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Timing Gear Set - Replacing timing chain

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@ Scud

 

Yes, this is the tensioner I was talking about.

 

@ Guzzimoto and SP838

 

For a race engine I would use a gear set. It absorbs less power and the disadvantages mentioned above are not detrimental for an engine that is always working at high rpm.

 

For a street engine I can only see advantages for the gears compared to the stock tensioners. The stronger Stucchi tensioner is the best solution for a street engine. Use a Strobo light and observe the iginition through the hole on the right: on any V11 with stock timing chain you will notice the timing variation. When installing the Stucchi tensioner the ignition is almost stable apart from the idle corrections done by the ECU.

 

My aversion for the gears is backed by some experiance: Once i reworked the gears (the oil pump gear) of a V7 to use it in my LM2. This involved a lot of work and eventually there was no way to install the oil pump gear: the oil pump was too nearby the crank. Displacing the oil pump by about 2 mm was the onnly way to make this setup work.

 

A friend of  mines V7Sports engine was distroyed by a collapsed timing gear: the abrased particles went through the engine which had to undergo a complete rebuild.  

 

My own V7Soorts gears worked fine, but were louder than a chain setup.

 

Straight cut gears are very loud and last much shorter. Aluminium gears show wear very soon and then get louder too. I have seen such gears with 20 000 km that I wouldn't install again.

 

It may depend on the quality of the gears involved, but these are my experiences.

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Well yeah, if you are using gears that are not designed specifically for your engine it is pretty obvious you might encounter some problems. The gears we are talking about are specifically for the V11, and they are made from high strength Al alloy.

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For a race engine I would use a gear set. It absorbs less power and the disadvantages mentioned above are not detrimental for an engine that is always working at high rpm.

 

 

A chain is actually a more efficient transmitter of power than a gear train. Typical chain losses are around 1%, gears around 3% or more.

Ciao

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Short term - I intend to upgrade the tensioner; thanks for bringing this to my attention.

 

Long term - the gears seem to make the most sense (at least for my situation) when the chain wears out, which some say happens around 20,000 miles.

 

Physics for Gear-Heads:

There are some different opinions and experiences here (perhaps due to part selection). This is what I assume:

  • Gears have less contact area than chains, therefore less friction, therefore more efficient.
  • Gears have less total mass than chain plus gears, therefore less rotational inertia, therefore more efficient. This potentially also makes the engine a little freer-revving - analogous to a lighter flywheel (and hopefully without the exploding-Scura effect).
  • Unlike chains, gears don't stretch (although they do wear). Therefore gears should last longer, maintain precise timing over their lifespan, and require less maintenance.

Can somebody who knows the science please confirm, refute, enlighten, or elaborate?

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Wait, what? I should be bracing for my fifth chain!

 

(I don't believe I've had the timing chest open . . . I guess I should put this on my 200.000 km service list.)

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Wait, what? I should be bracing for my fifth chain!

 

(I don't believe I've had the timing chest open . . . I guess I should put this on my 200.000 km service list.)

 

Now there's some real-world experience.  But if you are way beyond the mean-time-between-failures for chains, it might be worth looking at. Unfortunately, I don't know the MTBF for the chain, but the MGNOC article I linked to in an earlier post claimed an average life about 20,000 miles.  

 

You may be several deviations out from the mean  --  interpret that however you like.  <_>

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After monitoring this forum for these many years, I just haven't seen this as a recurring issue; kind of like the "soft valves/ bad guides" - it just has not materialized as predicted on a widespread basis.

 

I'm sure when I do my eventual major tear-down, something should be done about cam timing, but to dive onto it without any indication that your cam timing is jumping around and causing problems? :huh2:

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Thanks Docc, for being the observer and voice of experience. Given your experience, it seems the stock timing chain tensioner is also perfectly adequate.

 

FWIW - the V11 owners manual and the workshop manual don't even mention checking the timing chain, although the published maintenance schedule ends at 30,000 miles.

 

For comparison, I recently had the timing belt (not chain) replaced on my 2005 Toyota Tundra at 90,000 miles.

 

I guess my conclusion from this conversation is:  I'd still probably pop in some gears when the chain wears out. That could be a loooooong time from now..... but I'm putting another 200 miles on tomorrow.   :race:

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Chains out last belts on average. But a crappy chain tensioner can shorten a chains life. Still, I would think the stock timing chain should last a good long while. As it gets old, and the tensioner wear out, you may have lumpier idling and slightly less power. But usually those things creep in and as such are not really noticeable. The wifes V11 has over 60k on the stock chain, I have the gears but have not switched to them yet. I finally have a garage instead of a shed. Perhaps soon I will get to it.

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I fitted it to my cali3 it quietened the motor considerably. Couldn't notice any other benefits. I am going to fit them to my v11 too soon.

Which one did you fit to your Cali? Gears?

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I am wondering if anyone actually ever done this replacement. I saw this on Gutsibits. "Fits Moto Guzzi V11 Sport - Timing Gear Set Steel Ergal Spur Cut"

 

http://www.gutsibits.co.uk/pr/TheShop/index.php?f=e&Shnew=1&Model=1&ModelName=1100%20Sport,%20V11&Cat=ENA&CatName=Engines&spPage=15#topbar

 

I am wondering what benefit will this offer and would it really improve and upgrade anything

 

Any thoughts and knowledge about this subject would be appreciated

 

 

How soon we forget! Pete Roper [of sloppage sheet & midget porn empire fame] used to warn repeatedly against these things. Any engineer will tell you aluminum ["ergal" makes it sound oh so sexy, but it's still 6061...] makes for crappy gears unless they're running against something even softer [like nylon/Delrin], since against virtually any other metal it's eventually going to fret & fill your gearbox w/ shiny little aluminum flakes to ruin your day [& engine's life.] The switch from timing gears to chain drive simplified manufacture, and as long as you've got a good chain tensioner, doesn't really compromise anything. If you want to make the switch, insist on all steel gears [iirc, there's just one source for these, somewhere in the UK. If he's still doing them; it was years ago, & I didn't have the money to buy some for such a minimal return on investment besides "It would be cool to hear the gears whine on the overrun..." ;)] or at least a steel & brass combo. Aluminum has its place in many spots on a motorcycle, but in a gear train isn't one of them.

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I have a 'Chamber of Horrors' in my Flickr account of pics of buggered aluminium and aluminium /steel composite gear sets but I can't post pics here for some reason. I've given up arguing the toss with people over the suitability of aluminium alloys for timing gears as it always seems that their advocates have borderline personality disorders. If you want to try 'em? Fine! Don't be surprised or outraged though if they destroy your engine.

 

Pete

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Does anyone have a adress for gearset in Europe? Of UK? Thanks

 

 

 

Verzonden vanaf mijn iPad met Tapatalk Pro

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Does anyone have a adress for gearset in Europe? Of UK? Thanks

 

 

 

Verzonden vanaf mijn iPad met Tapatalk Pro

I have a steel set for the V11 and also for the Daytona engine from Joe Caruso in England but not an email address anymore. He is on linked in though.I dont think he's made them for years but if enough people get together he may run a batch.

 

EDIT

 

Try this... no garantees though. Sent him an email to say Hi and it didnt bounce so far.

 

joe.caruso@ntlworld.com

 

Edit 2....Joe got back to me and he's still making gears, so if anyone is interested drop him a line. Imagine these bad boys in your timing chest. Better than that agricultural chain:)

 

Ciao

EngineAsm1_zps61409bea.jpg

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