Synchro mechanism

Technical advice Q&A
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Norton
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#1 Synchro mechanism

Post by Norton » Mon Nov 21, 2022 10:55 am

Hi.
Manual gearbox 1973 series 3.
Rebuilding gearbox, new bearings etc. Worn layshaft and reverse shaft also needs replacing. Gearbox were making rumbling noises.
And gear stick moved forward when accellerating and rearward when decellerating. Have some sugestion that it might be worn synchro hubs. The syncro hubs, synchro rings & operating sleeves are dismanteled, but how can I determine wether they are good / worn / worn out? What to look for?
The box was shifting just fine, no crunches, grinding.
The hubs looks good to me, same with sleeves. There are some wear on synchro rings «teeth». But enough to cause any symptoms? I think ring for first is showing most wear.

See pictures, hopefully good enough? Operating sleeve: Screwdriver pointing at one of the teeth having three detent grooves.

Thanks. Rgds Harald
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DWW
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#2 Re: Synchro mechanism

Post by DWW » Mon Nov 21, 2022 3:16 pm

Hi, if you go and watch on YouTube a channel called garage time, a guy there is doing a Porsche 356 gear box with a similar issue on a recent video and goes into details of how to check and fix it.

https://www.youtube.com/watch?v=AplAVLZ0qw0&t=44s
Danny

1962 S1 3.8 FHC (1012/1798)
2015 Range Rover Sport SVR
"Experience is something you don't get until just after you need it."

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Norton
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#3 Re: Synchro mechanism

Post by Norton » Wed Nov 23, 2022 7:14 pm

Thank you. Chekced it out. It reminded me that I also have to look at the top lid, checking springs, balls, detents etc. Also found a video on what to look for on the synchro hubs. After wathing that one I think mine is fine - for now at least.
Harald

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DWW
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#4 Re: Synchro mechanism

Post by DWW » Wed Nov 23, 2022 10:37 pm

I am happy I was able to be of some help and hope things will go well with yours :bigrin:
Danny

1962 S1 3.8 FHC (1012/1798)
2015 Range Rover Sport SVR
"Experience is something you don't get until just after you need it."

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Allrand
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#5 Re: Synchro mechanism

Post by Allrand » Thu Nov 24, 2022 5:52 am

Everything looks fine. On reassembly I think it would be beneficial if possible to rotate the outer sleeves to a different position so that the detent balls run on new unwarn teeth.
Randall Botha
'64 3.8 fhc & '51 Mk 7

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Norton
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#6 Re: Synchro mechanism

Post by Norton » Sun Dec 11, 2022 8:27 pm

Moving slowly ahead. New layshaft, reverse shaft and ballbearings obtained. Waiting for a few hundred roller pins.
Reverse shaft, from packing looks like NOS. But had expected it to be shiny but it is matt black. Supposed to be like this? ( pickture ).
Randall, that idea occured to me. But the detent balls shall be in line with the operating sleeve teeth having three detent grooves. Maybe possible to grind new detent grooves in another position. If worn, could be reason for gear lever moving forward / rearward with accellerator pedal.

Rgds Harald.
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angelw
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#7 Re: Synchro mechanism

Post by angelw » Sun Dec 11, 2022 9:49 pm

Norton Wrote:
Reverse shaft, from packing looks like NOS. But had expected it to be shiny but it is matt black. Supposed to be like this?
Hello Norton,
That's what the original Reverse Idler Gear Shaft should look like. The shaft was machined to finished size and then heat treated, probably Nitriding, without a further finishing operation.

The Reverse Idler Gear Shafts I manufacture are case hardened and cylindrical ground after case hardening and appear as shown in the following picture. Notwithstanding that minimal distortion occurs with Nitriding, the advantage of finish grinding after heat treatment, is that all distortions is eliminated in the finishing operation.

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Regards,

Bill

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64etype
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#8 Re: Synchro mechanism

Post by 64etype » Wed Dec 14, 2022 3:52 pm

Bill,

Do you sell your reverse idler shaft outside of Australia? I need to procure one (Dallas, Texas area). Perhaps you could PM me?

Thanks, Eric
Eric

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#9 Re: Synchro mechanism

Post by Norton » Thu Dec 15, 2022 12:11 am

Bill thanks.
And as Eric, is it possible to obtain your rev shaft outside Australia?

Rgds Harald, Norway

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64etype
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#10 Re: Synchro mechanism

Post by 64etype » Thu Dec 15, 2022 4:23 pm

Harald,

Do you recall where you purchased the factory reverse idler shaft shown in your photos?

Thanks, Eric
Eric

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mgcjag
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#11 Re: Synchro mechanism

Post by mgcjag » Thu Dec 15, 2022 5:21 pm

Denis Welch does a lot of E type parts....they have this listed but no photo https://www.bighealey.co.uk/index.php?r ... ch=Jgbs188
Steve
69 S2 2+2 (just sold) ..Realm C type replica, 1960 xk150fhc

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#12 Re: Synchro mechanism

Post by 64etype » Fri Dec 16, 2022 12:48 am

Thanks. I sent them a message.
Eric

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Norton
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#13 Re: Synchro mechanism

Post by Norton » Thu Dec 22, 2022 6:28 pm

Have also checked out the website mentioned by Steve.

Eric, I got my shaft from a small web based jaguar part dealer here in Norway. ( sirwilliam.no ) They got most of their parts from sngbarrat ( I think ). It is run by a Jag enthusiast ( Tore ). They have some kind of deal with barrat. I could order from barrat myself, but then it will be at relatively high handling cost. Customs, postage etc. They order larger quantities at a time and can spread out the overhead cost.
However, the revers shaft is not from barrat, it came from their « network» Tore told me. And I didn’t ask any more. But if you order to US from this company in Norway I guess it would be very expensive.

Harald.

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