Michael Yount said:They shouldn't have had to make 'progress' -- it should've been a 4 valve motor from the start guys --- that's the whole point. They didn't take advantage of the OHC layout's benefits even with the 'improved' 2-valve.
you say the engine is no more although it is being used in a number of ford vehicles still! when you say other companys 4 valve v8s.....WHO DO YOU MEAN? cadalliac is the only other company that i can think of off the top of my head with a dohc v8 and that motor produces a whopping 270hp! in my opnion ford did a pretty good jobMichael Yount said:Modular2v - you don't have to look far to see how almost every other manufacturer out there EXCEPT Ford managed both bottom end and 7K power with their 4v V8's. Pretty straightforward really. Most of them have variable length runner intakes, and variable valve timing and/or lift. Ford finally bit the bullet on variable valve timing with some of their 3-valves. But 4 valves and variable timing/runner length would've made the motor too expensive for the market they were trying to serve - to 5spd's point.
Your comment about improvements in bottom end torque compared to the 4v illustrates MY point -- it doesn't make sense to build OHC unless you're gonna take advantage of the breathing/revving capabilities it gives you. If bottom was what they were after, you can get it less expensively with a pushrod motor. Just ask Chrysler and GM. The 2v motor for the most part was initially deficient on both ends. It didn't have bottom, and it didn't take advantage of OHC's long suit - unobstructed ports and multi-valve layouts that breath. They ultimately developed their way back to 'break even' after making a fundamentally poor choice on architecture. Of the architectural choices - 1) 4 valve OHC V8; 2) completely re-engineered pushrod motor a la GM/Hemi; 3) 2v OHC -- the least attractive was number 3. Which is probably why the engine is no more.
Modular2v said:you say the engine is no more although it is being used in a number of ford vehicles still! when you say other companys 4 valve v8s.....WHO DO YOU MEAN? cadalliac is the only other company that i can think of off the top of my head with a dohc v8 and that motor produces a whopping 270hp! in my opnion ford did a pretty good job
bmw uses several versions from 4.4-4.8 dohc V8s ranging from 270-365hp. all of these are n/a and don't rev higher than 6300. some of those have variable cam timing, and the only V8's in thier lineup with variable intake runners are sohc 4v design. imo ford has done an acceptable job with what the accountants have told them they had to work with. i still would rather see an "evolved" pushrod engine with a big bore, short stroke, and long rods. damn epa.Modular2v said:you say the engine is no more although it is being used in a number of ford vehicles still! when you say other companys 4 valve v8s.....WHO DO YOU MEAN? cadalliac is the only other company that i can think of off the top of my head with a dohc v8 and that motor produces a whopping 270hp! in my opnion ford did a pretty good job
Michael Yount said:Just a note - the Explorer is classified as a truck; in the mid-90's the emissions standards it had to meet weren't as stringent as for a car. You were right the first time - one reason the 4.6 came into being (since 2002 even in the Explorer) was because it was engineered to comply with ever tighter emissions regs. The 5.0L wouldn't have been able to get there without a complete re-engineering. Ford made a choice to go in a different direction. And given GM's success with the LS1/2 variants, as well as Chrysler's recent 'hemi' boom, there are those even at Ford who are wondering if they shouldn't have stuck with a clean sheet pushrod approach much as GM and Chrysler (hemi) have. It has made for a smaller, lighter power plants that are certainly not suffering in the power wars. (GM's 6.0L at 400HP and Chrysler's 6.1L at 425HP).
The basic benefit of OHC's are 2-fold: 1) it removes the pushrod from the picture completely freeing up intake port size/shape; and 2) valve train weight is generally reduced allowing higher revs, or equal revs with lighter springs (less losses). The downside is size/packaging/cost -- makes for a taller/wider/more expensive engine. All you need do is look under the hood to see how large the (especially) 3-valve or 4 valve mod motors are compared to Ford/GM pushrod offerings. And look at prices for aftermarket heads and cams for OHC stuff (you need two or 4 of them). Most automotive engine designers would tell you it probably only makes sense to go OHC if you're gonna fill up the chamber with valves (4 valve) and take advantage of the breathing capabilities. You'll pretty much see this at work with almost all imported V6/8's - nearly all of them are 4 valve (BMW, Lexus, Audi, VW, Infinity, Honda, Toyota, Acura, Volvo, etc., some Mercedes exceptions in years past). So many scratched their heads over Ford's decision to go with a 2-valve OHC engine. And even Ford has partially remedied that as all mod-motors are now 3 or 4 valve.
don't forget the original 5.0 engine in the E39 M5 and Z8. as far as the 7 series engine, it is a 4.6 sohc with variable valve lift(valvetronic), variable cam timing(vanos), and infinetly variable intake runners(deiza). the engine has a throttle body, but is only used for a backup and stays open 99% of the time. it makes 325hp/340tq, but feels like it has a roots blower because of the broad torque curve. the newer 6.0 V12 has a similar setup only adding direct injection.Michael Yount said:....and bmw has it's own Five-Oh.....
V10 -- 500 HP somewhere up around 8000 rpm
Michael Yount said:My comment about the 2 valve being gone -- check the 2005 product offering. The Stang, Explorer, 5.4L pickups are all 3 valve now. 4 valve versions available in some of the high-line stuff (Navigator for example). Is the base 4.6L 2 valve still available in the F150? Enlighten me - I don't know. When I read about the 3-valve showing up in so many vehicles, I (mistakenly it sounds like) assumed the 2V was gone. Sounds like you might still be getting it in pickups and Crown Vics.
i know he was only talking about the 2valve motors! I see them in excursions (5.4) expeditions (4.6) crown vics, lincoln town cars, mercurys etc and the 04/05 f-150 single cabs still sport the 2 valve on occasion my brother has one....and all those dohc motors just listed in the last post are larger displacement motors than the 4.6........my point is that the 2valve 4.6 is pretty stout for what it istjm73 said:He was talking about the SOHC 4.6. It's only used in police Crown Vics still and they are fleet vehicles only. Everything is 3V or DOHC 4V now.
Nissan Titan has a 5.6 DOHC V8 that makes like 305 hp 4900 and 379 ft-lbs at 3600 rpm. Toyota has a 4.7 DOHC V8 with 271 hp in their pickup.
Fords own 5.4 DOHC makes 300 hp @ 5000 and 355 @ 2750.
Modular2v said:i know he was only talking about the 2valve motors! I see them in excursions (5.4) expeditions (4.6) crown vics, lincoln town cars, mercurys etc and the 04/05 f-150 single cabs still sport the 2 valve on occasion my brother has one....and all those dohc motors just listed in the last post are larger displacement motors than the 4.6........my point is that the 2valve 4.6 is pretty stout for what it is
tjm73 said:Three letters..... NVH, and emissions. Period. That's why Ford changed to a different engine.
NVH (Noise, Vibration, Harmonics) was significantly reduced in the 4.6. Drive both back to back (I do regularly) and you'll understand how much smoother the engine runs and sounds. No pushrods makes the NVH values significantly lower. Rotation of cams is much smoother than the up, stop, down, stop, repeat action of the pushrod. It makes vibrations, noise and harmonics.
Emissions. The 4.6 was easier to make meet the stricker emissions guidelines that came on board around the mid 90's and moving forward.
In addition, they can have tighter tolerances and longer lasting engines with fewer warrenty claims.
They should have simply redesigned the 5.0 keeping the 4 inch bore 3 inch stroke dimension and giving it a totally new block and OHC's. That would have been a beast.
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