[NHRASuperStock455SD]

Originally Posted by Half-Inch Stud

So did the PMD engineers.

So was the PMD engineering.

Looks like a PMD engine... unique that way huh. HIS

Two of the original engineers from PMD now retired that worked on this project came up to me at Norwalk and thanked me for retaining the original design and keeping the valve train simple. I told them I didnt do anything, but copy a very good original design with a few modern day upgrades.

They then asked me who my valve train guy was? I told them and they said: You've got the best guy in the country....he used to work for us. I agreed. PMD was a great organization and a great product way ahead of their time.

[67'7F6'Bird]

What are you using for Rockers and Harmonic Damper on this one?

[NHRASuperStock455SD]

Originally Posted by Elarson

In my humble opinion....having done a lot of reverse engineering of a stock RAV head and creating my own billet heads......the RAV architecture has tremendous potential in many different conceivable formats.

Eric

I agree we havent even scratched the surface. With the push rod down the middle we can do almost 6 square inches. We can also put a much larger intake valve in. Until now Tony wasnt convinced our casting could support a larger valve, but now I think we can do it.

Here is the handwritten specification drawing for valve spacing for the head porter's casting.

Elarson how much are the ports raised in your billet head? How much did they flow? What size valves?

[NHRASuperStock455SD]

Originally Posted by 67'7F6'Bird

What are you using for Rockers and Harmonic Damper on this one?

This is a race engine. We are sending to Jesel. Spring pressure will be about 460 on the seat, Titanium valves. Damper will be Tony's decision.

[67'7F6'Bird]

Originally Posted by NHRASuperStock455SD

This is a race engine. We are sending to Jesel. Spring pressure will be about 460 on the seat, Titanium valves. Damper will be Tony's decision.

What are the Cam Specs?

[Dragncar]

I want to thank you too for just doing this. Keeping it inline and the stock Pontiac valve cover also.
Can not wait to see where these end up. Many have said they could never compete straight up with a "normal" head. If Tony says they are bad ass, who knows.
I do not think someone like him throws around that term lightly.

[NHRASuperStock455SD]

I will wait and let all the numbers speak for themselves. This means dyno Horsepower on Tony's dyno as compared to everyone else's numbers on Tony's dyno. Rich the dyno operator said their newly updated dyno puts all the numbers down 22-28hp at a 1000HP. Next we take it to the track and see what it ET's and compare.

Phil Monteith went back on with improvements and stayed the same. They also said all the engines that stay the same are wicked fast at the race track. I think Langer's number of 1190 is the real number.

We usually take the dyno number and the track number, then correct it to altitude and project the chassis efficiency. This puts all the variables into place for same dyno same flow bench.

We have Scott Rex, Phil Monteith, John Langer, Stacy McCarty, myself, all doing dynos multiple times. We all know what the cars should run coming off the dyno.

My 455SD went into the car last time 691HP and ran 9.77@137.79 at 2500 feet. It was about a tenth short last year. We got 711HP, but not all that configuration will fit under my stock hood.

[NHRASuperStock455SD]

Originally Posted by 67'7F6'Bird

What are the Cam Specs?

It is a 60mm race cam, we match it for the application and for the valve train. Since this has an offset valve train we will try to do it more with the cam than with the rocker. With the straight on valve train on the 406 RAV it will be a completely different story. We are in the midst of doing it now, but JC and I decided to wait till we get the final flow numbers particularly on the exhaust.

We have one guy who wants a big cam, but he doesnt have the valve spring for it. This is a no no. Many times Pontiac guys have gone to 1.8 intake rockers, then the cars slow down. This is because they dont have the spring pressure to do it. Of course you cant run crazy spring pressure on the street. Tony limits this to 275lbs driven very occaisonally on the seat and he screams about that.

On the 455SD we are trying the new springs that have 460lbs on the seat, but much less open pressure than normal(1250lbs). We surmize this will work in that 1/2 the spring weight is included in the overall valve weight. Since it is the valve weight that is directly porportional to the overall spring pressure needed, we can lower by reducing the weight of the springs. It worked pretty successfully in Stacy's motor, but he went a bit too soft. I have been known to show up to a dyno session with 8 sets if springs. Many times you can have a spring that has exactly the same pressures, but dont work well. Last time I did this, we had a spring that has the same close/open pressure as the Nextec, but it made 800 more RPM.

Tony is going to do it his way, then we will put mine on. I can always tell by putting red paint on the springs and see how much they spin. It seems the exhaust springs never spin. The intakes on a Pontiac dance all over the place.

I also spend a ton of time making sure that the lateral travel across the top of the valve is minimized. This is a tedious task that requires shimming. the SS Hemi guys charge $6000-$7000 just to set up and install the jesels on a Hemi. It makes power. Lateral travel on my SD engine I had down last time to 0.030. The Jesel specification is 0.060 max. I will go for even less this time. An adjustible one could change the dwell time of your intake lift in the high speed travel of the piston. This can affect power.

[Jim Robertson]

Lynn,
Maybe the head you show in your pic has been completely milled but your pics don't show it so here are a few clearer shots. Big water holes need to be addressed but nothing a good welder could not stitch up or implement a change to water jacket core box. The "side" of the head is fairly flat once the ports are exposed so making a cleanup pass to true the surface for the new bolt flange should be simple. Center head stud length could possibly be used for entire lower row.

[J.C.you]

Originally Posted by Jim Robertson

Lynn,
Maybe the head you show in your pic has been completely milled but your pics don't show it so here are a few clearer shots. Big water holes need to be addressed but nothing a good welder could not stitch up or implement a change to water jacket core box. The "side" of the head is fairly flat once the ports are exposed so making a cleanup pass to true the surface for the new bolt flange should be simple. Center head stud length could possibly be used for entire lower row.

Good pics, I was pushing this mod, not only for the improved exhaust flow, but shorter head bolts are a big plus in my view. Also we are putting this engine in a stock chassis, be easier to fab headers.

[gene simmons]

It no longer looks like anything from pontiac,definately not a RA V anymore.
Not sure why everyone has a hard on over these so called convertible ports. If the exh. ports are designed correctly to begin with,these added mods wouldn't be needed. JMO

Hate mail can be sent to.....

[J.C.you]

Originally Posted by gene simmons

It no longer looks like anything from pontiac,definately not a RA V anymore.
Not sure why everyone has a hard on over these so called convertible ports. If the exh. ports are designed correctly to begin with,these added mods wouldn't be needed. JMO

Hate mail can be sent to.....

no problem on your opinion, if we were doing a restro type build to satisfy the purists, i would scoff too. A 30cfm exhaust improvement on a max effort build will change cam timing events and make power.

[Half-Inch Stud]

Intake Runner Ideas: if the RA V head had a divider cast into each intake runner, from port-thru- pushrod area-to valveguide, then drill the casting for pushrod tubes. divider between pushrod and valveguide would have to taper away as approaching valveguide.

Idealized result is a boat-tail divider before the pushrod tube, for least shock surface,
Flow-velocity remains STRAIGHT after pushrod tube-to valveguide, CSAmin still defined by valveseat.

[J.C.you]

Originally Posted by Half-Inch Stud

Intake Runner Ideas: if the RA V head had a divider cast into each intake runner, from port-thru- pushrod area-to valveguide, then drill the casting for pushrod tubes. divider between pushrod and valveguide would have to taper away as approaching valveguide.

Idealized result is a boat-tail divider before the pushrod tube, for least shock surface,
Flow-velocity remains STRAIGHT after pushrod tube-to valveguide, CSAmin still defined by valveseat.

How about a 1/2" diameter pushrod and 5/8" sleeve in the middle of the port? You would have to have a airplane wing in the middle of the port.

Not in this build. Maybe for a smaller pushrod application.

[Tom Vaught]

Originally Posted by J.C.you

How about a 1/2" diameter pushrod and 5/8" sleeve in the middle of the port? You would have to have a airplane wing in the middle of the port.

Not in this build. Maybe for a smaller pushrod application.

Overhead Camshaft would eliminate all of these Pushrod in the Port issues.

Tom Vaught

[Ron H]

I'm not sure how a 21st century reintroduction of a 50 year? old design could look any more original?

Awesome work you are doing, Lynn. Light the world on fire!! Ol Injun and the Phoenix is Rising!

If you have all the numbers and a pure car, good on ya. These past few years have been incredible for Pontiac enthusiasts!

[Milepost]

Originally Posted by Tom Vaught

Overhead Camshaft would eliminate all of these Pushrod in the Port issues.

Tom Vaught

Tom, maybe you can answer on this..... I just can't see what is the major problem with a aero profiled pushrod tube down the middle. Sure, I can see how it would mess with the wet flow but look at the Ford Coyote engine and all the rest of the the 4 valve heads. They all have a siamesed intake ports and splitting the flow doesn't seem to be a problem with them. Maybe a professional porter with extensive experience with 4 valve cyl heads would be better choice here

[Half-Inch Stud]

Originally Posted by J.C.you

How about a 1/2" diameter pushrod and 5/8" sleeve in the middle of the port? You would have to have a airplane wing in the middle of the port.

Not in this build. Maybe for a smaller pushrod application.

No wing. We're talking DIVIDER (left/right) at the pushrod.

[Tom Vaught]

Try and answer your question, Milepost.

There is a difference between a .090" wall dividing two runners next to each other, (each side optimized for that Runner Volume vs Intake Valve Diameter). Split port with two small ports spread apart initially and later closer together at the valves (H.I.S. suggestion). Would make for a wild intake manifold.

In the case of the RA-V head, obviously without a sleeve surrounding the pushrod, you have a high potential for a leak, and can seal the top of the head with a normal Valve guide seal but how do you seal the bottom of the pushrod going thru the head?
A sleeve can be installed which will take care of that issue by being a slight press fit at the bottom into a female pocket and a pressed fit at the top of the rocker arm area.

But now it gets tricky, If you had a normal 11/32" (.343") pushrod in the sleeve your sleeve outside diameter would be about .080" (assuming a 1mm tube wall), so the sleeve outside diameter would be .424" blocking the airflow into the port.

So if you assume a Vane added to the sleeve (with the same 1mm wall thickness) you now would have a .504" diameter disrupting the airflow past the pushrod.

So now we move to J.C.s, "Big Momma" 1/2" diameter pushrod.

You now would have a .660" "pillar" blocking the air flow thru the port. If the port was 3" tall you would have very close to 2 SQUARE INCHES OF BLOCKAGE vs your normal
assumed 7.068 square inches of area (3" diameter port assumed). With the factory .343" pushrod and sleeve you would have 1.5 Square Inches of blockage.

About 21% less actual port area (when the air goes by the sleeve) vs the open port with the .343" pushrod. About 28% less actual port area (when the air goes by the sleeve) vs the open port with the .500" pushrod.

Even with the trailing portion of the vane trying to reestablish the 7.068 square inches of flow to the valve there is a lot of contraction/expansion going on in the port. Kind of like a "King Kong" push rod tube bulge at the side of a factory head. Everyone tries to reduce that bulge as much as they can on ported heads (typically by some grinding on the bulge but also grinding on the opposite side of the port from the bulge. Offset Rocker Arms/ Pushrods help that deal a lot.

So whether you have the vane or not you are sucking up port area and causing a disruption in the airflow to the valve.

Moving the pushrod out of the port allows the port to be bigger vs the 28% blockage with the race .500 pushrod/sleeve installation.

Hope that helps. Ford figured this deal out after the Tunnel Port Heads were dropped for the Ford 351/429 Spaced Port where the pushrods were out of the ports.

Tom Vaught

[J.C.you]

Originally Posted by Half-Inch Stud

No wing. We're talking DIVIDER (left/right) at the pushrod.

Question, do you think the air/fuel mixture flowing across a divided port would be equal from side to side? If you do, a divider may not hurt the efficiency of the port. BUT, if there is a variance in one side or the other of your divider theory, huh ohh... issues will arise, most likely wet flow issues.

This issue of leaving the pushrods in the middle of the port or moving them came up, sometime ago, especially with a big pushrod and sleeve. I wanted to move them and Tony agreed. Lynn mentioned a pushrod support he had been working on enabling a smaller pushrod/sleeve to be used where extreme spring pressures were involved. I took it from Lynn it had not been proven yet, and didn't want to pursue it, so it is what it is.