PC Pete Posted January 11, 2013 Share Posted January 11, 2013 Hello My first time on this forum so this is probably a question that has been answered before - apologies. Am now into my third build - and R400 and about to start fitting the (LSD) diff - ugh! It is, I hope, the latest BMW diff with latest carrier having read some of the posts from last year re the BMW diff carrier. Just contemplating the best oil to use. Mainly track use in mind. And while I'm at it - any thoughts on best gearbox oil? Many thanks in advance PC Pete Link to comment Share on other sites More sharing options...
Garth Posted January 11, 2013 Share Posted January 11, 2013 Hi PC Pete Welcome to BlatChat - how have you managed to build 2 Caterhams without visiting this forum before!? Have just had a refurbished box from BGH and they recommend Comma SX75 W90 GL4 for all type 9 boxes. I am sure others may have a different view but BGH were quite clear about this! (GL4 bit is important!) Cannot help with the diff - I just put in what Caterham gave me but that was for a Ford (very quiet!) diff! Edited by - Garth on 11 Jan 2013 11:29:27 Link to comment Share on other sites More sharing options...
irrotational Posted January 11, 2013 Share Posted January 11, 2013 For the 6 speed box there is a certain oil recommended that helps with notchiness when cold...a search of tech talk should reveal it...I can't remember Link to comment Share on other sites More sharing options...
k.russell Posted January 11, 2013 Share Posted January 11, 2013 welcome to the forum PCP, for the Gbox i was recomended Fuchs titan (silkolene) srg75 by SPC recently, and that is what is going in mine. Link to comment Share on other sites More sharing options...
Garth Posted January 11, 2013 Share Posted January 11, 2013 BGH designed the 6 speed box - so ask them which oil to use if it is a 6 speed Link to comment Share on other sites More sharing options...
Klunk Posted January 11, 2013 Share Posted January 11, 2013 Re. the diff oil, what do BMW use? Link to comment Share on other sites More sharing options...
patneale Posted January 11, 2013 Share Posted January 11, 2013 I have the 6 speed and used the Caterham recommended oil. It was always a bit of a pig when cold and needed a very hard pull into second. That was until I put Slick 50 in it. It is just a dream hot and very good even cold. The Diff also got the Slick 50 treatment and I think it is quieter, but it might have "run in" now that I have done 45,000 miles. Certainly when new the diff sounded if it was going to spit its bits into the road on the over run . Even a Caterham replacement under warranty was little better. Ford Parts ! Link to comment Share on other sites More sharing options...
duffield Posted January 12, 2013 Share Posted January 12, 2013 Hi I use Comma LSD oil (COML S80W901LS.) in my CSR 260 diff with a ZF plate LSD. The oil is designed particuly for Automotive Limited slip differentials. Price £3.60 a ltr plus VAT . You can order it from most automotive oil suppiers. I get it from NAPS Northampton just round the corner from Cosworth. Hope that helps Andrew Link to comment Share on other sites More sharing options...
PC Pete Posted January 12, 2013 Author Share Posted January 12, 2013 Many thanks for your help on this one - much appreciated. I'll have a think then see what MVC have in stock. Given that the missing bits arrived yesterday I may just get around to finishing off the front suspension today....... thus successfully put off doing the diff..... again! Note to self - must use the forum more often. thanks again. Link to comment Share on other sites More sharing options...
the.vet Posted January 12, 2013 Share Posted January 12, 2013 What is this magical Slick 50 gearbox treatment? I was worried my 6 speed was a dud ( only had car a month) but it now sounds a like a bit of stiffness is expected when cold?!? Especially first into second - makes pulling out of my drive onto the main road a bit interesting! Link to comment Share on other sites More sharing options...
patneale Posted January 14, 2013 Share Posted January 14, 2013 To The.Vet Slick 50 is sold at Halfords and they have variations for Engines,Gearboxes and Diffs. It is PTFE based and is a solution of the stuff they put on non stick flying pans e t c. The 6 speed Gearbox is made up from basically 1980's Sierra Cosworth XR4 bits. I had a chat with the designer of the 6 speed who was at the 50th Event of the 7 at the Norfolk Showground back in 2008. I pointed out this problem of very difficult change from 1st to 2nd when cold and pointed out that I had just driven a Honda Civic R type from cold with 500 miles on the clock and the change was as light as a feather. He said that modern gearboxes are built differently and the gear profiles are very different ( and I expect built to far better tolerances). These results in a much lighter change. That said the Caterham 6 speed is built to pretty tight tolerances, but 1980's tightness means stiff , but modern tightness means accuracy and slick. I have had to wait until now (45,000 miles) for the gearbox to be be worn enough to be really light from a cold start. Slick 50 helped a lot, but the downside is that you can beat the synchro if you rush the changes as the cones have less "bit" due to the PTFE. BUT of course if this is a problem you can change the oil back to normal oil. I would not recommend Slick 50 if you are going to track race the car as you will beat the synchro in rushed changes. OK for road use. The reason that Caterham use the old old 6 speed design is that it is tough and can take a high torque loading. Parker Racing told me that the gearboxes are the weak link in the car, but only because in the heat of battle on the track some drivers attempt clutchless changes (as they pull the lever from 5th to 6th before they push the clutch down !!) Properly operated they are OK.As a newcomer you find that the Diffs are dreadful especially on the overrun. But they are not usually any trouble just noisy. Another Ford crappy 1980's design, but reliable ! Hugh Robinson Link to comment Share on other sites More sharing options...
the.vet Posted January 14, 2013 Share Posted January 14, 2013 Thanks Hugh, thats great information. So long as I know it's normal I'll stop worrying about it! The car has only done 20k so maybe it'll loosen up as time goes by. If it becomes more of an issue I'll try the Slick 50 stuff. Cheers, Graeme Link to comment Share on other sites More sharing options...
I reply to every thread Posted January 14, 2013 Share Posted January 14, 2013 I would steer well clear of Slick 50 Link to comment Share on other sites More sharing options...
TonyR Posted January 15, 2013 Share Posted January 15, 2013 I would not put Slick 50 in a lawn mower, never mind a Caterham 6 speed box!! TonyR Link to comment Share on other sites More sharing options...
Johnty Lyons Posted January 15, 2013 Share Posted January 15, 2013 Weve discussed gear oil for 6 speeds for yrs Simple redline MTL No point in reinventing wheel. Remember we have an excellent search facility on BC and most problems will have been discussed to death many many times before they arrive at your door. Oh and I too would avoid Slick in a Caterham box. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted January 15, 2013 Share Posted January 15, 2013 In the build kit there should be a tube of Lube Gaurdfor the final drive put this in and top up with EP90, job done worked perfectly on my plate LSD. As above redline MTL for both 5 & 6 speed boxes, avaialable from various sources many with a club discount Link to comment Share on other sites More sharing options...
Paul Deslandes Posted January 15, 2013 Share Posted January 15, 2013 The original Ford built Sierra diffs were fine and the only noise came as a result of there being insufficient scope to mechanically isolate them sufficiently from the chassis. The problems started when the supply of Ford units dried up and remanufactured and cloned units started to appear. The machining of the components in these was poor and resulted in CWP whine and clonk. That's why CC were forced to adopt the BMW diff with all the attendant installation problems that have been revealed on this site over the past few months. If you can get hold of an original Ford XR4 7" front diff with a suitable ratio and the right drive shaft couplings you'll have a good unit. Edited to add, Redline MTL is definitely the oil to use in the gearbox for a slick shift. Edited by - Paul Deslandes on 15 Jan 2013 13:17:04 Link to comment Share on other sites More sharing options...
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