Edelbrock RPM cylinder head oil restrictors

[happystang]

I've heard of people installing Holley jets on stock heads to restrict oil, but what's the general consensus for Edelbrock heads? I've read that Edelbrock has already corrected the oiling issues by shrinking the oiling hole where the rocker assembly bolts on, but I've also read that they did not shrink the hole enough.

What have people been doing with these heads? Ideally I don't have to take brand new heads to the machine shop to have them drilled out for restrictors. I'm also skeptical of some these homemade restrictors where people simply drop in a metal rod and call it "good enough".

Thanks!

[cattleFEeder]

Throw these in, fit good and from a vendor that posts here  Barry R at Survival
http://store.survivalmotorsports.com/oilreforedhe.html

[Pentroof]

Why do you feel you need to restrict the oil to the rockers? I would first ask what rocker setup you plan on using before suggesting any restrictors.
Roller tips with needle bearing fulcrum? Yeah, squeeze 'em down. Bushed rockers with tight clearances? Not so much.

I feel the talk of "how" to restrict often overlooks the "why".

[happystang]

Why do you feel you need to restrict the oil to the rockers? I would first ask what rocker setup you plan on using before suggesting any restrictors.
Roller tips with needle bearing fulcrum? Yeah, squeeze 'em down. Bushed rockers with tight clearances? Not so much.

I feel the talk of "how" to restrict often overlooks the "why".

Jim,

I'll be using factory adjustable rocker arms and shafts. Almost everywhere I've read recommends using restrictors in the oiling holes, regardless of what style rocker arm I use.

[blykins]

I do not restrict with factory or bushed rockers.

[My427stang]

I don't restrict either with bushed rockers and in my own, I didn't restrict with Ersons

FYI - Restricting is to allow more oil pressure and to somewhere else, usually the crank, not to keep the heads dry.  Not saying you said this, but it sometimes the reason gets a little diluted

If the oil pan and returns are not adequate, that needs to be fixed.  After that, if the crank really needs the volume to keep a wedge at the bearing, then restrict. IMHO, only a high RPM engine really needs that, but defining high is different for everyone.

[Barry_R]

I always restrict bearing type rockers such as T&D or Ersons.  On OEM rockers or bushing type rockers I make the decision based on what I see during pre-oiling spinning the pump with a drill.  If we get an engine that just puts a ton of oil up top I will restrict it. 

Sometimes I will restrict an engine on the dyno if it is behaving perfectly but has hot idle oil pressure low enough to cause a customer to be concerned even though it's perfectly fine.  Customers like to see a number on the gauge, and restrictors will often add 5psi to the hot idle value.

[jayb]

I always restrict oil to the top end, regardless of the rockers or heads.  For sure a needle bearing rocker needs it, and perhaps a normal rocker doesn't, but based on what I've observed through my clear valve covers over the years, there isn't a lack of oil with the restrictors in place regardless of the rocker type.  Currently with old shafts and the older Comp Cams rocker arms on the 428 in my Mustang, I'm running 0.070" restrictors in the stock CJ heads.  Clearance between the shafts and the rockers is around 0.003".  There is a nice stream of oil running down the retainers at idle, and at 2000 RPM the oil splash pretty much obscures the view of the rocker arms.  No way I'm not getting enough oil to the top end.  I also run a stock 390 oil pan, stock windage tray, Precision Oil Pumps high volume pump, and six quarts of oil.  And I don't "pump the pan dry" as so many people seem to fear with a high volume pump, even after extended high RPM runs. 

I think probably a lot of combinations of oil pumps, restrictors (or lack of restrictors), pans, windage trays, etc. will work fine.  The setup described above has always worked well for me - Jay

[blykins]

I think probably a lot of combinations of oil pumps, restrictors (or lack of restrictors), pans, windage trays, etc. will work fine.  The setup described above has always worked well for me - Jay

And that's the main point.  There's lots of ways to skin a cat.

I've had good results with no restrictors, factory rockers, factory style pan with no tray, and a standard volume oil pump.  In one case, with your clear valve covers, I saw no flooding of oil (oil level under heads was barely covering the spring locators), but the top end was getting a sufficient amount of oil.  Oil pressure went up throughout the pull, up to 6000 rpm, peaking at about 68 psi. 

[fekbmax]

In the event the oil passage does need restrictions,  I have always used split roll pins, just tap them in place in the head at the stand location and wala, good to go.

[Joe-JDC]

For a street engine, you need all the oil to cool the valve springs and valve stems that is available.  I have lost a cylinder because of valve spring getting too hot from lack of adequate oiling in a CJ and the spring breaking while on a long trip.  Not fun.  Spring was dry, rocker arm was nearly dry.   Joe-JDC

[jayb]

My opinion is that using extra oil to cool the valve springs is not necessary, even with very heavy springs, unless you are running at sustained high RPM speeds.  I've run tests on how much the valve springs heat up on the dyno, and it is negligible at  low engine speeds, and not even that much at the end of a dyno pull.  I had to run the engine at 5000 RPM for over 60 seconds before I even saw a 100 degree temperature rise on the springs, over the oil temperature.  In your case Joe, if the rocker and spring were dry, probably heat from friction caused the failure.  Even with restrictors in the oil feed to the heads, none of the rockers or springs should be completely dry.

FYI, the engine I ran the my tests on used a valve cover with a hole cut in the front side, so that I could use an IR temperature gun to measure the temperature of the #5 exhaust valve spring.  The engine had 0.070" oil restrictors, which I always use, and the springs were 240 on the seat and 600 over the nose.  I can see why the NASCAR guys need to spray oil to cool the springs, because they run at extreme RPM for hours at a time.  But for the rest of us, all that extra oil is just not necessary.