billet cases

Richie was kind enough to let me come down to the Trimac shop today to perv at his wares, and bring home some eye-candy for you.

Some of the new case halves waiting to be trimmed up.

This is #002 of the first run a few years ago, and Richie said the new halves are a bit cleaned up on the inside.





We threw this on a bathroom scale, and it came in right about 7 kg. Richie said that the guy who commissioned the first run had cracked his Maney cases around the drive side main bearing, so that area is beefed up, Now, I dont know what Maney or stock cases weigh in at, but...

Dances with Shrapnel said:

The weight difference between a Maney crankcase and a Mk2a is a fart in a wind storm.

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Thanks again to Richie for letting me come down and spin the yarn. Now I just have to figure out how to slip these past the better half, needless to say all the rest of the shiny bits to go with them ... :mrgreen:

J. M. Leadbeater said:

...but please remember the gearbox has to deal with all the extra torque the motor is able to produce and that was designed even earlier for 500 c singles producing probably 25HP and no more than 25 ft lb of grunt at the crank..... luckily for us the designer used decent safety factors but as NVT or whatever they were called then even with the 750 motors the gearboxes were not up to the job as they poodled around the TT course...not till Mr Williams got his hands on the bikes. and found the mainshafts were deflecting etc etc.
.

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Bikes at this level all use TT gearboxes. Also made in NZ.

http://www.ttindustries.com/index.html

cash said:

You'll be 3D printing them next.

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I have some experience with laser sintered engine "castings" and would not recommend this technology for a Norton engine at all. Actually I considered this for a Timing cover with some changes to the oil gallery but after some testing I'm a bit disenchanted. 3D printed aluminium doesn't fancy vibration very much to put it politely.


Tim

johnm said:

J. M. Leadbeater said:

...but please remember the gearbox has to deal with all the extra torque the motor is able to produce and that was designed even earlier for 500 c singles producing probably 25HP and no more than 25 ft lb of grunt at the crank..... luckily for us the designer used decent safety factors but as NVT or whatever they were called then even with the 750 motors the gearboxes were not up to the job as they poodled around the TT course...not till Mr Williams got his hands on the bikes. and found the mainshafts were deflecting etc etc.
.

Click to expand...

Bikes at this level all use TT gearboxes. Also made in NZ.

http://www.ttindustries.com/index.html

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what are the diffs with the heat treated alum box vs magnesium?

johnm said:

Brooking 850 said:

Seems the Velo boys had a good time down at the Burt Munro with 1, 2, 3 finishes on the two KTTs and the big Velo. Chris Swallow, Cloud Craig Smith and Bill Biber on the big Velo. Chris also beat a lot of 750s on the street track with the 250 Eldee.

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it seems that the Burt Munro challenge is getting quite big,

http://burtmunrochallenge.co.nz/

84ok said:

johnm said:

J. M. Leadbeater said:

...but please remember the gearbox has to deal with all the extra torque the motor is able to produce and that was designed even earlier for 500 c singles producing probably 25HP and no more than 25 ft lb of grunt at the crank..... luckily for us the designer used decent safety factors but as NVT or whatever they were called then even with the 750 motors the gearboxes were not up to the job as they poodled around the TT course...not till Mr Williams got his hands on the bikes. and found the mainshafts were deflecting etc etc.
.

Click to expand...

Bikes at this level all use TT gearboxes. Also made in NZ.

http://www.ttindustries.com/index.html

Click to expand...

what are the diffs with the heat treated alum box vs magnesium?

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A bit of weight. Bruce Vernon the owner can tell you how much.

He can change internal ratios about a bit so ask him whats possible.

From experience with these boxes they are really amazingly good. He started out making heavy weight speedway boxes so they are very strong.

Make sure you specify exactly and clearly the mainshaft lenght. Dommie, Manx or Commando and the change direction. Reverse or normal.

A couple of years or so back he had some issues with supplied steel which was basically counterfeit spec. (This is becoming a big issue these days with even the name reliable suppliers). The aircraft industry is having issues. He only found out when he had his own analysis done. But apart from that they are seriously reliable.

gortnipper said:

This is #002 of the first run a few years ago, and Richie said the new halves are a bit cleaned up on the inside.





We threw this on a bathroom scale, and it came in right about 7 kg. Richie said that the guy who commissioned the first run had cracked his Maney cases around the drive side main bearing, so that area is beefed up, Now, I dont know what Maney or stock cases weigh in at, but...

Dances with Shrapnel said:

The weight difference between a Maney crankcase and a Mk2a is a fart in a wind storm.

Click to expand...

Thanks again to Richie for letting me come down and spin the yarn. Now I just have to figure out how to slip these past the better half, needless to say all the rest of the shiny bits to go with them ... :mrgreen:

Click to expand...

Hi David, thanks for coming in and having a look at our set up

Earlier this evening with brain just about totally disengaged I thought about these super expensive billet cases and wondered....so I looked at the video..... So where is the camshaft oil bath Mr Hopwood so carefully designed into his Dominator engine design to ensure the cam and followers were CORRECTLY lubricated at all times ESPECIALLY during the engine start up period? I quote his letter to me on the subject dated 21 July 1981. ............ 'The camshaft tunnel of the Dominator engine was designed to retain as much oil as possible and in fact collected oil from the flywheel rim.........'.
He also suggested how it could be replaced in my cases stating that the lip should run within 1/8 to 3/32 of the flywhhel rim to pick up oil from it.
Funny how standard UNmodified early Dominator motors with the camshaft oil bath never gave cam problems but later ones without this little design feature did.....a design feature slowly removed a bit at a time with every new edition of crankcase manufactured for which new patterns were required till by the time of the 99 and 650 cases it vertually no longer existed and was as much use as a wet you know what......The removal being successfully totally completed with Commando cases leaving just a big lump of useless alloy beneath the cam.
For the Geoff Monty/Dudly Ward MONARD Triumph engined race bikes ridden by the likes of the late Bill Ivy and others in my younger days they employed a positive oil feed to each cam lobe along with a gear oil pump to supply the increased oil required.(The cams being drilled and the new pump and timing cover required being manufactured by Tommy Mortimer, an ex AMC race mechanic). Of course Mr Heles Domirace motors also employed a positive oil supply to each cam lobe which was the reason (So a Gentlem who worked with Mr Hele told a friend) for adopting the 6 start worm on the pump which every mothers son later considered to be a must have go faster modification the ramification being that the rocker box drain system was not capable of removing the oil from the inlet side so it filled up with oil till it overflowed into the exhaust side but in so doing covered the inlet valve guides and owners then had a nice smoking motor. and could play at being a destroyer laying down a smoke screen to protect the convoy..just like Ariel Arrows could often be spotted doing from miles away!! Personally Joe Francis Motors flogged me a set of new Twiflex rings as the cure but they did nothing except cost me money. Then Tommy Mortimer suggested we take a look inside with the motor running and inlet rocker cover removed....and very quickly realised what the problem was along with being covered in oil. Guess why Commandos had oil seals on the inlet guides! Yet another Norton bodge to cure a problem? Personally on my Dommy I not only drilled out the return oil ways but still ended up added an external drain back into the timing chest from the inlet side of the rocker box which cured my problem but added yet another sounce of oil leaks!! Of course in those days of youth my motor was at or near max revs everywhere possible....which did not help matters one iota! Nor engine reliability!! But I was young and knew no better.
Shortly after receiving Mr Hopwoods letter I was reading and trying to inwardly digest the Piper Cams tuning notes book and found it stated on page 36 and I quote part of it....
'Research indicates that most cams that wear out start to fail during the first few moments of operation. We have found that many cams are irreparably damaged before the motor is started, because the basic rules of camshaft break-in have not been followed. The cause of premature cam and tappet failure is metal to metal contact between the tappet and cam lobe. Should this occur due to lack of proper lubrication or excessively high pressure due to valve train interference shearing the oil film, galling takes place................'
If you are not aware of what gallling is go use the web and learn. Basically once galling has taken place premature cam failure is assured.......and Norton and others made and sold replacement cams to satisfy the demand AND STILL DO SO.. The camshaft oil bath was included by Mr Hopwood so that the very first rotation of the cam had the lobes dipping into the retained oil thus providing correct lubrication between the cam and followers... it was NOT rocket science just good Engineering AND cheap to include at the original design and manufacturing stage.
I trust others mnufacturing new cases include the oil bath?? Hah hah how we olde farts do dream at times.... but it keeps a friend employed replacing it for his road and race customers IF they twist his arm hard enough that is because he hates doing the modification!!

Long point taken. So like how does a regular Norton owner fit an oil trough mod to the cases once opened up ? Another project.

So like how does a regular Norton owner fit an oil trough mod to the cases once opened up ?

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Build back up with weld, with all the risk of distorted cases. Then dress back for clearance which might take you back to where you started with a high lift cam or maybe not.

The billet cases look to have a bath anyway, looking at this pic you can see the bottom of the camshaft alley has a higher spot behind so oil will be retained.

" The billet cases look to have a bath anyway, looking at this pic you can see the bottom of the camshaft alley has a higher spot behind so oil will be retained. "

Yes this seems to be true in this picture. But if you look at 1 min 05 seconds in the video I would say not. So this could be an issue for street bikes. On a race bike you should pour oil down the push rods tubes before starting if it has been standing for more than a few days anyway so the problem shouldn't arise.

And park your street bike with the side stand and the whole concept is out as well. I don't know if it is possible to preserve the oil bath for any high lift cams.

Maybe that's the real reason the Commando engine is inclined forward. "Cheap and effective engineering solutions :lol: "

I believe this is the bike that the cases were manufactured for-

this photo was taken some years ago at Pukekohe when ridden by the late Paul Dobbs a gifted rider who lost his life at the Isle of Mann.

venting story?

The cases to have are the ones on the #1 bikes!

possm said:

I believe this is the bike that the cases were manufactured for-

this photo was taken some years ago at Pukekohe when ridden by the late Paul Dobbs a gifted rider who lost his life at the Isle of Mann.

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What frame is that - the swing arm is not Seeley ?

About Paul Dobbs. - When I was a kid, I was studying at night school. One year I studied 5 subjects and failed 3. My friend suggested I should join him at Otis Elevators, get transferred to London and go road racing in the UK. As my life turned out in Australia it might have been a very good choice. However I often watch the IOM videos and I know that because of the way I ride, I would probably have come home in an urn.

If you don't have a go - you'll never know.

I would suggest that the frame is a Rob North/Miles Engineering or copy of.

possm said:

I believe this is the bike that the cases were manufactured for-

this photo was taken some years ago at Pukekohe when ridden by the late Paul Dobbs a gifted rider who lost his life at the Isle of Mann.

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The big question is why did it blow up a Maney case? What's in this motor to create so much stress? Or don't they want anyone to know?

jseng1 said:

possm said:

I believe this is the bike that the cases were manufactured for-

this photo was taken some years ago at Pukekohe when ridden by the late Paul Dobbs a gifted rider who lost his life at the Isle of Mann.

Click to expand...

The big question is why did it blow up a Maney case? What's in this motor to create so much stress? Or don't they want anyone to know?

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Good question, they are tough cases...

jseng1 said:

The big question is why did it blow up a Maney case? What's in this motor to create so much stress? Or don't they want anyone to know?

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From what I was told it (very little) it did not blow up per se, but the case cracked around the primary side main bearing. No idea what was in the motor.