Topic: Geared Primary Drive

[scottly]

I am planing to add feed from return line. I will use 0.8mm like you recommended.
 

What to you mean by "return line"? If you mean the output of the scavenge pump, there is no pressure there to force oil out of a 0.8mm hole; at best you will get a dribble, not a jet.

[Tracksnblades1]

I am planing to add feed from return line. I will use 0.8mm like you recommended.
 

What to you mean by "return line"? If you mean the output of the scavenge pump, there is no pressure there to force oil out of a 0.8mm hole; at best you will get a dribble, not a jet.

Why won't it work? It is providing lube to the transmission now...?
Thats originally how I was planning on oiling a HyVo chain before Mirko took on the toil of the geared primary.
I think oil jet piston cooling could be added with the addition of a small low pressure oil pump. Perhaps properly sized it could do the HyVo chain also without exceeding the original scavenge pump's capacity.

[MessnerMoto]

scavenging pump has 7.5 liters of flow per 1000rpm

supply pump has 5.0 liters of flow per 1000rpm

but yes maybe scotty is correct that there is no build up pressure to force oil from 0.8mm hole? got me thinking

[eli]

I'm looking forward for Mirko's parts. Will try and make lots of pics etc.
eli

[Tracksnblades1]

Idler has two bearings and an oil feed via a jet as stated earlier.
 As for the piston cooling................No it relies on splash and I monitor the pistons closely and to date there has been no evidence of any problem.   Also I am running 3D ignition and as this reduces piston temps it is obviously a factor.

 Captain

Piston and Piston cooling revisited Cap.
Are your rod bearing clearances on the + side of 0.0015 ..?
Did you ever try running a water cooled CBR/CRF piston type in an air cooled cylinder..?
Edit Cap: Found some answers in your dated posts.
Thanks

[Captain]

  My preferred clearances (mains & big ends) is .018" as this allows the oil throughput to control the cooling requirements.  Something that is not generally considered by most but it is a very important function. For road racing or extended time under high RPM and load this is "very" important.

 Pistons:  I have been using a custom made design and utilising the most advanced tech available today. This means a fully 3D machined reduced height slipper type piston with shorter pins and all the other trick features. (It's a long list)

 Foot note:  I have never understood the reluctance and or the on-going preference for old-school pistons design and usage that everyone still seems to install. There is no mechanical/physical reason not to use current tech as it has proven advantages and I'm yet to identify any that are not.   

 Captain

[slikwilli420]

  My preferred clearances (mains & big ends) is .018" as this allows the oil throughput to control the cooling requirements.  Something that is not generally coincided by most but it is a very important function. For road racing or extended time under high RPM and load this is "very" important.

 Pistons:  I have been using a custom made design and utilising the most advanced tech available today. This means a fully 3D machined reduced height slipper type piston with shorter pins and all the other trick features. (It's a long list)

 Foot note:  I have never understood the reluctance and or the on-going preference for old-school pistons design and usage that everyone still seems to install. There is no mechanical/physical reason not to use current tech as it has proven advantages and I'm yet to identify any that are not.   

 Captain

Right you are Captain! And thats why these exist now for my 760cc road racer:





Did you mean 0.018" or 0.0018" for main and big end clearance? 18 thou would be massive and would cause oil pressure issues.

[Don R]

 So the scavenge line just dumps into the sump tank and doesn't really make back pressure? That makes sense.
 My brother had a big bore/stroke motor with a turbocharger. Built by the guy that owned our local Honda shop. It had an external pressure line and return for the turbo bearing.
 The original owner heard he had the engine and bugged him until he got it back, no idea where it went after that. 

[Captain]

  My preferred clearances (mains & big ends) is .018" as this allows the oil throughput to control the cooling requirements.  Something that is not generally coincided by most but it is a very important function. For road racing or extended time under high RPM and load this is "very" important.

 Pistons:  I have been using a custom made design and utilising the most advanced tech available today. This means a fully 3D machined reduced height slipper type piston with shorter pins and all the other trick features. (It's a long list)

 Foot note:  I have never understood the reluctance and or the on-going preference for old-school pistons design and usage that everyone still seems to install. There is no mechanical/physical reason not to use current tech as it has proven advantages and I'm yet to identify any that are not.   

 Captain

Did you mean 0.018" or 0.0018" for main and big end clearance? 18 thou would be massive and would cause oil pressure issues.

 Opps............ Fingers going too fast and not checking before I push the "enter" button.   It should read .0018"  (.0457mm)
 
 As for the oiling to the gear drive idler bearings I use the pressure side of the oil circuit (not the return) so surely you can find a appropriate place to access and do the same. 

 Captain

[Captain]

 For everyones benefit this is what my "used" idler gear looks like....... The smaller bearing version is the original design and the larger is the current improved version.  the latest is 4 x more load capacity and even greater durability and life.  This supplied with clean continuous oil supply has proven to be very-very durable and interfaces with the HY-VO tooth profile of the crank with no issues what so ever.   Why Honda never did this in the first place is something I will always ponder.

 Captain

[Tracksnblades1]

  My preferred clearances (mains & big ends) is .0018" as this allows the oil throughput to control the cooling requirements.  Something that is not generally considered by most but it is a very important function. For road racing or extended time under high RPM and load this is "very" important.

 Captain

Cap,

Whats your preferred weight oil , with your bearing clearances...?
Thanks for a peek at your piston. I figured if I could think of it, someone surely has already tried it.
At least at your horsepower level and application , I won't have to worry about those Etty bitty rings overheating in mine. Are you running the newer end gaps on the compression rings..? Or are you old school..?

Silk,
Thanks for a look at your piston too. That looks pretty much like a CRF piston +1 more ring.
Which begs another query. Have either of you or others tried the single compression ring type..?

Thanks again.

[Don R]

   To recap, the 750 auto crank has a different size hyvo gear than the 900 type crank?  That idler is crazy cool.

[Captain]

 Another picture of the my idler fitted into the carrier. For those that don't know this is for the DOHC race engines I'm involved with but is shown here to assist others about the degree of structural robustness required for successful operation.
 There is a lot (but not all) in this picture for those that understand the process.

 Captain

[Don R]

W0W. Impressive. I just reread the first post and am astonished by the pictures there too.

[Terry in Australia]

Beautiful re-engineering, I'll be interested to see how well it holds up in high performance race engines. I can't help but wonder though, if this is as simple as it appears, why hasn't it already been done time and again over the last 50 years?

Back in the day when I bought my first CB750 new there were big bore kits, cams, all manner of head mods, carbs, ignitions, clutches etc etc, but I don't remember ever seeing a gear primary drive kit, not even from RC, or Ape.

Did they never try it, or did they try and fail, or did they not consider it as that much of an advantage? Or were they just restricted by the limits of tech of the era? Fascinating.    

[Tintop]

Captain, is that a model of Garlits' drag Hemi motor in your photo.  I have one with the clear cover signed, and a photo of him signing it.

[MessnerMoto]

I had two days to revisit and redo mounting of idler.

Pictures speak for themselves.

This is a plug and play solution. Without any necessary modifications on engine cases. There is now 13 M6 bolts holding the "adapter plate". I think thats more then sufficient. Also adapter plate is also much more rigid then the previous solution.

Three locating pins that are used to positions oil pump in case are no used to position the hole adapter plate assembly.

The only drawback is that will add 20mm thickness and maybe interfere with exhaust.

I will take oil supply directly from adapter plate for idler

[slikwilli420]

I like the design and do have concerns about a new exhaust though. I suppose it wouldnt be a deal breaker to add 25mm or so to the length of the primaries and lower the collector some. Or use a DOHC exhaust. I would however make the plate so it can be bolted to the engine, but the oil pan and oil pump can be removed. I guess that could be achieved with a few studs replacing the bolts for the oil pan but then you run into clearance issues when removing the engine.

[Tracksnblades1]

...the only thing I can say is, WOWWWW!


Sent from my iPhone using Tapatalk

Re reading the entire thread again like Don R, I can only repeat  Medyo Bastos's single word declaration.

WOWWWW!
X        2
Mirko & Captain

[turboguzzi]

my mechanical engineering gut feeling (only 5 years in the air force R&D unit before i became a designer ) tells me that the area in red would be highly stressed, so maybe some sort of webs in green could help?
dont know the exact reaction vectors and might not be doable because of interference with other parts, so just my 2 cents

[MessnerMoto]

my mechanical engineering gut feeling (only 5 years in the air force R&D unit before i became a designer ) tells me that the area in red would be highly stressed, so maybe some sort of webs in green could help?
dont know the exact reaction vectors and might not be doable because of interference with other parts, so just my 2 cents

there is engine case oil line there. Also oil pump is there...

also I found equitation for calculating forces on gears. The force is 97% in Y(up) direction like Captain said it would be

I did FEA according to real torque that crankshaft is producing. The pictures are for 100N⋅m of torque... But it can hold more

[bwaller]

Would the force not be more stout on the opposite side from where TG showed his red mark?

[Old Scrambler]

Very Interesting development

With this conversion I assume the potential 12,000 to 14,000 rpms for a 761cc motor would be something less for a big-bore? You've got me thinking about an application for land-speed use at Bonneville

[Tintop]

my mechanical engineering gut feeling (only 5 years in the air force R&D unit before i became a designer ) tells me that the area in red would be highly stressed, so maybe some sort of webs in green could help?
dont know the exact reaction vectors and might not be doable because of interference with other parts, so just my 2 cents

Those were my thought as well TG.  Webs could be doable with a relief for the oil gallery, some thing like a 'flying buttress', with cross webs were the 4 6mm bolts are, but otherwise open to allow for oil return.  Assembly should not be an issue as you would mount the idler parts to the case 1st.

Would the force not be more stout on the opposite side from where TG showed his red mark?

Agreed Brent (97% upward according to Miko), which is likely why Captain's carrier is shaped as is.  However I think the issue here is Miko is trying to avoid case machining, which is required for Captain's DOHC application.

[MessnerMoto]

there is no need for that and there is no space for that... oil pump occupies green lines on yoss picture

I will recalculate stresses and deflection FEA... I will just increase thickness of adapter or remove less material from plate if needed. But 20mm thick aluminum plate with 13 M6 bolts... Probably over engineered already... will see after FEA analysis