p2v clearance problem
 

Hi.
I have a little problem with my build...

I'm checking piston to valve clearance and it doesn't work...
I checked with the hydrolic lifter i will be using, and there
is no problem, about 0.250 clearance on the intake....

But every body tell me to check this with a solid lifter.....
so i make one with my hydrolic.....reverse the plunger,no
spring, and rebuild it.....the cup is at is highest point, in
contact with the retainer clip......

And oups, my valve doesnt clear at all....My valve doesnt
even close...NEVER....when i bolt the rocker on the
head....it compress the valve even at its closed
position...so my valve is always 0.170 thou open all the
time....

So what's up with that?
Just by how the valve acts, i can see its not the right
way....Why the reading with the standard hydrolic roller
would be no good? And why my valve is open 0.170 thou even
when closed with this homemade solid.....Cant be my pushrod
lenght....too much difference.....a couple of thou
maybe...but 0.170!!!!impossible!
Any help would be apreciated...
Thank you




My engine spec

360 0.030 over
pro tru piston with valve relief
0.005 piston to deck
howard cam 229/233 0.523/0.523 110 lsa
1.6 roller rocker
iron ram big valve heads ported( by me!!) 259 cfm flow bench

tested after my job....
m1
52 mm tb
etc.....

Thank you

Maxx

Using a hyd lifter for this test allows the cup to depress all the way into the lifter body. You lose lift at the valve during the test so the P to V looks OK when it might not be.

You need to check with a solid lifter, but one that gives you the correct lifter preload with the correct length pushrod. Flipping the cup over is the wrong way to do it. That hangs the valve open all the time as you've found out.

What you need to do is make 2 old lifters solid, but using washers or tinfoil or something inside the lifter that lets you set the lifter cup height in the lifter body where it should be. Both valves should be closed and all slack should be out of the valvetrain when the lifter is on the cam's base circle. I use a set of lightweight checking springs for this so I'm not crushing the tinfoil in the home-made solid lifter during the test.

check clearance with a thin layer of clay on top of the piston and an old headgasket. Roll the engine 2 full revolutions. the valves will leave imprints on the clay if you're close. do at least one cylinder on each side. Keep in mind that adv or retarding the cam during installation can affect P to V.

I really don't see why everyone says to pull the lifter apart and make it solid by putting stuff inside of it. That is a long process that you can obtain much easier. When you make the lifter solid, you are really just trying to take any ability for the lifter to compress not letting the valve fully open. Why not just let it compress, and take up the slack with a pushrod length checker. This can be performed on an assembled engine, and there is no reason to disassemble it unless there is interference.

You will compress the lifter pushing all the fluid out. You will be able to feel when there is no fluid as the plunger will easily compress. Install you pushrod length checker and extend it to take up any slack when the lifter is on the closed portion of the cam. Now the lifter is fully compressed and the slack is removed basically making it a solid lifter. You can use it with zero slack or lengthen the pushrod length checker so that the valve is being pushed down .050 (or your desired clearance). If you have it down your desired clearance turn the engine over by hand slowly with no plugs and the other rockers backed off or pushrods uninstalled. If it misses you are good. If you decided to use the zero lash method stop in the problem areas and pry down on the rocker arm measuring your clearance to the piston. Do your 2 revolutions, and when you back off the rockers make sure your zero lash or desired depth did not change. If it changed, you did not have all the oil out of the lifter, and you will need to start over. It just seems much easier to me with the same outcome.

i check with a solid lifter, light checker springs and an adjustable pushrod. set the valve train to zero lash on the base of the lobe using the adjustable pushrod, then check ptv from there. a degree wheel and dial indicator gets more precise measurements than clay so it's what i prefer, but clay works for most.

If you installed the cup upside down and turned it over make sure you didnt damage a valve seal. It would have opened the valve much farther than it should have. If it stopped you could have even been binding the coils.