Oz Laverda engines

redax5 said:
Hi Phil,

Clem, you could go to 83.0mm by using custom liners which I have in stock by the way.
The protruding part at the bottom you would run at 1.5mm wall thickness by machining down the outside diameter which would allow you to use a 1200 size counterbore in the top case.
Can get any piston you want made these days but I have 83.0mm x 13:1 pistons in stock.
Might be a bit large for normal street engine.
We intend to use these pistons towards the end of the year but first I have to modify a set of cases to a through rod design on the engine studs so we can increase the clamping force to contain the compression.
The bore size is not a big issue, the weak engine stud design is by far the biggest hurdle
Red
Click to expand...

Are you talking case studs or barrel/head studs ?  Is there a history of failure in this area ?
 
Barrels, Heads - they go soft with heat cycled age, that coupled in with a dud design (direct alloy screw fixed) they all end up pulling like a geriatric man, one minute on the next flapping in the breeze  :o

Bring on through fixed head studs - I say.

 
I think Red may have that 32.7hp wrong, pretty sure he meant 32.7 TIMES as much HP. which makes it now 882.9hp. Should go pretty well now.... :D :D
 
Jotaman said:
Barrels, Heads - they go soft with heat cycled age, that coupled in with a dud design (direct alloy screw fixed) they all end up pulling like a geriatric man, one minute on the next flapping in the breeze  :o

Bring on through fixed head studs - I say.
Click to expand...

Please clarify what you mean by through fixed head studs....direct screw fixing with waisted studs to accomodate thermal expansion is thoroughly conventional practise...the detail design could be improved with threaded inserts in the top case, yes, maybe 10mm studs too but the risk is aggravating any tendencies to crush the head and barrel castings.
If you're talking through - bolts, top to bottom....IMO even more likely to produce casting crush and distortion. Denco here in ChCh as some will know produced a number of speedway motors and Bob made the head studs really strong...around 12mm I believe. They all gave head gasket trouble because of crushed castings until the studs were waisted to allow for thermal expansion.
It ain't simple....


 
redax5 said:
3 naked shots



big moment arrived, spun her over to build oil pressure
then, fired straight up

fanfuckingtastic,  :D

sounds awesome, very smooth running engine, no vibration issues at all on the bench, very crisp, spins up better then any Laverda I have built
no oil leaks, no bad noises, am happy so far
Click to expand...


Shouldn?t you have posted this under "Music in the Shed"?
The best music that can come from any shed. Well done Red.
 
redax5 said:
fanfuckingtastic,  :D
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absodamnedlutely!

Great, great work (as usually). would love to do similar things with my engine once it is necessary. But if I ever invest that kind of money, I think I will go and get me a 4-valve head made with new cam profiles...  :D

Honestly: It would be really interesting to see that bike on a dyno, compare it to Rob's results, see what you have done and what Rob has done to achieve it and maybe combine all these solutions. I always knew this engine has a lot of potential (but also a lot of limitations - see the studs and the softness of the material...), good to see it being freed-up and - even more importantly - USED!

pure magic for me I must say. But then there was a Laverda engine in 1976 that had 20 more horsepower to offer...  :D :D :D Shame that was such a heavy lump and even more a shame it never reached production...

So - cross my fingers the engine will keep up to money, time and afford thrown at it!! Cross my fingers for TeamOz, you deserve it, guys!
 
Laverdalothar said:
redax5 said:
fanfuckingtastic,  :D
Click to expand...

absodamnedlutely!

Great, great work (as usually). would love to do similar things with my engine once it is necessary. But if I ever invest that kind of money, I think I will go and get me a 4-valve head made with new cam profiles...  :D

Honestly: It would be really interesting to see that bike on a dyno, compare it to Rob's results, see what you have done and what Rob has done to achieve it and maybe combine all these solutions. I always knew this engine has a lot of potential (but also a lot of limitations - see the studs and the softness of the material...), good to see it being freed-up and - even more importantly - USED!

pure magic for me I must say. But then there was a Laverda engine in 1976 that had 20 more horsepower to offer...  :D :D :D Shame that was such a heavy lump and even more a shame it never reached production...

So - cross my fingers the engine will keep up to money, time and afford thrown at it!! Cross my fingers for TeamOz, you deserve it, guys!
Click to expand...

You cant compare the results Lothar, Im using an inertia Dyno, Red's is I believe a water brake dyno. With the cubic capacity increase/thermal efficiency mods, he would have a much more powerful/ better prepared motor and a great rider to boot.
 
What I like to see is racing improving the breed,even the failures teach you something and the best bit is I hope usefull info flows to other Laverda nuts,dispelling myths about what works and what docent.Even getting more Laverdas being used like there supposed to.With all the race intrest and the National Rally at the next race meet I am hoping a few long term projects make an appearance.Hope some testing info gets posted soon.
 
very interesting to learn about your through stud design ideas Red, my youngest son and I have been working on exactly the same thing,we were looking to achieve a metal plate in the cases, below the throat, with four tapered holes in them to take 9mm studs, but with a flared on the end of the stud, also threaded to 9mm, and possibly silver soldered onto new and longer studs, which also still thread into the existing 9mm  Timecerted threads, there by giving a thread at the lower end of about 30mm.Since he works full time for the MOD, (explosives toolmaking foreman) he has the expertise, and equipment, but lacks the time!
CLEM
 
Robjota said:
You cant compare the results Lothar, Im using an inertia Dyno, Red's is I believe a water brake dyno. With the cubic capacity increase/thermal efficiency mods, he would have a much more powerful/ better prepared motor and a great rider to boot.
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Well - if you accept a difference of maybe 2-3 %, it should at least be close to what the same dyno would show I assume (that's what correction factors are for, right...). It was also not meant as a pi**ing competition, please, it was more the "what can we learn from what" approach. I assume 95 % of this forums members will never ever try something that way. It would simply be interesting for me (who considered coating anyways for my next engine) what are the results, differences and approaches taken etc.

I am NOT (just to make that very, very clear, please) trying to get the best engine in the world or teach the experts their jobs. I am just willing to learn and understand what changes have what effect, what technologies do offer which benefits etc.. In an ideal world, the result could be a database just like Laverdamania showing owners their possibilities, in some examples with proves what did help where etc, what did it cost and so on and so on. I know that is almost impossible, as the engines you two have differ in so many ways from a standard engine, that it will be hard to set up. But maybe over time if all members post their results here and the changes they did, we could make up something that people can refer to when wanting to improve their engines during restoration or even tune them a bit for classic events. I know that I am a bit blue-eyed here to think that those who found the missing HP will disclose all their secrets. But hey - who does not ask doesn't get an answer, right?  :D

The coating might be even interesting for people that do not have a focus on highest performance but more on reliability/durability. In Germany f.e. Kexel advertises with this as being a good protection for Oldtimer engines, that typically have shorter rebuild sequences than modern engines. Even more, he said he never tested an engine with his coatings and without to show  power or torque differences, he only focusses on making the restoration last longer.

 
Laverdalothar said:
Robjota said:
You cant compare the results Lothar, Im using an inertia Dyno, Red's is I believe a water brake dyno. With the cubic capacity increase/thermal efficiency mods, he would have a much more powerful/ better prepared motor and a great rider to boot.
Click to expand...

Well - if you accept a difference of maybe 2-3 %, it should at least be close to what the same dyno would show I assume (that's what correction factors are for, right...). It was also not meant as a pi**ing competition, please, it was more the "what can we learn from what" approach. I assume 95 % of this forums members will never ever try something that way. It would simply be interesting for me (who considered coating anyways for my next engine) what are the results, differences and approaches taken etc.
Click to expand...

Have a read here Lothar, parts 1-5, :D http://www.dynapro.co.uk/true_hp.htm  Meanwhile, going to back to Oz Motors.

I had Ceramic coatings applied to my pistons, head and exhaust ports in 2008, however most of those parts are now in the scrap bin, one piston remains in the motor. I would do it again but the thermal dispersant the UK company applied to the underside of the piston, was rubbish, it washed off into the oil...grrr, so it is imperative to trust as always who does what. The rest appeared to work very well.
 
Robjota said:
Have a read here Lothar, parts 1-5, :D http://www.dynapro.co.uk/true_hp.htm  Meanwhile, going to back to Oz Motors.
Click to expand...

I did - so what is the conclusion: take two accelaration type dynos and - if set up correctly - they will maybe show wrong figures, but both almost the same wrong figures. So what's wrong with that if you want to compare? The real value is not the target, it is the DIFFERENCE.

For sure it is a hugh difference between rear-wheel power and calculated clutch power. That is why the "loss" is measured by pulling the clutch at top speed (which was not the case I assume on the dynos described in the articles above - or did I over read it?). Technology has moved on and when today you go on three different dynos (as I did with my bikes...), the 3 results are all in the same ball-park. Maybe all are wrong, but equal. So - if you want to compare as said two different engines, they will show the difference.

 
That heavily depends on the setup, Romeo. That is why on the acceleration type dynos they kind of measure the resistance the gearbox and primary drive produce by pulling the clutch at highest revs and measure how much speed of the rear wheel drops over normal. Can be as low as 7 - 8%, can be as high as 15 - 17% (all with normal running conditions, no broken bearings or completely rusty chains involved).

A good assumption is 10% - 12 % for the average I'd say. On the Jota I only ever measured rear wheel power, on the SFC we did both and the difference was about 14% with the 630 chain and the original wheels and about 9% with the 520 chain and the GSX-R-Wheels. That said, the 630 chain was not perfectly lubricated and - old!. The 520 was quite freshly installed and serviced well.
 
GregT said:
Are you talking case studs or barrel/head studs ?  Is there a history of failure in this area ?
Click to expand...

Greg,

Both are known to fail on hard-worked engines.

Nothing much happens when a case stud lets go, it drops to the ground and may cause a minor oil leak.  Things are different with the head studs.... the loose nut beneath the cam cover is pitched around like a pinball, then it either jams between cam and follower or drops down the cam chain tunnel where it invariably manages to snag itself between the cam chain and sprocket!  Instant demise.....

I have replaced both over the years on several engines, all of them weary and thrashed hacks.  The amount of damage from snapped head studs varies from, "lucky bastard" to "WTF?"

Although I haven't encountered such problems on my own engines, I will be fitting high-tensile head studs when I tear down the 3C to fit new pistons and the lighter crank.  Guess that after 36 years the studs will be well past their best.

piet
 
While on the subject of head studs, I'm just wondering whether anyone has used the angle method of tightening rather than torque. By that I mean running the nut down the thread until it makes firm contact, then tightening it through a specific angle (could be more than 360 deg).

The angle method sets a pre-determined amount of stretch into the studs, and is not affected by the friction variables as is the torque method.

To get some idea of the angle required, I was going to measure the angle that I had to turn the torque wrench through last time I did a head - but I forgot. It would be different for copper and fibre head gaskets anyway.

Cheers,
Cam

 
Thanks for the clarification Piet - I don't have the years of Laverda experience that some on here do...

So it's mainly broken studs with the occasional stud pulled out of the case ? And if the nuts rattle round the top end I'd assume they break at the section change close to the top or at the end of the thread.

Looking at the 1200 cases on my bench I'd say that an internal stud girdle for the lower ends of the head studs would be very difficult to do...but with the resources of the British MOD at hand, maybe. Personally, decent inserts in the upper case and lifing the studs for race motors IMO would help....road motor owners, you're on your own sorry. Shot peening the studs would definitely help life as would studs with a rolled thread.
Looks like there's a market for better quality studs...better material and rolled threads.
 
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