<VV> Hydraulic lifters

[Sethracer at aol.com]

In a message dated 11/2/2008 9:45:06 AM Pacific Standard Time,  
westerncanadacorsa at shaw.ca writes:

Ernie,

Keep in mind that there is a difference in the proceedure  depending on what
kind of lifters are in the engine as well.  The 1/4  turn is for stock
lifters, most rebuilds are going to have SBC, which I  usually give a 1/2
turn to (set  cold)

Regards,
Joel




The best thing about Hydraulic lifters - indeed the only good thing about  
them, is that they self adjust. If you have ever had an engine using solid  
lifters, you know that they are noisy and prone to clearance change - meaning  
timing change -due to temperature. Hydraulic lifters have some bad attributes -  
but these are well overcome by the self adjusting nature. It really doesn't  
matter where you set them - within reason - they will take up the slack and 
give  it up when needed. For racing or "racing-type" situations, you can use less 
 pre-load on a cold or hot setting. This gives quicker recovery when you have 
 floated a valve/spring/rocker due to over-enthusiasm. There is less oil to 
bleed  out of the pumped-up lifter. I believe Chevy's original recommendation 
intended  to place the internal piston about mid-way through its travel when 
set at near  room (or shop) temperature, giving it plenty of margin for hotter 
or colder  temps. The Corvair engine had some unique attributes that the small 
block Chevy  V8 lacked. The whole engine grows in width under temperature 
increase. That  moves the rocker arm pivot point away from the camshaft a bit (a 
little  bit). The lifter has to take up that slack to maintain full lift at the 
valve.  With mechanical lifters, you would have to set the clearance in 
advance to where  you think it will be when hot. That is why old VW flat-four 
engine had to sit  overnight and have the valves set cold. It was the only way to 
be  semi-consistant. The only successful usage of solid lifters in the Corvair 
motor  was for a very focused, unique usage, where you could predict exactly 
the  conditions of operation. That doesn't describe 99.9% of the Corvair 
engines I  have seen. For normal street usage, any hydraulic lifter that fits in the 
bore  of a Corvair case will probably work fine at 1/2 turn cold. Keep enough 
clean  oil in the motor and the lifters will be trouble free. - Seth  Emerson 
**************Plan your next getaway with AOL Travel.  Check out Today's Hot 
5 Travel Deals! 
(http://pr.atwola.com/promoclk/100000075x1212416248x1200771803/aol?redir=http://travel.aol.com/discount-travel?ncid=emlcntustrav00000001)