Why do people say "solid lifters' about Subaru OHC engines?

 

I'm new to Subaru engines. Are there actually lifters either between the rocker and cam or between the lifter and valve?

 

I thought that, in a shim-adjusted OHC valve train, there were no 'lifters' to speak of. Can anyone show me a tech diagram of the valve train of a '99 SOHC phaseII 2.5.

 

Thanks.

mpergiel99foresterlelmhurstil

Solid Lifters are usually put in performance engines. They are exactly what they sound like. You can really tell when an engine has these by the valve "tick" that you can always hear. Solid lifters can handle more stress than non solid lifters. I don't know to much about them but I thought I'd give you my .02.

I think I understand the question. There's really no identifiable component called a lifter, just the cam, rocker, and valve. I'd wondered about this before.

The term "lifter" goes back to the old days of "non" overhead cams that employed the camshaft, then a (solid or hydraulic) lifter, then a push rod, then a rocker arm, then finally pushing on the valve itself. My first car, a 69 Pontiac with an inline 6 was of this design.

 

With the Subaru 2.5L DOHC Phase I engine, the camshaft sits directly above the valve. There is still a "lifter" or more appropriately, a bucket tappet. This is a part that sits between the cam lobe and the valve itself. It has shims as well to adjust clearances. It is 'solid' piece of metal with no means of clearance take up like a hydraulic lifter.

 

I'm not sure what Subaru is doing with the 2.5L SOHC Phase II engine to be honest. I know that it uses rocker arms. Is there a hydraulic lifter in there somewhere? Who can answer.

 

My 85 Civic had an OHC and rocker arms. There was an adjustment 'screw' on one end of the rocker. While there was nothing that I would call a lifter, it was "solid" in the sense that there was no means of take up in the valve train.

 

Many years ago, I read of one manufacturer (forget who) that developed a tiny hydraulic lifter that would have taken the place of that adjustment screw as described in my 85 Civic. The lifter was about the size of the eraser on the end of a pencil. In contrast, the hydraulic lifter in my 69 Pontiac was about 5/8" diameter and 1.5" long. (I recall quite well... I changed a few.)

 

Commuter

The only thing I can see that the term 'Solid Lifter" refers to is that there is NO device between the cam lift and the valve to take up the clearance so the engine will be quieter instead of the tick-tick-tick the 2.5 makes.

 

The phase 1 2.2 did have hydraulic 'lash adjusters' which did serve this purpose. I do agree that the lifter was a product of the OHV engines of the late 50's and still some present ( Ford std 5.0L , Mopar 3.3 and 3.6 V6 to name a few, and these are hydraulic).

The 2.5 phase 2 uses a single cam with dual row of rocker arms. The rocker end riding against the cam has a roller to lower friction and the valve end of the rocker has an adjustment screw and locknut right out of the solid lifter / rocker arm engines of the past. Hence nothing to take up the small clearance and the audiable tick-tick-tick.

The 2.5 phase 2 uses a single cam with dual row of rocker arms. The rocker end riding against the cam has a roller to lower friction and the valve end of the rocker has an adjustment screw and locknut right out of the solid lifter / rocker arm engines of the past. Hence nothing to take up the small clearance and the audiable tick-tick-tick.

 

That is what proper adjustment is for. . . If properly adjusted, the rockers will not have enough space to make a ticking sound when they ride up on the lobe. The clearance listed in the manuals is the difference between the respective positions of the components when cold and when they have expanded after the engine warms up.

This is my experience since working on cars since the 60's.

 

If you have an engine with 'solid' lifters, and by this I mean no means to automatically take up the clearance, then you will almost always have the tick-tick-tick. By adjusting the valve as so to have no clearance when the engine it at operating temp leaves the engine exposed to 'burning the valve' if or when the engine ever has an extra load on it. There is no setting I have found, with direct contact that eliminates the clearance without 'burning' the valve train.

I know everyone has their own feelings on this, but Subaru's own site, endwrench, mentions the fact that the 2.5 is noiser than the 2.2.

So I'll continue to adjust these as stated in the manuals, and continue to hear the tick-tick-tick which to me sounds like a well running ehgine.

My M50 2 liter six banger in my beemer has a hydraulic valve train, so did my 944. I'll trade a few horses for not having to screw with valve adjustment anyday.

 

 

Of course, I'm not staging at the track, either...

The only thing I can see that the term 'Solid Lifter" refers to is that there is NO device between the cam lift and the valve to take up the clearance so the engine will be quieter instead of the tick-tick-tick the 2.5 makes.

 

The phase 1 2.2 did have hydraulic 'lash adjusters' which did serve this purpose. I do agree that the lifter was a product of the OHV engines of the late 50's and still some present ( Ford std 5.0L , Mopar 3.3 and 3.6 V6 to name a few, and these are hydraulic).

The 2.5 phase 2 uses a single cam with dual row of rocker arms. The rocker end riding against the cam has a roller to lower friction and the valve end of the rocker has an adjustment screw and locknut right out of the solid lifter / rocker arm engines of the past. Hence nothing to take up the small clearance and the audiable tick-tick-tick.

 

PII 2.5 subes have roller rockers? Very impressive. Thanks for the pic, but now I need to know how they're oiled. If they are splash oiled, that would easily explain the startup tapping, to me. Feeding oil down the rocker and into the bearing would be micro-work.

 

I thought about the alloy block and head, but that doesn't cover it. Expansion would make the valve train looser.

 

I'm increasingly impressed by these engines.