1962 650SS oil feed line to the rockers spindle of the head

[pierodn]

Hi.
My 650 SS has the oil line to the rockers spindles head with low pression system from oil tank return pipe.
Do you suggest to have much pression changing the scrolled rockers spindles with the flat one to go from timing to head?.
Thank you.
Piero

 

[guest76]

I swap to six start gear and worm, move the top end feed to the high pressure side (instead of return) and swap from scrolled spindles to plain.

I have only done this on our two Dommies because when I was rebuilding the heads, I found the spindles were worn and needed swapping anyway.

There is nothing wrong with feeding the top end from the return and using scrolled spindles - the oil feed rate is adequate.

 

[pierodn]

I swap to six start gear and worm, move the top end feed to the high pressure side (instead of return) and swap from scrolled spindles to plain.

I have only done this on our two Dommies because when I was rebuilding the heads, I found the spindles were worn and needed swapping anyway.

There is nothing wrong with feeding the top end from the return and using scrolled spindles - the oil feed rate is adequate.

Thank you for your prompt answer.
If i leave feeding the top end from return with scrolled spindles, is better, in any case, to swap to six start gears?.
Ciao.
Piero

 

[guest76]

For me, using the high capacity pump with six start makes sense - it became standard on the Atlas anyway, and is a great way to circulate more oil around the engine.

If you do swap to a six start, but leave the rocker feed on the return side, just keep an eye out for over oiling the top end.

Controlling the feed rate to the top end relies on the restriction at the "t piece" on the return line - it is easy to restrict it a little more if you find you are over oiling the top end.

 

[possm]

The Oil feed and return junction is larger on post '66 [6 start] as is the drilling into the crankcase.

 

[texasSlick]

For me, using the high capacity pump with six start makes sense - it became standard on the Atlas anyway, and is a great way to circulate more oil around the engine.

If you do swap to a six start, but leave the rocker feed on the return side, just keep an eye out for over oiling the top end.

Controlling the feed rate to the top end relies on the restriction at the "t piece" on the return line - it is easy to restrict it a little more if you find you are over oiling the top end.

I have the 6 start oil pump with rocker feed from oil return line, and do not have over oil feed issues. I also have the con rod squirt holes ... how the 6 start pump and squirt holes occurred on a '62 factory build Atlas is a mystery.

Slick

 

[norton bob]

IF you go for the 6 start gears and a bigger pump you are very likely to get too much oil in the mag area and a missfire and flood the inlet valve area with more oil than can drain away. you may also overoil the pistons if you drill the rods unless you fit better oil control rings , You may also suffer airation in the oil and cavitation damage to the shell bearings. And you will wear out your pump twice as quick . You will definately get more oil leaks. Why not just ride it?.

 

[dynodave]

bigger pump

Besides narrow gears for all early NHT with 1.5" crank and the later full width gear starting with the 1.75" crank (650), who makes and sells a "bigger"pump?

 

[Bernhard]

I have the 6 start oil pump with rocker feed from oil return line, and do not have over oil feed issues. I also have the con rod squirt holes ... how the 6 start pump and squirt holes occurred on a '62 factory build Atlas is a mystery.

Slick

Re; Con rod squirt holes, - this was first used on the Commando, but Norton later issued a press bulletin stating that the big end sheels should be turned around so that they blocked the oil holes.
Amazing what comes out of NVT / Norvil factory.

 

[dynodave]

I have the 6 start oil pump with rocker feed from oil return line, and do not have over oil feed issues. I also have the con rod squirt holes ... how the 6 start pump and squirt holes occurred on a '62 factory build Atlas is a mystery.

Slick

TS
The reported racing effort says there was 6 start gears quite early for NHT. Some early singles has 6 start except the "gear was thinner". I'd assume that meant the crank gear. Would it still have worked on a twin? IDK?
Is your case fitted with the early small diameter junction block hardware?
I guess I could make my oil pump tester case into small inlet for a flow rate test comparison.....does the size really alter the flow rate enough to matter?
Inquiring minds want to know the truth instead of rumors...

 

[texasSlick]

TS
The reported racing effort says there was 6 start gears quite early for NHT. Some early singles has 6 start except the "gear was thinner". I'd assume that meant the crank gear. Would it still have worked on a twin? IDK?
Is your case fitted with the early small diameter junction block hardware?
I guess I could make my oil pump tester case into small inlet for a flow rate test comparison.....does the size really alter the flow rate enough to matter?
Inquiring minds want to know the truth instead of rumors...

My oil junction block has 5/16" OD tubes. The internal passages in the case are 3/16" dia. if my memory serves me correctly.

does the size really alter the flow rate enough to matter?
Flow rates are insignificantly reduced by restrictions that are short relative to the bore. For example, as a rule of thumb, if a tube has a reduction in bore up to 20%, the flow is not likely to be reduced by more than 5%, if the reduced section is less than 10 bore diameters.

This bore/flow relationship is shown in data I posted regarding flow thru a fuel tap.

Flow Measurements on Ewarts Fuel Tap

A thread on the Commando Forum piqued my interest to make some flow measurements on an Ewarts fuel tap as used on the Atlas. The tap is pull for Main, and twist 90 deg. for Reserve. I measured the fuel delivery to the float chamber of the Monobloc carburetor, which included flow resistance...

www.accessnorton.com

The data shows for a fuel tap nipple of 0.218" bore, reducing the bore to 0.149" (31.6% reduction), the flow loss is merely 1.8%. In this case, the length of the nipple was about 1 inch or about 5.6 bore diameters.

Slick

 

[annajeannette]

For me, using the high capacity pump with six start makes sense - it became standard on the Atlas anyway, and is a great way to circulate more oil around the engine.

If you do swap to a six start, but leave the rocker feed on the return side, just keep an eye out for over oiling the top end.

Controlling the feed rate to the top end relies on the restriction at the "t piece" on the return line - it is easy to restrict it a little more if you find you are over oiling the top end.

Now what are you jibbering about and some of the advisce you been given is totally wrong and heres why now to use the six start oiling system you need to change some crucal parts like big end shells with oil holes in then and pain rocker spindels too so its a major stip down and rebuilt with the appropret parts so if I was you I would stick too the 3 start oil system if its good enough for a 650 and 750 atlas is ok for your bike just use good oil like a good 20/50 will be fine I have done thousand of miles on 20/50 and raced on it too

 

[guest76]

You are not me Anna.

I have not been given any advice - what I’ve done with my bikes is based on my research, findings, and testing.

In terms of the experiences I have shared here, it’s based on what works for me.
My criteria is a smoke free, leak free bike with a robust and well oiled engine.

As far as ‘jibbering’ and ‘totally wrong’ - I don’t think you are in a position to accuse me of either of those.
That’s the pot calling the kettle back, and I’ll thank you to keep your rudeness to yourself.

 

[Bernhard]

Now what are you jibbering about and some of the advisce you been given is totally wrong and heres why now to use the six start oiling system you need to change some crucal parts like big end shells with oil holes in then and pain rocker spindels too so its a major stip down and rebuilt with the appropret parts so if I was you I would stick too the 3 start oil system if its good enough for a 650 and 750 atlas is ok for your bike just use good oil like a good 20/50 will be fine I have done thousand of miles on 20/50 and raced on it too

Sorry, but the oil holes in the big ends shells is OLD ADVICE!!!.
NVT issued a press statement saying not to line up the oil holes in the big end shells for the Commando, it would be the same for any Norton.