I remember reading about Indy car engines running single piece engine/head without head gaskets thus allowing much higher compression ratios. Also something about using this for rally with ridiculous high boost. Am I crazy, am I making this all up? I couldn't find anything searching around the net, any resources appreciated!
There were lots built that way in the early days. Gasket construction wasn't up to the pressures. I think one of Jay Lenos recent vids has them working on one- Hispano Suiza, maybe.
Saito 4 cycle model airplane engines and designed with the head integral to the cylinder casting. They're reliable, solid engines but not the highest performing.
http://www.saitoengines.com/
Some Millers were like that iirc.
Offy's weren't just in Midgets. They pretty much dominated the Indy 500 until the Europeans came along.
In "The Unfair Advantage" Mark Donohue mentions the Ferrari 512 (race car) didn't use headgaskets. Apparently Ferrari got a bit snotty when the guys at Traco complained that the power was down because of the combustion leaks.
I thought ACVW's had no headgaskets.
Shawn
oldopelguy wrote: Probably thinking of the Offy engines that used to run in Midgets: Cool little motor. Saab also patented an engine with similar configuration as a variable compression motor just a few years ago. wonder who gets that patent now?
was that the one with the "hinged" block? I guess GM owns it now
the "Offy" was exactly what I was looking for, got the boost part mixed up between rally and Indy. Anyone know if there were ever commercially available engines of this type made in the last 50 years?
Pot head (no, not that kind) engines can handle tremendous amounts of boost. Look up a Detroit Diesel 149-series.
Crosley and Deutsch-Bonnet used this design.
Make your own. Nothing some backyard welding can't fix.
93celicaGT2 wrote: Make your own. Nothing some backyard welding can't fix.
Yup, that's what I was getting at, just wanted more historical background/info, has anyone on here done this? I've found some threads online, but any specific tips/tricks would be useful. I'm not going to do aluminum, that just seems way hard and I have no experience welding alum.
Thanks!
Raze wrote:93celicaGT2 wrote: Make your own. Nothing some backyard welding can't fix.Yup, that's what I was getting at, just wanted more historical background/info, has anyone on here done this? I've found some threads online, but any specific tips/tricks would be useful. I'm not going to do aluminum, that just seems way hard and I have no experience welding alum. Thanks!
Hmmm...........Now we're getting interesting. This isn't going to be on a challenge car is it?
93celicaGT2 wrote: Make your own. Nothing some backyard welding can't fix.
How are you going to weld between the cylinders and water/oil passages?
m4ff3w wrote:93celicaGT2 wrote: Make your own. Nothing some backyard welding can't fix.How are you going to weld between the cylinders and water/oil passages?
Well... blown head gaskets, and gaskets in general become issues when they blow out. If there's no way for the gasket to escape, or anywhere for the gases to go outside of the motor, you probably wouldn't have to welded those areas. I would switch to a metal headgasket at that point, though, and use some heavy duty head studs/bolts to really crank the sucker down, then weld away on the outside.
That may be flawed logic.
Assuming a pot head engine could be built from a conventional two piece design all of the other engine components would need to be beefed up to handle the massive boost and even then, you know this thing is going consume pistons and rings like a stoned college kid eats Doritos.
m4ff3w wrote:93celicaGT2 wrote: Make your own. Nothing some backyard welding can't fix.How are you going to weld between the cylinders and water/oil passages?
I was thinking more of closed deck motor, have head and block machined to match, machine groove around each water/oil passage on head, put in crush ring just large enough (this is the tricky part), bolt head in place w/o HG (def non-interference motor to start), weld head to block. 
ansonivan wrote: Assuming a pot head engine could be built from a conventional two piece design all of the other engine components would need to be beefed up to handle the massive boost and even then, you know this thing is going consume pistons and rings like a stoned college kid eats Doritos.
How many miles does a challenge car run 
Very good point, I would love to see/hear/smell someone pull this thing off... bonus points for using a diesel engine.
Valves are going to be a pain to change.
Perhaps this is obvious: The Offy motor was cast as one piece. The secondary machine work on the combustion chamber, valve seat insertion, valve seating, yada yada yada was done with tooling that reached into the head through the block. Many years ago I was acquainted with Stan Smith, Son of OG hotrodder Clay Smith. Stan worked for Offenhauser building the "Offys". He described the machining process to me.
Shaun wrote: Perhaps this is obvious: The Offy motor was cast as one piece. The secondary machine work on the combustion chamber, valve seat insertion, valve seating, yada yada yada was done with tooling that reached into the head through the block. Many years ago I was acquainted with Stan Smith, Son of OG hotrodder Clay Smith. Stan worked for Offenhauser building the "Offys". He described the machining process to me.
Please elaborate 
93celicaGT2 wrote: Well... blown head gaskets, and gaskets in general become issues when they blow out. If there's no way for the gasket to escape, or anywhere for the gases to go outside of the motor, you probably wouldn't have to welded those areas. I would switch to a metal headgasket at that point, though, and use some heavy duty head studs/bolts to really crank the sucker down, then weld away on the outside. That may be flawed logic.
The gasket can still go from one cylinder to another...
MadScientistMatt wrote:93celicaGT2 wrote: Well... blown head gaskets, and gaskets in general become issues when they blow out. If there's no way for the gasket to escape, or anywhere for the gases to go outside of the motor, you probably wouldn't have to welded those areas. I would switch to a metal headgasket at that point, though, and use some heavy duty head studs/bolts to really crank the sucker down, then weld away on the outside. That may be flawed logic.The gasket can still go from one cylinder to another...
That's why you'd have to get steel rings placed into grooves in both the head and block, least that's what I'm thinking, but then the need to weld it together diminishes...
I really need to think about how to accomplish what i'm going for here beyond machining the whole thing.
MadScientistMatt wrote:93celicaGT2 wrote: Well... blown head gaskets, and gaskets in general become issues when they blow out. If there's no way for the gasket to escape, or anywhere for the gases to go outside of the motor, you probably wouldn't have to welded those areas. I would switch to a metal headgasket at that point, though, and use some heavy duty head studs/bolts to really crank the sucker down, then weld away on the outside. That may be flawed logic.The gasket can still go from one cylinder to another...
And there's my flawed logic. 
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