I touched on this in another thread, so thought I would start a new one before taking that one off on a tangent. Before I knew any better, I epoxied screens into the openings in the lifter valley of my Gen VI block. I'm running the Melling 10778c oil pump with a stock pickup and 8 quart pan. This was all set up before I knew any better - I probably would not have set it up this way if I knew it could cause issues with oil starvation at high RPM's. I'm looking to hear from any others who have actually had issues with oil drainback and starvation with screens in the lifter valley. FWIW, planning to run a 10W40 or 15W40 synthetic oil. At this point for me, it's pretty much water under the bridge. Engine is buttoned up and close to being ready to run on the dyno. I am going to watch closely for signs of problems when we run it, but not sure if this type of problem will manifest itself with the quick runs that are typical on a dyno.

This is mostly a pleasure boat that will live most of it's life between 3K and 4K. No poker runs in my future, but an occasional short 5200 RPM burst is not out of the question.

Looking for input especially from experienced racers and engine builders who may have seen problems with this.

OK, let me phrase it this way - anyone running the screens in a marine engine without problems?

I am turning mine 6000 RPM and don't see any problems.

Thanks for the reply. Eight quart pan and HV pump, or something bigger like a 10? I'll probably be fine, just need to keep an eye on it early on and watch the oil level.

"Engine is buttoned up and close to being ready to run on the dyno". Your only looking at 2-3 hrs at the most to pull intake remove screens and button back up. Then you will have no worrys the rest of the summer in the back of your mind. For the record, I don not run screens either.

I have the valley screens in mine and not had a problem. I also have a 12 qt.oil pan so that could be the reason. The next time I have the manifold off I will be removing the screens.

http://www.performanceboats.com/dyno...y-screens.html


http://www.performanceboats.com/dyno...ey-screen.html

ICD, yep, I saw both of those threads - after the fact, of course!

I also saw the video on the other thread, and that's what got my attention. However, I can't see that much oil flowing out of the heads into the lifter valley, at least not at that rate of flow. Ever looked at the drainback holes on a set of AFR heads? They are about 1/2" in diameter, and there are two in the corners of each head. Only other place for oil to drain into the lifter valley is the pushrod holes. I would think this would be a bigger restriction to drainback to the pan than the lifter valley.

What is the best way to remove the screens if they are glued in with JB Weld? This is going to be fun, I have a feeling. Fawk!!

budman,the restriction in the heads plus additional restriction from screene in lifter valley is a bad thing imo.their is a reason we buy large capacity oil pans!i once had an engine come my way that spun some bearings.it had a 6 qt pan with valley screene installed by the builder who blamed it on the oil pump.no oil pump in the world can supply oil if the pickup is in air instead of oil.when we select what parts we use in our marine engines the most important parts are the oiling system.an engine that makes 1000 hp is useless in a offshore application if it cant maintain oil pressure after 45 seconds of wot.im not sure how you plan to run your new engine once it gets installed in your boat but if you built it to run hard,loose the screen.