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Oxyboxer with hvx mods and hydro lifters: tell me why it cant be done

Posted: Tue Aug 08, 2017 11:37 am
by flyguyeddy
I have been researching this and i have yet to come up with an answer. Perhaps im not searching properly.

Is there any reason you couldnt use the stock hydro lifters on a wasser case with the hvx mods? Too much oil into the lifters and head?

Re: Oxyboxer with hvx mods and hydro lifters: tell me why it cant be done

Posted: Wed Aug 09, 2017 12:51 am
by Piledriver
Why do you want hydraulic lifters?
Prefer sudden valvetrain failures with no warning?

I cannot actually see an issue with oil pressure, I also personally don't think you can have too much oil flow to the heads, as long as it drains.
...but I fail to see any upside with hydraulic lifters other than they are perhaps a little quieter at idle.
Assuming you have this in an aircraft, that's not even remotely an issue.

Re: Oxyboxer with hvx mods and hydro lifters: tell me why it cant be done

Posted: Wed Aug 09, 2017 4:28 am
by flyguyeddy
I may try shimming my current lifters solid then, as i do not wish to bush the bores

Re: Oxyboxer with hvx mods and hydro lifters: tell me why it cant be done

Posted: Sun Aug 13, 2017 1:23 pm
by Dan Dryden
I thought type IV lifters could be slipped straight in if you wanted to switch to solid...?

Re: Oxyboxer with hvx mods and hydro lifters: tell me why it cant be done

Posted: Sun Aug 13, 2017 1:35 pm
by Piledriver
Dan Dryden wrote: Sun Aug 13, 2017 1:23 pm I thought type IV lifters could be slipped straight in if you wanted to switch to solid...?
They can, that is what most folks do.

My only concern would be if you have a true "hydro" cam installed.
Most "hydraulic" cams are really just normal cams that work well with hydraulic lifters.
Purpose made hydraulic cams have very rapid ramps to slam the check valve in the lifter closed.

Solid lifters on a made for purpose hydraulic cam will destroy the valvetrain quickly.

One compromise would be to shim a hydro lifer to something like .005" internal stroke, the spec racing lifters (for classes that require hydro lifters) typically used limited stroke hydros.

You then set the lifters up for zero lash hot, or figure out how to set .005" preload cold (assuming CrMo pushrods)