Oil pouring through exhaust outlet

Graeme Mitchell · Feb 17, 2021

Hi all
I have been with the forum Norton 961 for some years and have recently bought a 1971 roadster. It had lots of work done and was told it was a runner but I fell foul of starting it with a crankcase full of oil. I decided to take the head off and clean out excess oil. All went well and could not see anything untoward so put everything back. Cylinders and rings are all-new oversized with rebore, the valves look new and seated well.
However, despite checking the oil in the crankcase was within acceptable limits after about 30 seconds from kick-starting oil started pouring from the exhaust outlet. I have now stripped back to where I have free access about the cylinder head and rocker covers removed.
I am not sure why oil is freely getting into the exhaust.
Does anyone know of any obvious causes I could look at before doing any further work?
Any advice gratefully appreciated

cash · Feb 17, 2021

Graeme Mitchell said:
Hi all
I have been with the forum Norton 961 for some years and have recently bought a 1971 roadster. It had lots of work done and was told it was a runner but I fell foul of starting it with a crankcase full of oil. I decided to take the head off and clean out excess oil. All went well and could not see anything untoward so put everything back. Cylinders and rings are all-new oversized with rebore, the valves look new and seated well.
However, despite checking the oil in the crankcase was within acceptable limits after about 30 seconds from kick-starting oil started pouring from the exhaust outlet. I have now stripped back to where I have free access about the cylinder head and rocker covers removed.
I am not sure why oil is freely getting into the exhaust.
Does anyone know of any obvious causes I could look at before doing any further work?
Any advice gratefully appreciated

Pouring! wow that sounds bad? Could be the exhaust guide has come adrift or broken? If the head is still on the motor shine a torch into the offending port and turn the motor over and check out the valve/guide and port.

Chris · Feb 17, 2021

I had a smokey oily exhaust drive side. It was in the Seeley MK3 & was informed it was because I had it so far over on the homemade side stand! The oil doesnt drain away so well from the exhaust valve spring pocket on that side.
Complete b***ocks. Exhaust guide was going up & down with the valve . Run the engine with the valve covers off! You wont get long & it will make a mess but you might be able to see what's going on.

baz · Feb 17, 2021

That sounds really bad
Was there any other work done on the head?
Have the rocker spindles been out?
Valve guides changed etc?

olympus · Feb 17, 2021

Rocker shafts fitted the wrong way round & oil flooding the rocker boxes?

kommando · Feb 17, 2021

Did you use sealant on the head gasket, if so did you check the small oil drain hole on the timing side is clear.

baldy · Feb 17, 2021

Had similar issue but it was gas coming out exhaust Looks like oil cause picking up black. Carb issue flooding.

Fast Eddie · Feb 17, 2021

What exactly do mean by ‘oil pouring from the exhaust outlet‘?

Do you mean smoke was billowing from the silencer?

Or do you mean actual oil pouring out (ie in liquid form)?

texasSlick · Feb 17, 2021

Loose valve guide, or crack in head near the valve guide. I sincerely hope the first. A rebore to oversize valve guide will take care of it. I am assuming this is occurring on one side only.

Remove the exhaust header and peek inside the port. Oil should be visible near the guide.

Slick

Lineslinger · Feb 17, 2021

Can you offer a more detailed/precise description of what you are seeing or put up a couple of photos? Lots of variables interpreting your written description

johnm · Feb 17, 2021

Had a friend with the same issue. Smoking like crazy and when shut down oil dribbled out of the header pipe.

Finally turned out that the multipiece oil rings had been installed deranged and totally misplaced. You said the motor had recent work.

However I also agree possible other causes are.

Loose valve guide.

Blocked drain hole

Head gasket leaking especially around push rod tunnels.

Cracked head - I hope not

A stud broken through into the exhaust port if someone has been modifying it.

Graeme Mitchell · Feb 17, 2021

Right, I have cleaned all spilled oil away, poured some oil in the well about the inlet valves, and cranked the engine over by hand ( plugs out and exhausts off) for a few minutes. The oil about the was sucked away even after a couple of refills and everything else completely dry. So, I can only assume that there is no blockage on the returns. but still none the wiser. I will refit it and see what happens when I start it up. Will remember to take a video

Graeme Mitchell · Feb 17, 2021

Fast Eddie said:
What exactly do mean by ‘oil pouring from the exhaust outlet‘?

Do you mean smoke was billowing from the silencer?

Or do you mean actual oil pouring out (ie in liquid form)?

Actual oil coming out from around the exhaust

Graeme Mitchell · Feb 17, 2021

texasSlick said:
Loose valve guide, or crack in head near the valve guide. I sincerely hope the first. A rebore to oversize valve guide will take care of it. I am assuming this is occurring on one side only.

Remove the exhaust header and peek inside the port. Oil should be visible near the guide.

Slick

strange enough no oil visible. I am going to refit and give it another start. this time taking a vid and lots of photos.

concours · Feb 17, 2021

"However, despite checking the oil in the crankcase was within acceptable limits"

You know it's a dry sump design, right?

Graeme Mitchell · Feb 17, 2021

concours said:
"However, despite checking the oil in the crankcase was within acceptable limits"

You know it's a dry sump design, right?

yes but I thought there will be some oil in the crankcase and that's ok, but left long enough will "wet sump" which I am assuming was my initial problem.

ashman · Feb 17, 2021

Wet sumping won't get oil out of the exhaust pipe, back in the early 80s when I built my hot rod 850 in the Featherbed frame I had the head work done by a so called bike head expert and after 2 weeks on the road had the same problem with oil from the exhaust headers, when the so called expert replaced the guides a crack on both sides of the exhaust guides was the problem he paid for it to be fixed and not by him, had to be welded and ported again, that was nearly 40 years ago and I am still using the same head with the original valves still and have had no problem since, not all experts are experts with Norton's.
Take your header pipes off and have a good look for cracks around the exhaust guides, was you guide replaced.

Ashley

Fast Eddie · Feb 17, 2021

Graeme Mitchell said:
Actual oil coming out from around the exhaust

At the head end you mean?

Before assuming the worst, cracked head, etc you should CAREFULLY check for leaks at the rocker cover gasket faces, rocker spindle plates, rocker feed pipes, etc. Small, almost invisible, leaks from there can run down to the exhaust port area very easily and create panic!

Mark Savage · Feb 17, 2021

ashman said:
...not all experts are experts.

I agree, or they don't always get it right. In 1980 I had a smoky Trident and was directed to none other than Bill Fannon who lived local to install some new guides, valves and springs.
It ended up worse, one guide even rattled up and down with the valve. I vowed to do all my own work after that where I could.

ashman · Feb 18, 2021

Another place to look is the lower studs that hold the front valve covers on as the oil can seep up the threads and drip down to the exhaust flanges, when mine seeped up those studs oil was everywhere and thought I had a blown head gasket but following the trail of oil it was the bottom studs, oil was running down the exhaust flange and around head gasket area, that was a easy fix by sealing the stud threads.
Its funny how a small leak can travel.

Ashley

Oil pouring through exhaust outlet

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