Re: Some details of the 2AZ-FE engine

C. E. White wrote:
> "Steve" <no@[EMAIL PROTECTED]
> wrote in message 
> news:AM6dnZjsFev_EhrVnZ2dnUVZ_vednZ2d@[EMAIL PROTECTED]
> 
>> ****ms-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.
> 


Probably a cost-of-production decision, IMO. rocker tip mounted 
hydraulic lash adjusters are so tiny they don't add any appreciable mass 
to the valvetrain, are almost impossible to "pump up" (I did a quick 
calculation a while back that indicates it would require over 700 PSI of 
oil pressure to "pump up" a lifter against valve spring pressure), and 
keep the valve timing events right on spec over the life of the engine.

Don't forget, Toyota is learning from GM too. Learning how to live on 
the laurels of the past and cut corners in the present. And how to 
introduce a gas-guzzling pig of a truck just in the nick of time for 
$4/gallon gas, leading to idling a ****ft at the new plant that builds it 
in about 1 year of operation. That's gotta hurt. And that doesn't even 
count the front suspension and brake recalls.... :-(