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A: Oil Pipework Oil consumption

robin stafford

Website User
VOC Member
Has any body checked the oil used on their twin . I have no oil leaks apart from the crank case breather to which has been extended to the rear pillion foot rest hanger cannot seem to seem to stop oil from leaking out when stopped about 1 inch dia puddle on the road. I have routed the breather pipe under the engine. would it be better to go upwards with the breather pipe but the route would not be easy . For the last 5000 miles i have been using fully synthetic mobile one 0/30 with the high content of ZDDP with no restrictors in the barrel feeds and no metering wires in the rocker feeds. no smoking on the over run or normal running . would you say that 500 miles per pint is ok . I think most of the loss is going on the road via the breather any ideas
 

Nigel Spaxman

Well Known and Active Website User
VOC Member
I don't think the thinner oil will run hotter, it might even run cooler, but whatever the temperature it will be thinner. The oil circulation rate in a Vincent is very slow so the oil in the tank doesn't get very hot. The oil at the hot places in the engine like in the head and the pistons must get hot. Around the intake and exhaust guides it is always going to be hot. If the oil is thicker less will go down there.
 

greg brillus

Well Known and Active Website User
VOC Member
The heat in oil comes from resistance mostly, so compare any Brit twin Triumph, BSA, etc......These run high oil pressures with a common shape oil tank.......The Vincent runs almost nill pressure and has an oil tank that acts like a big heatsink with plenty of air flow around it.......I read somewhere that a Vin is flat out getting an oil temp over 70 degrees Celsius on a hot day........So more of an issue with sludge forming in the base of the tank from moisture build up.........You want oils in the viscosity of 10 to 50 weight.......anything higher is too thick........I run a 15/w 40 diesel oil in mine which is still quite thin, but because of the cams in my engine it needs to spin quite fast when i kick it over or else it just wont fire up....... this no matter what kind of ignition I try, either coil or magneto made little to no difference........I don't ride a huge amount, perhaps 1000 to 1500 miles per year, so i just change the oil every 1000 or annually, the oil tank stays nice and clean, contents of the timing chest looks like new.........Good enough for me.
 

oexing

Well Known and Active Website User
VOC Member
Diesel engine oil is quite nice with a lot of detergent additives , so your engine will stay very clean inside. Multigrade types are great for starting by kickstarter certainly , and perfect for riders who don´t garage the bikes for many months. In that case a multigrade will drain a lot more down than a monograde like SAE 40 or 50. So monograde will stick better to the cams over long periods of no use so less wear in these critical components. But then, you can only do compromises many times.

Vic
 

robin stafford

Website User
VOC Member
I have been reading lots of posts on lubrication problems the prof had problems with the return supply, Starting the bike the looking at the return the oil spurts out within 8 seconds blipping the throttle looking at the crankcase breather nothing comes out for about 2 minutes letting the bike tick over after a minute or so oil starts drip out looking at the return nothing is returning only when I rev does the oil return I have a single start pump Do you think no restricters in the barrel feeds and the rocker feeds to much oil is building up at low rpm flooding the engine also when ticking over for some time revving, the return side goes into over drive plus some smoke from the exhaust , a few blips then it clears I think the level of oil is to high in the crankcase
 

vin998

Well Known and Active Website User
VOC Member
VOC Forum Moderator
Robin
One thing to look for is oil pump cap OP33. If the threads are not sealed properly then this end of the oil pump is the return and the pump rather than lift the oil from the sump can suck air past the cap threads instead and so slowly the oil in the sump rises.
 

davidd

Well Known and Active Website User
VOC Member
Robin,

It is hard to figure out the problem from the symptoms. It could be possible that the symptoms are not important.

Do you think no restricters in the barrel feeds and the rocker feeds to much oil is building up at low rpm flooding the engine
I would think the answer to this is no. I cannot remember an owner with this type of problem. But your two questions are related:
when ticking over for some time revving, the return side goes into over drive plus some smoke from the exhaust , a few blips then it clears I think the level of oil is to high in the crankcase
I think that you are leaving out some of the oil movement in the case. When the sump fills with oil during non-use, upon start-up the sump would certainly be overfilled. You describe the symptoms of sumping, but I can see that you think it is happening with the engine running. When the engine is running the oil that makes its way to the sump is picked up by the flywheels, scraped off the wheels into the scavenge chamber at the rear of the sump. The oil that is carried into the scavenging chamber is pumped from the scavenging chamber by the bottom of the oil pump and pushed up the oil line that goes to the rockers on its way back to the tank return.

I mention this because the scavenging portion of the pump will evacuate the scavenging chamber at a very high rate. I understand this scavenge pumping rate to be much higher than the rate that the front of the oil pump supplies oil to the chest.

The revving of the engine will dump some oil in the scavenging chamber (from the flywheels slinging more oil) and it will get pumped up to the tank very quickly. This may be the "overdrive" that you are witnessing. The smoke in the exhaust could be from oil in the tunnels flooding the valve guides momentarily. The oil supply to the chest is "non-interruptible", while the oil supply from the scavenging chamber is "interruptible" because the scavenging chamber can be run dry or close to it during idle.

David
 

greg brillus

Well Known and Active Website User
VOC Member
That 3/8" whitworth grub screw bellow the oil pump brass cap can leak too, especially if someone has got at it before.......If it leaks oil it will suck air........Just a small one to look at.
 

robin stafford

Website User
VOC Member
I think when the engine is on tick over the returning oil being pumped over the heads and leaking down the rockers and push rod tubes explains why nothing is going back to the tank dispite the return side of the pump being double the size so the crank case fills up an oil comes out of the breather. I still think that I need to slow the amount of oil to the rockers
 

greg brillus

Well Known and Active Website User
VOC Member
Didn't someone post on here a few years back about the rocker feed bolt holes being opened up a bit, and this caused too much oil to bypass back into the sump........when altering these things you need to be careful not to get carried away........
 

greg brillus

Well Known and Active Website User
VOC Member
Perhaps disconnect your return line at the base of the engine and run a length of flexible line into a clean container, then run the engine to see what it does.......It wont hurt to run it for a short while, that will give you some idea of what is going on.
 

greg brillus

Well Known and Active Website User
VOC Member
Your oil sounds too thin to me.......Do you know what your rocker feed bolts are.......Stock ,or the ET 100/1 Mod type.......Is it possible something has failed........ The bleed holes in the ET100/1 bolts are very small........could there be a restriction in your return line.......perhaps swollen up.
 

robin stafford

Website User
VOC Member
I have the standard rocker feed bolts that do not lock the rockers in the tunnel the return lines are new thicker oil will probably cure the the excess oil passage down to the cams and probably cure the problem. but I like the idea of using thin oil vincent owners always want to change things
 

davidd

Well Known and Active Website User
VOC Member
I now remember Neville's article, but not enough to discuss it. I put locking rocker feed bolts in David Tomkins' engine and he drilled out the oil holes. I remember checking Neville's article at that time. David runs the thinnest oil he can and it has worked well for him with no oiling issues. I can only say that the engine has good drainage and no leaks.

It is a little work, but I wonder if you could check the output of oil as Greg suggests and run the same test with the output of oil at the return. It could be timed and run at a similar rpm to see if there is a large amount of oil difference. It would tell you if there something to worry about. But I am not certain that the problems you are experiencing are not just a number of known, but small issues like breather timing or routing the tube vertically, locking rocker feed bolts, guide drainage, leakdown problems, etc.

Sometimes the cases have damaged scrapers or holes drilled through the bottom of the scrapers, which can alter the normal flow and scavenging of the engine.

David
 

ernie

Well Known and Active Website User
VOC Member
Didn't someone post on here a few years back about the rocker feed bolt holes being opened up a bit, and this caused too much oil to bypass back into the sump........when altering these things you need to be careful not to get carried away........
That was Neville, as RS above mentions. I think with such thin oil you should have metering wires in the rocker feeds. I also question synthetic oil in classic air cooled engines. When I tried it I suffered wear on the valve stems and upper guides.
 

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