be indexed so the thru holes for the head studs line up perfectly

[Mark Henry]

I think that's about it.
How would you screw them in, cut the fins off? (IMG:style_emoticons/default/smile.gif) Now I know why you asked about the splitports.

Are you going to weld a set of nickies in... (IMG:style_emoticons/default/blink.gif)

The 5th stud has also been done but it's just a bandaid.

[SpecialK]

I'm not sure if I'm pickin' up, what you're layin' down here....are you're talking about a "one piece cylinder/head" unit?

[TimT]

the welded headscylinders came on some 935's 962's etc

[Jake Raby]

I didn't have a torque wrench when I was 12, didn't use one till I was 13.... built a whole lot of stuff without one!

Its called a calibrated wrist.

[banderson]

Mercury outboards use a one-piece head/cylinder, but it’s a 2 stroke and the only feature is a spark plug hole.

How about brazing a 3/8 thick steel band around the top and bottom of the cylinder so the head can be screwed directly to the cylinder. This would take the expansion factor out of the equation as well as ensure that both cylinders are flat and tight against the head. You would give up 2 cooling fins at the top and bottom to do this.

[1973914]

The Interscope Indianapolis car (that never ran in anger) had welded heads too.

[lapuwali]

So called "monobloc" engines, with the head and cylinders cast as a unit, were pretty common up through the 1920s, esp. on supercharged engines running witches brew fuels. Porting wasn't really done much, then, and any valve seat that provided a seal was considered adequate.

The serious downside for current practices is you'd have to use the combustion chamber pretty much as cast. The valves could be done if you had a suitable extension to drive your valve grinding stones, and the valve faces are pretty close to perpendicular to the cylinder bores. Cleaning up the ports near the valves would be difficult, but not impossible.

As far as water-cooled heads goes, just welding boxes around the cooling fins on a stock head should be enough to get the jackets. I wouldn't even trim the fins. Maybe drill them to ease the water flow, but the extra surface area should be beneficial. An electric water pump and a small radiator, and you're in business. 10:1 compression ratios, anyone?

[seanery]

flatheads had the valvetrain built into the block. The head was nothing but the top of the combustion chamber. Pretty wierd looking.

[Mueller]

I had thought of the welding of a "waterbox" to fit the stock head, the problem is getting the box to hold a seal due to the welding of the old dirty material. I thought that is what the problem is with repairing the combustion chamber on damaged heads from lets say dropped valve seats.

I'm sure the outside of the head is cleaner and less contaminated than the combustion chamber......oh yea, I don't have a TIG welder so that is another reason why I have not tried this.........