Building a race bike

The air intake for the oil cooler is really neat! - have you considered an electric oil pump (HP) to supply the shell  centre mains and keep the original type  for the rest? - Can't wait to see dyno figures! - best of luck - Phil
 
Thanks Phil,

Yes i did consider it but I thought weight would be more as I would need a larger battery or a generator, as is I have a small battery and no charging system needed.
Plus I considered the power needed for a powerful oil pump to be more than a small electric pump would reliably give without having to worry about it.
I make Gerotor type oil pumps regularly for the old cars so this is something I could do with ease.  I thought about the std pump for the outer bearings but it would be so easy to add a little side feed into the "old" oil channel that I decided not to use it,  12000 rpm may be asking a little too much from it anyway.  Less complex also.  Cam / top end will be fed directly and not via the stud holes as I hate that method.  I will run the pump direct on the right side crank end as there is nothing else there now.

Also ordered new mains studs in MP35N which should give them a higher tensile than if I had gone to 11mm in EN24T.  Already got cylinder studs made in the same. 

J
 
julian said:
Hi all,

Quick update, lots to tell but not too many pics as yet.

Fitted the forks and new Magnesium triple clamps, Nice 7075 ally centre pin also for more weight loss.
Making up a new fork brace now which will have a special anti dive link Incorporated into it for a bit of fun.
Started to make the fairing / Oil cooler / steering damper / rev-counter mount,  the oil cooler will be mounted behind the headlight aperture so it resembles a headlight with the air intake bell adding to this quality. the fairing is mounted to the intake bell and the ally oil cooler duct mounted to the oil cooler,  the bracket for this doubles as the steering damper bracket and the oil cooler top steady also houses the rev-counter.  All good fun.

Engine mods.
To date I have been using the flow bench from a friend, now just bought one for myself, should have it later this week.  Superflow SF600. 
I then want to do the final port finishing on the head before scanning and doing all the production work to make it "Real"

Engine,  the dyno software that I am using tells me 11500 - 12000 rpm is possible but now the big one,  I need to keep the engine together at these RPMs,
Doing some research and talking to people who have been there, tells me that roller bearings on the big ends will be very problematic. 
Therefore due to several reasons,  the main ones being crank rigidity, crank weight, bearing reliability, ease of operation.  I have decided to go with a one piece crank with pressure feed into the centre two main bearings that will be shell bearings and will in turn feed their relevant big ends. The outer bearings will be a std ball on the dynamo end, and a std roller on the clutch end. The crank in theory can then loose another 500g taking it down to a total of 6.5kg and the Titanium rods should weigh the almost the same as the previous calculations due to the added weight of clamp bolts but reduction of the roller races and hard insert ring. 
New HP oil pump being designed as we speak.

Will update more frequently now if possible and if I have something interesting to say,  (hopefully interesting anyway)

Regards,
Jules
Click to expand...


what a great use of a trombone for the air intake ! seriously that looks so cool, Im sure its very practical, but the aesthetics are one of the nicest things I have ever seen. I have learnt so much from reading your thread, thanks for posting
 
If your outlet is at the top then you know you have a full radiator when it returns to the engine and it won't leak back. At least that's my take on it and how i would plumb it in.
Great project and would love to hear it running when she's finished.
Regards Andy 😁
 
As always, love reading your up[dates, Julian. Great to see it taking shape. 12,000? Yes, that is rather ... high! One piece crank makes a lot of sense with those sorts of figures being bandied about.
 
I fitted a Mocal oil cooler to the Motodd and mounted it with the spigots pointing down. Is that going to be a problem with oil starvation to the head while the cooler refills upon
start-up? Wouldn't have thought it any different where the oil would drain from the stud holes supplying the head.
Should I be worried? Would be a pain in the arse the flip the cooler.
 
12000 rpm with your stroke (67.5mm) gives a mean piston speed of 27 m/s. That's getting up into the very high end of engine performance.

I don't know much about performance engines, but I thought it was only top fuel dragsters that ventured above 25 m/s. Their engines only do a few runs before they're stripped and re-built. Sometimes they blow up in a spectacular way.

With your experience in bolting engines together, I presume you know what you're doing. Very interesting project.

 
There are quite a few production automotive engines around the 25m/s Cam, eg Honda S2000.  Professional competition motors are way beyond 25 these days and not just the short-lived ones like Top Fuel.

For example MotoGP has bore size limits in an attempt to artificially limit rpm, they are allowed an 81mm piston which means a 48.5mm stroke and hence an MPS ~29m/s at 18000rpm which they admit to (hence might be even higher).  Not only that, but they last and last, allowing only 5 engines for this season.  With Yamaha's cockups (or cheating, depending on your view) Morbidelli ran 13 or 14 race meetings on TWO remaining engines, admittedly dialled down a bit and certainly not doing 18k but not enormously far short of it.  Amazing.
 
So plain bearing big ends and roller one end and ball the other in the case, how typical is that these days. Just my ignorance showing. Just hearing how hard modern engines spin shows these revs are needed to be competitive. Will the oil pump be an uprated typical Laverda pump or something out of the box. Ti rods are used a lot in 4 valve Ducatis, will you use one being made for other engines or one-offs.
 
julian said:
I have decided to go with a one piece crank with pressure feed into the centre two main bearings that will be shell bearings and will in turn feed their relevant big ends. The outer bearings will be a std ball on the dynamo end, and a std roller on the clutch end.
Regards,
Jules
Click to expand...

Great project!  Curious why you're going to retain the rolling element bearings on the outside?
Cheers
Steve
 
breganzane said:
There are quite a few production automotive engines around the 25m/s Cam, eg Honda S2000. 
Click to expand...

OK. Thanks. My engine tuning knowledge (such as it is) comes from reading Phil Irving's books, which are no doubt a bit dated by now. I don't reckon there were many titanium conrods or ceramic coated engine innards around in Phil's day.
 
the current best roller cranks are of course 2 strokes. Flat cages, needle rollers and very stiff shaft assemblies make around 15,000 rpm safe. Current practise says it's not worth spinning a 2T faster than that as cylinder filling and scavenging suffer. You can't modify the speed of sound, lol.

Putting a roller on the drive end of the crank is logical when the loads are considered. But I'd point out that Ducati had to go to high speed special bearings to cope with revs lower than Julian is contemplating...

If you can get the material, Ti rods are not too hard to do. Guy I know here makes his own rods for classic projects in alloy and steel. If he could locate a supply in the small quantities he wants, he'd do Ti rods too. The Britten of course used shortened Indy Cosworth rods. Cut and welded - and they held up. I believe most of the running ones now have Carillos fitted...
 
Hi all,

Some very interesting questions and all worth answering.

Oil coolers in general should be mounted with pipes to the top to allow to fill fully and stop air pockets which are unbelievably hard to eliminate otherwise.
Been there and tried and regretted it.  On a road engine its not a big deal but this engine will be really on the limit and used hard 100% of it's life so want everything as efficient as possible.

Piston speed and accelerations are all within the norm nowadays,  We even spin our old long stroke pre-war engines to 21m/s on engines that last for years. and some of these have higher piston acceleration figures than this Laverda will have.
Besides, it wont stay together for long between builds so lifeing rod bolts etc is pretty simple.
It is funny though that just as Cam has said, when I started building engines 4000ft/min - 20m/s was considered high for an endurance type race engine, now we use 4250 on Pre-war long life sports type engines and 4500 regularly on pre-war race engines that hold together for several seasons with whippy cranks and not enough main bearings etc. Modern materials and better oils I think. Added to the more prominent use of aftermarket cranks and rods etc.

The roller on the drive end is being left as there will be a very heavy directional load on that end and the bearings I have available have a safe rev limit to 16k Rpm, I have had experience with shell bearings suffering on a gear driven crank end before and we solved it with a similar roller. Simply working from experience here.  The rod bearings on the other hand are more problematic and after speaking to smarter guys than me who have experience with failures in this department (ie my rod people) they tell me it will be hard to keep it together with roller big ends at 12k rpm. Even the factory teams gave up.  I'll take their advice.  Ball on the outer, again, My advice here and personal experience with 9000rpm pre-war race engines using ball and roller main cranks is that the rollers and the balls, if spec-ed correctly have no issues in the short use my engine will get between rebuilds.
Fingers crossed as only time will tell.

Ti Rods are common nowadays and easy to get made,  I will not even bother myself with more than a rough drawing before handing the reins to the men that do it on a daily basis.

Oil pump will be made by me and with a modern Gerotor type gear,  gears are already on their way and tested to 13,000 rpm at very high 150psi + oil pressures, gears designed by people who use the same design rotors (but bigger) in big power engines,  I will set mine at 80psi which sounds high but again from experience, solved a lot of problems by using 80psi when things were giving issues at 60.  Going to also feed the cam down the middle as we do with many race engines we build.  Actually very simple in the SF engine and then goes exactly where I want it to go.

Crank manufacture will be massively simplified now and massively stronger, tougher and more rigid than a pressed crank.  No chance of twisting out of phase either and no need for oil slingers and messing around trying to press things in line.

Everything will be coated with ceramics as far as is humanly possible. 

Really excited now to be honest.  The pressed crank was worrying me a little as I had a feeling it would give me some reliability issues.  Very confident now.

Regards to all,
Jules



 
Fair enough Julian. All logical answers based on experience. Looking forward to seeing the end result.

Details make a difference to rioller bearing bigend life....We have a small capacity tinkerers class here, 150cc usually Suzuki or hondas. i did a 2v one based on a GN125 just for shits and giggles. Changing from 4mm rollers to 3.5mm OD and a 3mm bigger pin stiffened the crank and let it run reliably to 16,000 rpm. The std 4mm roller bigends run to 14k last about 3/4 of a season. This one has been together now for four seasons. We offset ground the pin ends to short=stroke it too.
On the other hand, plain bearings....I have a little twin for the same class here at present. Half an FZR250/4. Relinered to 150cc. 18, 0000 rpm.

Yes, the RC30 has Ti rods. I have one apart on the bench at the moment. Looking for the NLA rod bolts - as the rods are bigger section than steel, they're longer than usual...At least Julian's setup won't need the coatings on the RC rods where they rub together.
 
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