Upgrade oil pressure restrictors for camshaft

[lbailey75@tampa]

What is the orifice size difference between the standard and upgraded restrictor for the camshaft housings ?
I am thinking about it.

[RSTarga]

My mechanic prefers upgrading the oil pump.

[Nditiz1]

The restricted is about 3/32. I can measure the stock when I get home.

[john walker's workshop]

Depriving the cam and rockers of oil flow doesn't make sense to me.

[allaircooled]

Here is a visual of the differences.

[gled49]

I’m with Walker, I see no up side to the restrictors.

[lbailey75@tampa]

According to Porsche - it decreases foaming of the oil returning to the case. It also increases the oil pressure to all the bearings and squirters providing more lubrication.
It has been suggested to drill the 3/32 (2.5mm) hole out to 5/32 0r 4.5mm

[theiceman]

i have the same micro holes in my bumper pad, what causes that ?

[proporsche]

Originally Posted by john walker's workshop

Depriving the cam and rockers of oil flow doesn't make sense to me.

yup, this...^^^^^^^....

Ivan

[bpu699]

I put them in my 930. Tracked it. Cams looked fine with the exception of 1 that was pitted…

[Flat6pac]

Personally, I would rather replace a cam in a Carrera or 930 than a crankshaft because of oil starvation on #2 or #5 which usually breaks the rod then wipes the inside of the case, oil pump and piston leaving you with a pile of junk.
Bruce

[Nditiz1]

Well if porsche decided it was a bad idea then they might not want to supercede all the previous versions. When trying to get a set of the restrictors I could only find the restricted ones based on the older part number.

[Zuffenwerker]

I like them in older engines that have lower oil pressure. My rebuilds always get a modified oil pump from Glenn Yee and #4 main groove. there is no need for the restriction because they have plenty of oil pressure. I have seen no harm from running the restricted orfice as is without modification.

Daniel

[MichaelSJackson]

So Porsche did this to reduce frothing. The increase in pressure is a side effect. Less frothing helps the oil pump's scavenging.

The smaller restrictors came into use with the 964 pump. So I don't understand the comment about a mechanic rather splitting the case to upgrade the pump instead? Sure the newer pumps are better, but if you upgraded the pump wouldn't you upgrade the restrictors at the same time?

I feel the question is, "Should you retrofit the smaller orifice in an engine with an older style pump?" I'm not aware of any examples of cam damage caused by these restrictors?

Here is an earlier thread with interesting inputs.

Cam Tower Oil Line Restrictors Redux

Michael J
'78 SC w/smaller restrictors

[RDM]

Originally Posted by john walker's workshop

Depriving the cam and rockers of oil flow doesn't make sense to me.

I never understood this either. Without the restrictor, is there not enough oil for the bottom end?