Norris 336 cam specs needed

Hello, This is my first post and I'm trying to locate specs for a Norris 336 cam that's in my 73 850 commando, Actually it looks like a 750 bottom end with a 850 top end. I've had this bike in the corner of the shop for the last 25 years and just could not figure it out, But with all the combined knowledge on this site I think I can start to piece this thing together with your help.
Thanks in advance,
Mike

Buggered if I know .



this might help.Theres a somewhat prolonged ' camshaft ' thread here , dredging through that might find something .

Setting the overlap just before tdc will get you going . but the CLEARANCES are the big issue . Usually a Norton Cam
is measured ( degrees ) with the Clearance set at .020 ,

Search out the Hogslayer tripe , here .think He Ran Norris .

My Ones BIGGER than Yours . :twisted:



cams-t12813-105.html

See That Spec sheets saying .015 . I ran .016 On a 2S no worries. With Decent Valve Springs , keepers . Shimmed .


Unmarked, Norris 4R, Electric penned Norris 358/368

flogged from google pictures links .norton norris cam .

alledgedly a NRP 225 /

once in a blue moon theres one for sale somewhere , WITH the Original Spec Speet PICTURED with it . Maybe itd help to look for another, for THAT. :shock:

From www.norriscam.com website:
Sorry the header didn't past across the top, but you get the idea. See 336S below.

CAM# ADV
DURATION DURATION
@.050" CAM
LIFT VALVE LIFT
W/1.1:1 VALVE LIFT
W/1.25:1 VALVE LIFT
W/1.4:1 INTAKE
CLEARANCE EXHAUST
CLEARANCE

329S 272 deg 232 deg .329" .362" .411" .461" .004" .004"
330S 282 deg 246 deg .330" .363" .413" .462" .004" .004"
336S 290 deg 254 deg .336" .370" .420" .470" .004" .004"

Never mind this was for VW. Interesting they use the same cam number.

illf8ed said:

From http://www.norriscam.com website:
Sorry the header didn't past across the top, but you get the idea. See 336S below.

CAM# ADV
DURATION DURATION
@.050" CAM
LIFT VALVE LIFT
W/1.1:1 VALVE LIFT
W/1.25:1 VALVE LIFT
W/1.4:1 INTAKE
CLEARANCE EXHAUST
CLEARANCE

329S 272 deg 232 deg .329" .362" .411" .461" .004" .004"
330S 282 deg 246 deg .330" .363" .413" .462" .004" .004"
336S 290 deg 254 deg .336" .370" .420" .470" .004" .004"

Click to expand...

Megacycle list some Norris grinds but not the 336, but maybe they know what the 336 grind is. I found the VW 336S earlier but decided it would just cause confusion.

illf8ed said:

Never mind this was for VW. Interesting they use the same cam number.

Click to expand...

Illf8ed - not so fast to discredit your finding as the wrong cam, since there is certainly a possibility that the VW 336S and the Norton 336 employ the same lobe. Of course there is also the possibility that it is not the same lobe, but consider the following.

The stock CDO lobe lift is ~ 0.332” and the 336S has a lobe lift of 0.336”, so very similar in this regard. A stock CDO lobe has duration at 0.050” lift of ~ 246-247 deg, and the 336S has 0.050” duration of 254 deg, so makes sense (to me anyway) that it would be a slightly hotter street cam (due to longer duration) than a stock lobe, but with minimal increase in lift.

Ratedspeed - I’m looking at your degreeing set-up and although it is not clear to me from the picture, it appears the foot on your dial indicator is small (short fore to aft), and using such a foot will distort the results you generate. The foot needs to be at least as long, fore to aft, as the contact patch on the lifters that were removed from the engine. Assuming you’ve been doing some cam measurement, what are you seeing for lobe lift and duration at 0.050” lobe lift?

Also, I don’t think Comnoz ever met a cam that he didn’t want to degree, so if the cam is out of the engine he may measure it for you. With his extensive database of cam data he could certainly identify the cam and/or other very similar analogs. Might want to give him a call and see if he'll measure it for you.

Thanks guys for the input.
Matt, The lobe profile on that Norris .358/.368 looks like a roller cam ?

illf8ed, I thought I was on to something too when I saw the 336S cam but, Yup a vee dub cam.

wz507, Yes that's a roller foot on the indicator, I was trying to get some reference numbers. I'm getting .325 max lift and 290 deg duration, That's what led me here looking for the specs. A few years ago lcrken mentioned that he had a 1976 Norris catalog and I'm hoping he still does.
Mike

RatedSpeed said:

Thanks guys for the input.
Matt, The lobe profile on that Norris .358/.368 looks like a roller cam ?

illf8ed, I thought I was on to something too when I saw the 336S cam but, Yup a vee dub cam.

wz507, Yes that's a roller foot on the indicator, I was trying to get some reference numbers. I'm getting .325 max lift and 290 deg duration, That's what led me here looking for the specs. A few years ago lcrken mentioned that he had a 1976 Norris catalog and I'm hoping he still does.
Mike

Click to expand...

I still have it, Mike, but it doesn't list a 336 cam, either for Nortons or any other bikes.

Ken

Ken, Thanks for taking time to look at the catalog.
Mike

There is an easy way to get the timing right. If you put the barrels on the motor with a dial mike on one of the inlet pushrods and set the inlet to 65 degrees BTDC, them map out the cam in 5 degree steps by rotating the crank, do the same with an exhaust pushrod - you will have a diagram with which you can compare your cam with others which appear on this forum. If you are using separate pipes with mufflers, the comparisons should tell you how to get the timing pretty right. If you are 3 degrees out, the power characteristics won't change much, i.e, the revs at which the motor comes on song. Generally speaking the exhaust valve won't open prior to 85 degrees BBDC, and the inlet valve won't open before 60 degrees BTDC. Ask yourself the question about how the cam designer decides what timings to use when he first fits his cam into a motor. If you fit vernier adjustment to the cam you can optimise it to suit your motor by systematically adjusting then testing

Just installing it to the stock timing marks will probably get it close enough, if you can't find a spec for the actual lobe centers. The other concern is finding the right clearance. Norris specified .015" for their all out full race cams, like the D and D+, but less for the more roadable cams. Their SS grind used .008/.010" clearance intake/exhaust. I don't have specs for clearance for any of their other grinds. I'd suspect the .008/.010" is more likely right for your 336, but it would be nice to know for sure. MIght even be more like .006"/008". That's a fairly common setting for aftermarket Norton street performance cams. Unless it's really high lift, .015" is probably not the right choice.

Ken

Thanks acotrel and Ken for your input on setting this thing up. I'm still searching for the specs in my spare time. What are your thoughts on the 750 bottom /850 top end, Is this a sound configuration ? It has the RH4 cyl head.