Look through the pages of some of the remote control airplane/helicopter mags...rotary valve engines seem to do very well there. I have a friend with a RC helicopter that has one. Aparently they are better suited to small engines as well.

 

Point taken on the intake - I was actually speaking with the LT1 in mind (LT1/LT4 intake will not readily fit without much custom work)

As with the intake and headers though, if you are laying out the $$$ for these heads they are going to require the ancilliary parts be matched to live up to their potential. To see the "gain from the heads" you are going to need the sheetmetal intake and possibly a custom set of headers (again I was limiting myself - incorrectly - to f-body/vette applications. I don't think there aren any off the shelf headers that will flow enough in late model applications).




The ZR1 did well because it had quite a bit of engineering in it. Still compare a Zr1 from the factory to a LS6 from the factory. Not take into consideration all the extra factors - motor weight, packaging size, fuel economoy, emissions, and power. I'm not saying they wont work and make good power - rather I think more power could be made with a good set of 18 degree or better heads.



5 valve heads are *MUCH* better than 4 valve heads. Really. As for audi, vw, etc. - look at the bore sizes. multivalve heads simply work better because of the flow dynamics on smaller bore motors. Which all these are. Even ferrari's, etc. look at the bore size. When it get's large you start having inconsistant flame fronts and burn times - due in a large part to the poor mixture motion on such a large bore - but also the large chamber size (and shape).

Again, I am not saying they wont work, etc. They will work and make good power - I just think for a NA application a good set of 18 degree heads could be better. My biggest concern is the strength of the valvetrain though - that's something you can't do anything about and just looking at that and comparing it to a jesel shaft setup...

What I really think would be interesting is combining these heads (4v) with a forced induction - blower or turbo setup. That changes the dynamics of the head flow greatly, and begins to favor the 4v configuration. How about a twin turbo 427SBC :eek: .

 

I remember seeing an article about the COATES rotary valve head. the valves were a weird ball shaped thing with cutouts on the side that flowed really well. they mounted on an overhead cam shaft and eliminate pushrods and valve springs. sealing and durability were the problems. they picked up over 150 hp on a small block without exploiting the higher rev range. not sure if anyone is still looking at this design.

the dominion heads don't look that good. ARAO I thought also made a true DOHC 4 valve conversion but it was around 9K. I have a ZR1 and I agree that without the overhead cams, the weight of the fancy rockers and asking 1 pushrod to open 2 valves (even with lighter springs) doesn't seem to make much sense. I would spend that 3500 on a good set of CNC heads and a roller cam and I think you would do better. 4 valves per cyl is sexy, but the NASCAR engines do pretty well considering the "low tech" pushrod approach. :conehead

 

RKreigh, your description of the rotary valve is simple and dead on. I should never doubt that there will be someone on this forum with the answer to any question! Although ceramics have provided the answer of how to seal these valves, I am not sure that they will ever see a production automobile application. Perhaps in light aircraft or in marine applications, but not in cars because it lacks the ability to have variable duration (which is what the automotive OEM seeks).

I'm still looking forward to seeing a successful Arao 32 valve setup, although not a cost effective method for power, I think it does have some potential. I believe that Arao's Harley Davidson heads have done much better for producing results.

Thomas

 

...have you reviewed the rules for NASCAR? To my knowledge anything more than 2 valves per cylinder (that must be actuated by pushrod) is a no-no. I think if these heads were allowed on a NASCAR the rule makers and safety engineers would have a field day verifying or imposing further restrictions on the motor... this assuming these 4 valve heads really flow better than ANY currently approved NASCAR setup.

I am not sure if the Coates design is what I saw back in 86-87 timeframe. I did a web search and found http://www.kitcars.connectfree.co.uk/page44.html . This is a pretty neat website that explains the Coates Rotary Valve technology. Because we have discussed this design in this thread I decided to look a little further because I had only seen the design once. :cool: stuff. What I saw back in 86 was the same technology but the rotary valve design, apparantly, had not evolved into a spherical shape yet. The top fuel motor I saw basically had two belt driven "cams" on either cylinder bank. I did get a chance to see the "valve train" and if I remember correctly they looked like nothing more than polished steel bars with cutouts in them. Was this the same Coates guy working on his design or was it somebody else? Who knows... all I remember was this guy was from Australia.

 

There was a write up in hot rod, it may have been 2 years ago now, about the coats motor.
http://www.coatesengine.com/

Cool stuff. If I remember right, they said they had a test car they were running around in the streets, kind of a sleeper street racer. I will have to dig that issue up.

 

Actually, I was thinking about supercharged & intercooled :D :D:D, but that will come a few years down the road. I'm having all the internals made so that it is just a simple bolt-on (along with the required injector change), then a tweak on the old laptop for the new DFI unit that will go in with this monster.

Anyone ever try water injection on a supercharged motor? Maybe I can have Hogan put in a second set of injector bosses for that as well? Just thinking out loud here.

I'll send you a note when I get to that stage for some pricing Chris...

 

Well I will be interested in how the 4v perform regardless, and glad to hear your plans include FI - that's really where they are going to shine (imho ;)).

Water injection has actually been used in production cars before, albeit awhile ago - it has somewhat fallen out of vogue. It works, but I wouldn't design a car around it - if you used it for extra hp at the track that's one thing - but the first time you are goofing around on the street and the water is low/out you get into trouble.

Especially if you are going with a good DFI setup (Fast/speed pro would be my suggestion, esp. with wideband) you shouldn't have any problem keeping the car streetable/out of detonation normally. If you haven't checked into it yet I would take a look at some of the ceramic thermal coatings out there - they will help a good bit with fighting detonation, and should make you a bit more power with a bit more fuel economoy. In a NA motor at lower powers it's iffy how big a help they are - I personally will still use them, but it becomes a close call. On a FI motor though they a really are an upgrade - at a minimum you can get the chamber and pistons (tops and skirts) coated.

Good Luck!

 

I looked hard at those 4v heads when I was planning my SBC 427. Although they have been around for awhile, the fact that I could not find a single, unbiased example of anyone using them prevented me from going that route. I ended up sticking with the proven 18 degree setup, using a pair of CNC ported Dart 18* heads, Jesel valvetrain, and a custom Hogan's intake manifold. The heads flowbenched 355/260 cfm out of the box, and helped the SBC 427 make 650hp/580 lb ft on the dyno. They also have good velocity and low/mid lift flow halping it make 500+ lb ft from 3000 to 7000 rpm, even making 425 lb ft at 2000 rpm. This is all on straight 92 octane pump gas and a smooth 850 rpm idle with 13" of vacuum.

I recently opted to convert to intercooled twin turbo's. Maintaining the same streetability requirements and 92 octane gas, I'm looking for around 1200-1300hp using two Precision Turbo and Engine PT-52 turbochargers, remote HKS wastegates, and a custom intercooler rated at 1500cfm @ 1.5 psi. This is basically the same setup as John Meaney's 1300 C4 Corvette featured in last month's Popular Hot Rodding. His motor was 406ci compared to my 427ci, and I'm using some of Precision's new .85 AR exhoust housing which should privide even better spooling and reduced lag.

Anyway, I would really love to see someone finally build a hot engine with those 4v heads and document it. Good luck on your build.

 

I know of two engines that have them in the DFW area. One is still beig put together to the best of my knowledge (going on 18 months) and the other one never got running quite right. One I have seen, the other I have only heard about.

FWIW, there are better options IMO.