FAO: people running big power 1*2s, JC5 gearbox strength?

[jack_davey]

Is it the actual diff that goes first? or is it the bearings collapse then the crownwheel gets mashed up by the other gears due to being out of alignment?

 

[jack_davey]

thought about perhaps getting the gearbox uprated by these guys: http://www.gearboxman.co.uk

 

[Carlos Fandango]

thought about perhaps getting the gearbox uprated by these guys: http://www.gearboxman.co.uk

Used before.....very good, highly recommended.

 

[Icarus]

Gearboxman aka CTS, competition transmission services. Good chaps I've used them in the past with no problems and good results.

Cheers
M

 

[Tom@JMS]

I'd pay attention to box lubrication though, specificaly oil temps. Get a thermocouple of there to give you an idea of box/oil temp and fit a gearbox oil cooler if required. Chances are it'll live a lot, lot longer that way!

On this topic I changed the box oil on my 59k 182 this week, and we have done a few others recently. As we know Renault spec the box oil as being virtually life long, but the box oil we take out is often black as night & cloudy/misty, completely shot imo.

Refreshing the box with a good fully snyth oil resistant to the thermal degradation Icarus is mentioning should pre-long the life of a standard box, even if it does not make a noticeable difference to the feel of using the box then & there.

One thing I am interested in is the box cooling. What sort of operating temperatures does an RS box run at under hard use, I assume a lot of the heat is transmitted through the block & then added to that is the frictional heat from the gears themselves? Has anyone experimented with box cooling, even if its just with a front/scoop mounted air source? Now obviously this would make sweet F.A difference day to day that would be noticeable, but the killer question is: on a hard driven car, even a completely track orientated vehicle would a cold air source for the box prolong box life?

 

[Macester]

when i changed the oil for my gearbox, the gear changes were much smoother for a while, would highly recommend it for people running high torque. I've been running 185lb/ft on my jc3 for the past 10k miles and its been fine.

 

[Icarus]

On this topic I changed the box oil on my 59k 182 this week, and we have done a few others recently. As we know Renault spec the box oil as being virtually life long, but the box oil we take out is often black as night & cloudy/misty, completely shot imo.

Refreshing the box with a good fully snyth oil resistant to the thermal degradation Icarus is mentioning should pre-long the life of a standard box, even if it does not make a noticeable difference to the feel of using the box then & there.

One thing I am interested in is the box cooling. What sort of operating temperatures does an RS box run at under hard use, I assume a lot of the heat is transmitted through the block & then added to that is the frictional heat from the gears themselves? Has anyone experimented with box cooling, even if its just with a front/scoop mounted air source? Now obviously this would make sweet F.A difference day to day that would be noticeable, but the killer question is: on a hard driven car, even a completely track orientated vehicle would a cold air source for the box prolong box life?

You need to actualy cool the oil, simply blowing a bit of ambient air over the box casings won't make a great deal/any difference. The box casing isn't cast with any form of heat sinks or similar so loosing heat into an ambient temperature air stream will be very difficult.

The only effective way on the JC5 is via a single point scavenge from the standard drain plug with a electric oil pump, through a air/oil radiator/cooler and back into the box through the fill level plug.

Cheers
M

 

[Tom@JMS]

The only effective way on the JC5 is via a single point scavenge from the standard drain plug with a electric oil pump, through a air/oil radiator/cooler and back into the box through the fill level plug.

Makes sense. What sort of oil pressure does the box run at when warm, considering the plastic filling toggle & loose as f*ck breather pipe it can't be much more than ambient pressure, maybe a little added by liquid expansion?

 

[Icarus]

Makes sense. What sort of oil pressure does the box run at when warm, considering the plastic filling toggle & loose as f*ck breather pipe it can't be much more than ambient pressure, maybe a little added by liquid expansion?

It's not an F1 box!! It's just splash lubricated so no oil pressure at all.

Cheers
M

 

[ben_p]

I bought a mocal pump, 8 row cooler and filter for my old box, exit on the front under the wing nut, re entry on the 5th gear casing.

 

[Tom@JMS]

Its sounds like a neat system. Did you drill and tap a new hole in the casing for the inlet pipe to fit into?

 

[ben_p]

Its sounds like a neat system. Did you drill and tap a new hole in the casing for the inlet pipe to fit into?

Yeah, you have to strip the box though (swarf)

Prob cheaper just to let them blow up, I only did it as I had a avanti gearset, rods and diff to go in (never made it in though)

 

[Icarus]

Just use the standard drain and refil points with appropriate screw in fittings. Much easier and allows it to be a bolt on setup then.

I've done this on Ford/Getrag 6 speeds and Sadev ST75's with good results.

Cheers
M

 

[jack_davey]

Yeah what you would ideally want is a heat exchanger. When I worked for PARR motorsport I had the joy of changing three clutches in one afternoon on a GT3 race car, thankfully they have some pretty awesome hoses that automatically seal when you unclip them from the coolant system to remove the gearbox, so you only get the tiniest drop of coolant on you when under the car! I imagine these fittings are quite expensive though along with buying a heat exhanger to cool the JC5 box.

Tom- I already regularly change the transmission oil in my 182, and it's not so much the blackness you want to be weary of, its the metallicy look where tiny pieces of metal are being worn off and collected in the oil. A reason why the original minis spend more time off the road than they do on the road, as they share the transmission oil with the engine oil - NICE!

 

[Martin_172]

iirc a JC5 is oficially rated to 200nm which works out around 148lb/ft from memory? so in standard form the box is on its rated limit, although ive been comforably running 160lb/ft for 2 years and people are running way more than that on them.

torque will kill them not bhp, regular oil changes and most importantly dont rush it and be rough with it is the key. thats why you get standard power ones braking and turbo ones not braking!

 

[Jay Payne]

Yeah, you have to strip the box though (swarf)

Prob cheaper just to let them blow up, I only did it as I had a avanti gearset, rods and diff to go in (never made it in though)

Didnt it go bang anyway?

 

[jack_davey]

hmm looked into making up a transmission oil cooler kit, quite pricey I think!

Plus I think I'd have to drill and tap holes into the bellhousing as using the standard drain plug and filler hole may mean that its overfull when the pump isnt running

 

[Icarus]

hmm looked into making up a transmission oil cooler kit, quite pricey I think!

Plus I think I'd have to drill and tap holes into the bellhousing as using the standard drain plug and filler hole may mean that its overfull when the pump isnt running

Only if you mount the rad above the oil level in the box. Oil runs downhill but not uphill ;-) You want the pump below box oil level anyway to aid priming.

Costs shouldn't be that bad. Suitable electric oil pump circa 80 quid, Setrab rad circa 60 quid, some jic fittings and hose at around 80 quid and a 95 degree thermo switch with 10 degrees of hysterisis is a tenner.

Cheers
M

 

[jack_davey]

yeah good point, common sense just kicked in! lol!

Yeah I looked at all the bits needed on demon tweeks website! Seems like a lot of stuff to cram into the bay!

 

[GodSpeed]

Only if you mount the rad above the oil level in the box. Oil runs downhill but not uphill ;-) You want the pump below box oil level anyway to aid priming.

Costs shouldn't be that bad. Suitable electric oil pump circa 80 quid, Setrab rad circa 60 quid, some jic fittings and hose at around 80 quid and a 95 degree thermo switch with 10 degrees of hysterisis is a tenner.

Cheers
M

Time to kick this thread in to life again. Have a few questions.

1. What about pump flow? Im considering a Mocal pump and it delivers ~7liters a minute, can it be to much?
http://www.demon-tweeks.co.uk/motor...-accumulators/mocal-12-volt-electric-oil-pump

2. Considering the 3/8 NPT connections on the pump and the threads in the gearbox what hose size/connectors would you go for?

3. What about adding an oilfilter to the loop, any need? http://www.thinkauto.com/acatalog/On_line_shop_In_line_filters_for_oil___fuel__333.html

Cheers

 

[nuvelungo]

View attachment 540420

you have adapted the masses of megane 225 to clio 172, will you have photos of how it looks?

 

[Krarl]

As previously stated...

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