for us automobile technopihiles

Topic: for us automobile technopihiles (Read 3056 times) previous topic - next topic

for us automobile technopihiles

September 03, 2008, 07:55:05 PM

http://www.decuirenginetechnologies.com/ springless valves for the pushrod engine.

http://www.decuirenginetechnologies.com/DET.html vdeo

should read technophiles, fat fingers ya know.

for us automobile technopihiles

Reply #1 – September 03, 2008, 08:36:29 PM

wow! looked like the cam was grooved or sumthing , to pull the valve closed....weird,,,,do they make them for all block sizes?

for us automobile technopihiles

Reply #2 – September 03, 2008, 08:36:28 PM

wow! looked like the cam was grooved or sumthing , to pull the valve closed....weird,,,,do they make them for all block sizes?

for us automobile technopihiles

Reply #3 – September 03, 2008, 09:14:47 PM

Interesting. Would be even more interesting to see it at high RPM, and to see how they'd deal with lash adjustment. A normal engine only needs to deal with lash adjustment for opening the valves; the valve springs themselves make up for any wear that might happen on the "closing" side. With that design you'd need to come up with a way to adjust for wear over the life of the engine, otherwise as the valve seats wore they wouldn't seal.

for us automobile technopihiles

Reply #4 – September 04, 2008, 12:47:46 AM

im not sure about that.
looking at the design, the valve spring is relocated to the bottom side of the head exposed to the lifter valley. It just relocates the spring to a different area basically putting the tension on the pushrod. as the seat wears, the spring will just pull in tighter.

I am having trouble absorbing the gain,, seems like the pushrod should still maintain the same tension but they are saying the valve spring is lighter in tension for some reason.

also,, cant figure out the connection part of the valve,, is that a standard valve there? with a clip on do hicky like thing a ma jig that bobs the valve up and down using the exising valve keeper knotches?

I think ill call them tomorrow

for us automobile technopihiles

Reply #5 – September 04, 2008, 12:59:55 AM

+2. I was thinking the exact same thing. It really doesn't seem all that innovated, mostly just more complicated then it has to be. They just relocated the spring? I liked the rotary valve idea alot more.

for us automobile technopihiles

Reply #6 – September 04, 2008, 08:13:33 AM

What spring are you guys talking about? I don't see any spring, all I see is a positive mechanical connection to the camshaft, so that the cam pulls the valve closed as well as pushes it open. I still don't see any means of pulling the valve closed so that it remains tight against the seat as the parts wear.

for us automobile technopihiles

Reply #7 – September 04, 2008, 08:29:05 AM

There is mention in the OHC video of a spring, but they make a point that it is to hold/seat the valve stem seals, and NOT to seat the valve.

They do show adjustments being made on the set-up, so perhaps the system would require fairly regular valve adjustments to keep the valve seated as things wear.

Looks interesting.

for us automobile technopihiles

Reply #8 – September 04, 2008, 04:18:02 PM

Quote from: Thunder Chicken;234894

What spring are you guys talking about? I don't see any spring, all I see is a positive mechanical connection to the camshaft, so that the cam pulls the valve closed as well as pushes it open. I still don't see any means of pulling the valve closed so that it remains tight against the seat as the parts wear.

You need to drill into the page under "other inventions" and click on the true link system. In there you will see the plain jane pushrod motor application more clearly defined.

The premis is that since you have relocated a tension device more closely to the cam / lifter, the tenstion of the spring can be derated due to some engineering dynamic my piddly little brain cant comprehend at the moment...............see linky.......
http://www.decuirenginetechnologies.com/trulink.php

Pete / Sam
If you guys get this,, go to electrical tech and click on the sticky up at the top where you find 1987 EVTM,, all wiring diagrams for a fox 2.3/3.8/5.0.

for us automobile technopihiles

Reply #9 – September 04, 2008, 04:24:05 PM

Somebody named "alex" will be calling me back today hopefully on these gems. Ill try to get pricing as well.

I think i like it!!

for us automobile technopihiles

Reply #10 – September 04, 2008, 04:49:17 PM

Looks very interesting this guy took one of those moments when I’m sitting around think of how to build/cheat/engineer more HP and did it.
I wonder how much HP loss is compensated in the fact that the cam is now also pulling the valves not just pushing them.
Does look neat though I’m sure it will be a few years to work out the kinks.

for us automobile technopihiles

Reply #11 – September 04, 2008, 05:26:54 PM

I spoke with alex, what a pleasure also to be able to talk with someone who started out working on cars at 18 and is heading to age 79 this coming sunday.

There really isnt too much that has happend in Nascar this guy does not know. He's worked for many of the greats in Nascar like Dick Trickle, Richard Petty ect.

He said that every so often he would run the dyno machine and observe/measure the nature of the three connection points a pushrod/ rocker has and its effects on valve float in order to solve it.

He said that he has ran engines to rpm's in the range of 7k and obverserved things you would have never thought posssible like the pushrod or rocker gap for a moment in time having a gap of nearly 3/8 of an inch ect. He said that at higher rpms, the parts will float naturally and that is amazing how it all stays together.

His idea makes the valve opening more contolled and also reduces the hp required to do so, which in turn frees up engine perfromance.
The mods to the connection of the rocker to the valve is done by means of hand made parts to include the clip you see on the roller part of the rocker. That clip is a bike chain clip that he found suitable since it was already heat treated.

Alex went on to explain that a normal engine seat presure is in the range of 90-100psi and that it will require about double that presure to fully open the valve. locating the valve more to the center of the engine and its placement in range with the lifter reduces the amount of spring tension through trial and error, reduces the flopping of parts where the rocker touches the valve and the pushrod touches the rocker, and also controls float and eliminates 66% of crashing a valve. Actually, alex insisted that it nearly eliminates it. The formula he uses,he had to make up along the way but it has a lot to do with the ratio of the distance from the fulcrum of the rocker to the center of the valve stem and its relationship to the hp required by the cam lobe to open and close said valve.

I am to supply my cam/valve/spring/head specs to alex and proceed with getting a conversion set made and supply him with consumer test data as well as dyno / track info of before / after for his records. This guy is really neat. I like older generation types who dont mind teaching when they know there are open ears and closed mouths.:bowdown:

for us automobile technopihiles

Reply #12 – September 04, 2008, 05:32:48 PM

Quote from: Chuck W;234900

They do show adjustments being made on the set-up, so perhaps the system would require fairly regular valve adjustments to keep the valve seated as things wear.

Looks interesting.

Sounds to me like it already needed adjustment...

Was makin' more noise than two skeletons screwin' on a tin roof... :hick:

for us automobile technopihiles

Reply #13 – September 04, 2008, 05:33:42 PM

Quote from: Innes;234954

Looks very interesting this guy took one of those moments when I’m sitting around think of how to build/cheat/engineer more HP and did it.
I wonder how much HP loss is compensated in the fact that the cam is now also pulling the valves not just pushing them.
Does look neat though I’m sure it will be a few years to work out the kinks.

take another look,, the cam is not pulling the valves closed, the spring is working the whole link. The pushrod is now under spring tension which is naturally following the profile of the cam lobe.

for us automobile technopihiles

Reply #14 – September 04, 2008, 09:06:05 PM

Quote from: jcassity;234949

You need to drill into the page under "other inventions" and click on the true link system. In there you will see the plain jane pushrod motor application more clearly defined.

The premis is that since you have relocated a tension device more closely to the cam / lifter, the tenstion of the spring can be derated due to some engineering dynamic my piddly little brain cant comprehend at the moment...............see linky.......
http://www.decuirenginetechnologies.com/trulink.php

Pete / Sam
If you guys get this,, go to electrical tech and click on the sticky up at the top where you find 1987 EVTM,, all wiring diagrams for a fox 2.3/3.8/5.0.

The "True link" system is not the same system as the springless valve system you touted in your first post. The true link system uses two valve springs (one on the valve, one on the rocker arm) and actually looks to me like it could work. The "Springless Valve System" has no valve springs, it relies on grooves in the cam and those chain-link looking things to pull the valve closed. You can see the groove in the cam here (look at the side of the lobe - note how the lifter doesn't even seem to ride on the cam lobe. It's riding on a pin that fits in this groove):

The springless system still looks to me like it would not reliably work, at least on a street engine expected to last 100k+ miles. A race engine that will be rebuilt after every race (or could even have its valves adjusted during a pit stop), maybe. Still, even with adjustment, the problem I see is that the valves would have to be adjusted for less-than-zero lash when closed, otherwise the system would not pull them closed all the way and they'd leak compression (which would quickly lead to burned valves). Less-than-zero lash on a valve that is being pulled closed by what is essentially a crankshaft and connecting rod would result in the valve hitting the seat very hard and closing very tight, which would rapidly "tulip" the valve head or even stretch the stem or other valvetrain components. This tuliping or stretching would soon result in "more-than-zero" lash, which would cause compression leakage.

If it seems like I've put a lot of thought into this, it's because I've been thinking about alternatives to the current cam/lifter/valve setup since middle school (we're talking early 80's here). I would sit in class and daydream about ways to elimimate the cam and use solenoids. Solenoids would allow infinitely variable valve lift, duration, and overlap. It could be changed on the fly and cylinder-to-cylinder. The throttle blade could be eliminated entirely, since you could throttle the engine by only opening the valves enough to let enough air in to idle.

Strangely enough, in my mind I could never overcome the valve closing problem with solenoids, either. If I used springs in my imaginary cylinder head the solenoids would have to be extremely strong (meaning large, heavy, and really sucking down the current) in order to overcome spring pressure and open the valves. If I didn't use springs the solenoids could be smaller, but they would close the valves too hard (unlike a traditional cam, which closes the valve gently as the lifter rides down the back side of the lobe, a solenoid would whack it closed suddenly). This would lead to the "tuliping" problem I mentioned above.

Even stranger, though, is that after a few moments thought I think I may have come up with a solution for the Decuir springless valve system. Install a shock absorber on each valve. It would not have to be a big shock with a lot of range of motion, just something with a few thousandths of an inch that allows just a bit of "stretching" between the valve seat and the camshaft. Perhaps a solid rubber block inside the "shock absorber" that would compress ever so slightly when the valve closed, yet rebound (again, ever so slightly) when the valve is open again. This would allow the valves to be pulled fully closed without stressing metal components. Here's a quick drawing of my idea:

Of course this idea opens itself to a whole new slew of problems. Aside from the extra weight (which would mean more inertia, which would make the engine more resistant to revving), I can't for the life of me see how you'd get this valve into the head. I drew it fully assembled, so just imagine trying to disassemble it :hick: