Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties oil filter

oil filter

Post Thu Jan 23, 2003 9:12 pm

Posts: 60
Location: Indiana

Hey guys I seen this the other day and was thinking about putting something like this on my "45"

Have any of you used anything like this?
I'm open to all comments.


Post Thu Jan 23, 2003 10:18 pm

Posts: 44
Location: Arizona
Ryan,..Most of the better engine builders agree that it takes a magnet with about 400 psi pull to hold the small particles in a running engine. The metal you see attached to the drain plug in your auto got there when the motor was turned off, and return to the oil supply when you start up. I believe magnets are the way to go, but it takes the rare earth type to do much good..GW

Post Fri Jan 24, 2003 1:22 am

Posts: 44
Location: Arizona
I suppose ideally, the feed oil should go tank, pump, filter, bottom end. and it's not just the magnetic particles that can cause grief, how about all the welding slag left over from manufacture. I have a Y2K 1200-S with 4 miles on it. Kept hearing about the rubber rumors and wanted a classic? There was over an ounce of metal and slag in the tank! Understandable, but what is junk doing in the tank of a homebuilt anyway. My wife is an RN and says she has seen open heart work with less care than I give an oil change...GW

Post Fri Jan 24, 2003 4:51 am
I sell a Tank Oil drain plug for 45's with a built in magnet.

Post Fri Jan 24, 2003 11:59 am

Posts: 67
Location: Australia
magnetic drain plug (where the crap settles anyway)clean the plug & change the oil real regular,


Post Fri Jan 24, 2003 4:48 pm

Posts: 44
Location: Arizona
Got me thinking about the pressure drop across a large fitting auto type filter. I know it can be a problem when dirty for high volume high RPM systems, but isn't HD low pressure low volume? The gear type oil pumps can pull as well as press, and as long as gravity keeps the line full to the filter, you wouldn't have a problem. The return gears gulp a lot of air and with the increased resistance from a filter it would contribute to airation. Not much of a problem for rollers, but not good for performance either. A real no no in low pressure Brit systems with insert bearings. All I'm trying to say is, do what you can to have clean oil, figure out wich system would be best for you and use large ID fittings. I'm one of them that uses pinion shaft oil passage resrictors and believe that when it comes To HD systems, Quality is better tan Quantity..GW

Post Fri Jan 24, 2003 5:11 pm

Posts: 198
Location: North Branch,Mn USA
I'd forget that thing and just change oil, a screen and a magnet,any peices big enough to be caught by a screen wouldnt get in between your rollers and race's any way,it's the small particles, I doubt that magnet would do much. Boy,J&P is that a high buck outfit or what?!

Post Fri Jan 24, 2003 7:04 pm

Posts: 171
Location: Wa.
Geez, been following this topic close as my servi has not only an auto sytle filter but a small cooling radiator also. I had to reroute some lines last summer for a cleaner look and came across the filter between the tank and the pump. Disconnected lines to see what the volume would be with or without the filter. Dribbled either way like an old man takin a piss with the clap, AND a bladder infection. Talked to a HD buddy who said that was the norm for flathead harleys and 50 wt. As I was putting it back together I thought better to have the oil backed up in the motor than in the tank so I routed the filter thru the return line. Frankies talk about low pressure 45 pump vs hi pressure sporty also was reassuring. I've always liked the idea of upgrading or modernizin older stuff if it improves performance and reliability, but this one has me a little anxious cuz if I'm wrong it's like Panic said "BANG" there goes my motor. Think I'll leave it in but would an oil gauge tee'd off the pressure switch help give me a warning if things are going south on me. Like what is the normal oil pressure exactly, and would it increase if the filter plugged up the way I have it routed now?? Or, where would the best location be for an oil gauge?? And other than allowing large crap to settle into the tank before being filtered, unlike into the oil pan of a car where the crank stirs it up anyway, isn't a filter a filter no matter where you put it??

Post Sun Jan 26, 2003 10:47 pm

Posts: 268

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