Thought I fixed the oil burning,, :(

I recently installed new valves/seals/rings. I had symptoms of oil burning due to guides/seals I did the rings since I was in there. It has new good quality seals and new valves with no excess clearance valve-to-guide.

However, today was the first time since reassembly that I really got the engine up to temp and now it is doing the same thing even more severely. I did some additional troubleshooting to see what I could see.

It is not an issue with oil/air from the crankcase breather to the tank and then to the air filter/into the combustion chamber - the hose is totally disconnected at the moment so the breather is just puffing to the atmosphere. HOWEVER, during the rebuild I was concerned at what I felt was an extremely small single oil drain hole from the intake rocker area to the crankcase. I was thinking that oil would actually drain slower than it fed into the box, and would, within a few minutes, be above the level of the valve guides. Regardless of how good the guide/valve clearance was or the quality of the seal, if oil stands above the level of the top of the guide, oil is going to get into the combustion chamber.

At the time I poured some oil into the rocker box and it took 3+ minutes to drain a couple oz of oil. But since they are all like that, I figured that it must be OK with the engine running and hot oil.

Today I decided to remove the int rocker cover and have a look at what was really happening with the engine running. I was dismayed to see exactly what I had feared - the rocker box will fill with oil faster than it drains. It will completely fill until there is enough oil to drain over and into the pushrod tubes.

I ensured the oil passage was clear when I reassembled the engine. I had a long pipe cleaner in the cylinder and, while lowering it in place made sure the pipe cleaner entered the crankcase passage. After tightening the cyl down I removed the pipe cleaner, inserted another one soaked in lacquer thinner, twisted it around and then blew out the passage from the crankcase side to ensure it was totally clear.

Of course, relapping the oil pump probably increased oil pressure/volume and may have actually contributed to the problem.

So...I can see the problem - insufficient drainage from the head. But I can't think of any way to solve it. Anyone have any experience or thoughts re this issue? Obviously it is not usually a problem since I haven't seen anything about it in the general Norton literature but it certainly exists on this bike and apparently always has.

Orientation of the lifters?

Is oil going to the ex side, if all of that is correct restrict the flow, although you shouldn't have to.

Are you absolutely certain the flats on the rocker spindles are all facing outwards, so that the inlet spindle flats face to the rear, and exhaust spindle flats face the front?

I did not do anything at all with the rocker spindles/rockers - did not remove them from the head. So I suppose they could be worn though there was no side/clearance (wobble) that I could tell.

One thing I'm wondering. Per diagrams, there is a hole in the rocker spindle that allows lubrication. The service manual says that the "flat" of the rocker spindle should face toward the rocker cover. A picture of the rocker spindle on Old Britts shows the flat with hole. Is this the only hole in the spindle?

THe reason I ask is that just a few minutes ago I made a little "L" out of safety wire that could slide inside the spindle. I could feel a hole on the side of the spindle that is facing TOWARD the middle of the head, which, if the flat is on the same side as the hole, indicates to me that at least the spindle I checked is oriented incorrectly.

Is there any other hole in the spindle or is the hole in the flat the only one? If so, someone previously oriented the spindles incorrectly. Perhaps this could cause the problem...

MexicoMike said:

Is there any other hole in the spindle or is the hole in the flat the only one? If so, someone previously oriented the spindles incorrectly.

Click to expand...

There should only be one hole.
http://rocbo.lautre.net/technique/norto ... p/033.html - Fig C7
http://rocbo.lautre.net/technique/norto ... p/034.html

Both the int and exh spindles have the holes (and therefore, it appears, the flats) oriented toward the center of the engine. So they are reversed from what they should be IF the HOLE is in the flat side of the spindle as the picture on the Old Britts site shows.

I read this on the Norton Owners Service guide: "ROCKER SPINDLES: The rocker spindles are fitted with the oil flats outwards -away from the holes in the rockers --because otherwise too much oil swamps the head."

Since my engine has the spindles installed in the opposite direction, it appears that this may be the problem.

NOW the question is: can I simply heat the head (by running the engine), rotate the eng by hand so the appropriate valve is fully closed so there's no valve spring load on the spindle, insert a large screwdriver in the end of a spindle and turn it in place? It doesn't appear to me that there is anything except the outer cover that prevents the spindle from turning. I don't have a bolt to use with a socket as a puller for the spindle.

MexicoMike said:

can I simply heat the head (by running the engine), rotate the eng by hand so the appropriate valve is fully closed so there's no valve spring load on the spindle, insert a large screwdriver in the end of a spindle and turn it in place?

Click to expand...

Yes, although extracting them a little first would probably help them to turn, but there's nothing to lose by trying, as long as you don't to apply too much force to the spindle slots.

Thanks, I'll give it a try. A little more research indicates that Atlas heads are supposed to have the spindle flats facing the inside of the cyl head; Commando heads are the opposite. I guess whoever worked on the cyl head previously was used to working on Atlas's.

MexicoMike said:

Thanks, I'll give it a try. A little more research indicates that Atlas heads are supposed to have the spindle flats facing the inside of the cyl head; Commando heads are the opposite. I guess whoever worked on the cyl head previously was used to working on Atlas's.

Click to expand...

Yep, that's because Dommie and presumably also Atlas rockers are fed from the return line and not from the feed line like Commandos

MM ,
although unlikely for all 4, the spindles may have turned all by themselves .
Sometimes the locating pins are so shallow that combined with the thicker gaskets and maybe a little deeper sitting spindle , the pins don't engage properly .
The later the engine the shallower the pins , as the machine on which they where made was wearing out .
With a suitable drift you can make them stick out further .
( or replace the plates by one piece alloy ones )
Isn't the internet wonderfull ?
You are tinkering in Mexico City , and people from all over the world are looking over your shoulder !
A webcam is the next step .

MexicoMike said:

Thanks, I'll give it a try. A little more research indicates that Atlas heads are supposed to have the spindle flats facing the inside of the cyl head; Commando heads are the opposite.

Click to expand...

Only about the last 1000 Atlasses had the double-speed oil pump and high pressure rocker feed the same as the Commando. And I would have thought that the Atlas spindles would have faced the same way as the Commando spindles, because the Atlas and early Commando engines are virtually identical? I do know the earlier low pressure rocker feed spindles were scrolled and didn't have the flat. [Edit] However, I have just checked the late twin manual and it does say the flats should face inwards (I didn't think they had any flats on them!) but I think the information probably applies to the low pressure rocker feed system!

I just checked my copy of Haynes' "Norton Twins - All models 1957 to 1970 (Excluding Commando)" manual.

It says the following: "The outer end of the rocker spindle must be aligned so that the two slots are in a horizontal position before it is driven flush with the jointing face. The flat on the spindle must face the rocker cover in each case."

Still, as it's a Haynes manual, there's no guarantee the information is completely correct.

ludwig said:

MM ,
A webcam is the next step .

Click to expand...

I might do that when I start my bike for the first time.

Re: Thought I fixed the oil burning...I DID!

Well, that appears to have been the problem... 3 of the spindles were 180 out (holes toward center of head) and one was spun slightly - keeper wasn't keeping, I guess. That one had the slots in the spindle at 10oclock/4oclock which meant that the spindle actually obstructed the oil hole to that spindle. Obviously it was still getting some oil, maybe splash because none of the rockers had any wobble when I had the head out and clean. Amazing what you find! I peened the tabs of the keeper so they would stick out a bit further and hopefully prevent the spindle from moving again.

I found a long bolt that fit the spindles so was able to make up a puller. Three of them needed to be pulled out about 1/4" to be able to be turned with my BIG screwdriver. Not surprisingly, the one that was at 10/4 didn't need to be pulled at all to turn.

I started up the bike and ran it for a while, watching the rocker box. It did not fill up as before. I still believe the oil drain out of the int rocker box is really marginal and I think that at high RPM it might still fill. Of course, at the higher RPM throttle openings, there isn't much vacuum applied to the valve/seals as there is at idle. I ran the bike and revved it up. There was a slight bit of smoke after holding it at 5k, shutting the throttle, and rolling it back on. But previously under the same circumstance it put out a cloud.

From the side view, you couldn't see the smoke but I have a black gate about 10 feet directly behind the bike and you could see it against the black gate, but not against the yard or other background.

Yeah, as Ludwig said, it's amazing what the internet can do - help from 1/2 a world away! So if we all had web cams mounted in the garage or wherever our Norton work is done we could do it live! I have a friend who would say that if you wanted a webcam wherever you do your Norton work, they would have to be mounted periodically along the side of the road.

Thanks All!

It sounds like you've found the problem Mike.

I'd always assumed that quite a bit of oil is meant to go down the pushrod tunnels, otherwise it wouldn't matter which way round the followers go and the cams would wear quickly due to lack of lubrication (What do you mean, they do anyway ? )

I would expect an engine that had been over oiled to smoke a bit until it had a good thrashing. Even the carbon in the combustion chamber will be soft and oily until then.

Did the retaining plate gaskets go back OK? If not, you'll be suffering from "Three fins up" syndrome very shortly

It seems a weird setup.. the exh rocker box has two 1/8" dia drains and they only run an inch or two before exiting into the push rod tunnels. The Int rocker box, which I would think would be much more critical drainage-wise, has ONE 1/8" drain, at the base of the right valve seat. The hole as not totally clear due to valve spring washer/heat washer. The 1/8" ID passage runs all the way down the cylinder, into a 1/8" passage in the crankcase which then turns in an almost horizontal direction into the primary chaincase. On top of that, the chain case is pressurized a bit by the breather which, it seems to me, would further impede the drain flow, trying to shove the oil back up the passage.

One thing I can tell for sure from observation...if the bike is running on the side stand, oil will pool above the level of the left valve guide before it can reach the drain. I really believe the engine should have a better int rocker box draining

The retaining plate gaskets seem fine but I'm mentally prepared for them to not be!

I don't think that I've ever left a Commando running on that spider's leg sidestand. Don't they shake themselves off it ? :shock:

MexicoMike said:

The 1/8" ID passage runs all the way down the cylinder, into a 1/8" passage in the crankcase which then turns in an almost horizontal direction into the primary chaincase.

Click to expand...

Primary chaincase...I hope not? :wink:

MexicoMike said:

I really believe the engine should have a better int rocker box draining

Click to expand...

Now you have fixed the problem...just have a little more faith.

"Primary chaincase...I hope not?"

Sorry...you are right, not the primary chaincase, which is on the LEFT side of the bike. It's the "Primary Transmission," on the RIGHT side of the bike where the breather and the Int rocker box drain is located.