Ribcase Gearbox Oil?

[jonclancy]

Shopping around as we speak. Will update with the final result. I'd be happy to loan my purchase to list members if needed.

(missed an auction that would have done the job - got a couple finishing this weekend).

[jonclancy]

Update,

I have an advance timing light now, Colourtune, compression tester and TDC finder. Happy to lend to registered Register members if they need this sort of stuff.

[Alan FIAT]

Hi Jon.
Have you bottomed your baulky change problem? I raced midgets years ago and clutch drag could be a problem, causing sticky changes, especially when everthing was really hot. Many people used aeroquip or copper pipe instead of original flexy pipe, but the solution was to fit a smaller bore slave cylinder, from I think, one of the Minis. At this remove in time I cannot remember which one, but a catalogue check should find it. Regarding oil, always used engine oil and had no problems.
The above assumes your box has no fundamental problems.

Alan

[jonclancy]

Hi Alan, Happy New Year!!

Sorry, I missed your post. I haven't yet got round to bleeding the clutch system (will replace the fluid totally when I do). AFAIK, the box is perfect as it was only recently rebuilt. I have Somerford Mini very nearby, so can pick up a smaller bore slave cylinder easily enough. I have a braided hose in the system - TonyL did not skimp on the spec when he built the car. It's on the list of jobs to do when I get a break in my current work-run. I was contemplating a New Year's Day run out, as the weather is so nice, but the huge puddles and new potholes have put me off.

[jonclancy]

erictharg wrote:
> I run GL4 gear oil. 75/90 weight. Similar viscosity to 20-50 engine oil but
> designed for gearboxes so better additive pack for gearboxes. But the
> Midget gearbox is such a crude affair I'm not sure it makes much
> difference!

I have just been into my local Halfords and they only had 75/80 GL4 out on the shelves. Now I'm back home, I see they appear to have 80/90 GL4 in stock. Or in the stock-room!!

Charles, All, is there any real-world differece with using either oil as a replacement for 20W/50? I want to try gear oil this year and the track-day season is almost here.

I did research the smaller clutch slave cylinder, but will need to re-attack as I have lost my notes. I have my fresh hydraulic fluid waiting to go in once the garage warms up to a sensible temperature.

(and my 1144 front pads - should be able to out-brake Splat with ease!! )

[Westfield 129]

Best bet is to use the original recommended motor oil in the transmission. You can try a synthetic, but remember, if the synchro rings don't have any friction, shifting may be difficult. In any case, you can always change back to dinosaur oil.

Redline MTL is a good synthetic gearbox lube, as is Redline Shockproof Light.

But in my experience, motor oil works best in the Ribcase.

[erictharg]

GL4 is not usually synthetic. It's just a spec that is designed for synchro gearbox usage, as opposed to using engine oil which did the job fine in the 60's (and likely still does) but it has a few different additive to suit a gearbox instead of an engine. I ran half a season using 15-50 synthetic engine oil as I'd run out of the GL4. No noticeable difference. If there's a significant problem with the box it's not likely the oil. As the others have said it's either the clutch or the synchro's. Don't expect too much from the synchro's though - My 3 - 4 change always grinds a little when racing. Those old synchro's can't do their job fast enough. On the road I usually double de-clutch to keep it sweet and for the fun of blipping the throttle.

[Pluscat]

Jon,
I had a similar problem with my box. Thou I use the rivergate/Datsun box, it uses the Midget clutch.
Shifting was fine when cold, once hot it became more difficult.
Never sorted the problem till recent. When I rebuilt my engine I noticed the the diafragm on the presureplate was warped a bit.
I replaced the pressureplate with a new one, problem solved!!
When you rebuilt the box you didn't replace the presureplate, did you?
I suspect that once a presureplate is installed and later removed, it will be warped and can't be used again.
It happend to me when converting to 5-speed.........

[Westfield 129]

If the clutch doesn't disengage cleanly, as with a warped or badly worn disc or release bearing, you will have shifting problems. I usually suspect the clutch if the effort increases along with the grinding or reluctance to shift. When I take the thing apart, unless it has been only a few thousand miles, I always have an extra disc, cover and release bearing. I also keep a spare Fidanza friction surface for my alloy flywheel. I hate to take the engine out more than once or twice every 10 years. Which reminds me, I need to order a new Rivergate disc. i am going to send it off along with my old Rivergate disc so that measurements can be taken for relining my old discs.

My Datsun box is running on Royal Purple gearbox lube. It seems to work fine, hot or cold, and the box, rebuilt prior to my installing it, shifts with a nice, light action, with unbeatable synchros.

I may change it at some point to the Redline, mainly so that I only need one lube for all the gearboxes and diffs here. The stuff works in the T9, my Renault's R30 with the ZF roller locked diff, and the TranX LSDs (with some LSD additive).

[jonclancy]

OK folks,

I have my GL4 80W/90 oil in my mitts. I went out for a run this afternoon - and cold is not the word for it!!! F.. F.. F.. F.. Fairly cold!

Anyway, the idea was to run the oil nice and hot prior to pulling the sump plug. I also chucked a coupel of powerful magnets on the sump plug, too.

The plug was tight!! But, Halfords' EXCELLENT "Shock & Unlock" did the job.

http://www.halfords.com/webapp/wcs/stor ... yId_165594

I drained all the oil into a washing-up bowl and it looked reasonably clean for 1000 miles or so. This was Halfords CLassic 20W/50. There was a metallic tinge to the oil (I was not surprised), but fishing around with my magnets didn't pick up any metal fragments at all.

I have the sump plug out and cleaned. I was seriously considering drilling and tapping the plug to secure a small "rare earth" magnet to the plug. The standard mag-plugs can't be used because it fouls the selector fork in the gearbox. My plan is cheap, easy to implement, and avoids any fouling. But... would you seriously bother?? I can't see the harm and it would only take a 1/2 hour or so to complete the conversion.

http://www.ebay.co.uk/itm/D-12mm-x3mm-H ... 4ab80eed3a

Any downsides to the plan? I intent to tap, screw and araldite the magnet in place. Or maybe stack two - they will still be below the rim of the plug.

I also gave the clutch a good few pumps and the gearbox was changing smoothly. I do have the clutch fluid change planned very soon and I suspect, as you all so, that this is the probable cause of my odd baulked gear-change (or me being lazy!).

Lots of little jobs. The first track-day is on 15 March. Still deciding on whether to go for it or wait until April/May. I'm 60/40 for at the moment. Car mods, weather, etc, etc. But looks like we'll be having a WSCC local area track day at Hullavington on Friday 19th April.