Lifter valley oil control issue with solid roller SBCs?

[PackardV8]

Our most recent build is a very trick Studebaker 259" V8. It has a custom solid roller camshaft and we chose Iskenderian .904" SBC solid roller lifters. They fit and work fine, but in hindsight, we should have gone with a Mopar version, since the Studebaker does not need the oil hole in the pushrod seats. With .020" valve running clearance, the oil was coming out of the lifter center holes and flooding the lifter valley and oil pressure would begin to drop before the end of a dyno pull.

There's most likely a simple answer to this question; in a solid roller SBC is with the same valve running clearance, it would seem the oil could also choose to flood out around the bottom of the pushrod, since there's nothing holding the pushrod in place to force the oil upstairs. So why don't SBCs have this oil control problem?

Our current thinking is just plug the hole in the pushrod seat of the lifter. Anyone see a problem with that? FWIW, when we did that, we immediately saw an increase in cranking oil pressure.

[cgarb]

Maybe it has something to do with the orientation of the oil hole in this application. Sbc has the oil hole perpendicular to the axle in the body above the groove, so only so much oil can fit between the bore and the lifter until the hole enters the oil groove. Maybe in your block the hole is exposed when the valves are closed and bleeding too much oil past. I see nothing wrong with plugging the hole as long as you do not need the oil for anything. Where are you plugging it at the pushrod seat?

[GARY C]

Our most recent build is a very trick Studebaker 259" V8. It has a custom solid roller camshaft and we chose Iskenderian .904" SBC solid roller lifters. They fit and work fine, but in hindsight, we should have gone with a Mopar version, since the Studebaker does not need the oil hole in the pushrod seats. With .020" valve running clearance, the oil was coming out of the lifter center holes and flooding the lifter valley and oil pressure would begin to drop before the end of a dyno pull.

There's most likely a simple answer to this question; in a solid roller SBC is with the same valve running clearance, it would seem the oil could also choose to flood out around the bottom of the pushrod, since there's nothing holding the pushrod in place to force the oil upstairs. So why don't SBCs have this oil control problem?

Our current thinking is just plug the hole in the pushrod seat of the lifter. Anyone see a problem with that? FWIW, when we did that, we immediately saw an increase in cranking oil pressure.

Do you run oil restrictiors in the block like an SBC Solid roller cam? Is your lifter valley drain back sufficient? If you plug the hole then how do you get oil to the top end?

Technically you can't flood anything that has proper drainage.

[MadBill]

..There's most likely a simple answer to this question; in a solid roller SBC is with the same valve running clearance, it would seem the oil could also choose to flood out around the bottom of the pushrod, since there's nothing holding the pushrod in place to force the oil upstairs. So why don't SBCs have this oil control problem?...

Presumably the Stude uses an oil feed to the rocker shafts and the drainback flows into the valley? The drilled lifters would bleed a roughly equal volume either directly into the valley in the case of solid pushrods, or there plus down the head drain holes from the rocker gear with hollow ones, thus doubling the total flow. Unless the valley is quite open, flooding could ensue. Of course, loose-fitting lifters would exacerbate the issue.

[GARY C]

..There's most likely a simple answer to this question; in a solid roller SBC is with the same valve running clearance, it would seem the oil could also choose to flood out around the bottom of the pushrod, since there's nothing holding the pushrod in place to force the oil upstairs. So why don't SBCs have this oil control problem?...

Presumably the Stude uses an oil feed to the rocker shafts and the drainback flows into the valley? The drilled lifters would bleed a roughly equal volume either directly into the valley in the case of solid pushrods, or there plus down the head drain holes from the rocker gear with hollow ones, thus doubling the total flow. Unless the valley is quite open, flooding could ensue. Of course, loose-fitting lifters would exacerbate the issue.

Would an extra/alternate drain line be possible solution on this type engine?

[Tom Walker]

Small block Chevys have the hollow push rods as an "escape path" for the oil, I assume your stude does not oil through the push rods. Could this explain what is happening in your engine? I think you have the solution solved in at least 2 different ways, lifters that do not pass oil to the push rods or plugging the oil holes in the lifters. Good luck, would be interested in what solves your issue.

[PackardV8]

The fix chosen was to block the transverse .125" hole which feeds oil to the pushrod hole. The Studebaker V8 oils through the rocker shafts and doesn't need this passage.

We cut 1/8" brazing rod to .900" long, put a slight bend in them and drove them into the lifter body. Seems firm and all the oil flooding has stopped.

[Tom Walker]

Thanks for the update, sounds like all is well now. A stude with a roller, that has to start some great conversations. Working with the vintage and unique engines that you talk about is interesting and sounds like a lot of fun and I would assume a great sense of accomplishment.

[PackardV8]

Thanks for the update, sounds like all is well now. A stude with a roller, that has to start some great conversations. Working with the vintage and unique engines that you talk about is interesting and sounds like a lot of fun and I would assume a great sense of accomplishment.

Thanks for the kind words. Making available parts fit obsolete engines can have unanticipated consequences. We delved deep into the parts book to find the .904" roller lifters with link bars from a V6 the correct length for the Studebaker lifter bore centers. They drop in fine, it's just the oil holes which we learned we don't need. Next time, we'll use Mopar lifters.

[PRH]

To the best of my recollection, all the solid roller Chevy lifters I’ve used have had the holes that feed the pushrods located above the oil band, and they do not have direct access to the oil gallery.
The metering mechanism that restricts how much oil can be fed to the pushrods is the lifter to bore clearance.

[PackardV8]

To the best of my recollection, all the solid roller Chevy lifters I’ve used have had the holes that feed the pushrods located above the oil band, and they do not have direct access to the oil gallery.
The metering mechanism that restricts how much oil can be fed to the pushrods is the lifter to bore clearance.

That's what we discovered. Studebaker V8 lifters are fed via a small vertical hole in the side of the lifter bore which does connect to the oil gallery and feeds the side of the lifter. When SBC roller lifters are installed in the Studebaker V8, the transverse oil hole in the side of the lifter lines up with that oil feed hole in the side of the lifter bore. The result is as long as the lifter is at rest, not being moved by the cam lobe, there is full pressure going up the pushrod seat. That was pumping the pan dry enough to cause oil pressure to drop within ten seconds on a full pull. Plugging the lifter oil holes solved that.

[PRH]

There's most likely a simple answer to this question; in a solid roller SBC is with the same valve running clearance, it would seem the oil could also choose to flood out around the bottom of the pushrod, since there's nothing holding the pushrod in place to force the oil upstairs. So why don't SBCs have this oil control problem?

Jack, I saw you had it figured out...... I was just answering the question you posed for the casual viewer.

[Newold1]

Jack

If the solid roller lifters you are using have a removable pushrod cup you can remove it and probably close the hole in some way or I know in some lifters I have seen very thin round disks mounted under the pushrod cup to either block the oil or reduce it's flow considerably through very small orrfice size.

The side oiling on the lifter body recess will take care easily oiling the lifter and cam with the oil from the bore.