have run 2 engines in the last 4 years with no return tubes,i watched the oiling with valve cover off and lots of oil runs down the push rods,as well as the return the heads 1 at each end  bottom front and rear, i used 289/302 vave seals have no execs oil consumption. have not had to adjust valves . it seems a no brainer to me. bothe engines befor rebuild had no oil going to most rockers the reg du to slug and lots of scoring. re the 289/302 seals  i trimed the umbrellas 1/8 in .just look at fes they get full presure to rockers. my oil pressure is 20psi at idel with5/30 oil and 50psi 2500 rpm.

Anyone know the depth that Mummert's cams are machined to?

You want to make sure that the groove is correct, no matter what else you do.

If it ends up with a lot of oil to the top end, it would be best to add a restriction in the rocker stand that relates to the oil feed of the rocker shaft.  Pinching the tube probably would not help because the tube sends oil straight down a pushrod hole.  If you pinch that closed and you already have too much oil then you will make matters worse because more of the oil that would otherwise effectively bypass the head is now being forced out of the rockers.

I don't know how "too much" oil is determined, though.  Maybe Ted can help with that.


Lawrenceville, GA

Thank you all for your help. I just want to make sure I'm understanding correctly. You guys are recommending to cut the center groove of my camshaft to .030 and crimp the oil drain back tubes? Or should I do just one or the other? I guess I could cut the cam first and then see how much oil is retained in the top of the cylinder head and then restrict the oil tube if it isn't enough?

A rebuilt my 292 last summer.  I have a very similar engine to yours.  I used the same cam.   The oil grove in the new Isky cam was .018" deep.  It was slightly wider than stock.  I cut the groove to .030" and installed it.  This increased the oil flow to the rockers substantially.  Previously, my engine had blocked oil tubes and pressurized rocker shafts.  I was worried that I would flood the top of the heads with oil, so I purchased new oil tubes and put it back to stock.  I have about 2,000 miles on my rebuild with no problems. 

Be careful with cutting the cam grove deeper.  You don't want too much oil either.  If that happens, you can always restrict the flow.

The engine is currently in the process of being reassembled. I just got it back from the machine shop. It's definitely more of a mild street engine. Fenton Tri-Power Intake, Red's Headers. Isky Cam and springs, mildly ported G heads. I don't plan on racing this engine. I just want to make sure I have a reliable cruiser and that I only have to have it all apart once. 

Customline 3859. 
-  Check the groove in the camshaft bearing surface for depth.  It should be .035 deep.  This can be corrected on an engine lathe. 
-  Grooving the engine block cam bearing bore is one way to insure oil flow up to the rocker arm shafts.  An alternate method is to use a camshaft bearing that has a groove machined in the outside diameter of the bearing shell to permit 360 degree oil flow to the oil flow machined galley in the cylinder head.  The purpose of adding a groove in the O.D. of the bearing or adding a groove in the engine block cam bearing bore is to cure bearing index hole mis-alignment in installation or turning in use.  Verne Schumann is the source for a set of Dura-Bond F9A camshaft bearings with the 360 degree groove in the center cam bearing.
Vern's contact information is:
Schumann's Sales & Service, Inc.
P.O. Box 128
Blue Grass, IA 52726
[phone 563-381-246  fax 563-381-2409]
-  The idea of pressurizing the rocker arm shafts is advocated by some and avoided by others.  The debate for me is influenced by the purpose of the overflow tubes.  The driver's side overflow tube is intended to supply oil to the distributor gear where it meshes with the camshaft.  The overflow tube on the passenger side is intended to provide lubrication to the timing gear set.  Personally, I advocate a compromise of crimping the overflow tubes to restrict oil flow out of the rocker arm shafts for engines I rebuild for street and highway use.  For high rpm and racing applications or for engines using aluminum rocker arms, I see benefit to pressurizing the rocker arms and drilling a hole in the block face to tap the oil flow to the front camshaft bearing to provide needed oil to the timing set.

Hope this helps!   


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

Specs for the center groove can be found here, as well as some detail about grooving the block.

http://forums.y-blocksforever.com/FindPost57214.aspx

There have been and still are many Ys running around with stock rocker arm oiling and it works fine, particularly if it is a fresh rebuild.  What kind of upgrade are you doing?

I think in general pressurizing is not a requirement for steel rockers but is preferred for aftermarket aluminum rockers.  There are some considerations when pressurizing and that is timing gear and distributor oiling since the overflow tubes do supply some oil to those areas.  There will still be oil getting to the timing gears via the front cam and main bearings and oil will still get to the distributor gear via the valley and pushrods.


Lawrenceville, GA

I read recently about Tim McMaster's pressurized rocker arms for increased oiling to the valvetrain. I also noted some people here mentioned also machining the center groove on their camshaft deeper as well. Is this necessary for a street engine? Is it a must if I'm going to upgrade my rockers? I am going to install an Isky cam(#301333), is there a way I can tell if the depth has already been machined to the appropriate depth? Are there any other oiling updates I should consider while my engine is apart? Any advice and information is greatly appreciated.