Don Terrill’s Speed-Talk

Should oil be restricted to pressure fed lifters???Thanks

Heres what Crane Cams has to say on restricting oil flow;
Newsletter Issues
Issue 222 January 2, 2007



Issue No. 222 January 2, 2007



Don’t Torch Your Valve Train With Oil Restrictors! - We do not recommend the use of lifter galley oil restrictors in either street or racing applications. Restrictors severely limit the flow of oil to the lifters, pushrods, valve springs, rocker arms and valve guides. This can greatly shorten the life of these components and cause them to fail! Your engine oil lubricates, as well as carries away the heat generated in these areas. Oil restrictors will raise operating temperature significantly and cause valve train components to prematurely fail. In roller lifter applications with high valve spring pressures, prolonged idling will also lead to less lubrication reaching critical areas, again leading to failure. The solution? Simple! You need only to occasionally “rev it up” and get oil flowing throughout the engine!

Guy

"Oil restrictors will raise operating temperature significantly and cause valve train components to prematurely fail."

Yeah and in certain applications... NOT using oil restrictors will raise temperature significantly and cause rotating assembly components to prematurely fail!

When Crane wrote that, all they were thinking of were the pieces they were selling. Not the rest of the motor. Restrictors are absolutely necessary in some circumstanses.

Bret

Never, Ever, run oil restrictors.

If you're finding too much oil up-top, you don't restrict the amount of oil going up-top, you increase the drainage back down.

The valvetrain needs all the oil it can get. That sometimes requires you to do a little work to get the oil to drain back down quick enough, but that's the difference between being an engine builder, and an engine assembler.

Running oil restrictors with oiling lifters is a great way to stick a lifter, and wipe out your cam.

PFC1 wrote:"Oil restrictors will raise operating temperature significantly and cause valve train components to prematurely fail."

Yeah and in certain applications... NOT using oil restrictors will raise temperature significantly and cause rotating assembly components to prematurely fail!
When Crane wrote that, all they were thinking of were the pieces they were selling. Not the rest of the motor. Restrictors are absolutely necessary in some circumstanses.
Bret

=
And those would be what?
Where is the logic in restricting oil to the lifters,, especially true with the newer pressure fed ones

By your statement I would have to assume you feel all the trouble people go to in adding spring oiling is a bad thing too??

PFC1 wrote:"Oil restrictors will raise operating temperature significantly and cause valve train components to prematurely fail."

Yeah and in certain applications... NOT using oil restrictors will raise temperature significantly and cause rotating assembly components to prematurely fail!

When Crane wrote that, all they were thinking of were the pieces they were selling. Not the rest of the motor. Restrictors are absolutely necessary in some circumstanses.

Bret

Seems to me that Crane had valid reasons for wanting their products to be protected from the damage caused by restricting the oil to them..........

In what circumstancew would restrictors be beneficial? Where would a reduction the of lubrication and cooling be beneficial in highly stressed, rapidly moving, hot parts?


tom

Have any of the three of you built a Big block Ford with an A460 block, wet sump, that turns over 9000 for 20 second intervals?

Bret

Many times a 351C can benefit from restrictors. The lifter bores are plunge cut into the oil galleries and bleed a ton of oil pressure off.
I run a .125" restrictor on the drivers (IIRC) side lifter gallery with a hydraulic roller cam. Seems to work fine on a street oriented motor. I recently pulled the lifters out and everything looks fine.
However I doubt Camking or anyone else will honor a cam warranty with restrictors.

PFC1 wrote:Have any of the three of you built a Big block Ford with an A460 block, wet sump, that turns over 9000 for 20 second intervals?

Bret

uhoh!

PFC1 wrote:"Oil restrictors will raise operating temperature significantly and cause valve train components to prematurely fail."

Yeah and in certain applications... NOT using oil restrictors will raise temperature significantly and cause rotating assembly components to prematurely fail!

When Crane wrote that, all they were thinking of were the pieces they were selling. Not the rest of the motor. Restrictors are absolutely necessary in some circumstanses.

Bret

I figure from my limited experience that you are restricting the amount of oil to the lifter galleries in an attempt to push more to the mains / big ends etc.
Is that correct ?

Cheers

Deek

PFC1 wrote:Have any of the three of you built a Big block Ford with an A460 block, wet sump, that turns over 9000 for 20 second intervals?

Bret

Bret is correct....running that block w/o one or both restrictor plugs is big problems . FRPP instructs a .060" minimum restrictor hole [some use smaller ...I do not] . Opening the fed to 3/32" or 1/16" on one end and .050"ish on the other end with give the "top" about all the oil it could ever use .
What works on a Dart BBC does not work in this application .

I run Clevelands with restrictors on solid flat tappet cams, using
the pressure fed lifters. No problems so far...

Before we say, DO or DONT use restrictors, as there is at times a place for them. We need to look at why we are considering their use.

The first thing to look at is ensuring you have adequate drain back, dont bother with anything unless you know you can get the oil back to the sump,, especially if you are considering restrictors to 'cure'/bandaid a drop in oil pressure at high rpm.

As has been mentioned, it may simply be poor return that causes the pressure to drop off.

Restrictors are often used in an attempt to reduce windage drag and this is fine depending on the use of the engine.

If it is indeed a windage problem you are trying to battle, better oil return control is the key, not just to restrict the ammount of oil. You can achieve as much or more lube to cam bearings, lifters etc and reduce windage by various means, ie- closed cam tunnel, oil return baffles, deflectors, etc.

In simple terms, the more lube, the longer the life of any given component. Along with a reduction in temp of particular components you will see a more even control of any heat generated.

Look at the use of the engine, drag, circle, circuit, boat ect, all these uses will put a different requirement on the oil return system in any given different engine. Eg, look at the angle of the oil drains in Clevo heads, they are not too far off laying flat with the engine at rest, hook it thru a long fast corner at revs and the centrifugal force on the oil in the drain gallery will make the oil stay in the head, it cant drain against the cornering force, the sump runs dry and there go's the bearings. Restrictors do absolutly nothing to change this dynamic, they simply allow less oil to the top end so it takes a longer corner to dry the sump out.

In many cases it is more beneficial to modify the route of the oil feed to various parts than it is to just restrict it to one part hoping that the extra oil will help another part.
Often high rpm bearing failures could be avoided by carefull rework of the champher's on the crank and the crank gallery intersect angles, then you can actually run less oil pressure/flow and achieve better bearing life/oiling.

Oil system modification/rework, including feed and return, YES.
Oil restrictors, Maybe, but only after carefull consideration of the use and or the fault you are trying to rectify.

There is no "fault" with the A460 oiling system....it was designed to be ran restricted . It's a very tunable system , all one has to have is a 1/4" npt plug and a few small drill bits . On the other hand I am not a fan of restricting the oil to the cam bearings in a bbf . It's just a matter of giving any given design consideration and knowing that there is not one answer for every block that was ever made .

I guess not.

I qualified my statement with "under certain circumstanses" The original author of this thread did not question what motor the restrictors were to be used for.

Where as others have made blanket statements such as "Never, Ever, run oil restrictors."

I guess if I were only an "engine assembler" and not a builder then I'd take such blanket advice, just install solid plugs where the block is tapped for restrictors and then I'd have no oil to the top. On an A460 block with many brands of solid roller lifters just one .0625 restrictor will feed the entire valve train (both sides) through all rockers when priming within a matter of minutes with cold oil. And actually the Ford in my opinion has a better designed drain down system stock(and no mine is not stock) than do the BBCs. On a BBC with solid rollers I have primed for as long as 20-30 minutes constantly rolling motor over to get oil through all rockers with NO restrictors. So tell me I should't install restrictors where the A460 block is tapped for them.

Here is my personal motor at 9000 or more two different pulls. The first is with just 1-.125 restrictor for top end, made two passes and lost rod bearings. Too much oil to top! Second pull is typical seasons worth of pulls with just 1-.0625 restrictor, and after a dozen dyno pulls and almost a full season bearings look good and the Lunati (PAC)75848 springs made it within the last three pulls of the season. Using a HAROLD BROOKSHIRE designed cam with .898 lift on the intake. No wear on cam either. Won both!

http://www.youtube.com/watch?v=Jv2_px9K6r4

http://s211.photobucket.com/albums/bb30 ... cumbia.flv

I really don't post on this forum very often because many here are much more qualified to answer questions, although I really like to come here and read and "learn". But, when I think I might have something to offer I will. I just don't understand why some assume they have such a high pedigree that they feel the need to make personal putdowns or insults.

Bret