xjs rear axle
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xjs rear axle
Will a xjs jaguar rear axle with lsd be suitable for a rover sd1 v8 with a lt 77 gearbox axle ratio i have been told is 3.08 although not sure Ed
Hi
From a little bit of research on tinterweb there seem to be a few ratios avaliable from about 2.88 to 4 and a bit, a 3.08 would probably be OK if you used it with an LT77 with a low first gear (sherpa van one) and did not want to race it, however what engine is going in font of this, as I recon a standard 3.5 would be over geared, where as a 4.8 or 5 litre engine probably would be fine with a standard first gear.
Best regards
Mike
From a little bit of research on tinterweb there seem to be a few ratios avaliable from about 2.88 to 4 and a bit, a 3.08 would probably be OK if you used it with an LT77 with a low first gear (sherpa van one) and did not want to race it, however what engine is going in font of this, as I recon a standard 3.5 would be over geared, where as a 4.8 or 5 litre engine probably would be fine with a standard first gear.
Best regards
Mike
poppet valves rule!
Re: xjs axle
The standard SD1 rear axle on manual V-8 cars is 3.08 - with either 14 or 15" wheels.oatcake wrote:Engine is rover sd1 about 200 bhp with cam /edelbrock carb and 4 into1 exhaust gearbox is out of same car a sd1 car is a kitcar weighing around 800kgs,.
Dave
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
London SW
Rover SD1 VDP EFI
MegaSquirt2 V3
EDIS8
Tech Edge 2Y
wheel size
At the moment car has 15 inch wheels i want to put on 16 or 17 inch wheels 
will this axle still be any good or is the final ratio too high or low (im sooo confused)
will this axle still be any good or is the final ratio too high or low (im sooo confused)
oatcake wrote,..
Provided the rolling diameter remains essentially the same, running 15, 16 or 17" wheels won't make any difference. In other words, as the wheel increases in diameter so the profile of the tyre is reduced, so the overall distance travelled in one revolution remains essentially unchanged.
Ron.
Hello Oatcake,At the moment car has 15 inch wheels i want to put on 16 or 17 inch wheels will this axle still be any good or is the final ratio too high or low (im sooo confused)
Provided the rolling diameter remains essentially the same, running 15, 16 or 17" wheels won't make any difference. In other words, as the wheel increases in diameter so the profile of the tyre is reduced, so the overall distance travelled in one revolution remains essentially unchanged.
Ron.
4.6 Rover 3500 P6B
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CastleMGBV8
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Oatcake,
For a lightweight kit car the Jag IRS is overkill and far too heavy, the cost to narrow, rebuild diff,hubs and calipers plus all the kit required to enable fitment into a diffferent car is also in the region of £1800.00
The normal diff for a lightweight is the Sierra unit which is available in a variety of ratios and LSD 3.31 would probably be suitable or if using tyres with a larger rolling radius then a 3.65/1 might be more suitable.
What kit are you talking about as this will determine how the suspension will fit.
For an example have a look at the Hoyle IRS for the MGB the ford diff will easily manage the power and torque of a Rover V8.
Kevin.
For a lightweight kit car the Jag IRS is overkill and far too heavy, the cost to narrow, rebuild diff,hubs and calipers plus all the kit required to enable fitment into a diffferent car is also in the region of £1800.00
The normal diff for a lightweight is the Sierra unit which is available in a variety of ratios and LSD 3.31 would probably be suitable or if using tyres with a larger rolling radius then a 3.65/1 might be more suitable.
What kit are you talking about as this will determine how the suspension will fit.
For an example have a look at the Hoyle IRS for the MGB the ford diff will easily manage the power and torque of a Rover V8.
Kevin.
xjs axle
The xjs axle has been shortened and rebuilt except for the springs and dampers the kit car is a ng tc v8 with standard front and rear suspension(i want to change the front as well) the ride is too choppy too much bump steer from the front still don't know what the axle ratio the diff is i got mixed up with the ratio the one i quoted was for the rover sd1 which is 3.08
hi
the bump steer is most likley down to the rack being in the wrong place, or it being the wrong length. with the steering straight ahead and looking from the front of the car (at ride height) place a straight edge so ti runs from the top centre of the inner suspension mounting to the bottom centre mounting, the end of the rack, where the track rod joins the rack should be on this line with the centre line of the track rod going through the point where the centre line of the top and bottom suspension arms meet in space. The line drawn through the outer point of where the track rod joins the steering arm and the line through the top and bottom hub pivots on each side should meet at the centre of the rear diff and a line down the centre of the track rods should meet at the front wheel centre line. Dra this out in chalk on the garrage floor if it helps. If the suspension/ seering originates as jag hubs and suspension links and a mk11 escort rack (common on kits) it will be half a mile out.
Move the rack for best compromise and modify the steering arms for best compromise and check the results by removing the springs and locking the steering in the straight ahead position and move the suspension through it's travel.
Best regards
Mike
the bump steer is most likley down to the rack being in the wrong place, or it being the wrong length. with the steering straight ahead and looking from the front of the car (at ride height) place a straight edge so ti runs from the top centre of the inner suspension mounting to the bottom centre mounting, the end of the rack, where the track rod joins the rack should be on this line with the centre line of the track rod going through the point where the centre line of the top and bottom suspension arms meet in space. The line drawn through the outer point of where the track rod joins the steering arm and the line through the top and bottom hub pivots on each side should meet at the centre of the rear diff and a line down the centre of the track rods should meet at the front wheel centre line. Dra this out in chalk on the garrage floor if it helps. If the suspension/ seering originates as jag hubs and suspension links and a mk11 escort rack (common on kits) it will be half a mile out.
Move the rack for best compromise and modify the steering arms for best compromise and check the results by removing the springs and locking the steering in the straight ahead position and move the suspension through it's travel.
Best regards
Mike
poppet valves rule!
-
CastleMGBV8
- Top Dog
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- Joined: Sat Aug 18, 2007 5:09 pm
- Location: Sidcup, Kent, UK
NG's were mainly MGB based as far as the suspension so if the front has lower wishbones and lever arm dampers for the upper links it is MGB and will have the MGB rack.
There is not a lot wrong with a well set up MGB front end but it may have been mucked about with and not perform as well as it should.
Does the car have a seperate crossmember? if so this will be the MGB one and therefore the pick up points and rack position will be as orignal MGB.
If the lower wishbones are less than horizontal at normal ride heigh in that the outer ends are higher then inner swivel point then bump steer can be an issue. it may be that the original springs have been cut to lower the car and this will increase the spring rate and lower it beyond the disirable position.
The car will be approx 100Kg lighter at the front than an MGB so really the spring rate should have been reduced unless you are using the car on track.
Can you post up a pic of the front suspension as this will answer many questions.
You have to host pics on photobucket or similar and copy and paste the url onto your post.
This car has a MGB front end but can't see if it retains the MGB crossmember.
http://www.madabout-kitcars.com/picture ... ts+Cars_TC
The rear axle will also be MGB and the standard ratio is 3.9/1 and the V8 axle is 3.07/1
The XJS diff should have one or two tags, one for the ratio something like 13/39 you divide the larger by the smaller and that is the ratio. if there is a second tag this will indicate powerlock or an abreviation PWLK?
Kevin.
There is not a lot wrong with a well set up MGB front end but it may have been mucked about with and not perform as well as it should.
Does the car have a seperate crossmember? if so this will be the MGB one and therefore the pick up points and rack position will be as orignal MGB.
If the lower wishbones are less than horizontal at normal ride heigh in that the outer ends are higher then inner swivel point then bump steer can be an issue. it may be that the original springs have been cut to lower the car and this will increase the spring rate and lower it beyond the disirable position.
The car will be approx 100Kg lighter at the front than an MGB so really the spring rate should have been reduced unless you are using the car on track.
Can you post up a pic of the front suspension as this will answer many questions.
You have to host pics on photobucket or similar and copy and paste the url onto your post.
This car has a MGB front end but can't see if it retains the MGB crossmember.
http://www.madabout-kitcars.com/picture ... ts+Cars_TC
The rear axle will also be MGB and the standard ratio is 3.9/1 and the V8 axle is 3.07/1
The XJS diff should have one or two tags, one for the ratio something like 13/39 you divide the larger by the smaller and that is the ratio. if there is a second tag this will indicate powerlock or an abreviation PWLK?
Kevin.
ng tc photo
That is exactly like my front suspension in every way, there aren't any tags on jag xjs axle, found some axle numbers various year of manufacture
3.54-1 3.6 and 4.0 litre
2.88-1 6.0 and 5.3 litre
3.07-1 5.3 litre
which one do i need ?
my engine is a sd1 3.5 200 bhp approx with lt77 gearbox
don't know how to send photo's, instructions would be welcome
3.54-1 3.6 and 4.0 litre
2.88-1 6.0 and 5.3 litre
3.07-1 5.3 litre
which one do i need ?
my engine is a sd1 3.5 200 bhp approx with lt77 gearbox
don't know how to send photo's, instructions would be welcome
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CastleMGBV8
- Top Dog
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- Joined: Sat Aug 18, 2007 5:09 pm
- Location: Sidcup, Kent, UK
Name ?
With a 15" wheel and 195/65 tyre a 3.07 would be fine. This will give gear speed of 1st 40 2nd 65 3rd 95 4th 133 and approx 2250 RPM at 70 MPH in 5th
Personally I would avoid bling wheels with rubber band tyres as they will ruin the ride and not really do anything for roadholding and look a bit silly on a car that has 1930's styling.
If you want larger wheels then a tyre with diameter of 25" will retain the above figres otherwise you will need a lower ratio
How are you planning to mount the jag rear end?.
Kevin.
With a 15" wheel and 195/65 tyre a 3.07 would be fine. This will give gear speed of 1st 40 2nd 65 3rd 95 4th 133 and approx 2250 RPM at 70 MPH in 5th
Personally I would avoid bling wheels with rubber band tyres as they will ruin the ride and not really do anything for roadholding and look a bit silly on a car that has 1930's styling.
If you want larger wheels then a tyre with diameter of 25" will retain the above figres otherwise you will need a lower ratio
How are you planning to mount the jag rear end?.
Kevin.
axle mount
I will be mounting axle with a jag irs x member welded to the chassis rails with front tie straps and anti climb bars to the lower diff support plate all parts will come from Pop Browns , at the moment the car has standard mgb hubs with 15 inch compomotive split rims with 215/65/15 front tyres 255/60/15 rear tyres,
they were on the car when i bought it front suspension is mounted on chassis with standard mgb crosmember
any help with ways to mount axle will be very much appreciated .
Regards Ed
they were on the car when i bought it front suspension is mounted on chassis with standard mgb crosmember
any help with ways to mount axle will be very much appreciated .
Regards Ed
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CastleMGBV8
- Top Dog
- Posts: 2334
- Joined: Sat Aug 18, 2007 5:09 pm
- Location: Sidcup, Kent, UK
Ed,
Pop Browns is where I would have directed you, Kris is very helpful and has all the parts you need to do the conversion.
If your chassis has square box sections that pass over the rear suspension position then welding in the crossmember should be fairly striaghtforward
His parts book shows how the lower tie bars should be installed with the inner pick up points in line with the lower wishbone pivot points which is far superior to the jaguar trailing arm arrangement that causes bump steer.
Also important to mount the IRS so that the correct geometry is maintained and careful measurement is required to determine whether you need a straight crossmember or one with a centre kick up, the book give a fairly clear idea of how this is done, basically you measure the desired ride height then work out the height of the diff to centre of hubs set at the correct position to maintain geometry and that is the height that the mount for the diff has to be.
The jag hubs are obviously 5 stud and it is difficult to have them redrilled for 4 stud MG pattern as the two patterns interfere but you can have the problem one welded, you have a similar problem at the front if you want to go all 5 stud.
Does your Jag IRS have inboard or outboard brakes, if outboard it is a late axle.
To determine whether it has LSD turn one of the hubs, if the other turns in the same direction you have LSD if it turns the other way you don't.
Re the gearing without a tag on the rear cover it's a bit awkward you can try locking one hub and then slowly turning the other hub and watching how many turns you get at the pinion, ie 1 turn of the hub might turn the pinion just over 3 times so 3.07 etc. otherwise remove the back cover and count the teeth on the cw & p
Once the ratio is known gearing can be calculated.
Kevin.
Pop Browns is where I would have directed you, Kris is very helpful and has all the parts you need to do the conversion.
If your chassis has square box sections that pass over the rear suspension position then welding in the crossmember should be fairly striaghtforward
His parts book shows how the lower tie bars should be installed with the inner pick up points in line with the lower wishbone pivot points which is far superior to the jaguar trailing arm arrangement that causes bump steer.
Also important to mount the IRS so that the correct geometry is maintained and careful measurement is required to determine whether you need a straight crossmember or one with a centre kick up, the book give a fairly clear idea of how this is done, basically you measure the desired ride height then work out the height of the diff to centre of hubs set at the correct position to maintain geometry and that is the height that the mount for the diff has to be.
The jag hubs are obviously 5 stud and it is difficult to have them redrilled for 4 stud MG pattern as the two patterns interfere but you can have the problem one welded, you have a similar problem at the front if you want to go all 5 stud.
Does your Jag IRS have inboard or outboard brakes, if outboard it is a late axle.
To determine whether it has LSD turn one of the hubs, if the other turns in the same direction you have LSD if it turns the other way you don't.
Re the gearing without a tag on the rear cover it's a bit awkward you can try locking one hub and then slowly turning the other hub and watching how many turns you get at the pinion, ie 1 turn of the hub might turn the pinion just over 3 times so 3.07 etc. otherwise remove the back cover and count the teeth on the cw & p
Once the ratio is known gearing can be calculated.
Kevin.
