Garden block test mule

[WConley]

I was wondering about those cap oil feeds myself.  You should know that at high rpm and load, the oil film pressure can easily exceed 5,000 psi at the bottom area of the cap!



Unless your oil pump is pushing over 5,000 psi, you're creating an oil drain there.  Yes, it will flow backwards out those braided hoses, reducing your effective bearing area.

Additional oil feeds at the side or top of the bearing do not see anywhere near those pressures, so they can be of some use.  I imagine you won't hurt anything with your setup, but you'll never see that type of oil feed on a maximum effort race engine.

[fekbmax]

Holly hell, 5000 psi ? Of oil pressure created at the lower half of the main ? And even 800 - 900 psi at the lowest pressure point. Good thing there's pressure valves in them there pumps.  Dam, I Can't believe all my fittings, lines, and oil pump haven't completely exploded in the past with that much back pressure. Idk, I have been doing this modification to my 7000rpm race engines since the 90's with good success. Very good crank and bearing life and wear characteristics. I think I'll give it another go.

[Bolted to Floor]

Pretty impressive fab skills you got there for adapting the belt drive. I really like the rubber bands your using to hold the valves in place. Don't know that I would have thought of that.

[WConley]

Holly hell, 5000 psi ? Of oil pressure created at the lower half of the main ? Dam, I Can't believe all my fittings, lines, and oil pump haven't completely exploded in the past with that much back pressure. Idk, I have been doing this modification to my 7000rpm race engines since the 90's with good success. Very good crank and bearing life and wear characteristics. I think I'll give it another go.

The pressure in your braided lines is only able to reach the max pressure that your oil pump bypass allows in the rest of the system.  You're just pumping a reasonably small amount of main bearing oil backwards into the point where the braided side-oiling line is tapped into the oil gallery.

If you're bored one day, just disconnect that side-oiling braided line from the gallery and plug the end.  Better yet, put a pressure gauge on it.  I think you'll be very surprised when it does indeed blow up.



 

[fekbmax]

Interesting, I'll make that test at some point. I have always ran an in line guage just before the oil log on the Sid of the block and it has always pretty much mirrored my main oil guage. I'll for sure make the test you suggest though once I get to that point and let it be known what i Find. For now though I'm not going to abandon it because I have been running this type set up for over 20 years with no issues at all with it. I know it's been done before on everything from 4 cylinder tuner cars to as far back as blown slingshots back in the 60's. I for sure am not the first to do something like this. PSE even made a type of external oiler kit at one point although I have only seen pieces and never seen one installed.
Also I'm a bit confused because acording to your graph even at 90* crank angle there's still roughly 800 - 900 psi of load which is well above the pressure relief in the pump as well so acording to this wouldn't that effectively cause the oil to be forced back out the main or top oil galley ? Wouldn't this effectively run the bearing dry ?

[WConley]

I'm not ragging on what you are doing Keith.  It's working for you so don't fix it if it ain't broke!  I just wanted to point out to other folks that you need to be aware of this hydrodynamic oil film pressure when playing with the oil feeds.

The key for adding additional oil feeds is the location on the bearing journal.  All of those applications you mention put the oil in at the split line or higher.  This little chart of oil film pressure tells the story:



The pressure rapidly builds on the bottom half of the bearing (cap-side) to thousands of psi.  Up top there's very little of that hydrodynamic pressure, so more oil can be introduced easily.  The biggest benefit of additional oil is cooling under high load.  The flow physically carries away the heat.

[fekbmax]

Believe me, I apresheate any and all information shared, I'm greatful. I'm just a low buck back yard builder lost in the distant past with little knolage but lots of experience if that makes since. If I'm wasting my time with something  it.would be a good thing to know, although I have went to far to turn back on this build so far.
Also I'm a bit confused because acording to your graph even at 90* crank angle there's still roughly 700psi of load which is well above the pressure relief in the pump as well so acording to this wouldn't that effectively cause the oil to be forced back out the main or top oil galley ? Wouldn't this effectively run the bearing dry ?

[WConley]

Hi Keith -

That graph I posted above is for a pressure sensor at the bottom of the cap as the crank rolls around through all four strokes.  If you take the pressure near the top of the bearing, those pressures will be very small.  That's why the typical factory oil feed is up there...

Notice the spike just after 360 degrees - That's the firing stroke starting to build combustion pressure.

[fekbmax]

Finally all done with port matching the adapter to the Cleveland 4v (massaged ports) Tunnel FAB and Funnel Web intakes i have. The ports turned out nicely on the intake side.



Also got the head side all done and matched up nicely to the Kuntz CNC intake ports. I'm concerned a bit about how much pinch there is after working around the pushrod passages. Especially #2,#3,#6,#7.  I'm wondering how much or how badly this is going to effect things.

[jayb]

The pinch will definitely affect your airflow.  The only way around that is to run offset rockers, and move the pushrod holes.  I know of at least one guy who plugged the pushrod holes and redrilled them outboard when he switched to offset rockers.  I also think you could fill the holes with an epoxy and re-bore them.  FYI I have a whole bunch of programs to move the pushrod holes outboard from the port, exhausts as much as 0.100" and intakes as much as 0.250".  If you decide to go that route, Keith, let me know, I'd be happy to rebore the pushrod holes for you - Jay

[fekbmax]

I have for sure been thinking hard about just that. I will for sure do it once it goes over onto the pond block and I go to the TnD race setup. Problem is I'm a good ways out from even getting a good start on that project. I have done some looking although not alot but does anyone make offset rockers for the regular single shaft type system? If so I'd like to get the info because I'd like to be able to make the mods to the adapter now if offset shaft rockers are available. Should offset lifters be used as well if I try and take as much pinch out as possible ?

[jayb]

I guess I'm not sure if anyone makes offset rockers for a normal FE shaft system; maybe Dove or Harlan Sharp?  I've always just gone with the T&Ds.  On the lifters, offsets of 0.188" seem fairly common, and that makes the pushrod angle less if you run one of the 0.250" offset rockers on the intake.  I run offset lifters in my high riser engine.  Not sure what that does, if anything, to longevity of the lifters, but it does give a little more room for the port.

[fekbmax]

Jay, (and others)
I may be crazy but ::
I think I have solved my offset rocker issue. I been messing around this morning and experimenting some. I was really wanting to use my erson rocker shaft assembly because I have made alot of mods to it so it will have 7 mounting points, (2 end head bolts and the center head bolt). What I came up with is some jessel rockers. A  roundy round engine builder friend of mine litteraly has boxes full of that stuff. I found some 178 ratio rockers that where straight,  .200 offset both left and right hand, .300 offset both left and right and some as much as .500 offer left and right. I'm sure the .500 is to much but the .200 and .300 are very close to your #'s. Ofcourse the shafts are smaller than the erson shaft but I figure I can press the bearings out and bush the rockers to the erson shaft size then re drill the oil holes for the roller and pushrod ends. Use the adjusters from my erson' s and be good to go. I fig its worth a shot, besides I like to experiment . unless this sounds like a terrble idea I think this is the way to go. He also has a bunch of offset solid roller lifters as well. I didn't sort through them much yet as I probably would just get new ones instead. If this doesn't sound to hacky then I'd be interested in having you re position the pushrod passages once I can mock things up and see just how far I need to go and if both the intake and exhaust need done. How much is the 178 verse's the 176 ratio gonna effect me. ? I pressed  the bearings out and stuck a make shift bushing In one of the jessels and slid it on the shaft against the erson. The tips, and pushrod end line up almost perfectly looking at it with a forgiving eye. Ofcourse more checking and measuring needs to be done but it was a quicky test as like I said I was supose to be working lol. Thanks for any input.

Also Jay, did you say once that you had elongated sleeves for the pushrod tubes ? If so would they fit in the re drilled passages so there would be something there to back up the epoxy ?

[jayb]

Sounds like good old hot rodding to me, Keith, I'd go for it.  Besides, Jesel is really good stuff.  On the pushrod holes, they are sized so that a 3/4" diameter thinwall aluminum tube can be squashed flat and pushed in there.  I don't sell those tubes, but they would be easy enough to make up.  If I remachined the holes, you could make up the tubes and put them in place, then fill the gap between the tubes and the port with epoxy, and I think that would work.

[fekbmax]

Got ya on the aluminum tube, wasn't sure if you had some already elongated or not. I can handle that no prob. I'd probably feel more comfortable letting you re drill the pushrod holes though. I know I could hack them up and make it work but feel like if I let you do them it would be much cleaner therefore much easier to make the repairs. Could you possibly e mail me with the info as to $ for doing the intake side and the best way and where to send it to ? Thanks for the help.