Oil restrictors or not??

[dirtplay18]

Helping a buddy with his sbc engine assemble and was wondering weather or not to put oil restrictors in the block. Always ran them with my roller cam, but he's running a flat tappet solid lift. I have seen guys run them with flat tappet but just curious what opinions are out there.

[dereksehi]

If you are running roller rockers I would install them for sure I usually go bigger than most I install the flat tappet ones from speedway and they have an .080 hole in each that keeps a little extra oil up top to help cool the springs. I also install these restrictors in engines with roller tip rockers and havent had any issues.

[CNC BLOCKS]

If they are a side orifice lifter don't run restrictors, I have never used any restrictors in any of my circle track builds and no issues so far.

[Confused?]

I have run motors with and without them. Performance wise, no difference. But, if you choose not to use them, make double sure the drain passages are opened up enough to let the oil back down to the pan.

[CNC BLOCKS]

I run a lot of HYD. .450 lift rule cams and any of those engines move a lot more oil through the push rods then any solid flat tappet engine that I have seen. So far no oil problems that I have seen.

Solid flat tappets seem to be regulated not to move much oil, restricting oil to the valve springs will cost you in the end.

[dereksehi]

I've restricted basically every circle track engine with the .080 restrictors and have pulled a valve cover off when running there is an awful lot of oil up there even with these restrictors must be enough to cool the springs because I've never had a pressure loss from springs that have run a couple seasons.

[let-r-eat]

I've restricted basically every circle track engine with the .080 restrictors and have pulled a valve cover off when running there is an awful lot of oil up there even with these restrictors must be enough to cool the springs because I've never had a pressure loss from springs that have run a couple seasons.

A .060 or .080 orifice moves a ton of oil when the oil warms up. Almost to the point the restrictors don't really do a whole lot. What they will do is starve things when the oil is cold with heavy oils. I open up the valley and never use them, personally.

[dereksehi]

Cold should not be an issue a race engine needs to be at least 170 before they hit the track or you will have problems if you run thick oil

[CNC BLOCKS]

My solid flat tappet engine I use .875 tool steel lifters from Precision or Diamond which are a side orifice which I have to modify the lifter on the left bank to supply more oil.

Solid Lifters I have used in the past never seemed to over oil the top end always a lot less oil then HYD flat tappet engine.

Might be different manufacture then I was using.

[dirtplay18]

The valley drain holes have been opened up, and they are full roller rockers. Considering the fact that restrictors is another thing he will have to go pick up, I will probably just opt to not run them for now. Thx for the input fellas.

[ford396]

CNC: What do you mean by a side orifice lifter. What do you do to modify and why? I am always trying to learn. Thank you

Bob

[CNC BLOCKS]

CNC: What do you mean by a side orifice lifter. What do you do to modify and why? I am always trying to learn. Thank you

Bob

Bob

I use a lot of the tool steel .875 lifters . The oil feed hole is not in the oil band but is on the side of the lifter about an 1/8 inch above the oil band which restricts the oil to the rockers.

I do cut a small groove from the oil band too the oil hole just on the lifters on the left side of the engine to create more flow to cool the springs unless the valve covers have are set up with sprayers.