How to add the Timing Chain Tensioner

[justkomodo]

Hi, I'm sure this has been covered in the forum but I can't seem to find the details.

I've got oil leaking out of the front of the engine so need to replace the seals, and given it's a radiator-out job my plan is to replace the timing chain at the same time (possibly including the gears, no idea what state they might be in), add a timing chain tensioner and a harmonic damper crank pulley.

I know I need the kidney-shaped timing cover for the tensioner, but I can't find details of what else needs to be modified? I believe another couple of holes are needed in the front plate of some sort?

If there's details already here (as I suspect) then please point me at them, I'm trying to get the shopping list together to get all the parts at once rather than leave the car stuck off the road for weeks!

The reason I'm looking at replacing the chain even though it isn't rattling horribly is I would rather not have to pull the car apart again anytime soon, and the car was off the road between 2000 and 2024 which is why all of the rubber everywhere has got so bad.

[philthehill]

Here you are:-
viewtopic.php?p=702680&hilit=timing+cha ... er#p702680

[justkomodo]

Here you are:-
viewtopic.php?p=702680&hilit=timing+cha ... er#p702680

Fantastic, thank you! Can I just check if the countersinking and replacing with screws is required if still using a simplex chain? I can’t quite tell which mods are for duplex and which are for tensioner.

[philthehill]

Are you retaining the Minor simplex with the two tensioning rubber rings or fitting the simplex with tensioner from the 'A' Plus engine ?
If you are retaining either type of simplex then the two 1/4" UNF bolts can be kept.
It is much better if you fit the duplex with tensioner as it is then 'fit and forget.
Good luck whatever you do.

[justkomodo]

I’m planning to have a simplex with the A+ mini tensioner, I’d seen posts saying the tensioner when used on the duplex can break apart because it wasn’t designed to have the pressure over that part of the pad? I should have been a bit clearer about the tensioner, sorry!

[philthehill]

Well I can assure you that I have never seen a tensioner break apart when used with a duplex chain. My 1380cc full race engine runs a very wild cam, heavy duty springs and would revs to in excess of 7500rpm on a regular basis. That said I am very particular when building my engines and maybe those pads that are known to have broken are on engines that have not had particular care and attention when being rebuilt. The tension setting of the pad is most important. It has to be not too slack or not too tight. The design of the tensioner is meant to remove the slack in the chain on the return side (no load) of the chain so there is no real requirement to have substantial pressure on the chain.
Phil

[justkomodo]

That’s rather reassuring! It seemed to be a problem on the mini forum, I’ve just refreshed my memory, the duplex runs just in the centre of the tensioner, but as you say it’s perfectly possible they just set the tension too high and created their own problem! There’s no way to know what state my gears are in until I take the front off so I will have to make the decision then, based on how bad it all is in there. Thank you for your help, either way I need a new timing cover!

[svenedin]

I intended to fit a tensioner and I have an engine front plate drilled and ready to go as well as the kidney shaped timing cover (this particular one with the flattened breather chimney) but several years after fitting a duplex chain there is still no noise so I have not bothered!

Stephen

[justkomodo]

That's useful, I'd heard the duplex can get noisy after a few thousand miles! What mileage have you done since fitting the duplex?

I've realised that the front plate has to be removed to drill and fit the tensioner which is also sounding like a major undertaking... My inital goal was to stop the endless pouring of oil from the front of the engine, it's coating everything! And doesn't look great in the work car park in the rain when there's a rainbow appearing under the car.

I'm close to saying leave it and just hoping everything is fine at the front! Which isn't the best way to maintain a vehicle.

[svenedin]

That's useful, I'd heard the duplex can get noisy after a few thousand miles! What mileage have you done since fitting the duplex?

I've realised that the front plate has to be removed to drill and fit the tensioner which is also sounding like a major undertaking... My inital goal was to stop the endless pouring of oil from the front of the engine, it's coating everything! And doesn't look great in the work car park in the rain when there's a rainbow appearing under the car.

I'm close to saying leave it and just hoping everything is fine at the front! Which isn't the best way to maintain a vehicle.

I have done about 15,000 miles since fitting the duplex.

There is no pressure of oil in the timing chain cover or there should not be. It would be advisable to check the engine breathing system is clear and working properly. Often people over tighten the fixings on the timing chain cover which results in the cover getting distorted and then it leaks more oil. A big leak is most likely the lip seal on the crankshaft. What age is your Minor and what engine? The early A-series engines leaked from the timing chain cover and various changes were made to reduce the leaks. The felt crankshaft seal was replaced by a proper lip seal and stiffening plates were added to the rim of the cover. The later ones had a lip seal and a ridge pressed into the rim of the cover to reduce the risk of it distorting. If the front panel of your car has been off relatively recently, removing it greatly improves access and makes replacing the timing chain cover seal and gasket a lot easier. On the other hand, if the panel has not moved in decades, it can be a horrible job to remove especially the hockey sticks.

Stephen

[justkomodo]

It's a 1967 1098, original engine now on 88,000 miles. Not sure if it had anything changed from stock before it was parked up, so far I haven't seen anything, but it stopped being used in 2000 and reappeared in 2024, since I got it a year ago I've done 4500 in it but it's been very frequently parked up with various problems, it would have been used a lot more otherwise!

As it was pouring oil down the side from the draught tube and side covers I've fitted a PCV valve and sealed breather setup, which solved the side and improved the front, but the front is getting worse again even with the negative pressure.

While the front won't have been off recently, so far I've been very lucky in that everything has come apart easily that are usually rusted, kick plates and gearbox cover both came out with no trouble, so it's possible the front panel will be ok (I hope).

oil leak

Morris front.jpg (445.16 KiB) Viewed 620 times

[svenedin]

From what i can see in uour photo, it’s the crankshaft lip seal that is leaking. With the history you give, the seal is ancient so it is not surprising.

Stephen