Over oiling

bigmike76 · Feb 4, 2014

I have a problem woth over oiling.

The cylinders have been rebored with new pistons and rings, it has had new valves there seemed to be little wear on the guides, it didn't have seals on the guides originally so none now, the rocker feed is pressure fed, the rocker spindles all face outwards.

I was reading about restricting oil feed to the top end as loads comes through, more than really needed I would say.

Any suggestions would be great.

Also, even with the valve clearences on the looser side of the guage, the top end is very quiet, to rattle, tapping or anything probably due to the amount of oil around I would guess!

Al-otment · Feb 4, 2014

Check the max. oil pressure cold. Should be approx. 50lb/sqin. Adjust by adding/subtracting shims to the PRV. Ideally you want seals on the inlet guides.

bigmike76 · Feb 4, 2014

Thanks will try that, it does only do when the oil fills the rocker spindles until then its fine. Its a 1968, can you fit valve guide seals on them?

toppy · Feb 4, 2014

Are you sure you have the correct type of rocker spindles an they are all fitted correctly ?

1up3down · Feb 4, 2014

Mike,

you did not state any symptoms of over oiling, why do you conclude this?

secondly, what exactly would be wrong with the head getting too much oil anyway?

it cools, it lubricates, and it goes down the tubes and holes to the bottom end

what is your concern?

bigmike76 · Feb 4, 2014

The symptoms are-

The top of the pistons and the plugs are getting very wet with oil after ticking over for a while, along with white smoke, but when you rev it the smoke doesn't get any worse really, I have taken the head off twice now and tried different head gaskets and inspected it for anything worn or blocked etc, then when I put it all back together and start it its fine for a minute and starts again. after it had been running for a while I drain the bottem end and get 1/8 of a pint of oil out, I have checked that the oil is returning and it is very well, so I pressumed it is over oiling at the top end.

The engine had never been apart from the day it was new, it had been stood not used since 1979, when the engine was stripped, the oil was very black and the inside of the casings were the same, and the whole engine looked like it had been stood in oil or covered for years, I had it vapour blasted and they had a real struggle to clean it up, maybe it was an oily running engine all thode years ago.

comnoz · Feb 4, 2014

If you have high pressure oil to the head you need valve stem seals installed.
The first of the Commandos came with high pressure to the head but the seal-less valve guides like the earlier models. High oil consumption was the result and Norton's fix was to fit valve stem seals. Jim

1up3down · Feb 4, 2014

Jim nails it, again

you are not over oiling

rather, the oil is getting past the valves and into the combustion chambers this coating the piston and fouling the plugs

time to fit proper valve stem seals, Mike

chris plant · Feb 4, 2014

hi bigmike,before we got oil seals fitted to valve guides we used to chamfer the guides to a knife edge in an attempt to prevent pooling on top of the guides,might be worth a try before going to the expense of new guides,valve seat cutting.make sure the oil drain from the inlet cavity is clear,have a look at whats happening with the inlet rocker box cover off,it should,nt fill with oil, my uneducated guess would be wet sumping,or too much oil in the crankcase for whatever reason chris

bigmike76 · Feb 5, 2014

Hi, I have removed the inlet cover and you could see how high the oil had come up, nearly half way up the cover, i have searched for the drain hole, but there doesn't seem to be one, could anyone let me know where it should be, also if I turned the rocker spindles so the flats face forward would the stop so much oil coming into the inlet cavity? I am sure I have read somewhere that some models around this year were done like this at the factory, but can't find it now

chris plant · Feb 5, 2014

hi mike,the drain hole is under the bottom valve spring retainer on the right inlet valve,it runs down through the barrel,into the crankcases then exits into the timing cover chris

bigmike76 · Feb 5, 2014

I would guess that the oil is going through the hole as there was only a dribble in the bottom, which leads me to think that is over oiling still when running, I have other bikes and they never have this much oil being pumped up to the top, this makes me think that if the flats are facing forward the oil is less likely to go straight into the inlet and give the drain hole chance, I am sure i read it do do with a mercury engine which is near enough exactly like mine beign an early model

olChris · Feb 5, 2014

chris plant said:
hi mike,the drain hole is under the bottom valve spring retainer on the right inlet valve,it runs down through the barrel,into the crankcases then exits into the timing cover chris

Is it blocked ???? "the drain hole is under the bottom valve spring retainer" so how does it drain.... Ive never seen what u got.......... Drainage, return is a problem ...............

bigmike76 · Feb 5, 2014

If the drain is unter the valve retainer, then the amount which can drain must be very small, so compare the rate at which it gets pumped up, it would never keep up.

I have just set up the prv the rattle test, before there was no rattle so imagine there was too much pressure.

I pressumed it all worked before many years ago, but have no idea how well, it could of left a cloud of smoke all its life, it sure looked as if it did.

I will try it again, but if its still the same I will make a regulator to control the pressure and amount of oil reaching the rockers, after looking at how dry other bikes are under the inspection cover then I don't have much to worry about.

I

chris plant · Feb 5, 2014

hi olchris,maybe I should have said the drain hole is obscured by the bottom retainer.meaning its hard to see with the valve gear in place chris

olChris · Feb 6, 2014

Have you had the head off recently........ Head gasket???? .......... In another life, the fitting of auto head gaskets could have been compromised by its orientation..

I get that you have plenty of oil up top, but it wont drain and bypasses valve guides and smokes up.............

IMO, Its not draining properly

Basic inspection method...
Take the sump plug out,
Pour enough of oil into all tappet access points (individually) and note the "draining" process.. Once full, if it drains (200mls+) within 30 secs or so then all good ... if it dont drain there is a blockage...

On a brighter note, many would be envious that there is plenty of oil up there..

Hope this helps.......

Rohan · Feb 6, 2014

Have you actually taken it for a ride yet, to see how this problem goes on the road ?

If its all new and still settling in, we may be jumping the gun here.
Also, the rings need a run with some quick bursts of acceleration so the gas pressure can make them seat properly.

P.S. How did domie engines before the Commando get on with/without stem seals.
High-pressure oiling to the heads happened a long time before the Commando - early 1960s wasn't it...

toppy · Feb 6, 2014

If the rocker spindles are the correct type with flats on and not the earlier type with scroll ( on which will flood the head) are the rockers a good fit and are the spindle fitted with oil feed hole the correct way?
If so check for blockages in drains through barrels of oil solidified oil or gasket sealer etc. also are you sure the base gasket is on the right way as it may have been wrongly fitted in the past sometime if its a pattern part or has been fitted with lots of sealant this may block oil flow.
There should not be that much oil in the head so check oil pressure as others have suggested

comnoz · Feb 6, 2014

Rohan said:
P.S. How did domie engines before the Commando get on with/without stem seals.
High-pressure oiling to the heads happened a long time before the Commando - early 1960s wasn't it...

High pressure head oiling didn't come along until the N15 and Commando in late 60's. The problems with no valve stem seal immediately became obvious.
The Atlas motors ran the valve train so dry that no seal was needed -and short life was expected. Many Atlases were converted to high pressure oiling to make the valve train last longer. And then seals are necessary. Jim

bigmike76 · Feb 6, 2014

Ok I have tried everything and the left hand cylinder seems to be getting better, and when running has a nice crisp pop, now I have noticed the right hand is still smoking a little more but has a less crisp chuffing sound, it is firing as I pulled the lead off the l/h but doesn't seem as powerfull, I have also now done a compression check and both cylinders are around 135 psi, it starts very easy and revs fine, could this be the rings haven't bedded in properly on the r/h.

I am running a single carb 30mm mk1 so rules out carb settings and I am also running electronic ignition with a dual coil, I have swapped the leads over and this makes no difference.

The valve guides have no ring for seals to fit either also what is the ideal valve clearences, I have them st to 6 inlet and 8 exhaust and are very quiet

Over oiling

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