Prop shaft doesn't fit through the tunnel!!??

Technical advice Q&A

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Atomlinson275
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Joined: Mon Oct 17, 2022 2:11 pm
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#1 Prop shaft doesn't fit through the tunnel!!??

Post by Atomlinson275 » Mon Apr 15, 2024 4:11 pm

I bought a replacement prop shaft from the usual suspects.

Looked really good although the black paint was quite poor. Especially in areas where the primer was missing?
I only know this as I stripped the black paint off very easily and found about half the surface area actually had any primer on it. Quality control - 'Nul points'

It gets even better.
I had fitted the engine and gearbox, so now it was time to fit my new shiny, freshly painted prop shaft. You would have thought this would be an easy quick job. Oh how wrong I was.
The prop shaft flange would not get past the constriction caused by the handbrake recess.
I thought I was going mad as it was so close to going through. I tried every which way but to no avail.
The flange would just not get passed.
I then measured the diameter of the flange and compared it with my knackered old shaft and found that it was 3 mm over on diameter. Quality control - 'Nul Points'

Image

Image

Just to do I final sanity check. I passed my old shaft along the tunnel and it passed without scratching the sides.

So here we go again another instance of aftermarket parts just not quite getting over the line with regard to fit and finish. I really do despair.
I am sure I could have rammed it up the tunnel and forced it through, scratching and damaging the sides of the tunnel and nobody will notice will they!!??

In the end I removed my flanges from the knackered original shaft and fitted them to my new prop shaft.
The next question is whether I now need to get it balanced?

So much for a 5 minute job!
Andy

1966 4.2 FHC
1989 Porsche 944
1995 LR Defender
1969 Daimler V8
1976 Triumph Bonnaville
1971 Kawasaki Z1

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Series1 Stu
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#2 Re: Prop shaft doesn't fit through the tunnel!!??

Post by Series1 Stu » Mon Apr 15, 2024 11:04 pm

Hi Andy, I feel your pain.

It looks like some half asleep drone working for said "specialist" has rounded 3.75 inches up to 100mm without considering the possible effects. Happens all the time in this game. Our cars were made under the Imperial system, so, please suppliers, stop using metric measurements.

I know it's not the point, but I wonder if it would have fit from the other direction.

Unfortunately, this stuff happens when someone gets hold of a set of Vernier calipers and then think they're an engineer. :banghead:

Going for a lie down in a darkened room now.

Regards
Stuart

If you can't make it work, make it complicated!

'62 FHC - Nearing completion
'69 Daimler 420 Sovereign
'78 Land Rover Series 3 109

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lowact
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#3 Re: Prop shaft doesn't fit through the tunnel!!??

Post by lowact » Tue Apr 16, 2024 10:30 am

I would not expect changing the flanges would affect the balance, which is mainly to correct the fabricated shaft. Was the new one sold as having been balanced, are there balance weights?
Regards,
ColinL
'72 OTS manual V12

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Mich7920
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#4 Re: Prop shaft doesn't fit through the tunnel!!??

Post by Mich7920 » Tue Apr 16, 2024 12:11 pm

Hi Andy,
why not correct or have the diameter corrected on a lathe?
You'd have a better chance of keeping it completely balanced.
If it really is balanced, changing the flange will damage it.
Mich
Michel
1965 E Type FHC - On the road / 1963 E Type OTS - on the road after Angus Restoration

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Paul bow
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#5 Re: Prop shaft doesn't fit through the tunnel!!??

Post by Paul bow » Mon May 13, 2024 9:01 pm

As mentioned above, I would be amazed if by substituting the new for old flange they’d be any difference whatsoever.. or indeed having the new machined to size, what I would be concerned is if it is indeed balanced correctly in the first place, a lot of these parts are what I’d call a starting point, you need (wrongly) to go over them.
Couldn’t you clean/service/balance the old one up and refit?It’ll be awful doing it twice, imo the original is far superior to alot of what’s bought from the usuals..
But without them we’d be stuffed, so must grumble too much ..
Good luck 👍
Previously...S1 OTS E type (sold)
S1 2+2 manual. (Sold)
S2 rhd OTS full resto finished 8/23
S1 3.8 coupe (full restoration yet to start!)

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politeperson
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#6 Re: Prop shaft doesn't fit through the tunnel!!??

Post by politeperson » Tue May 14, 2024 7:14 am

I wonder if your car has had any transmission tunnel/floor welding done? It is quite easy to weld a tunnel in a bit too narrow.
Its true, but Enzo never said it
Too many E types
XK120 SUs

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max-it-out
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#7 Re: Prop shaft doesn't fit through the tunnel!!??

Post by max-it-out » Tue May 14, 2024 9:41 am

Ask for some credit back from the supplier - £ 20 / hr for your time taken to correct the mistake :smile:
Mark

1968 series 1.5 roadster

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