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hey sr20 gurus, my local machine shop has informed me not to bleed the hydraulic lifters on my sr20 and leave them squishy instead of hard, from most videos on youtube i can see everyone pumping them up with oil, ive done my piston to valve clearances with Plasticine while the lifters where in and im worried it will be affecting my readings if the lifter is moving when my cam lobe has pushed on my rocker arm, any info would be good at the moment and what has everyone else done
Hum... I've built a lot of SR20s and I always bleed them. I wonder what is the reason behind this statement from your machine shop. I know for sure that SR20s lifters won't bleed by themselves only by running the engine. And the factory service manual does specify to bleed them as well. It will definitely affect the lift of the valves, as the lifter will compress instead of the valves opening. Also, as the amount of air in the lifters is probably not the same everywhere, so the valves won't open the same way...
There's bleeding and there's 'bleeding'.
The problem is in the very principle behind their operation - they are designed with an internal piston and chamber that is supposed to fill with oil to take up the excess clearances in the valve train - but if the lifter/follower is completely bled and filled with oil the clearance is not just taken up, but the piston goes past that point, to give what might be termed 'reverse clearance'that would prevent the valves seating until the lifter(s) leaked the excess oil out.
I've always left them to soak in oil overnight, sometimes with a few pumps to help insure they have oil internally, so they didn't operate dry at the start - even at the best they can take 5-15 minutes to self bleed and this seems to help.
i have also built my share of these and same as Gord i leave them to soak over night