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Timing chain cover.
Posted: Thu Jun 13, 2024 12:00 pm
by olonas
Has anyone encountered this before, where the oil seal recess is external?

- cover 1.jpg (111.36 KiB) Viewed 858 times

- cover 2.jpg (92.07 KiB) Viewed 858 times
Re: Timing chain cover.
Posted: Thu Jun 13, 2024 8:53 pm
by Bill_qaz
I believe A series has used both fitted from inside and fitted from outside using same seal just make sure it's the right way around when fitting.
Re: Timing chain cover.
Posted: Thu Jun 13, 2024 9:13 pm
by philthehill
As above.
BMC made the timing chain covers for fitment of the seal from either inside or outside of the timing chain cover.
Both versions use the same seal.
I have both versions of the timing cover.
I have as yet to discover a reason for BMC/BL changing the seal location in the timing chain cover.
Re: Timing chain cover.
Posted: Fri Jun 14, 2024 9:43 am
by olonas
Thanks all. Personally I think it's a better idea. Potentially makes changing the seal easier from the outside.
Although a few small bolts and a new gasket isn't too inconvenient.
Re: Timing chain cover.
Posted: Fri Jun 14, 2024 12:37 pm
by philthehill
To replace the seal you will still have to remove the cover as the cover is not stiff enough to resist having the seal knocked into place even if you can remove the seal.
To ensure that the timing chain cover was not distorted when knocking in the seal BMC had a special tool and support ring which sits under the cover and supports the cover while the new seal is knocked into place.
The seal has to be centralised around the crankshaft pully seal rubbing face - the only way you can do that is either to have the special BMC tool or use the crankshaft pulley as the centraliser. To centralise the seal you have to undo all the timing cover bolts/screws and then turn the crankshaft pulley so that the seal finds its own centralised position. When the seal is central the timing chain cover bolts/screws can be tightened.
The problem with doing the above is that the gasket can be torn or damaged and subsequently leaks oil.
The best solution is to remove the timing chain cover completely, remove the old gasket, fit a new greased gasket, fit the new seal (grease the lip), place the timing chain cover back on the block, fit the crankshaft pulley and when the cover is centralised fit and tighten the bolts/screws.
Re: Timing chain cover.
Posted: Sun Jun 23, 2024 3:13 pm
by geoberni
Sorry, I've just got back home after 9 days away and found that this was still unsent in my profile....

\
I must've turned the PC off in a hurry without checking....
Perhaps this might be of interest, it's the Engine section of the LCV parts manual, covering the 803cc engine, but the same parts are shown for the other engines also... They just superseded the design at some point and the earlier one became 'Not available'.\
See items 8 & 8A.
Although 9 and 9A are both illustrated in front of the cover, you can see that 8 and 8A are a different shape around the seal area.

- Timing Cover.JPG (224.37 KiB) Viewed 722 times
Re: Timing chain cover.
Posted: Sun Jun 23, 2024 5:03 pm
by philthehill
The reason that the timing covers are different around the seal area is because item 8 Pt No: 1G1586 has a felt seal and item 8A Pt No: 12G791 has a rubber seal.
It has nothing to do with the seal being fitted from the front or from the inside of the timing chain cover.
Re: Timing chain cover.
Posted: Sun Jun 23, 2024 6:23 pm
by geoberni
philthehill wrote: ↑Sun Jun 23, 2024 5:03 pm
The reason that the timing covers are different around the seal area is because item 8 Pt No: 1G1586 has a felt seal and item 8A Pt No: 12G791 has a rubber seal.
It has nothing to do with the seal being fitted from the front or from the inside of the timing chain cover.
Fair enough...Every day's a school day...
