Some details of the 2AZ-FE engine
in [Toyota]
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From: Retired VIP on 24 Jul 2008 13:28 On Thu, 24 Jul 2008 08:58:29 -0500, Leftie <No(a)Thanks.net> wrote: >Retired VIP wrote: >> On Wed, 23 Jul 2008 16:26:59 -0400, "C. E. White" >> <cewhite3(a)mindspring.com> wrote: >> >>> "Steve" <no(a)spam.thanks> wrote in message >>> news:AM6dnZjsFev_EhrVnZ2dnUVZ_vednZ2d(a)texas.net... >>> >>>> Shims-in-a-bucket cam followers for valve adjustment is positively >>>> stone-age (the last car I had so-equipped was a '78 Plymouth Horizon with >>>> the VW-based SOHC 4). Rocker-tip mounted hydraulic lash adjusters that are >>>> common now don't carry enough mass penalty to worry about and are commonly >>>> used in engines with 7500+ RPM redlines. That said, I never had to adjust >>>> the valves on that VW engine either. Everything else about it sucked, but >>>> the valves never needed adjustment! ;P >>> Numerous modern engines from Toyota and Nissan do not use hydraulic lash >>> adjustment. The most modern Camry V-6 does have hydraulic lash adjusters, >>> the older Camry V-6 and 4 cylinders do not. The engines without hydralic >>> lash adjustment do require routine valve clearance checking (if not actual >>> adjustment). I think this requirment is widely ignored. Interesting, Fords, >>> newest V-6 also does not have hydraulic valve adjustment - I guess they have >>> learned from Toyota. >>> >>> Ed >>> >> >> I guess I'm just to stupid for my shirt. How is increasing the amount >> of necessary routine maintenance as well as increasing the cost of >> operation a step forward? >> >> Jack > > > There are two problems with hydraulic lifters: they are more >expensive to build and, more to the point for us, they tend to fail long >before the rest of the engine. Who wants to have to spend $1k on new >lifters on a car with 150k miles on it? The shim & bucket type setup >rarely needs adjustment when properly designed (and it is as used by >Toyota and Volvo in their older engines) and it doesn't fail. I've had >two cars and one motorcycle suffer from hydraulic lifter failure. I'd >much rather have the valves adjusted every 5 years or so. Ok, I'll grant that hydraulic lifters are more expensive to build but 'they tend to fail long before the rest of the engine'? Maybe for people who don't change their oil but in over 35 years of car ownership, I've NEVER had hydraulic lifters fail. I have heard a lot of cars with solid lifters clicking and clacking down the road sounding like an old Singer sewing machine and punching holes in their rocker arms. This would seem to me to be another example of why bean-counters should be kept in a locked room. They should never be allowed to attend management meetings or review mechanical drawings. Jack
From: Leftie on 24 Jul 2008 17:16 Steve wrote: > Leftie wrote: > >> >> There are two problems with hydraulic lifters: they are more >> expensive to build and, more to the point for us, they tend to fail long >> before the rest of the engine. Who wants to have to spend $1k on new >> lifters on a car with 150k miles on it? > > > They FAIL before the rest of the engine? Hardly. Ask any mechanic how > many hydraulic lifters or lash adjusters he's had to replace because the > lifter or adjuster ITSELF was a root cause of a problem in the last 10 > years and I'll bet you can count the average answer on 1 hand, and if > you probe further you'll find that those were typically in badly > neglected sludged-up engines. My engines were not "badly neglected". The motorcycle was given full synthetic oil. The two Mazda engines may have had poorly designed oil passages, but I've also heard from other people abut lifters failing. Think of all the "stuck lifter" stories out there, and you may realize that it isn't just bad maintainance causing it to happen.
From: C. E. White on 28 Jul 2008 07:41 "Steve" <no(a)spam.thanks> wrote in message news:ONSdne4rssYfCRXVnZ2dnUVZ_hSdnZ2d(a)texas.net... > Scott Dorsey wrote: > >> >> This means hydraulic lifters, but it also means sealed chassis >> components >> that don't need regular greasing with every oil change but which >> fail >> before 80,000 miles is up. It means "sealed for life" >> transmissions, where >> that life is about half what it should be. > > Here here! Eliminating the dipstick on automatic transmissions has > to be the single most unnecessarily STUPID thing car makers have > done in the last 50 years. Maybe since the dawn of the automobile. Why? All my current cars still have dip sticks on the transmission, but there never seems to be any change in the level. I think eliminating dipsticks was a safety measure more than anything else - I remember reading that a significant number of transmissions were damaged because either they were over filled (people don't follow the instructions for using them) or the wrong lubricant was added tot he transmission through the dip stick hole (wrong ATF or just the wrong stuff - like engine oil). How may car owners ever use the automatic transmission dip stick? Ed
From: Steve on 1 Aug 2008 12:58 >How may car owners ever use the automatic transmission dip stick? > All of them with half a brain. How often do you actually add ENGINE oil? I never need to between changes, but I still CHECK it weekly. Same with the transmission fluid. The whole idea of maintenance is to CATCH a potential problem before it becomes costly. Eliminating the transmission dipstick pretty much guarantees a low-fluid failure will ultimately destroy the transmission, be it at 10,000 miles or 200,000 miles.
From: Steve on 5 Aug 2008 14:36
Vic Smith wrote: > On Fri, 01 Aug 2008 11:58:47 -0500, Steve <no(a)spam.thanks> wrote: > >>> How may car owners ever use the automatic transmission dip stick? >>> >> >> All of them with half a brain. >> >> >> How often do you actually add ENGINE oil? I never need to between >> changes, but I still CHECK it weekly. Same with the transmission fluid. >> The whole idea of maintenance is to CATCH a potential problem before it >> becomes costly. Eliminating the transmission dipstick pretty much >> guarantees a low-fluid failure will ultimately destroy the transmission, >> be it at 10,000 miles or 200,000 miles. > > Hard to imagine not having a trans dipstick. Open the hood of any late model Toyota. :-( |