Valve Lifter preload .

[alloydave]

Im doing some checks before firing up the 250 and i have all sorts of things going thru my head at the moment.The main concern is that i have installed a larger crow cam (510"lift)with anti-pump lifters ,but havnt put in pedistal shims under my non-adjustable roller rockers nor have i checked the lifter preload .My engine has been zero decked and the head has been surfaced ,what can i do to check preload i have a crane shim kit for a clevo sitting here .A couple of stockcar guys said they shimmed theres up untill they were a little bit noisy and got there best performance there, but i dont want a rattler of a street engine.I was going to put 030" shims under all the rockers as thats about what came off the top of the block and start from there .Anybody done this before with non-adjustable rocker gear?.

Cheers Dave

 

[xctasy]

Hydraulic lifters are the most freindly things if you follow the shop practice. Theres over 2.5 mm (98.4 thou) of lifter clearance that gets cleaned up by these miracles of modern engineering.

First up. do the 3 stage head tension 55,75, 105 ft/lbs.

The acid test is then to do what FrenchtownFlyer does.

At half the gross lift at the valve (510/2=255 thou), check that rocker arm is at 90 degrees to pushrod when the lifter is collasped hard down. If its not, then follow the standard Ford shop manual practice:-


1. Use lifter bleed down tool and collaspe lifter
2. Add pushrods
3. Use stop, no go gauge to check 0.0984" min, 0.1968" max clearance
4. use 0.060" thou longer or shorter pushrods to help get clearance

If that doesn't check out in spec becasue of pushrods are still too long, then shim up the sled fulcrum until it checks out.

so long as you've

a) coated the cam and lifter surfaces with a smear of molybedum grease b) added oil to the lifter tunnels and cam journals,
c) and checked the clearance,

then 2.5 mm of free float will be tasken up by the lifter preload.

After the rockers are clicked down with the torque wrench, you should just have dry lifter noise for a day or so to deal with.



Deano

 

[alloydave]

Thanks Deano i will rip it to bits and have a look during the week .

Thanks Dave