Merlin DOHC 8 valve Cylinder head drawings

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Madnorton said:
Without a whole host of modification it will still only work in the existing operating envelope that a big valve head can mange, different yes, but no enhancement. Some will also spot the issue in the first photo above.
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What is the issue in the first photo?
I,m sat looking at the drawing and it mystifies me you have seen something that you regard as an issue.
 
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Well that’s kinda what happened with Weslake / Nourish really, Weslake started out with the 686cc conversion for Triumphs, but as successive weak links were fixed, others were found, resulting in complete Weslake, and laterly Nourish, engines being produced.

It already happens with Norton’s to a large extent via Steve Maney et al. Many a hot rodder has put Maney crank, rods, cases, barrels, pistons, cams together to produce a hot motor. Stick a Fullauto head on top and you’ve got a completely none Norton, Norton engine!

Sticking an 8 valve head on top seems like a logical alternative to me...
 
Fast Eddie said:
Its not just a question of 4 valves vs 2 (although 4 is, of course, better). The other point is that you would have a complete bank canvass upon which to design ports and decide port sizes and maximise benefit from squish, reduce advance due to better combustion, etc, etc.

I really pushed the development of 2 valve Triumphs when racing them and peaked at 75rwhp. My NRE modded Triumph racer was 84rwhp and I never really tried to develop it much.

I think the real bottleneck will be the rest of the machine. When the power goes up, the stock crank, rods, cases, gearbox all take turns at become the weakest link !

Not to mention the stock forks, shocks, brakes, etc...

But I’m sure Dobba has already worked this out!
Click to expand...

The rest of the machine doesn't exist yet! High strength cases definitely (Merlin told me how they strengthened their cases)
The case will require modifiying anyway for the jockey shaft that takes the place of the standard camshaft.
A one piece crank wearing steel rods. Merlin said they used a standard norton barrel taken out to 920 but we now have the choice of one of Mr Maneys excellent alloy items.
Pistons Merlin used were Omega items, I dont know if they are still available but there are various manufactures of pistons for 920 nortons
The Gearbox i can see being an expensive item to sort. Merlin said the standard AMC box just broke! Give it a hand full and third gear just gave up and threw all its teeth away in a huff! I didn't ask them if they used an outrigger bearing on the gearbox mainshaft. (note to self, add that to the list of things to enquire about next time i talk to Merlin)
They used a Quaife box. Another possibility is a TTI box, like i said an expensive item to sort.
Primary drive will most likely be by duplex chain as i want it to have the electric start facility as per MK3. (Note to everyone, No one makes decent triplex chain anymore, not even reynolds)
The frame i might have to make if the standard frame doesn't come up to scratch. (I have made sidecar racing frames before now so that doesn't faze me)
All in all enough to keep me out of mischief for quite a while...
Regards
Peter
 
dobba99 said:
...Primary drive will most likely be by duplex chain as i want it to have the electric start facility as per MK3. (Note to everyone, No one makes decent triplex chain anymore, not even reynolds)
Peter
Click to expand...

Has anyone thought about adapting a HIVO chain for primary drive?
 
10+ yr ago Steve Maney 920 made 100.4 hp @ 7200.

My '68 P!! could not be given full throttle in 4th below 60's mph or would just smoke a street tire and turn into a sliding crossed up flat tracker into oncoming traffic just trying to pass a line of cars in time. It was marked by nail polish at 9000, which not knowing nothing age 19 routinely hit that and sometime over that on missed shifts or tire break free. If not built frame/forks 2" lower in front no way avoid wheelies limits but as was would float front 2" level with one touch/bounce back level on tapping kill button shifts WOT.

Ms Peel Combat stuck throttle made tach needle disappear from bouncing off both sides of the 0 peg, till snapped throttle close to gradually see needle bouncing off both side so peg then a few seconds later only bounced off hi side of peg then few more seconds needle wavered in the red zone then came to rest as expected. Jets of oil/smoke shot out every seam and fastener and took 30 sec for smoke to clear enough to see head was still on. So kicked it over expecting seized but ran ok for 2000 more miles but lost her sport bike embarrassing power. Later found out the crank ends had wobbled so much it jerked apart the cam chain adjuster so Boyer ign would over advance limiting rpms to 5000 under load.

Point being - add crank center support to list of things to do.
 
To tempt more non Norton imagination, I gave thot to OHC and how to turn it in compact package to find a neat way, small crankshaft where stock cam runs, 2 long connecting rods upward that connect to cam crankshaft rod journal pivots. Have not found images of this mechanism again but only took bit over inch dia space for rods with the crank wheels about same dia as cam lobes. Like tiny steam locomotive drive at either end. Whirligig inspiration.
https://i.pinimg.com/736x/74/e5/1a/74e51a8420824593621b9853e7a31006.jpg
 
You mean to use reciprocating rods off of the end of the old camshaft to drive a new overhead shaft, kind of like NSU used on their twin cylinder Prinz auto motors?

Although the Prinz engine drove the rods from the end of the crank.

Merlin DOHC 8 valve Cylinder head drawings
Hosted on Fotki
 
Yes that's example of compact dual crank cam drive. I pictured center connecting driven and cam shaft - trying to preserve basic Norton shape and lay out, avoiding 90' bevel drives or large pulley/sprockets. Out my league to delve into so good speed on your inventiveness.
 
mdt-son said:
snip - I note the date of drawings is 1979. It is really surprising that drawings are of such low quality. By 1979 CAD had replaced drafting boards in engineering, at least for complex tasks, and this project definately is one.
-Knut
Click to expand...
Interesting comment there Knut. I think you are basing this on high end stuff, oil industry in the North Sea for example. I rather think that 79 is very early for CAD - I started using 2D & 3D batch modellers in 1985/6 in the UK, and this was considered fairly advanced at that time for anything outside of aerospace, car industry, or major process design. CAD on PCs only really became useful in the mid to late 1980's, prior to that you had to have access to some seriously expensive hardware just to start.
I would be more surprised if the drawings had been done on CAD - and even if they were, the problems of trying to transfer that data int oa modern system would be non-trivial...
Cheers,
Steve.
 
SteveBorland said:
I think you are basing this on high end stuff, oil industry in the North Sea for example. I rather think that 79 is very early for CAD - I started using 2D & 3D batch modellers in 1985/6 in the UK, and this was considered fairly advanced at that time for anything outside of aerospace, car industry, or major process design.
Click to expand...

Steve, you are basically right. For a small company like Merlin, investing in a 3D CAD system by 1980 would have been absolutely prohibitive, and hiring a consultancy firm like we know today would have been very costly also - and these companies probably didn't exist yet. At that time most companies running CAD seats protected their investment and human capital like crown jewels.
At the end of the 70's a typical CAD system was a 16-bit minicomputer with maximum of 512 Kb memory and 20 to 300 Mb disk storage at a price of 125,000 USD.

In the UK, John Laing purchased a ComputerVision CADDS3 computer aided design and drafting system as early as 1975 to carry out investigations into the use of CAD in the construction engineering and building environment. Laing became the first CAD user in the UK Civil Engineering and Construction industry and were instrumental in developing and promoting the use of Computers in Construction. I remember my late father managed a civil engineering design office here in Norway. By 1982 they had a Matra Datavision Euclid 3D CAD (colour line graphics) running on a PRIME supermicro computer connected to a Tektronix colour display. First graduates being taught in computer graphics engineering technology were graduated in the US around 1983. However, these were early forerunners, and the propagation of basic 3D vector graphics CAD into smaller companies did not begin until the introduction of the PC around 1983/84 along with affordable software like AutoCad and MicroStation.

-Knut
 
dobba99 said:
The rest of the machine doesn't exist yet! High strength cases definitely (Merlin told me how they strengthened their cases)
The case will require modifiying anyway for the jockey shaft that takes the place of the standard camshaft.
A one piece crank wearing steel rods.
Click to expand...

Peter, if I were in your shoes I'd build my engine on a different bottom end. Hobot is on the right track - a decently supported crankshaft should be used. Why not build upon the new Norton engine intstead - the 961 ? With this engine, you get all your desired modifications for free, including a proper transmission. After all, it was a development based on the old Commando engine.
With a project like yours, you need to reduce the number of parameters in order to succeed.

-Knut
 
mdt-son said:
Steve, you are basically right. For a small company like Merlin, investing in a 3D CAD system by 1980 would have been absolutely prohibitive, and hiring a consultancy firm like we know today would have been very costly also - and these companies probably didn't exist yet. At that time most companies running CAD seats protected their investment and human capital like crown jewels.
At the end of the 70's a typical CAD system was a 16-bit minicomputer with maximum of 512 Kb memory and 20 to 300 Mb disk storage at a price of 125,000 USD.

In the UK, John Laing purchased a ComputerVision CADDS3 computer aided design and drafting system as early as 1975 to carry out investigations into the use of CAD in the construction engineering and building environment. Laing became the first CAD user in the UK Civil Engineering and Construction industry and were instrumental in developing and promoting the use of Computers in Construction. I remember my late father managed a civil engineering design office here in Norway. By 1982 they had a Matra Datavision Euclid 3D CAD (colour line graphics) running on a PRIME supermicro computer connected to a Tektronix colour display. First graduates being taught in computer graphics engineering technology were graduated in the US around 1983. However, these were early forerunners, and the propagation of basic 3D vector graphics CAD into smaller companies did not begin until the introduction of the PC around 1983/84 along with affordable software like AutoCad and MicroStation.

-Knut
Click to expand...

Ah, the days :-). I started on Medusa 2D & 3D (batch modelling) running on a PR1ME with these lovely Tektronix stroke writing screens. The uni also had a DEC VAX 11/750 which we used for writing solid modelling projects. While I really do not miss the problems of keeping a pen plotter working, it was always somewhat fascinating watching one working....
Later I was doing sales and support for CADDS5 and Medusa, then the world went over to parametric modellers for the simple stuff. As far as I know though, CADDS is still used for ship design due to the complexities & size of the models.
 
The 961 Norton engine still relies on a vertically split crankcase and only features a two valve head. That might give you some idea as to what is not worth pursuing. The Hinkley Bonneville has 4 valves, OHC and is quite mildly tuned but capable of taking up to 100 BHP, Rickman have developed it quite nicely.
 
gripper said:
The 961 Norton engine still relies on a vertically split crankcase and only features a two valve head.
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Exactly, and a 3 bearing crankshaft, Matchless style, and also a balance shaft. There is nothing wrong with a vertically split case if you put in precision dowels. The OEM two valve head -> yes, that's why it would make sense to try out a 4V head. The required rework of the Merlin design may not be that severe. I think this proposition is very interesting, even for the factory to consider. I always wondered why the 961 wasn't fitted with a 4V head in the first place ....

-Knut
 
mdt-son said:
There is nothing wrong with a vertically split case
-Knut
Click to expand...

Very true. Otherwise, Ducati wouldn't use them.

mdt-son said:
I always wondered why the 961 wasn't fitted with a 4V head in the first place ....

-Knut
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Join the club. I was a bit disappointed when I first learned the 961 was a 2 valver.
4V head for the 961 would be a nice little enhancement, and probably improve the emissions as well as performance. Plus the 961 is still in production with owners who might actually be willing to pay for improved performance.
 
---snag this private email content forward by hobot till LAB deletes it >>

As you know, I have the remnants of Dreers Norton America (What did not make it to Garner) and I have permission from Stuart as long as I
"Promote the brand in a positive light"

am playing with just switching over a XB9 Buell system to a Norton 961. The injectors dont know, dont care what they are bolted to.
SUCK-SQUEEZE-BANG-BLOW is all the same,, and the XB9 is a 984cc motor ( 88.9mm x 79.4mm). Buell stuff is cheap, and same basic setup, plus fuel pumps, sensors and other bits readily available and a very friendly and supportive community. I have contacts with some ex-Buell staffers and some other irrelevant Buell material but the point is,,, the 961 is very tunable.

If you use the Buell brain box,, All you need is a cord/dongle and for about $35 you can tune to your hearts content. If techy enough,, you can also do your own datalogging/mapping with a smart phone.
See: http://www.motorcyclespecs.co.za/model/buell/buell_xr9R 02.htm



Doug
lmcguire@ccgmail.net
Oregon 503-351-0518
 
Please persevere with your quest and share your experience. I have found myself pondering doing what you find yourself doing now. It is a great time to be a dreamer. Automated design and operational software and machining equipment that existed only in the highest levels of industry thirty five years ago are superseded by what you can find in small, privately owned shops. Maybe you team up with a local technical college. ATB !
 
I'll echo what rotorwrinch stated - follow your dreams. Unless you plan to wring the engine out with high rpm, the bottom end (especially later model) is plenty durable for a four valve application.
 
hobot said:
Duccati mention along with the NSU reciprocating crank/cam drive made me imagine a desmo 4 valve might be more doable/worthwhile than spring gizmos or maybe a hybrid, spring to close, rod motion to open. Air springs coming of age but so are electric solenoids to add to pondering.
Click to expand...

That's all very complicated, let's just start a new thread:

Norton 961 With A Blower:p
 
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