AMR oil pump/checkball mod, re wet sumping

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htown16

htown16

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First off I have searched on "wet sumping" on here and read a fair bit of the 96 pages that search generated, so I have a pretty good idea of what the various options are and their +/-. I'm specifically interested in information about the AMR oil pump/check valve mod particularly from someone that has had it done and can share how it worked out. I would rather not get into the various discussions again about check valves or ball valves in the oil lines or whether wet sumping is really a problem or not. Currently my 72 Commando, which I ride at most once a week, is draining its tank in a few days leaving the pickup screen exposed. I'm not willing to start the engine that way, so I end up draining the sump before every ride. Not only is this a nuisance but I am worried about eventually stripping the drain threads in the case. Last time I rode it, the primary started leaking oil vs the ATF which was in there and I drained about a pint of oil out of there. The seal seems to still be okay as no oil appears to be leaking in after a fairly long ride.
The AMR mod looks very similar to me to the way a BSA twin is setup which has a check ball and spring coming out of the the feed side of the pump. My 70 BSA was also a bad wet sumper, but I recently replaced the ball and check spring with new ones and fitted an SRM pump which has o-rings and it doesn't appear to be leaking a drop.
 
I finally bit the bullet and sent my timing case and pump off to AMR. I have not yet cranked up the bike, so cannot comment on how it worked out. In the least, I no longer have any non-Norton items in my oil feed line, other than worm clamps...and I have two less of those.

From what I can see, the mod is simple, straight forward, safe (no chance of total oil stoppage), and certain to greatly reduce oil seepage.

I simply decided the $70 cost plus two way shipping was cheap enough to solve the problem (to me, it WAS a problem, more than a nuisance).

Slick
 
htown16 said:
Even if you haven't started it, is the oil level dropping?
Click to expand...

Answer: NO. But the timing cover being off the bike and the oil tank dry, may have something to do with that. :D

Seriously, the AMR mod should, or ought to, reduce oil seepage to a MINISCULE level. I am sure some guys who have been running the mod will chime in and calm both our concerns.

Slick

11.29.14 ..... I agree with Machmitz57 (see below) regarding the ball and spring.
 
I had AMR install the check valve modification on my Atlas timing cover. They also service and install a rubber o-rings in the oil pump to help stop oil leaking past the shafts. I've had good luck with this setup. Seems to work fine. No complaints. The price seemed a bargain. The only downside I see is when removing the timing cover in the future the ball and spring will probably pop out and roll across the floor unless you've remembered they're installed. I have a habit of forgetting about shit like this.
 
If you read 96 pages then you must have read this, but may have skipped over it, so here it is again.
Not too many others will be able to report on results from 30+ bikes, so it carried a lot of weight for me.

by CNW » Mon Mar 08, 2010 11:55 amWe used the modification that AMR offers for many years. The first 30 bikes or so have it installed in the timing cover. These were done by another guy, I cant think of his name, that later gave the rights to AMR so they could offer the modification. I found the results very inconsistent with some bikes not sumping a bit and other draining down to the crank in a very short time. This was frustrating since I didnt know until the customers started reporting back to me after they took delivery of the machines. I know that some people dont mind the wetsumping but I dont want to tell my customers that they have to drain the oil out of the crank and pour it back into the oil tank before going on a ride.
 
I'd like to ask if anyone had their MK 3 done and if it was an improvement.

Thanks,

Jim
 
Matt didn't say what the success rate was but even it was 50% I still think I will try it. Even if it just slowed it down some. Right now its draining the tank dry in 3 days.
 
I had this done on my Commando and Atlas and it solved the wet sumping issues. (My commando would and Atlas would wet sump the entire tank in about a month. On the atlas that would result in a pool of oil under the bike.)
 
htown16 said:
Matt didn't say what the success rate was but even it was 50% I still think I will try it. Even if it just slowed it down some. Right now its draining the tank dry in 3 days.
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If it's draining that quickly, doesn't that mean your pump is excessively worn?
 
Fast Eddie wrote:

"If it's draining that quickly, doesn't that mean your pump is excessively worn?"

I think Eddie has a good point. You might consider having the pump rebuilt. The AMR mod would/should stop the wet sumping, but an excessively worn pump might not deliver optimum oil volume.

Slick
 
If there is a spring loaded ball at the pump output and the pump is not leaking externally, how could a Norton wet-sump?
 
texasSlick said:
Fast Eddie wrote:

"If it's draining that quickly, doesn't that mean your pump is excessively worn?"

I think Eddie has a good point. You might consider having the pump rebuilt. The AMR mod would/should stop the wet sumping, but an excessively worn pump might not deliver optimum oil volume.

Slick
Click to expand...

+1 Just hook on a (temporary) oil pressure gauge and determine the condition of your pump :!:
 
JimC said:
If there is a spring loaded ball at the pump output and the pump is not leaking externally, how could a Norton wet-sump?
Click to expand...

It can leak internally, as oil leaks across the pump from the feed to the scavenge side between the pump shaft and body as there's no seal between the two chambers although there's a modification where a groove is machined in the shaft to take an O-ring.
 
The AMR mod also includes machining and fitting 2 o-rings to separate the pump halves. They take the pump apart to do it, so I can get their opinion on the condition. I have an oil pressure test gauge. It has a 1/8 NPT male fitting. Any suggestions on how to plumb it in?
 
L.A.B. said:
JimC said:
If there is a spring loaded ball at the pump output and the pump is not leaking externally, how could a Norton wet-sump?
Click to expand...

It can leak internally, as oil leaks across the pump from the feed to the scavenge side between the pump shaft and body as there's no seal between the two chambers although there's a modification where a groove is machined in the shaft to take an O-ring.
Click to expand...

I guess I should have said externally and internally.

My take on the AMR mod, (and if you are doing it, include the pump mod, too) is it addresses the feed to scavenge side problem. I've had the mods done, both pump and ball and had no wet sumping since. I tried an intake line check valve and saw my hot oil pressure at idle go to zero. This was with a New Andover oil pump. Used a WOG valve on the intake for a few weeks, until I realized the foolishness of putting anything to possibly obstruct the intake to an oil pump. Besides that, those valves and associated clamps are flat ugly. Also, I'd rather put up with wet sumping than the Gyro Gearloose, forget-me-not gimmickry I've seen here.
 
I'm trying to get a feel for the market on my key/valve so I'll mark you down as undecided. :|
 
htown16 said:
The AMR mod also includes machining and fitting 2 o-rings to separate the pump halves. They take the pump apart to do it, so I can get their opinion on the condition. I have an oil pressure test gauge. It has a 1/8 NPT male fitting. Any suggestions on how to plumb it in?
Click to expand...

You need a double long banjo bolt, banjo fitting, suitable hose, and adapter from the hose to 1/8npt. The double banjo bolt is available from:
http://www.ebay.com/itm/Banjo-Bolt-Doub ... a4&vxp=mtr

The banjo fitting, already attached to a hose, and AN to NPT adapters are available here:https://www.pegasusautoracing.com/group.asp?GroupID=BRAKELINES

Pegasus also has the copper washers as well.

Use the double bolt and simply plumb into the rocker feed line at the head.
 
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