tony xa

Please any advise on oil restictions for my engine and if they are needed
My engine builder asked if I wanted to do this to keep the oil up top . He also said something about running a line from oil presure switch back to the front of the engine. but can remember someone saying it isn't advised .
engine is 393 clev solid cam hv oil pump 7 litre energy sump.

davis

You add the oil restriction to keep the oil out of the top end and in the pan where it can be fed to the mains and rods. There are several schools of thought on how to "fix" the Cleveland oiling system. They are based on engine performance/usage and budget.

The easiest way to spin to 7500-ish is to use mechanical flat or roller tappets and add restrictors to the cam bearings and to the right side lifter galley. You can't restrict the left side galley without blocking flow to the rear (#5) main.



This photo shows the basics of the Cleveland oiling system. Notice how the entire right side lifter galley is fed from the rear main? You can restrict flow to the right side, but not (as easily) the left side.

With restrictors to the cam bearings and the right side lifter galley, you're arguably fine to about 8000 RPM.



High RPM than that requires bushing all of the lifter bores, an $800 (US) process here. For that kind of money, an SVO block starts looking rather attractive.

With all of the mods, external oiling and dry sump, you can run a short stroke Cleveland to 10,000+ RPM. But anyone considering it today would be far better off buying an SVO/Dart or Fontana block.

:davis:

russxr67

Tony,if my engine builder asked me if i wanted to keep oil up top in my clevo then i would start running.clevo,s suffer from over oiling in the top end and the drainback holes are painfully small .you want your oil in the sump not in the rocker covers.

xbgs351

http://www.network54.com/Forum/messa...eid=1021551574

This is what I have done with my motor. This mod dates back to Allan Moffat.

davis

We build and race clevelands and the main problem with the oil system is in the front cam bearing oil feed. If you study it closely you will see that the oil feed hole to the front cam bearing is supplied directly from the main oil pump feed, the oil goes to the cam journal in one direction and back down to the crankshaft main journal from the oil feed hole that is supposed to supply oil to the cam journal. Study it closely and you will see what I mean. Putting the oil restrictor in the no 1 main does not do a thing . What you have to do is tap the oil feed hole for no 1 cam journal riht behind the bearing, this requires a very long tap, you then put the restrictor right up there. You then plug the hole in the no 1 main journal with a screwin plug.Put the other restrictors in the other mains as normal. And while your at it you can also make a restrictor for the no 1 main bearing oil supply to make it the same size as the rest, if you look at it you will see that it is about 20% larger than the rest. If you do some serious racing have the lifter bores bushed as well because the restrictor in the mains only work for one side lifter bores, if you study this closely you will see what I am talking about. We found this out the hard way, and a very costly way. We now race all season and do teardowns at the end and you can use the bearings again. This is good ole AUSSIE engineering, and you guys thought you knew it all.

Nothing like a braggart...but if he (whoever tony-t is) was so smart, he would simply install the cam bearing upside down after drilling a .060" hole in the bearing and dressing the hole for sharp edges. Saves a lot of effort and costs next to nothing and doesn't require sourcing a "very long tap."

Don't know WHO "engineered" this simple, low-cost fix, but whomever came up with it didn't brag about it. If the cam bearing can't leak oil out, it won't matter what restriction is or isn't placed in the feeds.

Then, all one has to do for most street/strip engines is to place a restrictor in the #5 main to control oil flow to the right side lifter galley. While bushing all of the lifters is better, this "fix" is low cost and easy to perform. Using .040" pushrod oiling holes is yet another choice for controlling oil at the top end. External feeds are required for constant and/or severely high RPM engines. Some feel that the front-to-back equalization is a good choice on street/strip engines, too.

:davis:

xbgs351

The cam bearing reversal is a good way of achieving the same result. You would still need to address the larger sized feed to the no. 1 main bearing.

The hardest part about this modification is drilling the holes in the restrictors, but we had to do that for the other restrictors anyway. Tapping the holes only takes a few minutes. You don't need a long tap. A standard tap and a shifting spanner does the job.

Tony campaigns a Phase 3 Falcon GT Historic Touring car. I have found him to be very helpful.

davis

Number 1 gets a .125" hole...as it has the responsibility of oiling the distributor gear...I should have stated that previously! Too much liberal dousing of the gray matter with cold beer! <dopey grin>

:davis:

clevo400

i was told solid cam clevo engines should always use oil restrictor kits and hydralic clevos not to. then i was told the oil is up there to cool the springs. thats why the old Bathurst engines were expiring because they restricted the oil supply up there and the springs frizzled. (the old halcon days !!!) then what about the 100 psi morosso oil pressure spring ??? what about restrictive pushrods ??? mate i bought both but haven't put any in just yet. i am supposing it doesn't matter if the engine is only to 6000 rpm !!! Ohh and late XD/XE black block clevos supposedly have them already installed !!!

__________________
regards
Stephen

xbgs351

Tony T runs a spray bar to keep the valve springs cool. Doing this he has been able make his valve springs last a whole season with negligible sag.