Offenhauser 4 cyl

[4sfed]

I would think the guides are screw-in such that you can install just the valves.

Then fit the guides and everything else..

pdq67

The guides are press-in . . . see the large flange . . . but valve is inserted first.

[turbobaldur]

Just 10 days ago I laid my hands on a modern artifact that has the sleeves in the head casting and not in the crankcase. The Nissan ZEOD 3 cyl turbocharged racing engine.

http://www.dailytech.com/Nissan+Coaxes+ ... e34217.htm

[Krooser]

An amazing event held every July…
https://www.youtube.com/watch?v=FJ-aS924OF4

[williamsmotowerx]

So the valve is inserted first, then the guide is pressed in. Those motors must have had a wide range of valve concentricity.

[OILEAKY]

I have two S & D valve seat grinders that have angle drive units that fit between the "drill motor" and stones, that allow grinding seats in Offy type motors. These appear to be made in the '30s, and still work great.

If I could figure out how to post pictures of them, I would do it.
Oileaky

[1989TransAm]

The seats are cut, not ground. The operation is like back spot facing with the tool piloted in the guide.

Here's a challenge for you . . . how do you install the valves in this early Miller?

Miller.jpg

If I am looking at the picture correctly that is an interesting piston design.

[4sfed]

Miller.jpg

If I am looking at the picture correctly that is an interesting piston design.

It's just a spherical dome with valve pockets.

[4sfed]

So the valve is inserted first, then the guide is pressed in. Those motors must have had a wide range of valve concentricity.

Isn't that what lapping compound is for? Then think about cleaning the seat and valve in a cylinder 3.4 in diameter when you can't remove the valve. My hand won't even fit easily in a bore that size.

[Aussie Dave]

The Hart 415T F1 engine from the 1980's, was a mono block too. I read somewhere the seats were the hard bit on that engine. there are some pics on the net of it.

Brian Hart did some amazing stuff for a small engine firm.

Cheers Dave

[jdperform]

Ah yes the Indy car offy, it was the first real race engine I worked on in 1975. Where I worked they would use a Neway type cutter with a u-joint type drive. I'm sure you could measure concentricity with a yard stick.
Up until they changed the amount of fuel allowed for a 500 mile race also with unlimited boost we were getting right at 1000 horsepower out of 165 cu in. I think most of the engines were getting around 1.2 mpg then. Rules changed then they only allowed 280 gallons of methanol for 500 miles and the old offy couldn't run that lean. Amazing really that's like dynoing today's turbo rice burner wot for over 2 solid hours under full load. Had brass bolt on counterweights.

[1989TransAm]

Ah yes the Indy car offy, it was the first real race engine I worked on in 1975. Where I worked they would use a Neway type cutter with a u-joint type drive. I'm sure you could measure concentricity with a yard stick.
Up until they changed the amount of fuel allowed for a 500 mile race also with unlimited boost we were getting right at 1000 horsepower out of 165 cu in. I think most of the engines were getting around 1.2 mpg then. Rules changed then they only allowed 280 gallons of methanol for 500 miles and the old offy couldn't run that lean. Amazing really that's like dynoing today's turbo rice burner wot for over 2 solid hours under full load. Had brass bolt on counterweights.

Thank you for the interesting insight. I never new the Offy was putting out around 1000hp.

[4sfed]

Ah yes the Indy car offy, it was the first real race engine I worked on in 1975. Where I worked they would use a Neway type cutter with a u-joint type drive. I'm sure you could measure concentricity with a yard stick.

Were you driving the cutting from the cylinder side through the universal or pulling in it from the valve spring side of the guide?

[wyrmrider]

Fuel rule also killed the Barney Navarro AMC 6
Fuel used to cool motor
I was pushing for intercooler and that would have happened if funds for a new chassis were forthcoming
Instead we only had 3 year old hand me downs
we ran for a long pull at over 1000 hp on the Champion dyno with Dick Jones at the throttle from 210 cu inches 50 lbs boost
Barney's single exhaust with Y diverter into two turbos was awesome off the corners, all the exhaust going into one turbo down low

[140Air]

The link that Krooser posted has pics of cast iron cylinders and head as one piece. Still curious how they did valve job? Stones with a flex shaft?

I think the tool head was inserted through the cylinder. Many air cooled aircraft engine head-cylinder units are similar. The cylinder is screwed into the head and is not normally disassembled.
Having no head gasket is a big plus.

[jdperform]

Yes from the cyl side. I don't remember how he would install seat rings. We farmed out a lot of machine work to Bignotti's shop. Piston failure was common. Watson would have so many blowed up blocks (no head remember) he would part them in the bandsaw (between cyls) and fly cut them smooth then cut an o-ring groove. He'd get close enough so that the cam towers would fit with a little massaging. Taking 2 hurt blocks and being able to make 1 usable one.