oil flooding inlet valves

interested if anyone has encountered similar problem please?

i have a 1962 750 atlas motor fitted to domiracer narrow featherbed frame

a problem evolved since fitting manx style oil tank ,

i have oil flooding inlet rocker box running down valve guides

hence james bond very smokey motor after idling hot

easy test to check if rings or head causing smoke is to block off oil feed to head and see if smoke stops

i wish i tried this test before fitting new rings ...duh

i have six start oil pump gears and straight rocker shafts fitted

i replaced valve stem oil seals,checked rocker shafts flats facing towards valves,check factory drain rhs of head all ok

eventually i fitted additional 9mm ID external drain from lowest point in inlet rocker box comes out under inlet manifold to rear of timing cover and the problem seems to be solved.

i use 50 grade penrite oil, max oil pressure is 40psi and when running hot 20psi at 2500revs/5 psi at idle

just wondering if anyone else had this problem and how they fixed it ?

domiracer22 said:

a problem evolved since fitting manx style oil tank ,

Click to expand...

Tell us more about this bit.
The oil situation was OK and all under control before fitting this oil tank ??

And perhaps we should also ask what was the previous oil tank being used ?

And3, we should also ask how was the high pressure oil being fed into the head plumbed from the timing cover, since the 62 Atlas didn't have any provision for this.

What we are getting at here that was this motor all good in the oiling dept,
and the change of oil tank upset this.
Or it is freshly built, and has never been good in the oiling dept.
Remember, we can't see what is sitting in your garage, we can only go on precisely what you describe to us...

This exact subject occurs in older posts, more often than you might expect.
With very vague symptoms and solutions I'd comment.
Although I don't have the 6 start arrangement on anything that wasn't born with it - yet. (in the works though).
Ain't old bikes fun !

thanks Rohan,

the 1962 dominator had original oil tank with 6 start gears on oil pump and oil feed to the head is from timing cover

i believe the oil flooding inlets situation was OK before fitting this oil tank as i purchased domiracer with manx style tank already fitted .

the bike was only ridden on country roads with no idling

and i live in Sydney and city traffic dictates idling .

it is possible problem was there since originally built, and has never been good in the oiling dept.


wih valve covers off and warm engine 1200rpm there is continual oil flowing/escaping from both sides between shaft and rocker shafts

clearances seem ok

i tried reducing flow rate by reducing 3 banjo bolts orifices from 2.5mm to .7mm but no difference

i have photos if i can work out how to post them

cheers rod

Atlas oil feed to the rockers should come off the banjo at the inlet to the oil tank. With the stock Atlas oil tank, there should be about 6 inches of oil head pressure at that point.

Oil feed coming off the timing cover is at engine oil pressure, which may vary from 30 to 60 psi. For reference, 30 psi is equivalent to over 1000 inches of oil pressure.

Therefore, feeding the rockers from the timing case can cause flooding because the Atlas rocker oil distribution is not designed for such high pressure.

The Commando engine feeds the rockers off the timing case, but the rocker axles must incorporate a design change to accommodate the increased pressure. I am not familiar with the Commando rocker axles, but your problem may be solved by substituting Commando axles for the Atlas axles.

Or, you can move the oil feed from the timing case to the oil tank inlet as in the original Atlas design.

Slick

texasSlick said:

The Commando engine feeds the rockers off the timing case, but the rocker axles must incorporate a design change to accommodate the increased pressure. I am not familiar with the Commando rocker axles, but your problem may be solved by substituting Commando axles for the Atlas axles.

Click to expand...

It sounded to me like this engine has been fitted with the rocker shafts that were intended for the pressure oiling to the valve gear, re the 'flats facing the valves'.. (?).

This is part of converting engines from bleed oiling to pressure oiling in the rocker gear....

domiracer22 said:

i tried reducing flow rate by reducing 3 banjo bolts orifices from 2.5mm to .7mm but no difference

Click to expand...

Assuming you do have the rocker shafts that were intended for pressure oiling fitted, maybe its time to start blocking off those banjo bolt orifices, one by one.
A lot of oil can go through a small hole given enough pressure, so if you have excessive oil then maybe there are too many holes. If you keep reducing them in size and number, eventually the oil supplied should be just right !!

Pics can be posted here by posting them to a free photo hosting place like photobucket etc, and then posting the link to them here with the button to make them display.
Have fun !

My 63 Atlas has the low pressure oiling system, and axle flats facing center. I would expect some other difference to exist for the high pressure system. In fact, it is my understanding that the flats are to aid the low pressure system, not limit the oil flow on the high pressure system. I could be wrong on this point, but it makes sense as such.

Rohan is correct in that a lot of oil under high pressure can pass thru a small orifice. His suggestion to limit oil flow by reducing the banjo orifice size may be a solution, but I would feel better to find the root cause of the problem .... that is, get the system working as designed, either totally low pressure, or totally high pressure, not a bodge to marry parts of each system.

Slick

domiracer22 said:

snip
i have six start oil pump gears and straight rocker shafts fitted

checked rocker shafts flats facing towards valves

Click to expand...

straight?
Do you mean unscrolled plain shaft with only a ground flat facing outward...toward valve?
1. I have seen old early long shaft rockers from early scrolled shaft heads with very ugly bores...IMO for the most part unsuitable for high pressure system. If so the original rockers may be sloppy worn out allowing way to much oil to flow.

2. Custom valve gear parts partially blocking/restricting the intake return hole. Are the heat insulating washers installed?

Oil holes in rocker shaft should be pointed away from the valves i.e. to the opposite side of the oil hole in the rockers themselves – this acts as an oil restrictor to the oil flow , failure to do that will mean copious amount of oil flooding the cylinder head.

Re:SHAFTS& ROCKERS

OK

High pressure systems. Plain shafts with oil feed holes "within" the flat. Flats and holes pointed away from the rocker ball end hole to prevent over oiling from 4 continuous HP bleeders and therefore loss of rocker lube/engine lube. This is what the book says right?

Low pressure systems. Scrolled shafts with oiler hole in a groove that feeds scrolls and flat equally , shaft hole is opposite flat.

1 bad? On these LP systems with the flat away from the rocker ball end feed hole, the ball hole does not line up with any scroll or the flat. the ball will starve. Therefore what is the point of the flat?

2 good? With the flat toward the rocker ball end the ball will get a bit of LP lubing throughout the arc of travel. Still pretty abysmal LP.

Am I missing something?

ADDED:
domiracer22 sez
"i have six start oil pump gears and straight rocker shafts fitted"

I also asked does straight = plain/unscrolled?

sounds like to me we got a high pressure feed to scrolled rocker shafts,you need to pull one out to see what you,ve got, if they are scrolled they need the low pressure feed from the oil return pipe to the oil tank

thank you for your thoughts all,

the rocker shafts are plain type as recommended for 6 start gears

but i had niagara falls of oil flooding out off shafts/rockers flooding rocker box causing oil to flood inlet guides and hence james bond smokey motor when hot after idling.

i ended up fitting a 9mm ID bypass hose from inlet to t/case and oil drains away and smoke gone.

i loaded pics on photobucket and pasted links below

cheers rod

http://s1383.photobucket.com/user/Rod_B ... s.jpg.html
http://s1383.photobucket.com/user/Rod_B ... f.jpg.html
[url=http://s1383.photobucket.com/user/Rod_Bowen/media/domiracer_zpsammy5vjc.jpg.html]http://s1383.photobucket.com/user/Rod_B ... c.jpg.html[/url]
[url=http://s1383.photobucket.com/user/Rod_Bowen/media/rocker%20box%20drain%20%201_zps1vwjyuzb.jpg.html]http://s1383.photobucket.com/user/Rod_B ... b.jpg.html[/url]
[url=http://s1383.photobucket.com/user/Rod_Bowen/media/timing%20case%20outlet_zpsoilczyue.jpg.html]http://s1383.photobucket.com/user/Rod_B ... e.jpg.html[/url]
[url=http://s1383.photobucket.com/user/Rod_Bowen/media/drain%20inside%20inlet%20chest_zpszwq3sqgz.jpg.html]http://s1383.photobucket.com/user/Rod_B ... z.jpg.html[/url]
[url=http://s1383.photobucket.com/user/Rod_Bowen/media/drain%20from%20outside%20head_zps2hsqienn.jpg.html]http://s1383.photobucket.com/user/Rod_B ... n.jpg.html[/url]

Interesting.
If you are bleeding off sooo much oil to the rockerbox,
your oil supply/pressure to the big ends isn't suffering is it ?

thanks rohan

i believe oil press to big ends ok

new oil pressure gauge reads 40psi cold and 20psi hot at 2000rpm running penrite 50 oil

the oil pressure line is last feed from rh banjo on head oil flow to rockers

because it is last in the line iam think oil pressure to big ends is equal to or greater than reading on gauge

cheers rod

http://s1383.photobucket.com/user/Rod_B ... i.jpg.html

Norton did not start fitting the Double speed oil pump worm until mid-1966, by the look of your rocker shaft they may be the wrong kind to use with this 6 start worm :?:
Using another oil drain system has not attended to the root cause of your problem –the rocker shafts fitted in the wrong way round- 180 degrees out :!:

1. Your pix shows the correct plain shaft for HP system.

A. Is your flat and hole AWAY from the ball end?

B. Your pix does not show....Do you have one of those crank case breathers anywhere on the head area...rocker cover or banjo style like 650SS? (very bad for drain down with high blow by engines). Do you have the normal timed cam end breather or is it plugged shut, how/where does it vent?

C. Have you ever back blown with high pressure air, your drain down from the timing chest back up to the head?

D. Your declared oil pressure is minimally OK but not great for a new engine.

Q; where is your rocker feed taken from is it a banjo bolt at the side of the timing cover or the return oil feed to the tank :?:

dynodave said:

A. Is your flat and hole AWAY from the ball end?

Click to expand...

I'll assume the flat is still toward the center of the engine as you stated earlier.

Bernhard said:

Q; where is your rocker feed taken from is it a banjo bolt at the side of the timing cover or the return oil feed to the tank :?:

Click to expand...

domiracer22 said:

new oil pressure gauge reads 40psi cold and 20psi hot at 2000rpm running penrite 50 oil

the oil pressure line is last feed from rh banjo on head oil flow to rockers

because it is last in the line I am think oil pressure to big ends is equal to or greater than reading on gauge

cheers rod

Click to expand...

In my humble analysis, it is obviously from the HP feed on the timing cover
My other questions remain...

re; “In my humble analysis, it is obviously from the HP feed on the timing cover
My other questions remain...” unquote

This is my conclusion to only I rather suspect that the oil pressure release valve is clogged up and wants cleaning out –don’t ask me how I know :!: (That big domed nut and double nut on the side of the timing cover)

Sounds like his OPV is is not contributing to his flooding. A seized OPV has yielded over 150psi. The opposite may be true...If anything the internal parts of the OPV are missing and you would have a lower pressure. Most OPV I've tested have opened 55-65psi and as rpm goes up the pressure does also...it does not limit the absolute pressure but only aids in limiting the amount of over pressure. It can often hit 75 but does not go to 150+...
When the oil is hot the OPV would almost never function.