mr_ed Posted August 26, 2004 Share Posted August 26, 2004 Makes propshafts!! Link to comment Share on other sites More sharing options...
MikeSA Posted August 27, 2004 Share Posted August 27, 2004 A question for the technically gifted guys I have managed to mount my Blackbird engine in my SV chassis so that there is a straight line back to the diff. It did involve making a bonnet scoop and partial encroachment into the passenger foot well. This was after seeing the damage a failed propshaft made in a mates car, he has gone back to a CEC. I currently have a reverse box and mild steel propshaft which has worked faultlessly. However I want to take out the reverse box and replace it with a straight through. Judging from the above comments would it be fair to say I still need a centre bearing unless I get a carbon tube. Could one not use CV joints instead of UJ's Any comments appreciated Hey, I just drive em - fast! Link to comment Share on other sites More sharing options...
mr_ed Posted August 27, 2004 Share Posted August 27, 2004 I'd say you almost certainly need a centre bearing, unless it is _right_ back in the passenger footwell, ie the prop is less than a metre long. The centre bearing to use is from a ford transit. Some people use the "old style", some people use the "new style". The new style has a larger rubber donut in it, and so is a bit more flexible. It is Omega shaped, whereas the old style has the mounts at quarter to 3. Theres a pic of the newstyle one here: http://www.westicles.net/orange/build/041201/ Regarding CV joints... I know of one car that uses them. The problem with them is that they're generally only rated for much lower RPM than present in a propshaft... because they're used in driveshafts, that run at 1/3-1/4 of the speed of a propshaft. This means they overheat and spit their grease out when used in propshafts. I think they absorb more power than UJs and require more maintenance. You can get some rated high enough, but big money. There are all sorts of propshaft couplings, like some CV disc based ones, but they all have design contraints such as maximum angle etc etc. If you've got a straight run back to the diff you'll have no problems at all. Link to comment Share on other sites More sharing options...
DanB Posted August 27, 2004 Share Posted August 27, 2004 But don't run a UJ based propshaft *exactly* straight - it needs a small angle on the UJs (half a degree will do) to run properly. Link to comment Share on other sites More sharing options...
mr_ed Posted August 27, 2004 Share Posted August 27, 2004 Dans right, and as I'm sure he knows, this is so the roller bearings in the UJs do not wear in a single point. If you had the prop completely straight, the X in the UJ would not move, by rocking slightly it helps distribute the wear and allows the grease to circulate. This angle can be in any plane. It'll be a shame to lose us "technically gifted" resources when blatchat goes members only 😬 Link to comment Share on other sites More sharing options...
DanB Posted August 27, 2004 Share Posted August 27, 2004 Ah, I'm sure they'll be fine - Dino will just tell them to buy anything with 'Caterham' written on it... *wink* Link to comment Share on other sites More sharing options...
MikeSA Posted August 30, 2004 Share Posted August 30, 2004 Thanks for the replies and still using the "technically gifted resources" If one does have a straight line could one not then discard the UJ's and just use composite flexible drive couplings. I believe they can handle up to about a 2 deg angle. Link to comment Share on other sites More sharing options...
DanB Posted August 30, 2004 Share Posted August 30, 2004 If it can handle the torque and revs then I don't see why not. I was rather keen on using the CTG (carbon propshaft manufacturers) titanium plate system until I saw the price... Link to comment Share on other sites More sharing options...
MikeSA Posted August 30, 2004 Share Posted August 30, 2004 That's the web page i was looking at.....so what was the Price Link to comment Share on other sites More sharing options...
Morls Posted September 8, 2004 Share Posted September 8, 2004 To answer the original question, the 'gearbox' mount used in the Caterham Fireblades is suitable for either a mech reverse (as per the Caterblades), no reverse but a transit bearing (as in my sweet Mavis) or an electric option (from ring-gear on output shaft or IRS diff flange). As Moom said, a telescopic rear section to a split prop means the prop can be 'shortened' to retro-fit a ringgear. To facilitate this, if I (or some series regs) require a reverse in future, I've added in the wiring to the dash and a switch (5 mins work and a coupla quid) and slotted the holes in the 'foot' of the centre bearing mount (5 mins`work). Life without a reverse is fine so far (and probably a giggle for anyone who'se seen the Tour 7 BitB video) and I'd deffo do the same again Mark Look it's Mavis here and Jubilee 7 here Link to comment Share on other sites More sharing options...
DanB Posted September 8, 2004 Share Posted September 8, 2004 Mike, Can't remember what the price was - I was speaking to them at the Autosport Tech show in January about it. It was enough to make me wince and go in search of a pint of nerve-calming-water though... Dan Link to comment Share on other sites More sharing options...
MikeSA Posted September 9, 2004 Share Posted September 9, 2004 Thanks, I have sent them a couple of e-mails but recieved no replys. ☹️ Maybe they priced themselves out of the Caterham market *eek*if that's possible ❗ The though of a nice carbon prop in place of all that steel is still very tempting Link to comment Share on other sites More sharing options...
DanB Posted September 9, 2004 Share Posted September 9, 2004 The difficulty with using a carbon prop in a BEC is that because you have propshaft adaptor plates at both ends (rather than a splined end which fits into a car gearbox) you really need a slider section in there, and CTG can't yet do carbon props with slider sections. I understand that they're working on it, but it's probably going to be next year before it's ready to do. Dan Link to comment Share on other sites More sharing options...
MikeSA Posted September 9, 2004 Share Posted September 9, 2004 Good point was wondering about that as I was in the pic's that there were no slider options and I currently have two, one each side of the reverse box. Probably a good think because I can't afford it any way Link to comment Share on other sites More sharing options...
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