Tell me about swapping to hydraulic lifters Options

[JeffBowlsby]

I hear they are done to eliminate valve adjustments on a T4 motor.

Other pros/cons?

Is there machining required or are they drop in and thus reversible?

[mepstein]

You don't do it on a 914 motor since you want it to rev.

[MichaelB]

I am not the expert opinion you are looking for but on the engine I rebuilt, started with a GA case (supposedly "unmolested") motor that had hydraulic lifters and dished pistons (which with the 914 2.0 heads must have dropped the compression a pretty good bit). I replaced both the pistons and added a 9590 kit. The case did have the secondary oil pressure relief valve (under cylinder 1) and it had copper plug behind the screw/plug to block it off. I believe most bus motors with hydraulic lifters had this plugged from the factory. As we know the bores for these relief valves are often poor/irregular or worn (and leak or stick). If you have a secondary valve, addressing it might be a consideration in keeping pressure up for the hydraulic lifters.

[Bleyseng]

I hear they are done to eliminate valve adjustments on a T4 motor.

Other pros/cons?

Is there machining required or are they drop in and thus reversible?

You need a different cam, pushrods for it to work. Not very sporty on the one 914 that had em I worked on. Killed the rev's.

[larryM]

https://www.google.com/search?q=914+hydraul...-8&oe=utf-8

your problem will be getting it to work with D-jet if that is your plan

i tried it in a 2.0 many yrs ago (circa 1990-93) with the intent to avoid continual valve adjusting

- WebCam 94 was the number back then - new numbers & several grinds now - find all the needed parts on this site
www.webcamshafts.com/mobile/automobile/porsche/porsche_914_8v.html

- the hydraulic engine vacuum profile is entirely different & it requires a LOT of tuning & fiddling to get it running anywhere near right

if not running D-jet you will like the result - the VW buses ran 'em with L-jet & you can likely find a lot of help on the Samba in that regard

fwiw i finally gave up trying to tune it & went back to a Web Cam 73 with D-jet and Ed Mazula 4mm overbore TB - it was a mid-range screamer!

there are old threads on this 'way back - pre-914World, but Samba is your best source

. yes it is reversible! - i did it - the adventure cost me a LOT OF TIME - at 35 hrs flat rate to teardown & reassemble, one must think hard about that prospect - that's X2 since it meant doing it twice

[Dave_Darling]

Ramp rates on the cam have to be set up for the hydro lifters, so you can't use a stock cam.

The valves still have to be adjusted, but if you drive the car regularly you won't have to do it as often as with solid lifters.

There is some argument about exactly how much pre-load to use on the valve adjusters when you have hydro lifters.

Generally the hydro lifter setups will impact high-RPM power.

Supposedly, if you do a solid-lifter adjustment on a hydro motor, you can kill it. I'm not sure I buy it, but someone who has dealt with more motors than I have insisted that had happened to him.

--DD

[rhodyguy]

Very annoying when the lifters have to pump up after longish durations of not driving the car. It can be noisy.

[r_towle]

It works, not optimum but it can be a dropped in thing.
Had a buddy do a 2.6 liter with them....he loved the lack of valve adjustment.
Rich