DIY_EFI Digest Tuesday, 10 September 1996 Volume 01 : Number 267 In this issue: Re: Fuel on the intake valves Re: Http address RE: Injector Flow Variation Re: Re: hi compressions Re: Re: hi compressions re: Re: hi compressions Ford EEC-IV Re: Re: hi compressions Re: Ancient History re: Re: hi compressions re: Ancient History (now fuel economy) Re: Where the heck have I been? Re: Ancient History Re[3]: hi compressions Re: Re Propane injectors Re: Re[2]: Re Propane injectors Re: troubleshooting a taurus Re: hi compressions re: Fuel Economy Re: Ancient History Oval Shaped Valves RE: Ancient History (now fuel economy) RE: Re: hi compressions Playing... Re: Ancient History See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "Hans Hintermaier" Date: Mon, 9 Sep 1996 12:34:44 MET Subject: Re: Fuel on the intake valves > FWIW, Nissan has been doing it since 1984 on their V6 engines. I'm not sure > about some of the other makers though. Actually, most of the fuel > atomization takes place through evaporation of the fuel on the hot intake > valve (at lower engine speeds). Various people have tried open valve > described as "Making Oil" due to the large amounts of un evaporated fuel that > gets washed down the bore at lower rpms. Supposedly the only way to make it > work is to aim the injector to hit the really hot exhaust valve. Obviously > this requires a specific head and manifold setup to accomplish. In WW2 there were direct injected aircraft engines (only experiments?) The injector was placed high in cylinder sidewall and sprayed on the closed exthaust valve. Hans hiha@xxx.de Munich / Germany ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Mon, 9 Sep 1996 08:42:00 -0500 Subject: Re: Http address >Hi > >Could anybody tell me if something is amiss with the efi332 >page. Unable to get access at all. > > > efi332 http://www.cim.swin.edu.au/~aden/web-docs/efi332/332_index.html > >Thanks > >George Lerm I had to keep trying tom ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Mon, 9 Sep 1996 08:44:03 -0500 Subject: RE: Injector Flow Variation >Is it worth testing them on the bench, flowing at 20%, 40% 60% and 80% flows for a while, and actually seeing how much they flow, and putting the adjustment into the code???? > > >Comments please... as I've never really thought about this bit of potentially disastrous mismatch. > I thought that's what SFI did for you ?? tom ------------------------------ From: "Robert J. Harris" Date: Mon, 9 Sep 1996 08:35:58 -0700 Subject: Re: Re: hi compressions Remember the Reichstag - ---------- From: Mark Pitts To: diy_efi ; 'Woodd, Michael' Subject: RE: Re: hi compressions Date: Friday, September 20, 1996 2:32 AM Problem comes, trying to work out the shims, so that both stems are working together, and not trying to compress two valve springs, by only pressing on one stem. Mark Of course, you could take ancient history 101 and re-invent the rotary valve engine and eliminate valves in their entirety. Basically picture a dual overhead cam with intake on one cam - exhaust on the other. Shove it down so that part of the cam is in the combustion chamber. Make the cam relatively large in diameter and hollow. Put a hole in it such that at a certain time, the hole opens to the chamber. Make the cams hollow and flow the gasses through it to the machined ports. No valves, just big timed holes, no springs so no float and very little friction. This was down during the thirties by the way. With modern ceramics and molycoatings, this concept slight might have a chance again - a lot better than a two stems valve or oval valve. Side note - when and why was fuel injection invented??? Answer - 1920's so that high performance fighter aircraft could maintain sustained inverted flight (upside down) without fuel starvation. Perfected for narrow power and rpm range aircraft engines by end of WW II. ------------------------------ From: "Robert J. Harris" Date: Mon, 9 Sep 1996 09:11:02 -0700 Subject: Re: Re: hi compressions Remember the Reichstag - ---------- From: Mark Pitts To: diy_efi ; 'Woodd, Michael' Subject: RE: Re: hi compressions Date: Friday, September 20, 1996 2:32 AM Problem comes, trying to work out the shims, so that both stems are working Of Course you could get really crazy. Remember the flathead ford V-8's, They had a really convoluted exhaust flow problem. Valve in block, port bending around the cylinder - all the way across the block and exiting thru a siamesed port on the center cylinders. An air flow nightmare. So some racers in the thirties and forties "two-cycled" it and made lots more power. Involved cutting an exhaust port looking just like a two cycle engines around bottom dead center and running a separate exhaust pipe. Opened around twenty five degrees before and after bottom dead certer. At the end of the compression stroke - port opened and a significant chunk of exhaust left the engine. Exhaust stroke pumped some of the rest thru the stock exhaust Yes, at the bottom of the intake - some charge went into the exhaust or some exhaust came back into the engine, but the vast improvement in exhaust flow far made up the loss in intake efficiency. - ---- Sniveling Tirade Follows - Cut Here ---------- No - was not invented at a university, nor were eurocentric book writers really interested in writing about colonial backyard mechanic's improvements in crude production engines so you had to see it to remember it. No, it was not tested on street engines, no it was not proctology examined to infinite detail, yes it was less than optium, no - nobody ever wrote much about it. but it f____ng WORKED. All I am trying to say is that there is a gold mine of ancient history to be examined for "new" ideas and what is considered "NEW" was probably invented in the thirties and nearly perfected by the various air forces. ------------------------------ From: SRavet@xxx.com Date: Mon, 9 Sep 96 10:08:24 CDT Subject: re: Re: hi compressions "Woodd, Michael" Wrote: | | | Steve says... | | >This might be a dumb question, but why not non-circular valves? I guess | >they wouldn't be able to spin. Is that a problem? I can see corners being | | >bad, but what about a nice oval shape? | | >- --steve | | It should be possible to use two valve stems to stop it spinning. What | about making an oval valve with two stems at the, and machining an | existing four valve head to have two oval valves? You could use the | existing valve guides. Has this been tried before? Could be tricky to | make the valves, with two stems and all, but not impossible. You could spline a single shaft to keep it from spinning also. But, valves rotate now by design, right? Why, and what would happen to an oddly shaped valve that couldn't rotate? - --steve Steve Ravet sravet@xxx.com Baby you're a genius when it comes to cooking up some chili sauce... ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Mon, 9 Sep 1996 13:35:59 -0500 Subject: Ford EEC-IV Check out the I'LL SHO-U-PERFORMANCE Web site at www.cwci.com/isup/ Tom ------------------------------ From: Dirk Wright Date: Mon, 9 Sep 1996 14:39:36 -0400 (EDT) Subject: Re: Re: hi compressions On Mon, 9 Sep 1996, Robert J. Harris wrote: > All I am trying to say is that there is a gold mine of > ancient > history to be examined for "new" ideas and what is considered "NEW" was > probably invented in the thirties and nearly perfected by the various air > forces. > > Yeah, I discover that all the time here at the patent office. You wouldn't believe the ideas people have come upo with over the years. Stuff you thought was new turns out to be ancient history. **************************************************************************** Dirk Wright wright@xxx.gov "I speak for myself and not my employer." 1974 Porsche 914 2.0 "A real hifi glows in the dark and has horns." 1965 Goodman House **************************************************************************** ------------------------------ From: Markus Strobl Date: Mon, 9 Sep 1996 15:11:42 -0500 Subject: Re: Ancient History > Do these numbers really bother anyone? 12mpg highway for a 455? I mean, > I've read about 46-48mpg from a turbo v-6; 28-30mpg from 5.7L z/28's, > and 31mpg from 5.0L mustangs. While I don't believe any of them; [snip] > I have driven in far too many 30mpg > 5.0L mustangs (only to get 18-20) and 27mpg 5.7L '95 Z/28s (only to get 22.5) > Maybe those cars get that kind of mileage at 60mph going down a hill with a > tailwind, a real skinny driver and at a high altitude (higher altitudes get > better gas mileage, especially with efi). > When I say highway, I mean just that: jump on the freeway and drive. That also > means slowing down a little, speeding up, passing the old people, showing a > Porshe > a thing or two :) [snip] > Arnaldo Echevarria You better believe it: when driving from Dallas to memphis, speed range 70 mph to 95 mph, I got 27.5 mpg. Most of the tankful was driving at 80mph. A friend in a '95 Trans Am that made the trip with me had a best of 28.5 (his engine was more broken in, mine was fresh at 2k miles). - ------- Markus '96 Z28 w/ mods. Proof that OBDII is not the end of performance. ------------------------------ From: James Weiler Date: Mon, 9 Sep 1996 15:06:22 -0700 (PDT) Subject: re: Re: hi compressions On Mon, 9 Sep 1996 SRavet@xxx.com wrote: > > You could spline a single shaft to keep it from spinning also. But, valves > rotate now by design, right? Why, and what would happen to an oddly shaped > valve that couldn't rotate? > > --steve > Well there are a few engines out there that have valves that DON'T rotate. These are the old Boss engines from Ford (302,351 and the 429). These valves are held in place by keepers that pinch the valve stem (ie the keepers don't butt against eachother). The result are valves and valve seats that don't last as long but the pay off is less risk of dropping a valve at high RPM. My Boss 351 is set up like this, I just had the heads redone and the exhaust valves had to be replaced because of this. (or so my machinist told me...he seems very trustworthy) Just my two cents...(and my first post to this list!) cheers everyone... james ------------------------------ From: Arnaldo Echevarria Date: Mon, 9 Sep 1996 18:44:02 -0400 Subject: re: Ancient History (now fuel economy) >The biggest influence on fuel consumption is in pumping work (ie >manifold pressure, or lack thereof). OK > >If you choose to run a 400+cid engine, then to produce the sort of >power necessary for cruising (10-20 hp), you will be running >relatively low manifold pressures compared to a smaller engine >producing the same power. Remember, the manifold depression is >un-recovered, therfore represents a power loss. At the same RPM? Could you clarify this? An engine requires a minimum a/f ratio to overcome frictional losses, keep inertia (accel=0), and move the drivetrain (i'm speaking about a fixed RPM, fixed speed). The manifold pressure is just a function of the throttle position and the rpm, not of the load, at least I don't think. Now if you place a heavy load on an engine at low RPMs, then you have to give it more air and/or gas; well, here's where I confuse myself. Is the load a cause or an effect? > >The slower you spin the engine, then the higher the manifold pressure >is for the same airflow (power), hence your pumping work (losses) is >less. Dropping the axle ratio (numerically) will give you benefits in >fuel consumption at the same (road) speed simply because you have your >foot on the throttle harder (strange but true! :) Wait. You said that the higher the manifold depresion, the higher the power loss. Now you say that the higher manifold pressure you get less pumping work (ie better fuel economy)?? Now I'm really confused. Which is it? OK then you say that dropping your axle ratio gives you better gas mileage, which I agree (when I went from a 2.79:1 final drive ratio to a 2.05:1 ratio on a 305 I went from 16 to 21.5MPG). But then you say it is because you have your foot on the throttle harder? No way. On that same car I remember barely touching the gas when cruising at 75mph (about 2000rpm or so) when before I would have to get on it at least 3/8 pedal. How low you can go on RPMs is really a function of engine size and bore/stroke ratio. I had a friend with a 5.0L mustang try the same thing with very little success (he lowered the gear ratio so much it would need a higher throttle setting to keep the same mpg.) To me, as a rule of thumb, gas mileage is proportional to throttle position (relative to car, of course). The more you can stay off the pedal, the better (and of course this goes for carburators only) Arnaldo MPG) >>Running lean does effectively the same thing, by running the same >fuelling level, but higher airflow, the manifold depression is >reduced, saving power. > > > > > > > ------------------------------ From: "Edward C. Hernandez" Date: Mon, 09 Sep 1996 18:46:49 -0400 Subject: Re: Where the heck have I been? In case anyone is wondering, I am in class for two weeks, followed by a week's business trip to Europe to take on another pair of intake manifolds. Apparently, I am not busy enough... I have 266 unread messages in my box now. By the time I get back, who knows how far behind I will be. Sigh. Wish I could read more of your stuff, much less respond to it. Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: "John Faubion" Date: Mon, 9 Sep 1996 18:17:03 -0500 Subject: Re: Ancient History > >Mainly by reducing frictional losses at the lower RPM. > > This would be more of a factor with a big block, since it has higher > frictional losses due to increased bore, stroke, stc. Well with any engine for that matter. The bigger the bore, longer the stroke, the number of rings, the number of cylinders, ad nausem, the greater the frictional losses. But no matter what engine it is the greater the RPM the greater the frictional losses. > I wasn't aware of the magic number of 5252 RPM, how did you arrive at it? > I can't see this applying to ALL internal combustion engines across the board... Well actually I didn't. :) Mr. Watt did around the 17th century. Draft horses were used to pump water out of mines. The horses pulled a 12 foot lever to turn a capstan which in turned operated a pump. He figured the horses could apply 180 pounds of force to the lever. The circumference of the circle was 75.4 feet (2xPIx12). The horses could make 144 trips around the circle in an hour or 2.4 per minute. So the horse traveled at 180.96 feet per minute (2.4x75.4). Watt then multiplied this to arrive at 32,580 ft-lb./min (181x180) which he rounded up to 33,000 ft-lb./min or 550 ft-lb./sec (33000/60). This became the standard definition of horsepower. Now to get back on track for your question. Horsepower is a force in pounds applied over a distance in feet in a time of 1 minute. To convert the engines rotational force into horsepower, we need to know how far the free end of a 1 foot lever travels in 1 minute. That is the circumference of circle with a radius of 1 foot times the RPM of the engine. The circumference would be 2 times PI times 1 foot or 6.183 feet. So our formula would be 6.183 times RPM times torque (in ft-lb.). This could then be divided by 33,000 to arrive at horsepower. We end up with a formula that looks like this: 6.183xRPMxTorque - ---------------------------- = Horsepower 33,000 If we then divide the left side by 2 time PI we eliminate the 6.183 on top and reduce the 33,000 to 5252.11 which we round down to end up with: RPMxTorque - ------------------- = Horsepower 5252 This is how you can calculate horsepower from torque if you know what RPM it was taken at. > As far as best cruise RPM, depends if it's a Honda 750cc four or a 512ci > Caddy, doesn't it? You're right, I shouldn't have included HP in that list, To a point yes. Overall it will depend on a multitude of factors, such as cam timing, chamber design, flow characteristics of intake and exhaust systems, and etc... Everything has to be taken in the overall system. This is the biggest problem of most hot rodders. They will add headers, an intake and a wild cam, and when the car runs slower that it did stock they complain about all of the parts they bought. If they considered the entire car as a system and matched the components to run in a compatible range and then changed the gear ratios to use that particular range, they would be much happier and the car would be much faster. John Faubion jfaubion@xxx.net ------------------------------ From: dzorde@xxx.au Date: Tue, 10 Sep 96 09:42:07 Subject: Re[3]: hi compressions My understanding has always been that the valve spins to promote even seat wear and to avoid the valve sticking due to constant hammering on the same spots. Dan dzorde@xxx.au ______________________________ Reply Separator _________________________________ Subject: re: Re: hi compressions Author: diy_efi@xxx.edu at INTERNET Date: 9/10/96 8:15 AM On Mon, 9 Sep 1996 SRavet@xxx.com wrote: > > You could spline a single shaft to keep it from spinning also. But, valves > rotate now by design, right? Why, and what would happen to an oddly shaped > valve that couldn't rotate? > > --steve > Well there are a few engines out there that have valves that DON'T rotate. These are the old Boss engines from Ford (302,351 and the 429). These valves are held in place by keepers that pinch the valve stem (ie the keepers don't butt against eachother). The result are valves and valve seats that don't last as long but the pay off is less risk of dropping a valve at high RPM. My Boss 351 is set up like this, I just had the heads redone and the exhaust valves had to be replaced because of this. (or so my machinist told me...he seems very trustworthy) Just my two cents...(and my first post to this list!) cheers everyone... james ------------------------------ From: pantera@xxx.com (David Doddek) Date: Mon, 9 Sep 1996 20:33:56 -0500 Subject: Re: Re Propane injectors >> >Is there such a thing as an electronically controlled diesel injector? >> >(aka instead of the usual mechanical fuel pump distributor thing..) >> > >> Yes: >> >> But diesel injection needs around 25,000 psi of fuel pressure, so the >> injector is a plunger piston pump that is operated off a lobe of the cam >> shaft (twice as wide as the one that opens the valves). The electric >> solenoid is a bypass port that when ON blocks the outlet of the injector >> 'pump' and forces it into the cylinder. When OFF the flow returns to the >> fuel tank. > >Aaah, I see why "EFI diesels" are only recently appearing. Do they >really use 25000 PSI?? I thought it would only be a few hundred PSI. > >Craig. > > Yes, the pressure is that high. Some times it can get as high as 35000. David J. Doddek |pantera@xxx.com Owner SGD Electronics & Development Engr for Caterpillar |h 309 685-7965 Formula SAE Team Sidewinder 94-95 |w 309 578-2931 89 T-bird SC, 69 Fairlane w/SGD EFI |fx 217 428-4686 74 Pantera w/Electromotive Tec-II Twin turbos and Nitros | Hey, If you are going to go fast, go REEEAAL FAST. | ------------------------------ From: pantera@xxx.com (David Doddek) Date: Mon, 9 Sep 1996 20:34:00 -0500 Subject: Re: Re[2]: Re Propane injectors > > Guess you don't want a pipe to burst while you are leaning over it, or > you may just loose a few body parts. > > Actually the high pressure area is at the tip of the injector which is located far in the center of the cylinder head. Then again the injector is only about 1.5 inches in diameter and 8 inches long. The high pressure is necessary to cause an adequate atomization and still be pressed into the cylinder when the flame front is active. Remember the diesel fuel in burnt as it is injected. Thus you have to overcome combustion pressures. David J. Doddek |pantera@xxx.com Owner SGD Electronics & Development Engr for Caterpillar |h 309 685-7965 Formula SAE Team Sidewinder 94-95 |w 309 578-2931 89 T-bird SC, 69 Fairlane w/SGD EFI |fx 217 428-4686 74 Pantera w/Electromotive Tec-II Twin turbos and Nitros | Hey, If you are going to go fast, go REEEAAL FAST. | ------------------------------ From: pantera@xxx.com (David Doddek) Date: Mon, 9 Sep 1996 20:34:11 -0500 Subject: Re: troubleshooting a taurus >mike wrote: > >>... >>The taurus has a very hard time starting after sitting overnite or >>over perhaps 8-10 hours. Takes a large amount of cranking with no >>firing, then stumbles slowly to life. Ambient temperature doesn't >>seem to have any effect. Computer reveals no fault codes, pump and >>filter are good. >> >>Isn't there a fuel accumulator which should maintain fuel pressure >>when sitting? If this was faulty would it allow pressure to drop - >>forcing the pump to charge the system again before it could start? > >No accumulator, it needs to be a leak-free system, for obvious reasons. >It does sound like fuel pressure has gone away. Assuming this is a V6, >(you don't say, and you don't even say what year) there is a Shrader >valve near the front where you can measure fuel pressure. It should be >35 psi at idle, and about 25-30 after sitting. > >Turning on the ign should cause fuel pump to run a couple of seconds, >then stop. Try switching on and off once or twice before starting to >see if that helps. > >EFI in my '86 Sable V6 has been almost flawless in 115K miles. Had to >correct a weak idle recently by de-coking the air bypass. > >RD > If you have a fuel problem, then it would not run or start hot. The fuel will pressurize in a few seconds from zero pressure and the engine will not always hold pressure for a long time. It does not have to. My car looses all pressure in a matter of minutes. The problem sound like a cold starting problem, ie cold engine ie not hot. A cold (ambient) engine requires extra fuel to start until the cylinder surfaces get hot. Takes about 3 minutes on an average day. A little longer in the winter. The computer detects this by measuring the engine temp with sensor and giving the engine extra fuel. Try changing the engine coolant temp sensor. It sounds like it has failed to a level that does not trip the diagnostics, but gives the computer a false signal making it think the engine is hot and thus gives it no starting enrichent. This is why it still starts when it is warm. David J. Doddek |pantera@xxx.com Owner SGD Electronics & Development Engr for Caterpillar |h 309 685-7965 Formula SAE Team Sidewinder 94-95 |w 309 578-2931 89 T-bird SC, 69 Fairlane w/SGD EFI |fx 217 428-4686 74 Pantera w/Electromotive Tec-II Twin turbos and Nitros | Hey, If you are going to go fast, go REEEAAL FAST. | ------------------------------ From: Clint Sharp Date: Mon, 9 Sep 1996 22:31:28 GMT Subject: Re: hi compressions In your message dated Monday 9, September 1996 you wrote : > Of course, you could take ancient history 101 and re-invent the rotary > valve engine and eliminate valves in their entirety. > This was down during the thirties by the way. With modern ceramics and > molycoatings, this concept slight might have a chance again - a lot better > than a two stems valve or oval valve. I read an article in a UK (?) magazine not too long ago about a company that has achieved this, I think they claim to have invented the concept so I was surprised to read this message. - -- If you have a problem with excess cash, mail all those unwanted notes in plain packing to; clint@xxx.uk ------------------------------ From: RABBITT_Andrew@xxx.au Date: Tue, 10 Sep 1996 10:12:26 est Subject: re: Fuel Economy X-Ceo_Options: Document begin 660 ceomail.msd M/CY)9B!Y;W4@8VAO;W-E('1O(')U;B!A(#0P,"MC:60@96YG:6YE+"!T:&5N M('1O('!R;V1U8V4@=&AE('-O2!F M;W(@8W)U:7-I;F<@*#$P+3(P(&AP*2P@>6]U('=I;&P@8F4@2!L;W<@;6%N:69O;&0@<')E6]U(&-L87)I M9GD@=&AI2!M86YY('!E;W!L92!I;B!T:&4@=V]R;&0@=7-E($U!4"!S M96YS;W)S+@T*#0H^/E1H92!S;&]W97(@>6]U('-P:6X@=&AE(&5N9VEN92P@ M=&AE;B!T:&4@:&EG:&5R('1H92!M86YI9F]L9"!P6]U2!B96-A=7-E('EO=2!H879E('EO=7(@#0H^/F9O;W0@ M;VX@xxx.BD- M"CX-"CY786ET+B`@66]U('-A:60@=&AA="!T:&4@:&EG:&5R('1H92!M86YI M9F]L9"!D97!R97-I;VXL('1H92!H:6=H97(@=&AE(`T*/G!O=V5R(&QO6]U('-A>2!T:&%T('1H92!H:6=H97(@;6%N:69O;&0@<')E6]U(&=E="!L97-S('!U;7!I;F<-"CYW;W)K("AI92!B971T97(@9G5E M;"!E8V]N;VUY*3\_($YO=R!))VT@2!T:&4@:6YV97)S92!O9B!E86-H M(`T*;W1H97(N#0H-"CX-"CY/2R!T:&5N('EO=2!S87D@=&AA="!D6]U(&)E='1E6]U M('-A>2!I="!I2!N M;VXM;&EN96%R(&1E=FEC97,L(&%N9"!T:&4@8VAA6]U(&1I9"!H879E('EO=7(-"F9O;W0@;&5S6]U Date: Mon, 9 Sep 1996 19:56:51 -0700 (PDT) Subject: Re: Ancient History At 06:17 PM 9/9/96 -0500, John Faubion wrote: >> I wasn't aware of the magic number of 5252 RPM, how did you arrive at it? >Well actually I didn't. :) At least you're honest... Obviously, I should have consulted my elementary Physics text. This brings us to the formula: > RPMxTorque >------------ = Horsepower > 5252 And, from a previous post: >Of course the ONLY rpm where torque, horsepower and VE could all peak at >the same time is at 5252 rpm. I don't see how you arrive at this conclusion. If you substitute 5252 for RPM in the above equation, all you get is the fact that HP must = Torque at this particular RPM. This does not mean that they are all maximums at this RPM, only that they must be equal. This should mean that regardless of the engine, the horsepower and torque curves should cross each other at 5250 RPM. I dug out some old HP Books editions like "How to Hotrod Smallblock Chevys" and perused some of the comparative "before + after" Dyno curves. A few of them had torque and HP curves equal at 5250 RPM, but most didn't. Obviously, there are other factors at work here. >If they considered the entire >car as a system and matched the components to run in a compatible range and >then changed the gear ratios to use that particular range, they would be >much happier and the car would be much faster. I agree wholeheartedly. Unfortuneately, most speed shops are only interested in getting your money, not your money's worth. regards dn dnorquay@xxx.com ------------------------------ From: "Hans Hintermaier" Date: Tue, 10 Sep 1996 09:13:04 MET Subject: Oval Shaped Valves Hi all, I own some books of "Apfelbeck", his philosophy was the "radial diametral" 4 valve head. His construction goes back to the '30th when he built up his first head for 500ccm singles. The last engines I know were prototypes for KTM and Rotax around '92. Between he made F2 4cyl. 2lit., BMW sidecar racing- and other engines. He also experimented with more than 4 valves, but his flowbench results for his radial-diametral head were much better than for any other concept. If anybody of you wants to construct a new head, :-) I can give you the book-titles or ISBN, or some GIF's of his latest KTM-head. They rebuilt an LC4 engine with it, it makes more than 90HP out of 500 ccm... There are also lots of easy theoretical and practical tips for every motor-screwer included. Sorry- only in german language, I think. Hans hiha@xxx.de Munich / Germany ------------------------------ From: Mark Pitts Date: Tue, 10 Sep 1996 09:59:09 +-200 Subject: RE: Ancient History (now fuel economy) As to the pressure in the manifold.... On the suck stroke... if you have HIGH DEPRESSION, the vacuum in the = manifold tries to suck the descending piston up, or just plain doesn't = help (grab a syringe, and see how hard it is to fill with water by = pulling). But, if turbo, or supercharge, or just plain acoustics is used to get = positive pressure in the manifold.. i.e. NEGATIVE depression, or comonly = called pressure, this will (theoretically) help push the piston down the = bore (now jam the syringe in the end of hose pipe, and the other end to = the tap (faucet?) you filled the bowl you were sucking from, and turn = on the pressure (turbo), now dry yourself off, and go and find the = plunger, cos that is probably the only accurate syringe you have for = measuring head capacities). Mark ;-) - ---------- From: Arnaldo Echevarria[SMTP:aec@xxx.net] Sent: Tuesday, September 10, 1996 12:44 AM To: diy_efi@xxx.edu Subject: re: Ancient History (now fuel economy) snip: >The slower you spin the engine, then the higher the manifold pressure=20 >is for the same airflow (power), hence your pumping work (losses) is=20 >less. Dropping the axle ratio (numerically) will give you benefits in=20 >fuel consumption at the same (road) speed simply because you have your=20 >foot on the throttle harder (strange but true! :) Wait. You said that the higher the manifold depresion, the higher the=20 power loss. Now you say that the higher manifold pressure you get less = pumping work (ie better fuel economy)?? Now I'm really confused. Which is it? ------------------------------ From: Mark Pitts Date: Tue, 10 Sep 1996 09:32:54 +-200 Subject: RE: Re: hi compressions Valves kinda 'continually' grind themselves in... you would end up with = an ill seated valve, that could wobble slightly in its hole, and = eventually break its stem....=20 Mark - ---------- From: SRavet@xxx.com] Sent: Monday, September 09, 1996 5:08 PM To: diy_efi@xxx.edu Subject: re: Re: hi compressions "Woodd, Michael" Wrote: |=20 |=20 | Steve says... |=20 | >This might be a dumb question, but why not non-circular valves? I = guess | >they wouldn't be able to spin. Is that a problem? I can see corners = being=20 |=20 | >bad, but what about a nice oval shape? |=20 | >- --steve |=20 | It should be possible to use two valve stems to stop it spinning. = What | about making an oval valve with two stems at the, and machining an | existing four valve head to have two oval valves? You could use the | existing valve guides. Has this been tried before? Could be tricky = to | make the valves, with two stems and all, but not impossible. You could spline a single shaft to keep it from spinning also. But, = valves=20 rotate now by design, right? Why, and what would happen to an oddly = shaped=20 valve that couldn't rotate? - --steve Steve Ravet sravet@xxx.com Baby you're a genius when it comes to cooking up some chili sauce... ------------------------------ From: Mark Pitts Date: Tue, 10 Sep 1996 10:14:07 +-200 Subject: Playing... Is ther any reason why I cant build my own mass meter wth some nichrome = wire, and a foot of 6" drain pipe? Cos what I've seen of them thats about it. Plus a burn off circuit, and a bridge for doing the current measurement. Like, I think the Idea is: Keep the current constant, measure the = voltage across to get that current, have another bit of wire as a = reference, and an absolute air temp/ atmospheric pressure reading, and = away you go? Yes... no ... who cares I got mine from the breakers....? Any comments really? (I'll even take 'Dont be stupid' for this one!) Mark ;-) ------------------------------ From: M HILL Date: Tue, 10 Sep 1996 09:23:09 GMT0BST Subject: Re: Ancient History > >Of course the ONLY rpm where torque, horsepower and VE could all peak at > >the same time is at 5252 rpm. > > I don't see how you arrive at this conclusion. If you substitute 5252 for > RPM in the above equation, all you get is the fact that HP must = Torque at > this particular RPM. This does not mean that they are all maximums at this > RPM, only that they must be equal. This should mean that regardless of the > engine, the horsepower and torque curves should cross each other at 5250 > RPM. I dug out some old HP Books editions like "How to Hotrod Smallblock > Chevys" and perused some of the comparative "before + after" Dyno curves. A > few of them had torque and HP curves equal at 5250 RPM, but most didn't. > Obviously, there are other factors at work here. > I believe the point that is trying to be made is that if HP = Torque only at 5252 (which is agreed). Then this is the only place where they CAN both be a maximum. Not that they are a maximum. But that this is the only point where they can both be a maximum at the same time. Martin. ------------------------------ End of DIY_EFI Digest V1 #267 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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