OHC heads for Small Block Chevy?!?!?

[Drax240z]

I would guess combustion chamber sealing combined with thermal expansion would be the biggest hurdle... it isn't a layout that lends itself well to sealing.

[rsicard]

Braap: Thanks for the response. I never thought about the area and volume of the 4 valve per cylinder advantage which is very technically positive. With the extra chains and extra valves that makes the engine more mechanically complex and bulkier in the engine compartment. The GM Gen IV small block has variable valve control also, to what extent I am not certain. The less moving parts there are to an engine the better.

[sweetride2go]

Brapp, didn't you guys discuss valve train harmonics and complications with pushrods at higher rpm's? But then again, maybe that doesn't directly relate to a drawback from the pushrod v8 since that discussion is set on a goal of a high RPM engine...

 

I would love to create a OHC small block, but from the pictures they get really bulky. I wonder from the pictures posted of the converted engines, how much weight is added?

 

Ryan~

[jt1]

Have any of the OHC conversions made more hp than the standard configuration?

 

The Moser is my favorite, it has massive cool factor.

 

jt

[A. G. Olphart]

Look under the valve cover on the link I gave.

 

Look closely...

 

Muahahahahaha!

 

 

Being old, all I saw under the valve covers was words--- these the ones you meant?

"Compare the similarities between Schubeck engines and the engines winning at Lemons and Indy."

 

Didn't realize the influence of the 24 hours of Lemons had been that pervasive.

 

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[dr_hunt]

Something a little more proven. About 600HP in street trim.

 

http://www.falconerengines.com/bio/bio_irl.php

[bjhines]

The biggest drawback in the OHC design is the SIZE of the completed motor. I replaced the engine in my van a few months ago and found the OHC FORD v8 was way too big to get into the Datsun, or any other small car.

[kamikaZeS30]

http://www.falconerengines.com/bio/bio_irl.php

 

$45,000?!?!

 

For that price-tag, you could engineer something from scratch. I know they're outlawed for racing; but if one wants the efficiency of OHC, without any of the drawbacks or want something better than cam-driven valve-trains period-- one could build an electrical solenoid-actuated, computer-controlled valve train. No more mechanical drag, what-so-ever (well, one must have an alternator). 45 large for a street motor? I could probably build a damn fusion battery powered electric motor that would produce more torque than a internal combustion engine could ever hope to achieve, for that price.

 

To me it makes sense to go to solenoid valves, anyway. But, I think since the Renault incident (?) they're not legal in any racing series that I know. For street applications, the benefits would be amazing and one would think that with that kind of available precision in valve timing not only would one be making more power, but it would increase mileage and reduce emissions. Unless I missed something somewhere.

 

DOHC is a pretty cool idea, I liked the Integra GS-R I used to have, amazing what that little 1.8L would do. I just think that when you get into the bigger displacement engines it starts to become a point of diminishing returns due to weight, center of gravity and the fact that your RPM limits come from terminal piston speed and the rest of the bottom end, not the valve train.

[grumpyvette]

solenoid valves,.... since the Renault incident ?

 

 

PLEASE EXPLAIN IN SOME DETAIL?????????????????????

[kamikaZeS30]

solenoid valves,.... since the Renault incident ?

 

 

PLEASE EXPLAIN IN SOME DETAIL?????????????????????

 

 

Well, I'm not 100% sure on the Renault incident story but I can give you an abbreviated version: Renault designs a V-8 motor with the intention of running it as a contender in grand-prix racing. The engine did not have cams, rather it was a computer controlled valve train with valves that work in much the same way as a fuel-injector, a magnet is energized for a period (a single pulse) closing the valve, when it is de-energized the valve opens. This allowed for much longer durations without the worry of heavily weighted spring producing drag on a cam, in-turn creating more stress on rotating parts and mechanical drag. For some reason, "the secret" had been let loose (although, I'm pretty sure anyone with two brain-cells to rub together has thought of this before); the reason that I heard is that a competing factory team was butt-hurt and went to extreme lengths to find out the huge technical advantage the Renault team had and that the technology was universally banned. Sounds far fetched to me, that's why I didn't tell the whole story. However, since I heard that story probably 10 or 11 years ago, I've been fascinated with the idea. I've seen some research done on it, a lot of design concepts, and knowing what I do know about engineering and basic mechanics, it seems feasible to me. The overall design of the valve would be very similar to those currently used, just the means by which it is opened and closed changes.

 

Then again, I do know that if you google "Solenoid Valve Engine" you'll get several hits from academic institutions with engineering students and faculty alike building them. So, the Renault story maybe kind of like an episode of MacGyver, who knows.

[PanzerAce]

Isn't the new Fiat engine using solenoid actuated valves for atleast one side?

[BRAAP]

RTz and myself witnessed a demonstration of the original EVIC engine, (in the link below), run at one of the P.R.I.M.E. Model engine shows a few years back. Interesting to watch the engine run as he showed different aspects such as skip-a-cycle, etc. Would love to see this applied in larger scale. Would also like to see more discussion regarding the title of this thread too.

 

http://home.cogeco.ca/~davebowesevic/Mk1%20Engine.html

 

 

[kellysautosport]

This was a very interesting thread to read. It surprised me that nobody mentioned the Mercury Marine/Lotus engineered 32valve DOHC LT-5 that came in the C4 ZR1. I just mentioned it because i sure wish GM produced more of them because i sure would love to have one...

[Tony D]

Something along the same lines:

 

 

Just for the record, Coates was contacted about doing a head for the Nissan L-Engine. R&D costs as well as protyping costs were offered to defray development costs on their end due to the acknowledged low-volume market it would cater to---they were unwilling to do the work. Even after an offer of 'minimum run payment' was made to get a one-off run of minimum production made just to supply people in the Datsun Community who were serious about the advantages of the Coates Setup. At the time I worked with a company who had a large investment with them doing rotary valve conversions for LNG service on large diesels in city busses. I was disapointed in their stance.

 

If you remember I put up some photos of JeffP's engine while on a Superflow Dyno. The shop where that occured... the owner made his own DOHC Chevy Heads. He has four sets. Next time I'm in the shop, I'll make a point to snap some photos and chuck them up here. unless something else tasty there distracts me again...

Edited August 1, 2010 by Tony D

[Tony D]

On solenoid valves: DEVAS

 

On four valve-per-cylinder SBC's...you don't need OHC's to do that, there ARE 4-Valve heads which use pushrods! No different than an old two-stroke Detroit Four-Valver Diesel.

 

"There is nothing new!"

[kamikaZeS30]

Dealing with OHCs, a lot, and now starting to get into the push-rod stuff, the valve trains in the hydraulic push rod set-ups seem much quieter. I like hearing the engine, i.e. the exhaust tone, I don't like hearing the valve clack all the time. That's where my preference is for the V8s.

 

Although, some of the Japanese (Nissan) V8s have pretty quiet OHC systems, but they're hydraulic IIRC.

 

I can't imagine how incredible it would be to have something like a Chevy small block, with 4 valves per cylinder and variable lift/timing. Whether it is worth spending 4 times what I spent on the entire motor, to buy a set of heads to do it, is entirely another story.

Edited August 21, 2010 by kamikaZeS30

[thehelix112]

For the VK56DE, I believe, after reading this: http://www.titantalk.com/forums/attachments/titan-general-discussion/9430-endurance-5.6l-attachment.pdf is not hydraulic, but that a lot of effort went into making the chains quiet.

 

Dave