Propshaft Length

SteveB · Post by **SteveB** » Sun Aug 21, 2011 10:45 am

Hi, can anybody tell me the correct flange to flange length of a 4.2 FHC propshaft?
I am reliably informed that all propshafts are the same length with the difference in wheelbase being taken up by the overall length of the gearbox.
The trouble I have is that I have 3 propshafts all of different lengths.
The one that came with the car is seized solid on the splined joint and attempts to free it have damaged the ?eyes? of the yoke where the UJ fits rendering it scrap. I have bought another shaft which has a part number on it identifying it as from a SIII or 2+2. The flange to flange length of this is 33 inches with the sliding joint fully pushed back, my estimate of the distance from my diff pinion flange to the centre of the gearbox mount bush (near as makes no odds the position of the gearbox output flange) is 32 inches.
The 3rd shaft I have which I was told is from a 3.8 car is the shortest of the 3 with a length of 29.25 inches when the sliding joint is around the middle of it?s travel.
Has anybody any ideas?

PeterCrespin · Post by **PeterCrespin** » Sun Aug 21, 2011 11:21 am

SteveB wrote: ...my estimate of the distance from my diff pinion flange to the centre of the gearbox mount bush (near as makes no odds the position of the gearbox output flange) is 32 inches....

Has anybody any ideas?

Ideas? Yes, your 'near as makes no odds' isn't near enough and does make a difference.

All E-type shafts are the same length and the centre of the gearbox mount is well forward of the output flange face, since obviously this is the rearmost datum on the gearbox and well back from the casting face, never mind the mount centreline.

The rear mounting is a threaded boss at the back of the tailshaft extension casing. The boss is about 1 1/2" wide (from memory) so obviously the centre of it is at least 3/4" forward of the rear edge of the housing. Meanwhile, the output flange clearly extends behind the alloy tail housing, partly because the flange itself is about 5/16" thick and partly because the bolts need to fit between the two. All measurements are guesses but the principle is clear.

So without measuring anything directly, as I am not near the relevant parts, you can be quite sure your guesstimate is too long if you think the centreline of the rear mount is the forward measuring point for propshaft length. Hence the 3.8 shaft and V12 shaft will both fit ,I'm sure, other things being equal.

Pete

SteveB · Post by **SteveB** » Sun Aug 21, 2011 7:28 pm

OK, sarcasm and out of context quotes aside, can anybody answer my question - "What is the length of a SI 4.2 FHC propshaft"?

Nick · Post by **Nick** » Sun Aug 21, 2011 9:28 pm

Pete,

If they're all the same length what takes up the 9" difference in wheelbase ?

Nick

PeterCrespin · Post by **PeterCrespin** » Mon Aug 22, 2011 8:45 am

The extra length is all in the tailshaft extension. SWB E-type gearboxes are the 'short' type - shorter than any other Jaguar AFAIK. All other Jaguars have either a long tailshaft housing - putting the rear flange anywhere from about 9 inches to 18 inches behind the gearbox - or one of several overdrive types, or both.

Because the LWB E-types were the only ones that had an automatic option, they made the LWB manual box identical in length to the BW automatic (also used in the XJ6 etc.). To do this, the rear cover of the short gearbox was simply replaced with a longer extended one housing a long tailshaft to bring the rear flange out in the same position as the auto. This was the 'standard' LWB E-type box for all three Series also used in entry-level manual XJ6 and a few hundred of the first XJ-S cars. Most XJ6 boxes apart from a few 2.8s or real base models had a 'Compact Type A' overdrive, which is the same length as the empty extension and so comes out identical overall to the auto and plain-Jane 4-synch.

All propshafts on all Series XJ6 or E-types were the same length for manual or automatic cars so do not need to be changed when doing a switch.

PeterCrespin · Post by **PeterCrespin** » Mon Aug 22, 2011 9:00 am

SteveB wrote:OK, sarcasm and out of context quotes aside, can anybody answer my question - "What is the length of a SI 4.2 FHC propshaft"?

Sorry Steve - no sarcasm intended - or written, as far as I can tell? Where was I sarcastic? Where did I qoute out of context???

You asked two questions of which I answered the second and gave relevant information when meauring your car for the first. Was I not supposed to go to the second without answering the first exactly?

Nobody has given you a measurement. Why? Probably a) because people are busy and b) it's not exactly an easy thing to obtain, unless someone happens to have a propshaft lying around fully assembled. Even then, it has to be measured at the correct extension to match whatever yours is. It's a sliding overlap of several inches, so measured length is variable and for all I know the fully-closed or fully-extended lengths differ across the designs used. Ultimately, this doesn't matter at all does it, if all are interchangeable?

I think my post gave you every bit of information you need to assemble your car. I am sure once you measure from the right point as indicated, you'll find your shaft suits your car. Propshaft length per se is not important at all, provided the parts are E-type as claimed. The length will be right in servic,e regardless what model E-type it came from or is fitted to.

I do not have any more relevant information, so if that is too incomplete then feel free to ignore my answers, as is your right. However, I'd prefer it if you didn't impugn my motives in taking the trouble to reply. Hands, feeding, biting etc.

Pete

ChrisC · Post by **ChrisC** » Mon Aug 22, 2011 2:31 pm

I replaced mine when I fitted a 5 speed gearbox so I have the original in the garage and will measure it tonight...

SteveB · Post by **SteveB** » Mon Aug 22, 2011 4:32 pm

Many thanks Chris, thats exactly what I need as a confidence check before fitting the engine and gearbox. With different length shafts I don't want to get everything in place and have to remove it again because I've put the wrong one in.
Either max or min length will be fine as long as I can compare like for like.
I appreciate the help.

Steve.

ChrisC · Post by **ChrisC** » Mon Aug 22, 2011 5:22 pm

Ah.... mine is seized so I cant tell you min-max lengths but it came off the car like that so it must be right..

The length from the end of flange to the other end is 31 inches with perhaps 1" movement on the spline?

If you have a prop that can achieve 31" you must be pretty close...

For info my car is an early 4.2 FHC

JimmyS · Post by **JimmyS** » Mon Aug 22, 2011 8:09 pm

Hi Steve,

I've just measured the prop shaft I have standing in the garage for my early 4.2 FHC. Flange mating surface to flange mating surface measures 32.5 inches. I pulled the splined end all the way out in my effort to see if it was seized or not

This left an overall length of 26.75 inches. Don't know if I mated the same splines together when I put the end back on, I also don't know if the propshaft is balanced as an assembly or not. One question answered, another one raised! Hope this helps.

Jim

SteveB · Post by **SteveB** » Mon Aug 22, 2011 8:27 pm

Thanks very much Chris & Jim, just the info I needed, it at least rules out the shorter of the two shafts I have.
On the point of re-aligning the two parts of the shaft after seperating them, casting my mind back to my apprenticeship days the yokes at either end of the shaft must be in the same plane, even if out by only one spline it will be obviously wrong so it must either be right or 180 degrees out. My second shaft is marked with an arrow on each section to ensure correct re-alignment, it is faint but it is there which deals with the balancing issue.
Thanks again.
Steve

JimmyS · Post by **JimmyS** » Tue Aug 23, 2011 9:11 am

Hi Steve,

Point taken about the importance of correct alignment. Following your reply, I read my Haynes manual and had a look for the alignment marks! The one on the propshaft is obvious, the one on the sleeve yoke, not so. I think it will be under its rubber gaiter. The gaiter is reluctant to move, so I'll leave it in the meantime. I found when re-engaging the sleeve yoke it could be pushed further in than it was last time. This gave a revised overall length of 31 and an eighth inches, so much nearer Chris' figure.

Regards,
Jim

Series 1 · Post by **Series 1** » Mon Aug 29, 2011 10:32 am

78cms fully compressed. 89 cms fully extended. (Or 30 3/4" and 35 1/16" if you prefer).

That's one I just took off my 3.8. Shorter one on now for 5 speed gearbox.

SteveB · Post by **SteveB** » Sat Sep 03, 2011 5:20 pm

Hi and thanks to all those who replied with information.
I tried fitting the engine and gearbox today but found as I suspected that my longer propshaft was indeed one inch too long even at it's shortest, something I must say I was prepared for from my initial measurements to the gearbox mounting. So out came the engine again to fit the short propshaft, this time the splined joint came apart before the flanges mated!
I think the shorter shaft may well be from a car that has had a 5 speed conversion fitted therefore needing the propshaft to be shortened. The longer one, despite popular opinion being that they are all the same length is never going to fit. A shaft the same dimensions as Series 1 refers to above would fit perfectly. Perhaps Beaulieu next weekend may yield something or I may have one of my present ones professionaly lengthened/shortened to fit - anyone know of someone around the Hampshire are who does this sort of work? In the meantime it's engine out again!

Steve

vee12eman · Post by **vee12eman** » Sun Sep 04, 2011 10:24 am

Hi Steve,

I kept quiet during the earlier part of your enquiry because my Series III has a non-standard gearbox (Getrag), with a spline output rather than a flange. The only way I could measure mine was to install rear suspension, then the engine transmission, take measurements, then get the shaft made to measure. Now that you have the engine in place, even temporarily, you can do the same.

I had an original propshaft from the car (a 2+2 Auto originally), together with the propshaft which mated with the gearbox, which I was told came from an XJS. I was going to either get these mated, or have the XJS shaft shortened/lengthened as appropriate, so I shopped around for a company to do it for me, drew a diagram with exact measurements then took both shafts and the diagram to Bailey Morris in Cambridgeshire. I know it's not near Hampshire, but you could always get stuff couriered about. They recommended a complete new shaft as there were problems with both of my shafts (can't remember exactly what) and also because a new shaft meant new couplings, flanges and the like. Actually, this is where the money is, as a length of tube for the shaft is relatively cheap. They said there might be problems as they had no end flanges for my flanged end, so it would be a bit slow.

Slow? Bu!!5h!t! I took it in on Monday, and had a phone call on Thursday to say it was ready, sorry about the delay, but the flange had come from another company somewhere. I drove to pick it up on Friday and was gobsmacked with the shaft. Bloody brilliant and one of the best purchases I made for the car before coming over here. I fitted the shaft later that day (I had removed the rear suspension for access and by six in the evening the car was back on it's wheels and one of the most worrying thing about my conversion to 5-speed without a kit was well and truly behind me. I recommend Bailey Morris highly, here is the site, give them a call and ask, it can't hurt to get a quote:

http://www.baileymorris.co.uk/index.asp

photos are here:

It wasn't too expensive, though I can't remember exactly how much.

Good luck,

Regards,

ChrisC · Post by **ChrisC** » Sun Sep 04, 2011 10:47 am

I decided to have one custom made rather than shortened..

I live on the Surrey - Hampshire border so not a million miles from you.

I can highly recommend:
Propshaft services
Central way
Middlesex
0208 844 2265

www.propshaft-services.co.uk

The spec for mine was upgraded to have sealed for life UJ's and heavier duty than standard. The cost was ?153 all in.

Series 1 · Post by **Series 1** » Sun Sep 04, 2011 12:46 pm

Steve

Guess a new one is more desirable but you can have my original one if you want it. I'm in Surrey near Gatwick.

Angus

SteveB · Post by **SteveB** » Sun Sep 04, 2011 8:55 pm

OK thanks very much for those recommendations. ?153 sounds very reasonable - I've probably spent that much already chasing round in circles! (and much cheaper than recently advertised Recon ones)
I did measure my flange to flange distance as suggested with the engine and box in place and it was spot on 32 inches.

Steve

PeterCrespin · Post by **PeterCrespin** » Sun Sep 04, 2011 9:03 pm

SteveB wrote:The longer one, despite popular opinion being that they are all the same length is never going to fit.

All E-type propshafts are the same effective length as far as I am aware. What you have could be anything, but if it's an E-type shaft it will fit all E-types of either wheelbase and any one of the five gearboxes used.

Not sure if my opinion is popular but I'll settle for factually correct. On the other hand, if you have data that prove the above to be in error, I will of course immediately change my opinion and thank you for the info.

Pete

etype_F57 · Post by **etype_F57** » Mon Jan 13, 2020 6:28 pm

Hello,
I bougth a 5speed gearbox and the shortened propshaft from eliteracing for my S1 4.2 etype : (http://eliteracingtransmissions.com/cat ... es/jag-t5/)
and got a proshaft which is not telescopic.
According to me, this fix-length proshaft will generate wear in both gearbox and rear axle. This is the reason why jaguar uses a telescopic propshaft.
Does someone use this fix-length propshaft , whats your experience?
Does someone know if there is a manufacturer which can provide a shortened telescopic propshaft?

best regards Pascal

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