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I know this isn't the case here as you have the OEM lifters, but I do sometimes wonder just how much preload will cause a valve to remain slightly open when using adjustable lifters. I do believe that adjustables should be used whenever ANYTHING is changed related to the cam chest, cylinders, head gaskets, heads, and rockers. I just have a hard time believing the distance from the lifter seat to the rocker cup can remain exactly the same down to .020"...
But I often read things like this: "Noisy valves with .100 preload? Try .125... Try .135... Try .140... Try .145... (where I settled on) Try .150..." What does it actually take to keep a valve from completely closing?
I know this isn't the case here as you have the OEM lifters, but I do sometimes wonder just how much preload will cause a valve to remain slightly open when using adjustable lifters. I do believe that adjustables should be used whenever ANYTHING is changed related to the cam chest, cylinders, head gaskets, heads, and rockers. I just have a hard time believing the distance from the lifter seat to the rocker cup can remain exactly the same down to .020"...
But I often read things like this: "Noisy valves with .100 preload? Try .125... Try .135... Try .140... Try .145... (where I settled on) Try .150..." What does it actually take to keep a valve from completely closing?
The only way you are going to keep the lifter from completely closing the valve is by bottoming the plunger in the lifter body and cranking a few more from there.. As the motor heats up you'll gain clearance.
I've always adjusted solid lifters by feel, whatever it took to spin them easily and then maybe 1/2 a turn and test again until you got the feel you wanted.
If that was too tight, back off and try again. The idea wasn't to measure a preload, it was to spin easily without any slop.
Can't do that with hydraulic lifters regardless of adjustable unless they're bottomed out.
I'm thinking about pulling the check ball out of the hydraulics and see if there's enough adjustment in the rods to run them as if they were solids.
Just a thought .... but either way, having the adjustable rods will open some options that I don't have right now ... without a bunch of extra work.
The only way you are going to keep the lifter from completely closing the valve is by bottoming the plunger in the lifter body and cranking a few more from there.. As the motor heats up you'll gain clearance.
That's what I first thought as well, but you don't think it's possible for a pushrod to be too long once there's oil pressure in the lifter (in a scenario where the plunger hasn't bottomed out when static)?
Originally Posted by Robottom
I've always adjusted solid lifters by feel, whatever it took to spin them easily and then maybe 1/2 a turn and test again until you got the feel you wanted. If that was too tight, back off and try again. The idea wasn't to measure a preload, it was to spin easily without any slop.
Can't do that with hydraulic lifters regardless of adjustable unless they're bottomed out.
Yup, I've always adjusted solid lifters the same way. I like solid lifters. Never a problem.
NOTE: I'm not having any issues with pushrod adjustment, I've had them in and out many times and am confident they're properly adjusted... I'm really just curious (not concerned) about the notion of making them "too long."
That's what I first thought as well, but you don't think it's possible for a pushrod to be too long once there's oil pressure in the lifter (in a scenario where the plunger hasn't bottomed out when static)?
This is kind of what I suspected, meaning that somehow the lifter kept allowing more oil into the bottom end to the point where the exhaust valves weren't being allowed to close completely. I'm amazed at the amount of crud in the seats. I did talk to a guy that does heads and valves etc professionally and he said
"clean em up and put em back together", "they're all like that", "you can't believe the number of guys I get in here wanting a valve job and don't need it".
That's what I first thought as well, but you don't think it's possible for a pushrod to be too long once there's oil pressure in the lifter (in a scenario where the plunger hasn't bottomed out when static)?
Nope. The not sure what you mean by pushrod too long. Maybe lifter too long? It can't, as the lifter cannot lift the intake/ exhaust valve off the seat by pressure alone. Lifter only gets long enough to take up the slack, Once the cam lobe swings around and lifts the valve off the seat the only thing the lifter does is collapse slowly. You can float the valves to pump up the lifters but with EFI you have a rev limiter.
Here's what the head looked like after about 15 minutes with an old spoon, butter knife, small flat bladed screw driver and some stainless steel wool.
Note that there is still a lot of scum in the intake and exhaust, some of that's loose from the head the rest came off in a few more minutes.
Then I cleaned up the valves, fortunately for me I have a drill press, made this job quite a bit easier.
After that I did a little lapping with cordless drill and just regular rubbing compound.
I reversed directions with the drill several times so as to not have any weird galling in the guides etc.
Definitely not what the experts would use but made a shiny ring.
Here's the end result for the head ....
And here's the end result for the valves
The exhaust still looks kind of ratty but way better than it was before.
I'm hoping to get at least a few thousand more miles out of them before doing major head work.
I called around several folks and the best deal I got was $50 a hole, = $200 for both heads.
That's NO new parts, NO disassembly or reassembly, JUST machine work.
Then I talked to the guy I told you about earlier and he told me clean it up and put it back together.
I really didn't think I was loosing power or compression before, just getting some what I thought was lifter noise.
We'll see if that goes away after this or if it continues.
HEY ROCKOUT ... When am I going to get my Rocker Kit? Has it shipped yet?
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