All Small Six Restrict Oil Feed to Head on high RPM 250?

[mad_science]

My previous 250 developed spontaneous oil starvation issues at high RPM that went away after letting the motor sit for ~30sec.

With a new oil pump and tight clearances on new bearings I think it might've been pumping all the oil into the head/valve cover.

It's a common mod to FE engines that see racing and I've heard it suggested here.

Building a new motor so I've got the chance to drill/tap/otherwise restrict flow. Blocking oil flow to something just feels kinda unintuitive, so I'm just a little worried about overshooting on the restriction and killing the valvetrain.

Has anyone here done this successfully and if so how'd you do it?

 

[wsa111]

What kind of rocker arms are you using?

 

[mad_science]

Stock non adjustable 1.5:1, non-oiling lifters/pushrods

 

[drag-200stang]

Even if you put a high volume pump in, it would suck up no more oil than the small pump if oil pressure is the same, I do not know the oil path to the FE V8 rockers, but what i do know is that on the SBI Six, the oil goes from the main oil galley to #7 main bearing over a slot in the bearing up a drilled passage to the rear cam bearing then around a grove in the cam journal to a drilled passage that goes up to the block deck, then over a notch in the head to the head bolt hole, up around the head bolt to a drilled passage to the rear rocker stand, and up around the stand bolt to hollow shaft. Lucky any oil gets there at all.
If you want to experiment, I would tap the head at the stand oil hole for a restrictor that way you could test easily. There Is thoughts that too much restriction at the head could cause the oil to leak at the head gasket, but I do not see it.
You do not want to starve the rockers of oil and you need oil to cool the spring and the valves.

 

[bubba22349]

My previous 250 developed spontaneous oil starvation issues at high RPM that went away after letting the motor sit for ~30sec.

With a new oil pump and tight clearances on new bearings I think it might've been pumping all the oil into the head/valve cover.

It's a common mod to FE engines that see racing and I've heard it suggested here.

Building a new motor so I've got the chance to drill/tap/otherwise restrict flow. Blocking oil flow to something just feels kinda unintuitive, so I'm just a little worried about overshooting on the restriction and killing the valvetrain.

Has anyone here done this successfully and if so how'd you do it?

The Oiling System on these Ford Small Sixes is quite good for what it was designed to do! If you think it was pumping all the oil up to the top end you have a couple things you can try. I don't think the link to the post on the FE example is an Apple's to Apple's comparison to your 250 though they were the same designer's that worked on both of those engines. But he was using Roller Rocker Arm's and those could get by with a little less top end oil, the stock Rockers would need more oil then a Roller set up.

I think you talked about working on the Oil Returns on the Head and Lifter Area and that's a very good Idea the tops of the holes could be funneled out so that the Oil starts to Drain into the hole faster and you could also grind some Channels to get the oil to go to the returns faster same for work on the top of the head. On my Race FE's this was part of my Basic Block Prep doing all the Oil Returns along with opening up the Oil Passages to the Oil Filter Adapter (also used the best larger passage Oil Filter Adapter) and opened up were the Oil Pump Mounting was. This worked on the FE Top Oiler Blocks and also the 427 Side Oilers which were the best, since they oiled the Mains and Rods First.

I think what you really need even more is a lager Oil Pan Capacity of like 2 or more Quarts that would do your 250 Six wonders running at High RPM. This was one of the first things I did on my old Drag Cars was to Drop the Front Sump about 2 1/2 inches. If you are short on ground clearance on your car than you could just add some side boxes or Bump Outs for the extra capacity something like this. https://www.summitracing.com/parts/mor-20535
On my 427 SOHC I had a really nice Custom built Oil Pan with two sumps each with its own Oil Pump Pick Up and 10 Trap doors 2 Side Bump Outs, it also had a built in Windage Tray and a Crank Scraper too. Best of luck

 

[powerband]

I would appreciate knowing the RPM' range you are operating the250 and how it is built to sustain that RPM operation.

thanks


>

... $ .02 - if the oil is pumping up to the head uncontrollably, the oil pressure sending sensor port could be used with a pressure relief valve to divert/return the excess flow/pressure ... ?


.

 

[THE FRENCHTOWN FLYER]

My previous 250 developed spontaneous oil starvation issues at high RPM that went away after letting the motor sit for ~30sec.

With a new oil pump and tight clearances on new bearings I think it might've been pumping all the oil into the head/valve cover.

It's a common mod to FE engines that see racing and I've heard it suggested here.

Building a new motor so I've got the chance to drill/tap/otherwise restrict flow. Blocking oil flow to something just feels kinda unintuitive, so I'm just a little worried about overshooting on the restriction and killing the valvetrain.

Has anyone here done this successfully and if so how'd you do it?

Do it.

I had exactly the same issue when I installed a crossflow head on my 300 (with shaft mounted rocker arms). Not the same engine but the same issue. Originally my rocker shaft was supplied with oil by two 1/8" holes. I restricted these down to .060" and it could probably even be smaller but on-track videos show the oil pressure holding.

 

[drag-200stang]

Do it.

I had exactly the same issue when I installed a crossflow head on my 300 (with shaft mounted rocker arms). Not the same engine but the same issue. Originally my rocker shaft was supplied with oil by two 1/8" holes. I restricted these down to .060" and it could probably even be smaller but on-track videos show the oil pressure holding.

FTF, where did the oil come from for the cross flow, not like what I posted in post #4 I assume? I had the same problem when I dry decked my block and ran a1/8'' line off the sending oil port. Had to block most of the line to not flood valve cover. He is also running endurance races.
I am not saying do not do it but be careful. I would concentrate on drain back, competing blow by., oil control, drop the pan, doors, scraper, windage tray, baffles, and more volume of oil in a deeper sump.

 

[THE FRENCHTOWN FLYER]

FTF, where did the oil come from for the cross flow, not like what I posted in post #4 I assume? I had the same problem when I dry decked my block and ran a1/8'' line off the sending oil port. Had to block most of the line to not flood valve cover. He is also running endurance races.

I read it. Wow, that's a really circuitous route for the oil. Mine was straightforward. I installed 2 tubes down into the lifter galley and these connect to passages in the rocker stands. I restricted the oil at the head face.

 

[drag-200stang]

I would appreciate knowing the RPM' range you are operating the250 and how it is built to sustain that RPM operation.

thanks


>

... $ .02 - if the oil is pumping up to the head uncontrollably, the oil pressure sending sensor port could be used with a pressure relief valve to divert/return the excess flow/pressure ... ?
Powerband, that could starve oil to the #7 main bearing, that is where the rocker shaft first starts to get its oil.

.

 

[drag-200stang]

Oh, I forgot to say because the main oil galley is half in the lifter bores that if bores are worn and the lifters are on the small size that can add to more oil having to drain back by the three drain back holes in the lifter galley.

 

[mad_science]

would appreciate knowing the RPM' range you are operating the250 and how it is built to sustain that RPM operation

Lives 85% of its life between 3000 and 5000 rpm, with shots up to 5500 at certain places, assuming all is well. Would love to go to 6k, but building for that is more work than I'm willing to put into this thing.


We have a massive radiator and massive oil cooler. Doing new 255 pistons, ARP rod bolts, rods with no oil squirter hole, new rod and main bearings.