check valve

A guy brought over a MK3 with a top end noise problem he wanted identified. He bought it from a guy who bought it from a guy in Indiana. It looks really good. Not sure how long the middle man had it. Great compression. It starts easily. He started it for me and the noise (harsh metal clacking) did not sound like valve adjustment but it was a place to start. I took off the valve covers and noticed right away that it looked very dry inside. I pointed this out to the owner. The valve clearances were double what they should be. I retorqued the head and set valves. Fired it up without the ex rocker covers on and saw ZERO OIL FLOW. I loosened the rocker line..again ZERO OIL FLOW. YIPE! In his oil feed line to the motor is the common inline check valve, that will go immediately. It was doing the jobb and the oil tank was full to the top. The down side is the crankcase had not wet sumped and kept the bottom end lubricated. Fortunately he resisted the temptation to ride it but he now wants a full motor inspection. I have always been very leery of wet sump valves and this is proof.

Ouch! I just hope it didn't get enough time to cause any harm to the bottom end.

No way to know without a teardown. So the choice is to get the oil flowing and see what happens or the long expensive process to tear it down and inspect/replace parts. On the plus side, the current owner contacted the 2nd owner about the engine noise. The 2nd owner refunded $1000 so that will go a long ways.

So be it. My MK 111 came my way after spring loaded check valve failure and rebuild. Earlier photos of it show the problematic valve in place before damage ,rebuild ,and my purchase of said vehicle. I'm convinced now these valves are the devil's work as the danger of them sticking closed is not worth the ri$k.

seattle##gs said:

No way to know without a teardown. So the choice is to get the oil flowing and see what happens or the long expensive process to tear it down and inspect/replace parts. On the plus side, the current owner contacted the 2nd owner about the engine noise. The 2nd owner refunded $1000 so that will go a long ways.

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seattle##,
There is no way of telling how much damage has been caused by lack of oil, but that $1000 will go for most of a rebuild on the bottom end... cam, lifters, crank grind, new shells + con rod hardware, gasket kit, etc. And that doesn't include labor. Lucky that it didn't throw a rod. :shock: If that engine is making noises, then I would recommend a tear down. One thing I always do when I re-start my bike from a long winter of inactivity or on a rebuild is to pop the seat off the bike, then kick start the bike and get the engine going. I then open the oil tank filler cap and look at the oil return to see if oil is returning to the oil tank.
I shake my head every time I hear about this wet sump quick fix. :evil: IMHO I live with the wet sump issue. I know at start up, I am always getting my cam splashed with oil the moment the engine starts. Oil gauges and oil sensors are on other threads on this site and are good to explore and food for thought.
Cheers,
Thomas

A MK3 with an inline check valve in addition to the one in the timing case? Is that like braces and a belt, but without the positive outcome?

I guess failed faucet washer, AND that the rod bearings/journals are junk :shock:

How much is an oil pressure gage worth now? :wink:

" One thing I always do when I re-start my bike from a long winter of inactivity or on a rebuild is to pop the seat off the bike, then kick start the bike and get the engine going. I then open the oil tank filler cap and look at the oil return to see if oil is returning to the oil tank." False sense of security. The faucet washer/crank seal can be failed, but scavenge will be observed. Get a gage. :idea:

seattle##gs said:

In his oil feed line to the motor is the common inline check valve, that will go immediately. It was doing the jobb and the oil tank was full to the top. The down side is the crankcase had not wet sumped and kept the bottom end lubricated.

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Couple of questions:
1. what type of 'common' inline check valve was fitted?
2. 'the crankcase had not wet sumped' then how was the bottom end kept lubricated?

Be sure to check the conrod small ends.

Mike B.

I had one of those plastic valves that came apart at speed. It cot me $2000 USD and I did all the labor.
I too will live with wet sumping! Although the +0.40 pistons, stage 2 cam and 21 tooth sprocket almost made it seem worthwhile,,,,uh no it didn't!!! But it is better then before.
Ride On
Dave

concours said:

" False sense of security. The faucet washer/crank seal can be failed, but scavenge will be observed. Get a gage. :idea:

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I have one and use it at start up and during riding.
Cheers,
Thomas

I do not know how many miles were on it after the check valve was fitted. The motor started in a couple of kicks and sounded very good..and didn't smoke, of course. Still, it had a sharp metal clack sound in the head area so we stopped and I did some investigation.
Next, I will remove the small plug in the crankcase bottom and see if any oil comes out. If there is about a cup I will feel better about the situation. The owner also complains of extreme vibration. I will check the isolastics and all engine mounting bolts. I would like to replace the feed oil line eliminating the check valve, pump a lot of oil over the rockers and cam, start it and check for oil pumping. If all looks and sounds good I would like to take it for a few blocks and see what he means about the vibration. By the way, it has a single Mikuni so the vibration should be minimized. He has hinted that the flywheel might have been turned around on the crank but I do not know what he has based this on. I would like to experience the vibration before I pull the motor apart but I am taking a chance. I can send the crank off to get it balanced and ground if need be.
I do not know who makes the valve but it is a small plastic piece with a clear band. approx one inch long not counting the spigots. I seen several of these.

seattle##gs said:

I do not know how many miles were on it after the check valve was fitted.
I do not know who makes the valve but it is a small plastic piece with a clear band. approx one inch long not counting the spigots. I seen several of these.

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I have seen this type fail. :shock: Don't use them. There might be a thread link in this forum. Do a search.
Regards,
Thomas

One more Norton motor sacrificed to the God of Bodges instead of just fixing the problem ....

I had to sacrifice my own BSA motor before I woke up and realized that putting a check valve on the suction side of a rotary pump is the worst idea since someone said ‘yeah let’s take this suspiciously large wooden horse into Troy, statues are all the rage this season ...'

But it won't stop the next guy from doing it. It's just SO quick and easy; snip snip, clamp clamp and it's ALL fixed! Until it blocks the line.

Lannis

I told the owner to accept the fact that Nortons wet sump. I showed him the comstock breather assy. and told him that is as good as he can hope for.

There are other methods that work just fine, however a MK3 should be quite continent all on it's own.

The ball and spring supply line check valves are a much proven bad idea, not sure why they are still being manufactured and installed.

Glen

I replaced the feed line and check valve with a single piece of hose. Oil in the tank looked pristine. I drained the crankcase, it had about a 1/2 cup of dark goo but no metal bits. Pumped about a cup of oil over the rockers and cam. Started it and oil flowed immediately through the motor and back into the oil tank. I cracked the rocker banjo and oil flowed easily from it. The noise in the top end really lowered in volume but occasionally there was the metallic clack. Drove it 4 blocks. All seems well but the owner still wants to tear it down for an inspection. he also complained of acute vibration going down the road. First place to look was the isos and they were locked up tight. I did a quick .010 clearance front and rear and the thing smoothed out like a Norton should. I'm sure other surprises are ahead.

One can only hope that the valve was operational, and only locked up after sitting idle for a while while being sold.

I pulled the motor apart today and it was very fortunate that I did. The STD pistons were badly scored along with the cylinder. Oddly enough there was no damage to the cam and lifters. When the rods came off the bearing shells STD fell out of the rods. They were down to the copper with only a trace here and there of the original bearing material. The steel cap on the right side rod showed discoloration from heat. Is that rod still usable? The crank rod journals have scoring and they taper .002.

Sad that an unneeded accessory ruined the engine. A MKIII will wet sump but only after a long period.

Was the original factory valve and spring still in the timing cover?