Add oil restrictors with heads on?

[unclewill]

BBM aluminum heads - anyone use restrictors that don't require tapping?  I'd like to avoid pulling the heads...

[Yellow Truck]

I got the restrictors from Barry R, they just dropped in under the rocker stands. I understand Holley jets work as well - just drop in.

[unclewill]

Thanks!

[Drew Pojedinec]

Holley jets will fit with BBM heads?  for some reason I thought the feed hole was smaller.

[fekbmax]

Split roll pins work great.

[unclewill]

The issue is the rocker stand thread insert blocking part of the hole, so grinding is required?  I don't have the heads in front of me at the moment but I have read that the heads should be off before grinding on the insert to avoid contamination of the oil passage.  I can use the old shopvac and magnet trick but if I have to cut threads in the aluminum the risk goes up.
I REALLY REALLY don't want to pull the heads when the repair is right on top.

[Posi67]

You can put pretty much anything in that hole to restrict flow. Trouble is you never know whether it's too much or too little. I like a lot of oil up top to cool the springs but then I only go 1/4 mile at a time. I wouldn't drill or tap but anything you drop into that hole can't go anywhere.   

[scott foxwell]

Some guys will say it's better to put restrictors in the deck instead of the head. This helps take some pressure off the head gasket and reduce leakage. I did mine in the heads (iron) but I drilled and tapped so I could have better control of the amount of restriction.

[blykins]

A BBM head won't take a Holley jet and it will be hard to get anything down in there if the insert hasn't been relieved. 

I like to restrict the head so that if I or the customer has a change of plan, it can be fixed easily without pulling the heads off the engine. 

I've done a little of everything though....if it's an FE that oils through the pushrods, I've plugged the feed in the deck and I have also clocked cam bearings so that the heads don't get oil. 

[unclewill]

Thanks Brent, that's what I thought.  I'm going to pop off the rocker stands to see what can be done.  Was hoping someone may have done this before and had an easy fix to share.  I'll post info if I come up with a clever way to deal with it....

[XR7]

I made some "drop in" restrictors for Edelbrock heads when I ran them years ago. I believe the BBM heads have a 3/16" oil passage just like Edelbrock. What I did was use some 3/16 brake tubing, or maybe it was nitrous tubing, and cut off a piece maybe 1 1/8" or so long with a tubing cutter. This made the inside hole smaller than the actual tubing ID, I enlarged it with an awl and dropped them in under the rocker stand. You don't want it too long but anything shorter the what it takes to touch the bottom and not stand proud enough to get in the way of the rocker stand. I think one set I made for someone else I had to reduce the outer diameter a little so it would go down in the hole, maybe the tubing was a little different exact size on the OD. I could pull them back out with a magnet.

You never mentioned what size restrictor you will be running, or more importantly... what rockers you will use. I have found that the needle bearing rockers need a smaller hole as they will bleed more oil off the shaft (something between .053 and .060), where a normal bushing rocker on a good fitting stock shaft can use a bigger hole as they don't bleed as much (like .080 to .100). I just used number drills to "gauge" the hole diameter. I would spin the oil pump with a drill and check out your oil flow so you can see what is going on there.

[Dumpling]

Why exactly are restrictors needed.  For what applications?

[unclewill]

High rpms cause too much oil to pump into the heads so you restrict the oil feed passage.

[unclewill]

Thanks XR7!  I have various solutions to play with now.
I was planning to go about .070 or so but we'll see what fits.

[Dumpling]

Couldn't you just run an external drain line off the back of the valve cover?  Don't have to mess with the rockers, could put a valve on the line to open it at different flow rates or turn it off entirely.