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Excessive oil from crankcase breather pipe.

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Excessive oil from crankcase breather pipe.

Posted by tim_harris at October 23. 2017

Having recently bought a 1959 Dominator 99, and being new to the model (my other bikes are Commandos) I need some advice on the amount of oil coming out of the crankcase breather pipe. This is routed to the underneath of the crankcase behind the primary chaincase, unlike the Commando, which returns to the oil tank. Is this correct?

 When I bought the bike I was told that the engine had been recently rebuilt, although, as it was bought from a deceased persons estate, there was no paperwork with it. It also wet sumped quite  frequently, but it helped enormously when I replaced the oil pump with a new one from Andover Norton. When the bike is running, in less than five minutes it has peed about 2-3 eggcups full of oil from the crankcase breather pipe. Is this normal for a Dommie? I don't really think it can be, but you never know with these old bikes.

Can anyone help with the reason for this, and a possible cure?

Many thanks

Tim

Re: Excessive oil from crankcase breather pipe.

Posted by robert_tuck at October 23. 2017

There has been plenty written on this subject but a newly rebored engine can suffer with blowby till it beds in . If you are going to leave the bike for more than a few Days then wet sumping is likely and you need to deal with it by draining the sump or other means. I deal with it by arranging the breather to run into the Tank tower (on a DL) plus running the bike at least weekly at very low revs for a mile or so to avoid blowing out the mains seal into the primary.I check the oil level and if very low,drain the sump , a later sump filter with magnet plug helps (although the old sump spanner will not fit the new filter unit,thanks AMC!) and none of your dommy spanners will fit the magnet ,thanks again!).They fit on my bike though after heavy file work.I will probably fit a tap at some stage despite all the  doom mongers.

Re: Excessive oil from crankcase breather pipe.

Posted by howard_robinson at October 24. 2017

Hello Tim - That does sound a bit excessive even for a newly-honed bore.  May I ask - how long had it stood since the engine rebuild ? I'm wondering if  an oil scraper ring has stuck in......As you have a late wideline frame you would be able to fit the later slimline oil tank with the 'return tower' as per the later 650's and Atlas's.  Then connect the breather accordingly with the longer breather pipe.  There is also a take off to breathe a mist to the rear chain. A better set-up all round.  Of course you then would not know if excessive oil was passing through the crankcase breather so it's better to sort that out first.  As Robert suggests a valve/tap to stop the wet-dumping may be the answer if you're not running it weekly. I use the Mick Hemming's valve on mine (so far trouble-free) but I know there are doubters out there and much has been written on that subject should you wish to read it and frighten yourself !! Keep emptying the sump before you run it until you've done around 80 miles or so to bed-in the bores.  Good Luck , Howard

Re: Excessive oil from crankcase breather pipe.

Posted by robert_tuck at October 24. 2017

The new pump may be bigger than needed and may have 6 start gear set. Could over supply the earlier motor?.

Re: Excessive oil from crankcase breather pipe.

Posted by tim_harris at October 24. 2017

Previously robert_tuck wrote:

The new pump may be bigger than needed and may have 6 start gear set. Could over supply the earlier motor?.


Hi Robert,

The new pump was the correct 3 start type, and was only fitted to help the wet sump problem, which it has done to a large extent. It has not affected the oil output from the crankcase breather.

 

 

Re: Excessive oil from crankcase breather pipe.

Posted by tim_harris at October 24. 2017

Previously howard_robinson wrote:

Hello Tim - That does sound a bit excessive even for a newly-honed bore.  May I ask - how long had it stood since the engine rebuild ? I'm wondering if  an oil scraper ring has stuck in......As you have a late wideline frame you would be able to fit the later slimline oil tank with the 'return tower' as per the later 650's and Atlas's.  Then connect the breather accordingly with the longer breather pipe.  There is also a take off to breathe a mist to the rear chain. A better set-up all round.  Of course you then would not know if excessive oil was passing through the crankcase breather so it's better to sort that out first.  As Robert suggests a valve/tap to stop the wet-dumping may be the answer if you're not running it weekly. I use the Mick Hemming's valve on mine (so far trouble-free) but I know there are doubters out there and much has been written on that subject should you wish to read it and frighten yourself !! Keep emptying the sump before you run it until you've done around 80 miles or so to bed-in the bores.  Good Luck , Howard


Hi Howard,

Thanks for your suggestions, I believe the chap before me used to ride it regularly and just topped up the oil every so often. Undecided

I'm not too worried about the wet sumping, as it seems to be a lot better after the new pump was fitted, and I don't really like the idea of a tap in the oil feed line, as I know that one day I will forget to turn it on! Wink

I do like your idea of fitting the later oil tank, this seems like a good solution after I figure out what's happening in the engine. I think I will continue to run it for a couple of hundred miles to see if it settles down, but first I have to get the gearbox off for refurbishment by SRM, as it has more neutrals than gears in it. Sealed

 

Re: Excessive oil from crankcase breather pipe.

Posted by tim_harris at October 24. 2017

Previously robert_tuck wrote:

There has been plenty written on this subject but a newly rebored engine can suffer with blowby till it beds in . If you are going to leave the bike for more than a few Days then wet sumping is likely and you need to deal with it by draining the sump or other means. I deal with it by arranging the breather to run into the Tank tower (on a DL) plus running the bike at least weekly at very low revs for a mile or so to avoid blowing out the mains seal into the primary.I check the oil level and if very low,drain the sump , a later sump filter with magnet plug helps (although the old sump spanner will not fit the new filter unit,thanks AMC!) and none of your dommy spanners will fit the magnet ,thanks again!).They fit on my bike though after heavy file work.I will probably fit a tap at some stage despite all the  doom mongers.


Hi Robert,

Thanks for your comments. As I said, fitting a new oil pump has helped a lot with the wet sump problem, so I'm not too bothered by that. At some stage someone has fitted the later magnetic sump plug, so draining it is a simple affair.

I will run it in for a while longer to see if the breather problem settles down, and keep my fingers crossed.

Re: Excessive oil from crankcase breather pipe.

Posted by robert_tuck at October 25. 2017

My 99  refused to "run in"  untill after many  thousands of miles past including some full bore blasts round tracks. The breather into the tank is not a final solution either, Tank breathing becomes an issue and condensation in the tank can rear its head. Engine emissions are acidic and are not the best thing for rear chains. I have a large bore vertical untimed breather on a single and only h20 comes out.

Re: Excessive oil from crankcase breather pipe.

Posted by anna jeannette Dixon at October 25. 2017

Hello  fit an oil dump tank  you can buy nice ones off eBay  and the thing to be worried about this new oil pump it one to fit a commando or not  has 3 starts are not the same oil pump the commando one are that bit bigger inside with wider gears  made for higher pressures  so if this is the case you need to take your engine out for a complete rebuilt and update on rocker shafts plain not scrolled  and large end shells with holes  and pressure relief spring   or have the original oil pump refurbished  at RGM motors


Re: Excessive oil from crankcase breather pipe.

Posted by tim_harris at October 29. 2017

Previously anna jeannette Dixon wrote:

Hello  fit an oil dump tank  you can buy nice ones off eBay  and the thing to be worried about this new oil pump it one to fit a commando or not  has 3 starts are not the same oil pump the commando one are that bit bigger inside with wider gears  made for higher pressures  so if this is the case you need to take your engine out for a complete rebuilt and update on rocker shafts plain not scrolled  and large end shells with holes  and pressure relief spring   or have the original oil pump refurbished  at RGM motors


Hi Anna, thanks for your comments. I am sure that the oil pump fitted is correct for the model 99, it came from Andover Norton who specialise in these Nortons. I can't seem to find any oil dump tanks on eBay, I don't suppose you have a link do you?

Many thanks

Tim

 

Re: Excessive oil from crankcase breather pipe.

Posted by Andy MacKenzie at October 29. 2017

Tim,

Have you checked the compression to get an idea whether the rings are sealing?  A leakdown tester is a useful tool to identify where leaks might be occurring.

If new rings were fitted without a rebore and the bores were not de-glazed, the glaze/lacquer could prevent the rings bedding in - does the engine smoke at all?

Not suggesting you try this, but I was told this story by an ex Wellworthy (piston and ring manufacturer) engineer.  A new set of rings had been supplied to a haulage company for a large truck engine.  After fitting the rings and re-installing the engine, Wellworthy received an irate call from the company, complaining that rings were faulty, as the engine was smoking badly and was down on power.  Wellworthy sent a service engineer round and he confirmed the symptoms.  When he asked if the bores had been de-glazed before fitting the rings, there answer was no! He removed the engine air filter inlet duct, asked for the engine to be started and got out a tube of Vim, which he then proceeded to lightly dust into the intake duct.  Whilst still shaking in the Vim, the smoking began to subside and after about few seconds had ceased altogether.  A test run found power restored and no further problems were encountered. Who needs de-glazing tools!  Finding Vim, Glitto or similar now might be the tricky part though.

Andy

Re: Excessive oil from crankcase breather pipe.

Posted by Dan Field at October 29. 2017

Re: Excessive oil from crankcase breather pipe.

Posted by Julian Wells at October 29. 2017

Sounds ideal -- if you want to turn your bike into a lemon ...

 

Previously Dan Field wrote:

I saw Ajax powder a while ago, lemon scented, would that be ok?!

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2053587.m570.l1313.TR0.TRC0.H0.Xlemon+ajax.TRS0&_nkw=lemon+ajax&_sacat=0

Re: Excessive oil from crankcase breather pipe.

Posted by paul_standeven at October 29. 2017

The Commando oil pump has 30% wider scavenge gears, and perhaps wider pressure gears as well.  If you fit such a pump to an early machine, surely this will just mean that it scavenges a bit better, and has a higher oil pressure - something the early bikes seriously lack.  It is fitting the 6-start gears which require the plain rocker shafts and other oil system modifications of the late bikes

Paul

 

Previously anna jeannette Dixon wrote:

Hello  fit an oil dump tank  you can buy nice ones off eBay  and the thing to be worried about this new oil pump it one to fit a commando or not  has 3 starts are not the same oil pump the commando one are that bit bigger inside with wider gears  made for higher pressures  so if this is the case you need to take your engine out for a complete rebuilt and update on rocker shafts plain not scrolled  and large end shells with holes  and pressure relief spring   or have the original oil pump refurbished  at RGM motors


Re: Excessive oil from crankcase breather pipe.

Posted by ian_soady at October 30. 2017

I've read of people using jeweller's rouge in a similar way to Vim although I'd hesitate to do it myself......

Re: Excessive oil from crankcase breather pipe.

Posted by anna jeannette Dixon at October 30. 2017

Previously paul_standeven wrote:

The Commando oil pump has 30% wider scavenge gears, and perhaps wider pressure gears as well.  If you fit such a pump to an early machine, surely this will just mean that it scavenges a bit better, and has a higher oil pressure - something the early bikes seriously lack.  It is fitting the 6-start gears which require the plain rocker shafts and other oil system modifications of the late bikes

Paul

 

Previously anna jeannette Dixon wrote:

Hello  fit an oil dump tank  you can buy nice ones off eBay  and the thing to be worried about this new oil pump it one to fit a commando or not  has 3 starts are not the same oil pump the commando one are that bit bigger inside with wider gears  made for higher pressures  so if this is the case you need to take your engine out for a complete rebuilt and update on rocker shafts plain not scrolled  and large end shells with holes  and pressure relief spring   or have the original oil pump refurbished  at RGM motors


Hello yes, it's all very well to have more oil going round your engine but with narrow return passages the oil find the weakness point to bleed out of,  usually the rocker cover end caps,  or valve guides  So you not gaining anything,  Yours  Anna J

Re: Excessive oil from crankcase breather pipe.

Posted by anna jeannette Dixon at October 30. 2017

Previously tim_harris wrote:

Previously anna jeannette Dixon wrote:

Hello  fit an oil dump tank  you can buy nice ones off eBay  and the thing to be worried about this new oil pump it one to fit a commando or not  has 3 starts are not the same oil pump the commando one are that bit bigger inside with wider gears  made for higher pressures  so if this is the case you need to take your engine out for a complete rebuilt and update on rocker shafts plain not scrolled  and large end shells with holes  and pressure relief spring   or have the original oil pump refurbished  at RGM motors


Hi Anna, thanks for your comments. I am sure that the oil pump fitted is correct for the model 99, it came from Andover Norton who specialise in these Nortons. I can't seem to find any oil dump tanks on eBay, I don't suppose you have a link do you?

Many thanks

Tim

 

Hello there are loads of dump tanks On eBay  try putting in oil tanks and breathers mods  yours     anna j

Re: Excessive oil from crankcase breather pipe.

Posted by sundarraju_sivaraja at November 03. 2017

Tim,

 

I had the same issue as yours with my Norton Slimline 500cc engine.

Oil is leaking out from the crankcase breather like open a water tab. I asked many people around and seems like no one has experienced this kind of issue.

The only similarities between you and me are the engine is newly rebuilt. I keep the engine like 1 year plus after the rebuild before assemble and start the bike. Some people advise checking the piston rings, camshaft breather disc & spring.

Now I assemble back the engine with new spring, disc & piston ring. Haven't started the bike yet. I'll update again if I solve the issue and you please keep updating.

Re: Excessive oil from crankcase breather pipe.

Posted by tim_harris at November 03. 2017

Previously sundarraju_sivaraja wrote:

Tim,

 

I had the same issue as yours with my Norton Slimline 500cc engine.

Oil is leaking out from the crankcase breather like open a water tab. I asked many people around and seems like no one has experienced this kind of issue.

The only similarities between you and me are the engine is newly rebuilt. I keep the engine like 1 year plus after the rebuild before assemble and start the bike. Some people advise checking the piston rings, camshaft breather disc & spring.

Now I assemble back the engine with new spring, disc & piston ring. Haven't started the bike yet. I'll update again if I solve the issue and you please keep updating.

Ok, thank you. 🙂

Re: Excessive oil from crankcase breather pipe.

Posted by tim_harris at November 03. 2017

Previously Andy MacKenzie wrote:

Tim,

Have you checked the compression to get an idea whether the rings are sealing?  A leakdown tester is a useful tool to identify where leaks might be occurring.

If new rings were fitted without a rebore and the bores were not de-glazed, the glaze/lacquer could prevent the rings bedding in - does the engine smoke at all?

Not suggesting you try this, but I was told this story by an ex Wellworthy (piston and ring manufacturer) engineer.  A new set of rings had been supplied to a haulage company for a large truck engine.  After fitting the rings and re-installing the engine, Wellworthy received an irate call from the company, complaining that rings were faulty, as the engine was smoking badly and was down on power.  Wellworthy sent a service engineer round and he confirmed the symptoms.  When he asked if the bores had been de-glazed before fitting the rings, there answer was no! He removed the engine air filter inlet duct, asked for the engine to be started and got out a tube of Vim, which he then proceeded to lightly dust into the intake duct.  Whilst still shaking in the Vim, the smoking began to subside and after about few seconds had ceased altogether.  A test run found power restored and no further problems were encountered. Who needs de-glazing tools!  Finding Vim, Glitto or similar now might be the tricky part though.

Andy

Hi Andy,

thanks for your comments, I’m not sure I fancy tipping vim down the engine! 😳

But checking the compression is a good idea, I hadn’t thought of it. I have a leak down tester if I can find it amongst the tardis that is my garage!

I’m away for a few days, but I’ll give it a go when I’m back. I don’t suppose you have an idea as to what the psi figures should be? I am thinking about 100psi maybe?

Many thanks,

Tim

Re: Excessive oil from crankcase breather pipe.

Posted by michael_sullivan at November 03. 2017

Here is a stupid question (you can consider the source):

Are the oil hoses fitted the wrong way around? i.e. the high volume side of the pump is feeding the engine?

Mike

Re: Excessive oil from crankcase breather pipe.

Posted by ian_hay at November 03. 2017

Previously michael_sullivan wrote:

Here is a stupid question (you can consider the source):

Are the oil hoses fitted the wrong way around? i.e. the high volume side of the pump is feeding the engine?

Mike


Hello Mike,

Do you think it likely that if the delivery pipe were connected to the return side of the pump that it would still pump oil around the engine?

Regards, Ian.

Re: Excessive oil from crankcase breather pipe.

Posted by ian_soady at November 04. 2017

It would until it had used up everything in the return pipe - which isn't a lot.......

Re: Excessive oil from crankcase breather pipe.

Posted by anna jeannette Dixon at November 04. 2017

Previously tim_harris wrote:

Having recently bought a 1959 Dominator 99, and being new to the model (my other bikes are Commandos) I need some advice on the amount of oil coming out of the crankcase breather pipe. This is routed to the underneath of the crankcase behind the primary chaincase, unlike the Commando, which returns to the oil tank. Is this correct?

When I bought the bike I was told that the engine had been recently rebuilt, although, as it was bought from a deceased persons estate, there was no paperwork with it. It also wet sumped quite  frequently, but it helped enormously when I replaced the oil pump with a new one from Andover Norton. When the bike is running, in less than five minutes it has peed about 2-3 eggcups full of oil from the crankcase breather pipe. Is this normal for a Dommie? I don't really think it can be, but you never know with these old bikes.

Can anyone help with the reason for this, and a possible cure?

Many thanks

Tim

 

hello member  now what do you call excessive oil coming from the breather  pipe  on startup you will get an excessive amount of oil coming out of the breather pipe as all this is oil that's run back into the crankcase sump area and on startup the crankcase pressure forces this oil out , and the only way out is through the timed breather  witch Norton manufacturer to do just this,  so you can say it's only doing its job,  and this oil then was supposed to be used for lubricating the rear drive chain,  but what I have done with my two Norton twins  is divert this breather  into a catch tank and halfway up there is an outlet for oil to then run down to lubricate the rear drive chain, in a drip feed  more like a scot oiler dose, you can by nice alloy catch tanks from eBay under  car performance  parts, now I do hope this may  shed some light on things    yours   anna j

Re: Excessive oil from crankcase breather pipe.

Posted by Andy MacKenzie at November 05. 2017

Tim,

There are a number of variables to consider when measuring compression, so it would be difficult to give an exact figure that you should expect to see.  Gauge accuracy, piston ratio, head skimmed?, compression plate?/gasket thickness, engine temperature, etc all have an effect.  As an estimate, 100-120psi would seem about right - the delta between cylinders should hopefully be less than 10psi; much more and I would investigate.  A little oil added to the upper cylinder after the first test is always useful to see if the results is higher, indicating ring leakage, and your leakdown tester is handy for checking whether pressure holds and and listening for valve leakage (with ports exposed).

Andy

Re: Excessive oil from crankcase breather pipe.

Posted by anna jeannette Dixon at November 08. 2017

Previously Andy MacKenzie wrote:

Tim,

There are a number of variables to consider when measuring compression, so it would be difficult to give an exact figure that you should expect to see.  Gauge accuracy, piston ratio, head skimmed?, compression plate?/gasket thickness, engine temperature, etc all have an effect.  As an estimate, 100-120psi would seem about right - the delta between cylinders should hopefully be less than 10psi; much more and I would investigate.  A little oil added to the upper cylinder after the first test is always useful to see if the results is higher, indicating ring leakage, and your leakdown tester is handy for checking whether pressure holds and and listening for valve leakage (with ports exposed).

Andy

 

 

Hello To test for any piston ring leakage  now you need to remove your cylinder head or best done in your rebuild of your engine, now to test you need your hand over one cylinder and press down on the kick starter so the engine turns over quickly do this a few times  and remove your hand and see if you have oil on them  or oil coming up the bore, you should not have any oil coming past the piston rings  if gaped right,  your piston compression rings,  end gap should be no more than 8 thou and on more than 10 thou for the oil rings . to test for valve leakage  with the cylinder head removed  turn the head so the valve are looking skyward, and rest the head so it does not move, and mix up white  spirts and a small dab of engineers blue  and stir well in until blue  now with this pour this blue mix into the dished part of the cylinder head around the valve so it covers them, and leave it to stand and watch for any blue running out of the inlet or exhaust ports   this need to be done without valve springs in place  if you have nothing running from the ports you have a good valve seal ,   yours Anna J Dixon

Re: Excessive oil from crankcase breather pipe.

Posted by tim_harris at Sunday 21:51

Many thanks to everyone who responded to my message. I think I have found the problem, (thank you Andy) after measuring the compression it seems that I only have 25psi on each cylinder, so it looks like a head off job to see what the problem is..... Frown

 

 

Re: Excessive oil from crankcase breather pipe.

Posted by robert_tuck at Monday 02:17

Don't think it would run with only 25 psi,  you must be doing it differently to normal.

Re: Excessive oil from crankcase breather pipe.

Posted by anna jeannette Dixon at Tuesday 18:27

Previously robert_tuck wrote:

Don't think it would run with only 25 psi,  you must be doing it differently to normal.

Hello 25 psi is just ridiculous you will have more than 100 psi  each cylinder or you must be using Newton-meters  per bar   So do a retest  before you take the head off for no reason yours  Anna J

Re: Excessive oil from crankcase breather pipe.

Posted by David Cooper at Tuesday 20:18

For the compression test you need to open the throttle wide to make sure it can breathe in as much air as possible, and kick several times.

If just one cylinder was that low, then it might have a hole in it (been there, sadly), but holes in both seems unlikely.  A hole on one piston leads to oil in all sorts of undesirable places, not to mention loss of power and LOTS of smoke, at which point even the most reckless rider will probably stop before even more damage takes place.

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