Been doing some str8 8 design work

**dlomshek** · 09-11-2010, 10:26 PM

Lately I've been thinking a lot about some posts concerning the need for a new cylinder head design for the 320 ci straight eight.
Attached is a starter drawing of a cross-flow head with individual intake and exhaust ports. The compustion chamber has been redone as a shallow hemi type with shallow valve angles of 17 degrees to the vertical.

I teach Computer Aided Design, at the state university, using CATIA.

David Lomshek
Pittsburg, Kansas

**dlomshek** · 09-11-2010, 10:30 PM

Here is another shot of some of my tinkering with a new straight 8 320ci cylinder head.

David Lomshek
Pittsburg, Kansas

**JR9162** · 09-12-2010, 12:48 AM

Looks good. We need one for the 248/263 as well. Ever look at the 15 degree VW v6 cross flow head design?

**Bob** · 09-12-2010, 07:32 AM

Both pushrods have to come up the same side of the engine if you are going to use the original block.

**bob k. mando** · 09-12-2010, 02:32 PM

Both pushrods have to come up the same side of the engine if you are going to use the original block.

time to convert to OHC and just keep a dummy cam in the block to run the oil pump or whatever else is going on.

**JR9162** · 09-12-2010, 06:22 PM

Originally Posted by Bob

Both pushrods have to come up the same side of the engine if you are going to use the original block.

That can still be done using an exotic rocker arm assy, roller cam, roller tipped rocker arms, needle bearings on the rockers, using a hardened rocker arm shaft or stud mounted rocker arms. A lot depends on the location of the spark plugs...

**dlomshek** · 09-12-2010, 11:28 PM

Originally Posted by JR9162

That can still be done using an exotic rocker arm assy, roller cam, roller tipped rocker arms, needle bearings on the rockers, using a hardened rocker arm shaft or stud mounted rocker arms. A lot depends on the location of the spark plugs...

So far I haven't decided if it's worth the effort to go all the way to OHC or not. At this stage I'm just exploring options and doing a lot of thinking. Pretty soon I probably need to buy a complete 320 engine to analyze.

One of the things I am pondering is if a head can be produced in two pieces. Upper and lower halves. This would allow all of the inner details, like water passages, to be milled with a CNC mill. This eliminates the need for cores. Problem is I would not want to bolt the two halves together. I'm looking for some furnace brazing process that would allow the two parts to be joined into one.

A number of years ago some special flathead heads were produced as two halves but the two pieces were bolted together then. Obviously flathead heads are much simpler than OHV ones.

I'm open to any and all ideas; let me know the opinions out there. Not sure where this is going but it's a very interesting design project for me.

Dave Lomshek
Pittsburg, Kansas

**39CENT** · 09-13-2010, 12:58 PM

well, you can try a "pentroof" combustion chamber, like the nailhead, which is really a grunt type engine design, like most Buicks.Lots of lo to midrange power. Actually the nailhead is half of a pentroof design used usually with OHC designs. Pushrods could be used with by using wierd monkey motion designs,[a la V8-60 arduns.] If you want to see a wild Buick engine design find a cutaway of the 1951 Lesabre engine! It shows that Buicks engineering wasnt behind the times.

**bob k. mando** · 09-13-2010, 04:27 PM

find a cutaway of the 1952 Lesabre engine!

just so you know, that was the experimental all aluminum 215ci engine from the 1951 GM concept car.

something was funky about that, was that a hemi design? i forget.

here we go, i found a little on that, it was supercharged dual fuel hemi:
http://www.jalopyjournal.com/forum/s....php?p=5125784

**39CENT** · 09-13-2010, 09:06 PM

I found an article on Buick history in the April 78' issue of cars n parts. It was about the 1951 Lesabre concept car,
which was driven by the head of engineering for years after.
Its working concepts used in many of the future GM cars today. The engine was an aluminum 215 inch V8 square bore n stroke, carbed,dual fuel [gas n alcohol] blown, 2 valve , pushrod , pentroof [simular to hemi]alum heads! 335hp 388#torq, 10.5-1, 3 ring popup pistons, and tested at 140mph on Buicks test track. The article has the cutaways but i havnt been able to copy it up. The whole car has almost all the design features of todays cars, tilt/tell steering wheel, ball joint susp, etc, etc, I,ve never seen an engine like it, they sure were holding back on us in 1951!
If we had just a pentroof combustion chamber like the naihead in our straight 8,s, they would be twisting axles.