You know Leo put a Turbo 4200 in his Stude, but can you believe the speed it turned WOW !!!!!

That's why so many are switching over to the Atlas engine. In the NHRA Comp Eliminator ranks the N/A version of them makes over 700 HP at only 256 cubic inches. This is almost 200 HP more than you can make with a N/A 250 with a lump head in the same class. So its instantly made the older 6 cylinders obsolete in these classes.

I thought OHC and 4-valve engines had a separate class designation from pushrod motors.

They do have a different class for them but everyone has jumped ship to the Atlas powered classes because you also get more HP for much less money too.

Wondered who was watching,

Leo's speed was 170+ that's in the 7's when he gets then right converter in the car. What an accomplishment.

Could not have happened to a better guy, works hard for the club and loves his inlines.

That's awesome! When are you switching over Harry?

Nope, too old too poor and the 37 is only certified for 8.50's and for sure too heavy.

But I am still going to have fun with the "OLD" 292 and carbs!

You know back in 1962 when this engine just came out, I thought why does't every one go to it instead of the old junk, now I know why.

Harry

"I thought why does't every one go to it instead of the old junk, now I know why."

Well said Harry, and some day when the 4.2s are the old junk they will understand.

After my friend tuned Gary Hart's atlas engine in his GMC, he has repeatedly said I should get one for my Firebird because the cheaper and easy power that comes with them comparatively. No dice, I like the soul of my old engine since I drive it more than race it.

I think folks built them because the indexes were comparatively soft. Now that the class indices have been CIC'd a few times to bring them into the same (insane) world of money-chasing-performance-gains I haven't seen any rush of new cars in those classes. Do you know of others set to debut new cars? Some racers I know alternate between dragsters/altereds, 4.2s/ Ford 240-300s depending on which index is most favorable.

No I don't know anyone currently building anything new, but a lot of our old customers have switched over to them. In Comp form, these engines are a lot less expensive to build than our 292's were, and they can make more power and last longer.

Yup. You may remember that when I first saw some of the performance numbers coming from the first factory 4.2s I declared on this forum,

"The King is dead (Ford's 300). Long live the King (GMC 4.2)".

That must be the way the way the flat four guys felt when the V8 came along, and the flathead guys when the Chevy small block showed up. I'm happy on the fringe that used to be the ragged edge.

Its all in the head design...

Once you get past the control electronics the engine itself is pretty simple inside.

I'm still confounded that more inliner's are not making the switch. Its most likely the last inline 6 we will see out of Detroit for a long time..

As a whole we are a very progressive group . Most of us are still clinging to our God, our guns, and our obsolete engines. We don't mind shouting encouragement to the new age. Several guys in our local have 4.2s now and there are more in the works. I do realize that one of these would make a better fit in my '68 flatbed than my planned 292/TBI/Turbo and probably easier and cheaper, but so would a Cummins.

I believe the head design of all multi valve engines are very poor, they only work because of the multi valve configuration, the ports are all too low for a decent angle to the back of the valve head. The manufactures used the multi valve to make the engines shorter in length. I would like to see a 4 valve with the ports up high, even higher than the best chevy small block head. Remember "Smokey" you want to flow around the whole valve not just one side.
Not to knock 4 valves they do work but still not the best possible. Look at the Pro Stocks of today!

If only I had a block of aluminum.

I think the 4 valve motor cycle cylinders heads are pretty good design myself.

180 or so HP out of a 1 liter, 1000CC's

200 or 300 HP Ninja for 2015 1000 CC's

https://www.youtube.com/watch?v=vAo0LWQFxdE&feature=em-subs_digest

MBHD

I personally don't care about bikes at all. They just turn a zillion RPM like an Indy car, I hate that rice rocket sound.

Give me a an engine that makes a lot of torque that keeps pushing you back in the seat, that why I love turbos they never stop pulling.

Low entry angle on many multi-valve production engines is intentional. It is one method to improve burn rate and reduce emissions. An engine with high flowing ports and a relatively quiescent charge motion in the chamber may not run as well as a head with a higher burn rate but less Vol eff.

I saw this first hand with a prominent NASCAR team owner who once personally took a head from one of his cars that was not running up to his expectations, took it to the flow lab, masaged it until it flowed like a mother - and made less power - because the burn characteristics were diminished. No names here

What speed and time did it do?

tlowe see previous post.

I think the low ports are for more hood clearance, how would it influence burn rate, if you decrease air flow to make more power something is wrong with your combination or tuneup, if you want to increase burn rate give it more advance, who cares about emissions on a race car.

Well, for starters, a low port entry angle can induce "charge tumble", a common method on 4-valve engines to increase the rate at which the fuel in the chamber is consumed, and thus, the rate of pressure rise against the piston. If you can increase the rate of pressure rise against the piston after ignition commences then you can reduce the ignition timing. If you reduce the optimum ignition timing then you will do less "negative work", i.e., the pressure that is building as the piston is approaching TDC actually is working against the crank and reducing power. So your premise ..."if you want to increase burn rate give it more advance"... is fundamentally flawed and a common misconception of how ignition timing affects performance. Ideally one should strive for an engine that needs as little timing advance as possible to reduce the negative work.

Don't think for a minute that Detroit wouldn't lay the engine over like a slant six if it meant picking up a bunch of power by raising the ports.

As fas as ..."who cares about emissions on a race car"... I care about emissions on every engine I own, from my DD to my lawnmower to my race car. My grandchildren are going to inherit this earth as are their grandchildren. I don't want the entire earth to have the air quality of a Beijing.

Just curious if you have looked a 4200 head close up..

The valves are canted over toward the ports about 35-40*.

If the port and valve size was so poor then explain why each intake valve contributes ~175 cfm at 0.500" lift at 28" water pressure on a 1mm OS 2006 head..

From what I have seen the short side radius is almost non existent. This is what makes the air stand up and flow
all around the valves.
I'm more concerned with turbo engines were tumble or swirl do not mean anything and I agree the less timing the better, also a reason to use a turbo, sometime every internal combustion engine will run a turbo.

What does the above 4 valve flow with both valves open when flowing? 2 x 175 = 350 cfm or less?

I believe a small block chevy is at 400 cfm now.

I love this. I think I'll be quoting it at some future drunken hoodlum hot rodder rave.

Feel free, by the next time I read it I will have forgotten I made it up.

Sorry I have created such a fire storm about the 4200.

I only touched on the edge of the faults that I perceive of the engine, Why did't GM keep the original design that won Pikes Peak and Baha? Money, marketing, for sure not engineers.

I myself think the flathead combustion chamber design is one of the best and could be one of the most fuel efficient engines, if you want swirl and tumble with low ignition timing .

I don't follow the crowd, I like to think outside the box.

Again sorry for ruffling everyone's feathers!

A flathead combustion chamber has a horrible surface-to-volume ratio, even though it is an undersquare design which favors S:V. It will spew hydrocarbons.

Think of all that air and fuel in the cylinder going BACK through that small transfer slot then igniting. Its like a pre-combustion chamber, everything lights off very quickly. I know the surface area on any of our flatheads is less than any V8 and for sure any 4 valve head. Penthouse chambers have a very dead chamber as far as mixing the A/F. That is why racers use a curved dish piston to try and get the mixture to swirl and tumble on the up stroke of the piston. They also have little or none as far as quench area.

Just my thoughts

Not to open old wounds but, I was just at the PRI show in Indy and seen the new 4 valve head from the Ford eco-boost engine and the ports come in at a very steep angle to the valve maybe this is why it is such a hot engine.

I guess Ford thinks like me!

Nice show, too bad I didn't see you. Was that the head in the ferrea booth?

Yes I think so, also it had 8 intake ports for the 8 valves a very cool idea.

If your are interested EngineLabs.com has this article currently on the Ford EcoBoost.


http://www.enginelabs.com/features/pri-c...t-engine-parts/

I was referring to the 4 cylinder. Don't know what the other heads look like.

Turbo-6, Yes, realized that, but thought the potential was interesting and wonder if the mods can apply to a 4 banger.

Seen a lot of pistons of that design at different booths at the PRI wonder the reason for all the designs in the top?

Would like to see the 4 valve 4 cyl head again just seen a quick glance on the way out.

Direct injection piston. Just like diesel's, it promotes fuel mixture and controls the flame front.

I had seen a really cool animated gif of the spray pattern and burn, but now can't seem to find it.

But here is the Hot Rod article.
http://www.hotrod.com/how-to/engine/1501-direct-injection-is-the-future-of-efi/

Thanks, I feel like I'm from the model T days myself.

I guess most of this is for emissions not HP.

I stay with carbs much more simple to tune for myself.

Kind of a cake and eat it too deal. By having direct injection the risk of detonation/pinging goes down, so compression ratios can go up and up. And with increased compression comes more HP.

Apparently this is Cunningham's 4200 turbo engine out of the 66 chevy II wagon that ran hot rod drag week 10 years ago. Been siting at Self's shop for a number of years.

It made 1150 HP with a mild tune right before it went into Leo's car.