yoeddynz

Discuss here about Yoeddynz's little Imp project...

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If I was you I'd look into setting up a sort of crank/cam sensor arrangement with your chain drive oil pump setup. Something that either kills the engine or throws a warning light when the chain stretches/wears beyond allowable limits.

That's a scary setup that could cause a lot of financial/time damage if it lets go

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Probs better with the sprockets you ended up with, the Shimano ones have the shifter ramps in them.

 

Should have used campagnolo though you know

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On 19/07/2020 at 15:19, yoeddynz said:

Cheers KK. I do actually have a little folder on my laptop dedicated to just pics of sexy looking 911 engines and I think I would probably be banished from Oldschool if I fit anything other than itbs. I'm definitely going to use efi though so sadly, some might say, it wont have the full on classic look of webers lined up.

But I plan to try my best to have the engine 'classic' looking, in a 60's race car inspired sort of style . I won't have brightly coloured AN fittings and braided lines etc that for me often ruin a classic engine bay.

Here's a neat vid of a cafe racer styled Goldwing, stripped down with 6 webers. Its pretty neat....

https://youtu.be/iuuiHgzlgp8

If Burlen get their SU injection to market, 6 of these would look cool.

Burlen-SUi-Fuel-Injection-Carburetor-2-1

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3 hours ago, ajg193 said:

If I was you I'd look into setting up a sort of crank/cam sensor arrangement with your chain drive oil pump setup. Something that either kills the engine or throws a warning light when the chain stretches/wears beyond allowable limits.

That's a scary setup that could cause a lot of financial/time damage if it lets go

Feel free to explain to me what's so scary about it? Its not finished yet. What you've seen so far is a mock up. 

@tortron yeah i considered using an 8 speed cassette and having a variable oil pump speed. Campag for max italian street cred.  Or shimano because it works better.... 

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It's just running the oil pump right?

I reckon that would be fine, it's in a bath. Even if it stretches it will still run the pump. If it breaks the oil pressure light will come on.

Single speed chain is pretty strong, in an ideal world you would run duplex but whatevs.

I guess the speed/inertia might be an issue, but apart from it not being duplex it is the same setup as a cam chain bar pitch differences.

/trustmeimanengineer

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1 hour ago, ThePog said:

It's just running the oil pump right?

I reckon that would be fine, it's in a bath. Even if it stretches it will still run the pump. If it breaks the oil pressure light will come on.

Single speed chain is pretty strong, in an ideal world you would run duplex but whatevs.

I guess the speed/inertia might be an issue, but apart from it not being duplex it is the same setup as a cam chain bar pitch differences.

/trustmeimanengineer

yeah just an oil pump. Previously there was a smaller chain that ran two oil pumps plus a water pump! So as far as torque loadings go the chain I have selected is pretty burly and compared to the torque a strong rider can put through a chain its nothing. Wear over a long time is the issue but yeah- oil bath.

Certainly going to find out over time how long it lasts.

 Treat me and my engine as an interesting experiment in the testing of bicycles chains.

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i was getting 10000k out of 9 speed chains without ever washing them and them being full of wet sand 75% of the time, and loading me plus 50kg of gear through them. They never snapped, just got longer

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I'm curious to see how the flywheel/gearbox setup looks when you get to it.  The casting/layout doesnt do to many favors, the frequent use of the mill makes for good content for us on the other side!

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I'm still quite far behind on the updates so that bit has just yet to be posted up. After lockdown ended and I kind of 'went back to work' with paid work coming back in the goldwing project went right to the back burner so to speak. In fact I have spent more time in the last few weeks typing out these posts than I have working on the engine! Something to do with it being warmer inside than out in the workshop. Now we are right into the start of building a mezzanine so engine fettling is going to be put aside again.

Lucky I have a few 'updates' still to be released eh :-)

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Nice work. Motorbike chain too bulky for space constraints? / You've already done it now. From what I know of its the whipping that kills the chains normally - which is related more to the tensioners failing than anything else

Could just run a oil pressure feed to your ECU, that way if it drops below x psi it goes into limp mode / warning light if you're paying attention

Will you have a guide down one side of the chain, and the other with the tensioner? (Pic below is of a gemini setup, 3 is the guide (I think steel backed with a teflon sort've thing) 4 is the tensioner arm, 2 is the spring loaded tensioner 

G161Z GEMINI/I-MARK/IMPULSE SOHC 8V 1.6L '1981-93 ITEM NO ...

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yeah sort of like that - definitely  tensioners.  Possibly a guide on the longer chain.

Interestingly ford removed the guide on their later duratec engines because whip is not really a thing on oil pump drives- the oil pump acts as a buffer (always a consistent resistance) and so takes away the pulses that you get on the cam chain setup for example. So ford found somewhere they could save money.

 

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That gemini set up is the same as the 70's mazda setup (ma etc) mazda's run a chain dive oil pump with no tensioner or guide. Never seen one break, only stretch.. How long does it need to be? 

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I'd be running the chain off a reel mower. I've broken too many bike chains to take the chance. If that chain fails, its GAME OVER! For your engine. 

The oil pump chain drive from a Mazda rotary is double row no? 

Some things should always be over engineered imho.

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There's no room for double row. Anyway- the chain I have selected and bought wont be snapping in a hurry. Wear over thousands of miles is more my worry but I'm not losing sleep over it. Its all just a fun toy to play with.

Next time you need a chain fitting please let me fit it for you-  decent quality chains on bikes should not snap if fitted correctly. They'll only give trouble if mashed up in a previous situation like dropping down between the rings and chainstays etc. Then you can go riding with me again :-)

Mazda rotary chains are single row- well at least the 12A ones are that I'm familiar with.

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9 hours ago, yetchh said:

That gemini set up is the same as the 70's mazda setup (ma etc) mazda's run a chain dive oil pump with no tensioner or guide. Never seen one break, only stretch.. How long does it need to be? 

Neither chain is very long and are as short as I can go - if I remove a link the teeth will clash.

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engines not fit for purpose and bicycle parts is how we went from horse and cart to the moon in a hundred years

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I think even something as simple as a hall effect sensor/proximity switch that detects when the chain tensioner has had to extend too far due to wear would really help in this situation.

As Bort says, one second without oil pressure at 7000 rpm and all of your hard work is toast.

I've been lead to believe that there are subtle differences in chains that make them suitable for different environments - bike chains are pretty much expected to operate at low speed under high load in a dirty environment, quite different to what they will see in an engine.

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