Everything New is Old

[brianl703]

Originally Posted By: OVERK1LL

Yes, but by the same token, that new 80GB hard drive will transfer data at twice the rate of the earlier drive and make substantially less noise.


Probably consume less power too, and the major killer of hard drives is heat. (The more power they consume the hotter they run).

 

[Jonny Z]

Originally Posted By: Aldaris
Originally Posted By: edhackett
My 1982 2.5l SOHC, 2 valve NA GTV6 made more horsepower, torque, and got more MPG than my parents DOHC, 4 valve 2.5l Lexus.
Not surprising. The ES250 was an abortion, a hideously bad badge engineering clone of an already marginal Camry. It absolutely paled next to its trend-setting stable mate, the then-new LS400.


That makes more sense. I was thinking he was speaking of the IS250 2.5L V6. Year the old ES250 sucked big time.

 

[Steve S]

Originally Posted By: Chris142
The 46 year old Cummins diesel in my Peterbilt has roller cam followers.
Does it have 4 valve heads?

 

[Steve S]

Originally Posted By: OVERK1LL
Originally Posted By: 01rangerxl
Some 1960s Jeeps had SOHC engines, which were not very common then.


Yup. Ford made the 427 SOHC in '64 I believe, and the "Indy Cammer" (DOHC Windsor) in '62 or '63.

Many European companies had been using them well before that.
overhead cams are cheaper to build.

 

[Steve S]

Look at the V6 valve area as compared to the 4 cyls .Then look at the Chevs ohv engines mpgs and compact size as compared to the big bulky ohc engines.

 

[OVERKILL]

Originally Posted By: Steve S
Originally Posted By: OVERK1LL
Originally Posted By: 01rangerxl
Some 1960s Jeeps had SOHC engines, which were not very common then.


Yup. Ford made the 427 SOHC in '64 I believe, and the "Indy Cammer" (DOHC Windsor) in '62 or '63.

Many European companies had been using them well before that.
overhead cams are cheaper to build.


I wouldn't say that. It cost Ford a fair bit MORE money to retrofit both those engines with OHC setups. They were originally cam-in-block designs.

You then have to grind twice the number of camshafts, use far more metal to make the heads, potentially use twice the number of valves, locks, keepers, springs, seals....etc. Then all the extra chain or belt guides, pulleys....etc. I cannot see it being cheaper.

OHC designs have the potential to make more power than a traditional OHV design and provide the ability to have better control over the valve events, as well as multiple valves per cylinder. You also don't have the intrusion of the pushrod hole compromising the design of the intake port.

You then have the idea of combustion chamber design; with all the high-efficiency chambers being of the pent-roof design..... The ONLY pushrod chamber I know of that resembles a pent-roof is Dodge's new "HEMI" chamber.......

 

[Aldaris]

Originally Posted By: Jonny Z
Originally Posted By: Aldaris
Originally Posted By: edhackett
My 1982 2.5l SOHC, 2 valve NA GTV6 made more horsepower, torque, and got more MPG than my parents DOHC, 4 valve 2.5l Lexus.
Not surprising. The ES250 was an abortion, a hideously bad badge engineering clone of an already marginal Camry. It absolutely paled next to its trend-setting stable mate, the then-new LS400.


That makes more sense. I was thinking he was speaking of the IS250 2.5L V6. Year the old ES250 sucked big time.
The IS250 is a sweet car