Srtaight Cut drops V Standard Helical ?
Turbo Mini Forums

"As TRANSLATED by the lizard with one eye"

"
Hi all

I'm just looking for some input on this.

I built two engines within a short time of each other, one with standard drop gears and one with s/c items. The one with s/c drops was putting out 130hp and 110fp/lb. The one with the std drops was making 127HP and 108fp/lb.

The one with s/c drops has failed the idler gear, is missing 3 teeth and chewed a primary bush.

The one with the standard items is still ok, even though it has seen more use.

The Question how strong are the standard drops?

Some input from some of our gear experts would be great

Regards
Paul

"

Edited by PaulH on 10th Nov, 2009.

That's really confusing, I'm not sure what is what. Any chance of a re-word?

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

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TRANSLATION:

"
Hi all

I'm just looking for some input on this.

I built two engines within a short time of each other, one with standard drop gears and one with s/c items. The one with s/c drops was putting out 130hp and 110fp/lb. The one with the std drops was making 127HP and 108fp/lb.

The one with s/c drops has failed the idler gear, is missing 3 teeth and chewed a primary bush.

The one with the standard items is still ok, even though it has seen more use.

The Question how strong are the standard drops?

Some input from some of our gear experts would be great

Regards
Paul

"

Edited by theoneeyedlizard on 7th Oct, 2008.

In the 13's at last!.. Just

Note to self dont write Post with a IPhone there shit thanka mr theoneeyedlizard

Edited by PaulH on 7th Oct, 2008.

There are people on here who know more about this than me, but my take on this is that it should not be unexpected.

S/C gears are weaker than the equivalent helical gear. They were developed for lower power losses as you experienced.

The problem with the helical gears is the side loading caused by the gear design.

By the time the helical gears find there way into one of our boxes, they have already completed a full life cycle.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I take it this is a slick shod racer we're talking about?

youd be right there all right

Someone just make double helical gear kits and drops. All our problems will be solved

On 12th Nov, 2009 Paul S said:

I think Gary OS has taken over my role as the forum smart arse

Hi
Nowt wrong with posting on an iPhone!
It's a doddle, it even manages with my shite typing!
Cheers
Gavin :)

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On 7th Oct, 2008 spanner181187 said:
Someone just make double helical gear kits and drops. All our problems will be solved

Edited by minimole23 on 7th Oct, 2008.

sounds like poor quality drops, or poor assembly. s/c drops can take more than 130bhp and last well. (i'm sure i have more than 130bhp and mine have done over 15,000 miles)

I recon its your primary bush thats failed first and taken the idler.

The SC drop I have, Minispares ones, the primary gear front bush if FUBAR'd after 3000 miles!!!!! and I have heard this a couple of times.

I just bought the floating bush and it looks a nice fit, hopefully this will solve the problem. But why it failed in the first place is a mystery.

sprocket. i had a similar problem, the bush at the tail end of the crank (furthest from engine) spun in the primary gear, you could hear a screatch from it as you lifted the clutch. i got the gear rebushed and it started again, and yes i did oil the bush on assembly. i'm not sure it was the solution but i greased the bush and refitted and its been fine since (been apart a couple of times)

I have used lithium wheel bearing grease on all the primary gears I install, ant the SC one was the only one to fail. I have installed an identical set in another engine and they are fine.

the Primary bush failed, It was replaced it failed again, the crank was checked for size each time and it was well inside of spec, both of bush where of the floting kind

the idler failed at another stage earler a good wile befor the pimary bush problam these where both MS products, at this point I am far from convinced that s/c drops are the way to go.

has anyone here had the std items fail on them as yet I havent ?
regards,
Paul

ive had an idler shred its bearing and the transfer case housing, but it was quite a high milage, standard engine that we just bolted a stg 3 kit onto

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

have you tried grease on the bush? mines been fine since i greased it. took it off when i damaged a piston and then again when i changed the oil seal and clutch plate.

I have always put them on with Engine asembly lub which is something the same as Grease.

Edited by Sprocket on 7th Oct, 2008.

Easy tiger lol I said something the same and bleve it or not its what we used on all our racer Motor bikes with fantastic results dont get me rong this is no ordinary engine asembly lub its that millers VEHP stuf Im told that stands for "Very Extreme High Presure" im not totaly convinced. The grease is a good idea I like the sounds of it, but im not convinced it is solving the problam but simply masking the efect.

EDIT: Because im having a very bad keyboard day.

Edited by PaulH on 7th Oct, 2008.

Just my thoughts...

VEHP = Very Extreme High Pressure (maybe)

So EHP = Extreme high Pressure...

and EP = Extreme Pressure (which it does) but EP80 or EP90 is what I put in an old skool gearbox or hypoid differential.

This is because the EP additives are specifically designed for the very high point contact loads in certain gearboxes and differentials.

I certainly wouldn't put EP80/90 in a Mini gearbox/differential though.

What I'm saying (probably very badly) is that the "Extreme"/"Extra"/"High" etc doesn't mean it's right for everything.

We're talking about a bronze bush here that for 99.9% of its life will see no movement at all, and for 0.1% of its life a few thousand RPM.

I don't have the answer but I don't think something with fancy names/letters is necissarily the right solution.

Schrödinger's cat - so which one am I ???

Describe the actual failure here. Are we talking about a failed idler gear / teeth or a failed primary gear / bush?

This is simply not clear right now as the story seemed to change?

HI dave I think this has gone a tad of topic all right,

I decribed two separate problams I had with S/C drop gears

The first Primary Gear bush failure, The failure I experenced was the inner bush split and ended its life on the botom of the drop gear housing this problam occured twice on this engine.

the second problam
was a failure of the idle gear, the failure the occured on this gear was it broke three teth off at the base of thr gear it seemed as if the where in mesh with the input shaft gear at the time as the input gear teth seemed to have some dammage to them and the pimary seemed ok.

Edited by PaulH on 7th Oct, 2008.

I think the MED solution is perfect by placing the bearing in the idler gear and mounting it on a spigot side thrust issues reduced considerably.

Own the day