427 SOHC Pontiac Hemi
 

I had to start a thread beacause some bozos arguing back and forth about somthing that no one cares about got the "Hemi head Pontiac" thread closed.Thanks.Pontiac Jack,that aluminum,fuel injected,modular,427 SOHC Pontiac V8 was a real motor.One or two are still in existance today.They were built in 69-70 and less than a dozen were made.They had a RAV crank and rods and made over 600 HP.Do you think Chevy was going to allow it to be produced.Chevy killed the SOHC 428s and the RAVs.Pontiac was set to install the RAVs in production vehicles.Anyway that 427 Hemi did exist in running form and has real Pontiac roots.If some high HP Pontiac heads were to be built at least the RAV and the SOHC Hemi have Pontiac roots so you could call it a Pontiac.Start canting the valves on a wedge head and it is a BBC,and we cant have that.The last I heard one of the remaining 427 Hemis had a broken cam follower and one had to be custom built so it could run again.I belive the engine is up in Washinton state.

re sohc
 

i'm all for the pontiac "look" if the velocity and flow numbers are there without canting the valves.......... if not, fooey with the "look".

just want to be on an even playing field with other makes and run with current technolgy instead of outdated parts.........

we have 2 very nice blocks available, one with "registered mains" HUH OHHH, "BBC", can't run that one tho, OH WAIT! both blocks have a CLOSED LIFTER VALLEY too, "BBC", that takes 'em both out......... back to the factory block..........he he.

sorry to be smart about it, but all makes of engines/ heads/parts/etc. are copied/ revised/improved upon all the time..............

we can let the basic pontiac engine design keep pace with other brands or fall further behind...........

a hemi design would be cool if the numbers are there, for sure.........

Where did you get your information on this SOHC Hemi that Pontiac produced in 69-70? Where are the one or two left in existance? Are you sure you're not confusing this engine with the earlier OHC 421 like the one Mac McKellar has in his GP? Up until your statement, the entire Pontiac community (including the likes of Pete McCarthy and Jim Wangers) was under the impression that this was just an engineering exercise that never got off the ground...that the block/heads were just a "mock-up" and not real pieces. Surely if anyone would know about this engine ever being built in running form, it would be Jim Wangers, and in the last 30 years, he's never made a peep about it (yet during this time, he's talked plenty about other engineering exercises, including the R.A. V program).

DRAGNCAR,

I agree with Brian, show us some documentation that the engines were actually run on a dyno and made the 600 HP you mentioned.

As Tom Nell was the Father of the RAM AIR V and would have supplied some of the parts for the engine if it truly ran how come he has never mentioned it in any of his presentations?

I will ask him about this tomorrow if I can get ahold of him.

Tom V.

Okay, I'm (again) looking at the Oct '70 Hot Rod Magazine article "Lightweight, Hemi-headed...and Beautiful". Very interesting reading for any performance-engine fan, not just Pontiac. Here are a few direct quotes, in the order they occurred in the article:

"...the Advance Design Group headed by Hulki Aldikacti."
"The project goes back several years."
"Intake valve diameter is 2.40" on the large-valve engine, and 2.19" on the small-valve high-rpm design; while the exhaust measures 2.00" in both cases."
"Intake and exhaust ports are round, and in the low-speed engine, intakes measure 2.08"; they are 1.90" on the high-speed design. Port diameter is 1.73" on the exhaust for both V8's."
"Valving on the current experimental engine produces 100 psi oil-pump pressure, but 300 psi is possible."
"This high-speed V8 is capable of running at speeds in excess of 8000 rpm..."
"In its present experimental form, the complete engine weighs 550 pounds, give or take a few..."
"Pontiac's chief engineer, Steve Malone..."
"Estimated horsepower of the hemi-head Pontiac is 640 hp at 7500 rpm. There are less than a dozen of these engines in existence..."
"Anyone we met who had anything at all to do with bringing this engine to life, from General Manager Jim McDonald to .... was quick to brag about the end result."

Although the lead photo does appear to be a mockup, other photos in the article clearly show many actual metal parts- block, heads, head gaskets, cam towers, valves, crank, main cap/girdle, rods, oil pump, pistons, distributor, etc. One photo even shows a block/head assembly mounted to a Spintron-type fixture, used to "...test drivetrain dynamics on Pontiac dyno."

I sure don't know whether any were built. Could we possibly contact Aldikacti or Malone or McDonald?

As I've said before, I've been enthused about many of the engine's features, especially since I started campaigning my M/T hemi. I'd sell my sister to have outboard rows of 14" long 9/16" bolts tying everything together, all the way from the cam stands down to the one-piece malleable-iron combination main cap/girdle! And a die-cast aluminum block would be like heaven! Not to mention zero-length pushrods! I also like the way-oversquare 4.257" bore with a 3.750" stroke, and the 3" main diameters. One of the induction systems tested was electronic fuel injection- this was in 1970!

you know everyone tom. i dont know how you know all this but id love to pick your brain.

Hmmmmmm...one should be very careful about taking old magazine articles for gospel. Remember when CARS magazine voted the 1973 SD455 GTO as "Car Of The Year"?

That would have been Awesome a Pontiac Hemi in a 70 T/A or a 70 GTO --I did read something about the OHC 421 in THE GRAND PRIX --one TEST driver said it was the most powerful car he had ever driven .

That Hot Rod article is the only place I've ever seen anything about that motor. Someone must have some info on them if they truely exist. I hope some 'real' info surfaces before this thread gets off track. Maybe Tom can get to the bottom of this. I'd still like to determine how many sets of M/T hemi heads were made. I know Jack and Steve have some but how many more are out there? Honestly, I love the look of the hemi and even if a RA V head would make more power, I'll still build my hemi. Sometimes it's not about being the fastest, especially if you're not running heads up. Just my opinion.

The only way you get a motor to make a LOT of high rpm HP, is to LOWER the velocity of the ports in the low-mid rpm range. A port only flows so "fast", when it reaches the speed of sound (goes sonic), it quits flowing. So build a head with lots of velocity at idle and mid range, it's a dog at high end and gets WALKED ON by a 1964 Ford 427 ancient wedge engine. Keep that in mind.

A motor has to start out with LOW velocity to make high rpm HP. Otherwise, the port just reach sonic sooner and quit flowing. You got it all mixed up there. Sure, you can choke the ports down and make more mid range torque- but without a doubt, you will lose high RPM power.

The motors that rule the roost, are high rpm motors, not mid-range motors.

The Pontiac SOHC was just a copy of the Ford SOHC- Ford already did that in 1965, where do you think they got the idea from ?

Quote:

"The Pontiac SOHC was just a copy of the Ford SOHC- Ford already did that in 1965, where do you think they got the idea from?"

I agree that Pontiac probably got the idea for the PONTIAC SOHC in the 1970 article based on previous work they did on the RA V engine. The RA V engine was a "knock-off" of the Tunnel Port 427 Ford head. Everyone admits that deal.

The 427 PONTIAC SOHC was not a "Knock-off" of any Ford work to my knowledge. The SOHC technology went back MANY YEARS farther (to the days of Sir Harry Ricardo's research (among others)) so Ford cannot lay clain to that design, therefore the PONTIAC 427 SOHC was NOT a copy of the Ford 427 SOHC just a different level of the Ricardo work.

I called Tom's home and got his answering machine, left my number, etc. He typically is very good about calling me back so maybe he can share some other insite into the engine.

Tom V.

ps Pontiac Jack, before I worked for Ford Research I worked
for several years in Advanced Engine, (a group just like the group that looked at the Pontiac SOHC engine in 1970). We
have built several design engines that never made it past the dyno stage. We have a few others like the V-10 4 valve 6.1L
modular engine that made it into the Shelby Concept Cobra
and was featured in the "RIDES" program. Non were ever
sold to the public or were intended to be, purely engineering
studies.

I don't know if this statement is in anyway relevant to this thread, but I have always wondered what it meant. John from The Goatfinder published this included in article regarding interviews with Bill Knafel.

"Whether the hemi-head "Porcupine" Tunnel Port engine has survived is unknown, it's the only one ever built"

He was referring to the 70 Tin Indian, since John is now passed away I have no way to ask what in the world he was implying. Any ideas?

That would have been the engine we are describing.

Porcupine refers to splayed valve angles and there were only two tunnel port concepts to my knowledge. The RA V and the concept engine.

Tom V.

REALLY.....

Hmm... I wonder how John would have had a clue to say something like that. Very interesting. Good lord the trouble it would cause to pursue this one, NOT FOR ME. I'll observe this discussion.

the mar 1968 Hotrod mag has a great article on the OHC pontiac engines.There is a pic of McKeller standing in the center of 5 diff developmental engines on the cover.Great article with some obvious things that were staged for the mag.There is a 3 valve head with ports similar to the RA V layout but with a convential port layout bathtub intake with 3 FI throttle bodies on it.That head also has a exhaust port without the droop snoot turn down.In fact it looks like a RA V that had the exhaust cut off.There is also pics of the 2 valve cammer that I think is in Macs 63 car.There is also a pic of a DOHC 4 valve per cyc with X ram FI that was developed in 1963.They were way ahead of their time when you look at the stuff they were working on.Tom V,Mac might be the guy to talk to on some of these engines.Tom

Sure were ahead of their time. Just look at the OHC-6...it was in production nearly 30 years before this type of automotive engineering became the "norm" in the industry.

You mentioned the 6 cylinder OHC engine, Tom. My uncle replaced at least 3 cylinder heads on a Firebird that belonged to a good friend.

The heads still obviously needed some work but were innovative for their time. Typically there is a three year minimum engineering
window before production so the work Mac McKeller did in 1963 and 1964 probably was directly tied to the 6 cyl OHC.

I have spoken with Mac on several occasions about his 63 engine
and the memory is not what it used to be (for any of us). LOL!

Tom V.

When the first OHC V-8 was tested at Pontiac in the early 1960's, it was a terrible failure. The cams seized up in the cam housings in the heads.

The premier Pontiac engine that was actually released by Pontiac and raced and successful to any degree, would have to be the RA V program.

Agree!

Per Tom Nell who just called me back:

The DOHC engine was the work of Bill Collins who replaced John Delorean. The DOHC used a cog belt system driven at the rear of the engine. It was a 3 valve engine. The cog belt system did not work well and several engines bent valves during testing.

The chain drive system came next located on the front of the engine. Funds were not available to do proper cast aluminum covers so sheet metal covers were fabricated. The sheet metal covers leaked badly on the dyno so several times testing had to be shut down. Eventually the DOHC 3 V testing died a quiet death.

The first SOHC V-8 engine was the "McKeller Engine"

It was based on V-8 parts using the valve train from the OHC-6 so I was in error on that part, the OHC-6 design work came first. Pontiac engineers installed the engine in a couple of vehicles for tests at the Milford Proving Grounds on Saturday mornings. The engine did not perform to expectations. Main issues were lubrication issues in the upper valve train, (Cam towers in the valve covers, etc.)

Tom Nell (who was Mr. Ram Air V in the late 60s and early 70s) says they he had no knowledge of any SOHC 427 mechanical FI engines actually being built, much less being tested at Pontiac. He did say that the marketing and design guys were proposing stuff all the time.

Hope this helps in the discussion.

Tom is enjoying his retirement in Michigan and has provided info for a couple of recent Don Keefe articles, check them out.

Tom V.