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Making Hybrid Sierra Drive shafts
JamesMcMc - 15/8/14 at 08:11 PM

Hi there all! Need some advice on making hybrid sierra drive shafts.

I've read absolutely loads of posts and bits on sites about this but need some answers to conflicting info...

Okay, I'll start with what I have: A 2003 MK Indy with a noisy open diff (non-LSD/ tripod/push-in shaft) with a drum brake set-up. I have bought a replacement 7in XR4x4 LSD (bolt on shaft/lobro).

I understand that if you buy the inner or diff-end lobro CV joints, it is possible to take the tripod shafts, remove the inner ends and fit the lobro CV joints.

My questions are these: Are all tripod shafts suitable for conversion? I.E the sizes/number of splines? Some people say only the Sierra dohc & diesel shafts work. I know there is a large variation in thickness and length - http://www.super7thheaven.co.uk/Sierra_Rear_Drive_Shafts

Also, I understand that the tripod shafts have a spring in the CV joint to allow movement and keep them centered, the lobros don't. Some say to use the spring (glued in) when building up the hydrid.

Any advice on the whole build would be much appreciated - I'm not totally stupid, but also not an engineer, so please be nice!!!

Thanks in advance, I know you lot will have the info!


snapper - 15/8/14 at 08:43 PM

As I understand it the main thing is the shaft diameter
You need the thicker desiel push in shafts to fit the bolt on Lobro to


snapper - 15/8/14 at 08:54 PM

I have a guide somewhere if you U2U me your email I'll find it for you


JamesMcMc - 15/8/14 at 09:11 PM

Mmm... read something about this before. I (think) my shafts are from a 1.8 - seem to measure 23mm diameter?


baz-R - 15/8/14 at 09:29 PM

mine where the right diamiter but had the wrong spline 1.8cvh (92)

you could get some new ones made by www.jandrcvjoints.co.uk
about as reasonable as anywhere and will do some of the working out for you


or convert to full disc rears


JamesMcMc - 15/8/14 at 09:38 PM

Thanks for the reply. Yes, by the time I've bought and farted about with parts (and wrong parts!) it would be nice to get some off the shelf items - just didn't know anyone did them!

I think going to a full disc set up would be more complex... I've a BEC, and according to Andy from AB Performance, the drums are fine because of the low weight. Also, would need new bearings, uprights, discs, calipers etc.. not sure my 2003 Indy would take the uprights????

Looking for the fastest, easiest solution so I can get the car back on the track and start overtaking my mates in their 2014 Caterham Academy cars...


ste - 15/8/14 at 09:44 PM

http://forum.wscc.co.uk/forum/index.php/topic/101143-lsd-diff/

some pics here


theprisioner - 15/8/14 at 10:38 PM

I had custom drive shafts made by this lot:

http://www.cpsdrivelink.co.uk/

They are so knowledgeable quick too.

If you supply the two half's of what you want success guaranteed. They have a friction welder and can extend, match, anything to anything. If you have the bits then even better.

The custom length shafts 2x cost me £140 total completely refurbed CV's both ends.


JamesMcMc - 16/8/14 at 09:51 AM

As I posted this in the wrong forum (Engine & trans) I had this reply, so I thought I would re-post it here:

posted on 15/8/14 at 23:20

I've built and am using a set. You have to use the late Sierra diesel or DOHC 27mm tripode shafts as these are the only ones that have the matching spines for the 100mm Lobro joints. Most tripode shafts seem to be 24mm and there are a few thinner ones from early small engined Sierras around. Once the outer can is cut-off from the innner joint you can remove a circlip and remove the centre from the shaft. The Lobro joint can then be put on instead and retained with the same circlip. I havent had any problems - the outer tripode joint has enough movement in it to accommodate the change in shaft length due to suspension movement on my RH 2B which uses the entire Sierra rear suspension. Might not be the case if you were doing this on a Sierra where the suspension movement is probably much greater. The main problem is finding 27mm drive shafts in good nick!





Do people agree? If it is the case I'd just buy new lobro CV joints and 27mm shafts from J&R - or better see if they will make them up for me?


Dusty - 16/8/14 at 12:41 PM

My sierra donor was a 2.0L pinto injection. I did a lot of internet surfing. Found conflicting information. Bought a sierra viscous diff off ebay, toddled down to partco and bought two CV joints. It worked. The shafts are 27mm. Did I get lucky or are there lots of 27mm shafts out there. It does seem that having 27mm shafts is the critical starting point.
Get under the car, measure them and you may be lucky.
Mines been running since April 08. Second best mod I have done to the car in its lifetime. I suspect a tired viscous diff is well suited to a seven.
If you have 27mm shafts just go for it. Last time it was on RR I had 158 at the wheels. ST170 engine injected.
There are a few pics in my archive.

[Edited on 16/8/14 by Dusty]


matt_claydon - 16/8/14 at 01:17 PM

http://www.locostbuilders.co.uk/viewthread.php?tid=113835


Wadders - 16/8/14 at 03:11 PM

i had mine made up by GB engineering years back, but have a look at this thread, loads of info



http://www.locostbuilders.co.uk/viewthread.php?tid=93289


Gary 7 - 16/8/14 at 04:09 PM

http://www.locostbuilders.co.uk/viewthread.php?tid=93484


JamesMcMc - 20/8/14 at 10:04 PM

Okay, so still have a few issues:

It seems you need 27mm driveshafts - everyone agrees. However what people cannot answer is what length these need to be or (also crucially) how many splines the driveshaft needs on the 'inner' or diff end. This is important because the Lobro joints won't fit the wrong number of splines.

So looking at the info on super7thheaven.co.uk it would seem that lobro driveshafts for 7in diffs have 25-splines inboard, so I would assume the push in shafts need to be 25-spline too?

Everyone keeps telling me late diesel or dohc driveshafts are correct but when I asked J&R CV Joints they said there are 5 different lengths??

Bored yet?


baz-R - 22/8/14 at 12:47 PM

quote:
Originally posted by JamesMcMc
Okay, so still have a few issues:

It seems you need 27mm driveshafts - everyone agrees. However what people cannot answer is what length these need to be or (also crucially) how many splines the driveshaft needs on the 'inner' or diff end. This is important because the Lobro joints won't fit the wrong number of splines.

So looking at the info on super7thheaven.co.uk it would seem that lobro driveshafts for 7in diffs have 25-splines inboard, so I would assume the push in shafts need to be 25-spline too?

Everyone keeps telling me late diesel or dohc driveshafts are correct but when I asked J&R CV Joints they said there are 5 different lengths??

Bored yet?


no you get j&r to make you a brend new bespoke complete shaft with new joints to suit lobro to sierra drum hub you need to speek to the tech guy there (cant rember his name) give him the mesurments he asks for

iirc it was around £120 a side