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Oil restrictor for 50FL bottom end?

Bottom End (crankcases and crankshaft)
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Oil restrictor for 50FL bottom end?


Post by daddy-o » Tue Jul 03, 2007 6:02 am

I'm about to tear down a 50FL. I was going to rebuild it using an S+S aluminum oil pump and S+S 4:1 oil pump drive gears. The pump claims to put out 33% more oil than the stock cast iron pump, and with the 4:1 drive gears (stock are 5:1) there should be more than enough oil circulating through this motor. I was told that I should put in a restrictor to the feed to the bottom end, reason: too much oil to the rod rollers can cause skating etc. Ever heard of installing a restrictor? You thought please.

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Post by Jack_Hester » Tue Jul 03, 2007 1:35 pm

First. Please register. You will get far more responses when you do. Members respond better to other members.

Now to the pump. Save your money and don't buy any aftermarket pump. Replace your original, only if it is damaged beyond repair. Your OEM pump provides more oil than the engine will ever need. And, the scavenger can remove more than the feed can provide. This eliminates the need for restrictors. Your engine needs a steady flow of oil to lubricate it's components. As there is no way to measure flow, pressure is the means to measure this. Your OEM pump has a factory recommended setting on the pressure regulator. If yours is an original for your engine, you have an adjustment on the regulator, just under the cap. Set it to the book. Then, when the engine is hot, you can adjust this to a 5 to 10 psi setting, observed at a fast idle. You will have to attach a gauge to the port where the pressure switch is mounted. Don't adjust while engine is running. You will have an oily mess coming out around the adjuster. Run, check, stop, adjust. Run, check, stop, adjust.


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Post by fourthgear » Tue Jul 03, 2007 1:46 pm

I have the S&S oil pump on my 48 model( going to put one on the 65 too ) and have had the oiling system changed to the late type Shovel oiling system ( for better oiling to the Hyd. lifters and upper end and I am running solids ), which I believe your instructions with the S&S pump give you ( you can go to S&S web sight to view them ). I have restrictors in the passages to the upper end , in the case where the cyl. and case meet( don't know if they are factory or some one added them ) . I was told that in Knucks and early Pans you could ( thats could ) feed too much oil to the upper end, I was told to leave them there . I'm not saying to do that , a lot of Pans are running late mod. & S&S pumps with no problems and not restricting any thing .Some say the OEM pumps are adequate and that may be true to some extent and if every thing is working to spec's ,the are, but why not bring the oiling system into the twenty first century , its nice to see oil pressure period. The more flow you have will of course have a higher oil pressure signature , more flow means better lubrication and a cooler running motor, the bearing skating is much debated , here and else where , there are a lot of factors that have to happen for the skating to occur, IMO. Some just see any thing not OEM , is bad for the motor .You will no doubt hear for others here , I hope !

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Post by Cotten » Tue Jul 03, 2007 3:11 pm

Its late overhead oiler Pans that are prone to flood, not early models.



Thank you all for your info


Post by daddy-o » Tue Jul 03, 2007 3:37 pm

thanks again!

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