Inliners International Forums General Discussion Hi Performance 4 valves per cylinder

Hello everyone, this is my first post and I would like to share an idea a few friends and I have had. (I am also not sure where to post this as it is a Performance/EFI thing so I will make 2 posts one in Performance and one in Blown and Injected)

If you do not care to read my story... please skip the following paragraph

Well, it all started in high school when I was your typical V-8 crazy not actually knowing much but loving cars kid... After my first car died (a 1994 Oldsmobile 88) I began searching for something cool, something with a big V-8 something American and from the 60s... After realizing limited funds I settled for a 1966 Chevelle with a 230 straight 6. Fast forward 4 years and now I am in College(Mechanical Engineering) working in my Engineering departments Machine/Fabrication shop. The 6 is a true workhorse engine never actually breaking more than say wasting 30 min of my time on the side of the road fiddling with things to get it to run. However, I came across a deal I could not refuse for 300$ a 1985 Toyota MR2... After a quick rebuild and many hours cursing and wishing the Japanese had taken any consideration into people who work on their own cars... It is up and running. It also came with 2 spare cylinder heads. NOW HERE IS THE INTERESTING PART.

What if I scaled up the peppy 4AGE(1.6L, 4 valves per cylinder, Dual Over Head Cams, 112hp, 98ft-lbs tq, and a redline of 7600rpm) to the 230(3.8L)?

Has anyone tried something like this?

MY boss, who has been in the CNC business for 20+ years, has agreed to help me out.

I have already started hacking the 4AGE head to pieces(good old band saw) and will start the process of modeling it in AutoCAD Inventor.

Megasquirt will provide the EFI and Distributorless Ignition into the equation.

What I need to know is what will take a Chevy 230 to 7000+ rpm, rods, pistons, cranks, etc?

What does it take to cast a 40-50lb piece of Aluminum?

Any Input on the matter will be greatly appreciated

what will take?

10 times what replacing the engine will cost, and several years.

If you've got the knowledge,resources and ambition I would say go for it.

If you have access to a mill (CNC prefered) you can build the cylinder head in layers and save the $50-100,000 to have one cast. Mill the combustion chambers in one side of a chunk of aluminum then mill part of the ports and water jacket in the other side. Build the other half of the head from another piece of aluminum. Practice on a piece of oak lumber to work out your layouts.

Good luck and have fun.

Ron

Wow that is a really great idea, I don't think I would of ever thought of that... so literally mill the water passage ways then bolt a top on(simplified version..)? that would really help with the you know not needing a massive crucible filled with molten aluminum.

I'm not sure if this is a good idea or a foolish idea, but..

You might want to google some of the model builders sites. there are many of those folks that build running internal combustion motors(small scale) Some seem rather complex. Some of those folks may be able to offer suggestions on how to proceed as far as the heads, cams drives etc.

Sincerely:
Paul...aka xerxes

I have another thought; why not consider making it a 2 valve/cylinder, single overhead cam design with cam followers and eliminate the pushrods and rocker arms. The head could easily be made to flow enough to make plenty of power. Just design a good intake and exhaust port and your there.

I built a 1952,302 GMC truck engine with 1950's, 308 Hudson connecting rods, Pontias wrist pins and a custom JE forged piston. I saved 1.25 lbs per piston/rod/pin. The engine turns 6000 rpm easily and makes 347 HP @ 5400 RPM on the dyno.

Ron

The cam can be driven off the front of the engine with Gilmer belts and gears. About $150 for the whole drive system.

Think outside the box ....besides it's just a piece of metal that's waiting for you to make it into something you want and need. Keep me up to date if you proceed with your project. I may be able to help.

Ron

I have considered something along those lines before. Either just build up the 6 keeping push rods, or throw in a pontiac sohc 6. I have heard great things about both approaches and they make good numbers. However they are both simply not my "style"

I enjoy high winding Naturally Aspirated engines(like the 4AGE, and the BMW straight 6's) I know that with a good lump port design and bigger valves these heads can flow, but they still have their limits with only 2 valves per cylinder(look at the 240z,260z,280z crowd they can make a good 300+ hp with turbos but once those engines hit about 6000 the TQ plummets due to not enough high rpm flow)

Another thing that is stopping me from just shooting for a TQ monster is my stroke(3.25inches) not much of a throw there compared to your 302's 4inches. Plus the chevelle I own will be going through some major weight reduction(planning on a final weight of 2700-2800lbs((from about 3200lbs))) so all that low end grunt will not be needed cause a tall rear end and a nice manual 6 speed can get it going. I am also shooting for making hp/l comparable to a built 4AGE(somewhere around 90-100hp/l) which means I am going to have some pretty aggressive cams(sacrificing low end TQ but, the sheer size of the engine should make it have decent driving characteristics), something like an 8000 rpm redline, and about 11:1 compression...

You sound truly interested in my project and ANY help/ideas/construstive criticism is GREATLY APPRECIATED.

With the fairly conservative HP/L figure you are seeking, that goal is not going to be hard to obtain with the siamese head and other performance components available for these engines. I have built several 250's that have made 2.05 HP/CID, and were very reliable race engines, and still used the "lump" siamese head. Sure a multi-valve head or even a "Cammer" style head would be very exotic, but don't sell short the potential of the existing technology on these heads. I think if you don't end up with a better head or combination than what you could have with the siamese style head, you really haven't gained anything, for all the work involved that you had to do. Its still an interesting project to consider, and would like to see how you proceed with it....

I have to ask how did you pull 512.5 hp out of a 250? Thats 125hp/L... The Honda S2000 squeezes 239 hp out of a 2.2L and thats only about 109hp/L and the Cosworth Duratec gets 260 hp out of a 2.3L which is aobut 113hp/L. I am in now why trying to discredit you, its just these are two new performance engines with all the modern bells and whistles of today(that rev to 8000+), and they still do not hit that kind of hp/l number(125hp/L).

These are full tilt NHRA Competition Eliminator engines, and would in no way could be street driven. They have ultra-high compression and insanely large camshaft lifts,and naturally, ported "lump" head to the max, but the potential for these engines to have that sort of output with factory head and blocks and crankshafts is able to be done with relative streetable HP in a detuned state and is also within reach. Especially if you were to use the Kirby style 12 port head, which is by far, many levels above the siamese head. In a recent Hot Rod magazine article, Kirby had a 450 HP street driven 250 featured in the article with one of his 12 port heads on it. I think your underestimating the potential with what you have to start with. Don't get me wrong, I definately would like to encourage your forging ahead into uncharted territory, because that what I do also, but again if you don't end up with something that is better than what is currently available can produce, then thats a lot of work for not much gain, I think. Keep approaching it in the same way you are so you can evaluate it, and im sure you will come up with something promising and leading edge.

Ah, yeah I should of stated this is going to be streetable orentiated. From what you are saying though maybe I should up my stakes... Now I am thinknig 100-110hp/L of streetable power. I am fixed on an rpm screamer though, as I like peeky(but not undrivable) engines. So I Plan on keeping it a 230.

As for being able to just get a 12 port head, I am a calculations/optimal/insane type of person so, I want to build my own head.

I plan on using ~1.5in intake, and ~1.2in exhaust valves.

If you can, talk to Bruce Crower. He built his own crossflow head for a 1928 Nash. If I remember right, it was machined into 4 pieces. It was sandwhichedand butted together. It is a straight 8. I believe there is a Toyota engine with the same bore centers as a Ford flathead V8. More than one has looked into putting the OHC or DOHC heads on one. Good Luck

The Toyota "S" L4 DOHC engines are about the same at 93.5mm (3.819"), but IIRC the Ford has staggered bore centers like many older engines.

Your enthusiasm is commendable, but I'm afraid you're too far down the learning curve to understand exactly how much work this is. Just making the cams will cost several thousand.

whatswithumans,

Some cylinder head design work that has already occurred for the 230/250 engines:

DOHC 4 Valve Heads
Project started by Primatech Motorsports, using 2 cylinder heads from the Chevrolet 3.4 liter V6 DOHC 24V engine, not produced
http://www.highperformancepontiac.com/features/hppp_0606_pontiac_sprint_six_engine_build/index.html


SOHC 2 Valve Head
Pontiac 230 & 250's 1966 - 69
http://www.classicaldrives.com/50226711/pontiac_ohc_straightsix_finally_gets_some_respect.php
http://firstgenfirebird.org/FAQ/engine/OHC.html
http://www.webrodder.com/article.php?AID=360&SID=4&CID=15
http://sohcsix.yuku.com/

93.5 / 25.4 = ~3.6811..., and this is for a chevy straight 6...



I can not seem to find much information on the 3.4L V-6. Would you happen to know its valve sizes?

I have finished hacking up the 4age head, and will be posting pictures of combustion chambers, intake/exhaust ports, water passage ways, etc in a few days.

93.5 / 25.4 = ~3.6811...

Yes, I'm quite familiar with the metric system, thank you.
That's what's called a "typographical error", in which I cut and pasted data from a page containing an error without actually doing the math. The similarity should have been to the Toyota L4 DOHC “AZ” motor at 3.81888612" (97mm), the Ford is about 3.80". I'd prefer to correct the original post, but in their wisdom the moderators have decided to make all errors permanent.

and this is for a chevy straight 6...

And, to acquaint you with how a BBS work: that post was a response to the prior post, which refers to the Ford V8 - and says so (see the little "[Re: jimmy six #35]" at the top?).

3.4L V-6

Much 60° data, poke around a bit: http://60degreev6.com/forum/f91

This is really interesting and sounds like a fun project. I wouldn't forget about Leo Santini's hybrid V-thing head. That might be a good starting point. Perhaps you might consider doing this first and then taking that knowledge learned and applying it to the 4 valve concept.

Ah, I did not realize. I apologize for being so snappy. However, I do realize this is a large and expensive project to take on, but I feel it will be worth the time, effort, and money.

If you're looking for a DOHC head design, you might take a look at an old 3.8 Jaguar head, if you can find one. It's even the same displacement as your Chevy. Sounds like a very interesting project you have going.

I looked at that jag head, but the cylinder bores are way to off, thanks for the suggestion though.

Here are a few pictures of the 4AGE cylinder head I will be basing my designs on.

The 3.8 is also about the oldest OHC high volume production engine I can think of (1948?): long stroke, wide included angle, large radius chamber section - the opposite of what would be done today.
If you're trying to get a sense of what a single cylinder would look like, it should be as close to your final bore size and stroke length as possible since "scaling" isn't very accurate to determine port and valve sizes.

I believe the bore centers on the Chevrolet 3.4L V6 match the Chevrolet 250 L6. The 3.4L V6 appears to be the best cylinder head to work with for reasonable fabrication. The cylinder head bolt pattern is not exactly the same.

http://www.highperformancepontiac.com/features/hppp_0606_pontiac_sprint_six_engine_build/index.html

The bore center for the Chevrolet 3.4L V6 is 4.4 inches, same as the 250.



Specs for the 3.4L V6:

http://www.60degreev6.com/content/34L_DOHC_Engine_Specifications?s=21c574b1c0591984b68ef8dd0ccd5203

Regarding the milling vs. casting, I have read about a number of people who produced heads for hot-rod Model-A Fords that way, so it can definitely work. I guess if you get a good design and have access to CNC you might even be able to sell a few copies.

Leif