PRW AL Rocker Oiling Mod

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nm9stheham

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Here is another thread for the FWIW series. We primed our new 340 oiling system, and the oil just slowly flows out of the existing PRW AL rocker side clearance and oil hole to the adjuster/p-rod. No evidence of any spray that will reliably get oil over onto the valve tip, the spring, or the roller and its axle. Our testing has been static, with the cam oil holes aligned for each side, so even with continuous oil flow, there is no oil to the valve tops. DartVader reported oil dryness like this, and eventually pulled his AL PRW's, so we were concerned about this.

So we drilled another oil hole out of the rocker body up near the top of the valve relief area below the roller arm. We used a 3/32" bit (.094") and that is the same size as the oil hole to the adjuster side. I did a ton of rocker oil system measurements so see how the new hole might adversely effect the flow to the existing oil hole and to the rockers' roller bearings. The overall flow out of the rocker will only increase 15% with the 2nd oil hole, so that looks good. If we need more oil, we now know where the restrictions are in the system, and have some idea what to do where. (I can put out that info if there is interest.)

BTW, the new hole matches the size of the hole over by the adjuster, and is at the same height. It is in thicker rocker body material, and the material stress level over in that area should be significantly lower than around the adjuster hole. So, I am not terribly concerned over any weakening of that area. (Famous last words, right? LOL)

Here are some pix:
1) The jig is a 7/8" maple dowel from the hardware store, smoothed and oiled to keep the wood fibers under control. This is a very snug, stable holder for the rockers. We did this because we wanted to put the new hole in an area that is radiused and this allowed us to change the drill angle as we started each hole. We started the hole at a slight off-angle into the radiused area and then could turn the rocker to drill at the final angle we wanted. That desired angle is just off tangential to the roller.
2) This shot is looking down at the hole, to show the hole angle is pointed at the bottom of the roller and top of the valve tip. It also shows the location of the hole, just where the spring relief starts to decrease in size above the spring.
3) This is the flow to the springs now; this area was dry before. The oil looks like it is even wicking up into the roller and its axle, which is good. This is with constant oiling while engine priming via a drill at 600 rpm, 10W30 at room temp, and 65 psi out of the block pressure sensor port. The oiling to the adjuster is similar. The flow will be less when running due to restrictions. We'll have some valve covers on with observation ports cut in the top to check this while running. Side clearance on the rockers is .016-.017" total between each pedestal pair (i.e., that is the total side clearance per rocker pair plus shims).
 

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Good work, most people just bolt aftermarket rockers on, without a clue as to what is now happening with oil to the spring and valve tips..
 
Nice! Really nice. With the prior report, the quick check was worth it. A few minutes of thought and your fixin stuff. Would you have pictures of the rocker at different angles. (Or various amounts of depressing the spring downwards?)

I thought (AKA- daydreamed) about making plexiglass extra wide valve covers just for fun. Never got there. But that would be cool. Really see what's happening under there.
 
Would you have pictures of the rocker at different angles. (Or various amounts of depressing the spring downwards?)
Well, I am not sure if you want pix of the springs depressed with or without oil. I have no pix with oil, but have attached some without oil. I was checking the tip wipe when we first got these many weeks ago, and used some test springs. Pix order is 0 lift, medium lift and max lift. I think the max lift pix is at about .550"; we are only going to .500". The wipe movement looked pretty good to me.

I will try to retake some on the re-assembled head with real springs while it is on the stand in the next day or so. Sorry these pix angles and ranges are not consistent; makes it hard to get a consistent view of the tip contact.
 

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