Timing Cover Leak

[svenedin]

Having been very pleased with myself to have an engine entirely free of leaks for over a year I now find myself with a leak from the timing chain cover (again). ESM fitted a duplex chain and sorted out the leak in November 2022 but I noticed that there were a few drips when I did the timing a month or so ago. Now there is a small puddle.

I have read the (many) threads on this subject but before I go hung ho about it I thought I would check a few things.

I understand that the starter dog is 1 5/8" and if a socket is used a very deep socket is needed. I have also read about using an adjustable spanner and a block of wood and operating the starter to free the starter dog (after releasing the lock tab).

I am proposing to take the radiator out and the front grille so as to have unimpeded access.

I have heard that that oil can leak where the countersunk screws are fitted in order to fit a duplex chain. I am proposing to buy the Allen key screws and fit them with Loctite. I do not know what ESM used but I think their kit contains ordinary screws not Allen screws.

I also plan to fit the more expensive and allegedly better gasket from Minispares. This one: http://www.minispares.com/product/Class ... o%20search

Before I take anything apart though I will check that all of the 11 fixings on the timing cover are secure (I will tighten opposite pairs).

I have never done this job before. Ideally I would like to fit a harmonic crank damper at the same time but they are out of stock (AHU1878)

I am a little suspicious that it is leaking here again and the possibility that the timing cover may be distorted. I do have 2x spare engines on the garage floor and could swap the cover if needed.

Stephen

[philthehill]

Whether the screws used are cross head or Allen the screws must be locked in place.
Loctite 243 - Threadlocker is the one to use.
BMC latterly added a strengthening plate to the timing cover flange to help reduce the possibility of leakage.
There is no need to use joint sealer on the timing chain cover gasket - just smear the contact faces with grease.
Use the crankshaft pulley to centralise the timing chain cover seal before tightening the timing cover bolts.
Do not over tighten the bolts as that can distort the cover.
!/4" UNF........6lbf.
5/16" UNF....14lbf.

[svenedin]

Whether the screws used are cross head or Allen the screws must be locked in place.
Loctite 243 - Threadlocker is the one to use.
BMC latterly added a strengthening plate to the timing cover flange to help reduce the possibility of leakage.
There is no need to use joint sealer on the timing chain cover gasket - just smear the contact faces with grease.
Use the crankshaft pulley to centralise the timing chain cover seal before tightening the timing cover bolts.
Do not over tighten the bolts as that can distort the cover.

Thank you Phil

My timing cover is one of the later 1098 ones with the pressed in ridges which I assume was an attempt to stop it distorting.

Stephen

[philthehill]

The later timing chain cover had the ridges incorporated as an attempt to stop any leaks.
Below is an after market strengthening plate similar to that fitted by BMC/BL. It can be used with all types of timing 'A' Series chain covers but may need slight modification to fit pre 'A' Plus engines.
https://www.ebay.co.uk/itm/125957263378 ... gLl2PD_BwE

[svenedin]

I have had a look at the 2x 1098 engine blocks that I have in my garage. One has the early timing cover with no strengthening ridges between the fixing holes. The other has the strengthening ridges. I think I am going to strip the fan, fan pulley and timing cover from one of the blocks, strip and repaint them and then swap all of that over when I sort out the oil leak. I had a look underneath and the leak is definitely from the timing chain cover. It looks like ESM used lots of blue gunk which is not a good sign.........I also managed to find a damped pulley AHU1878 so that will also go on at the same time. I just hope the leak does not get much worse in the meantime because it takes time to strip, de-rust and paint parts. Engine enamel in particular takes an age to fully harden and it is currently too cold to paint. Of course I may not be able to get the starter dog off an engine outside the car but both scrap blocks are well seized so it may be possible...

Stephen

[philthehill]

If there are any cracks in the rubber of the AHU1878 crankshaft damper pully my advice is that it it should not be used.
The cracks indicate that the rubber is starting to disintegrate which could lead to the two piece pulley coming apart and damaging the engine or surrounding items.

[svenedin]

If there are any cracks in the rubber of the AHU1878 crankshaft damper pully my advice is that it it should not be used.
The cracks indicate that the rubber is starting to disintegrate which could lead to the two piece pulley coming apart and damaging the engine or surrounding items.

Thank you for the advice. It’s a new pulley from a Mini supplier.

[svenedin]

One other thing that I meant to ask. Although it seems very likely that the leak is from the timing chain cover, is it possible that the leak is actually from behind the engine front plate? I note there is a gasket behind the front plate. I am wondering whether there is any sense in replacing that gasket at the same time as doing the timing cover or whether I am just making work for myself for no reason.

Stephen

Here is the engine that I intended to harvest the timing cover from and also the fan and fan pulley so that I can refurbish the parts. I will put the parts from the engine in the car back on the spare block. The fixings have been generously doused in penetrating oil for 2 days now

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[philthehill]

Whilst you have the front of the engine apart I would advise that you change the front engine plate gasket.
If you find that the gasket is faulty and leaking after you have replaced the timing chain cover gasket and seal you will only kick yourself.
It does mean removing the timing chain and timing sprockets but that is no great deal.
Getting the timing gears right on re-assembly is easy as there are timing marks on both the crank shaft and camshaft sprockets.
Check the condition of the camshaft thrust washer whilst the camshaft sprocket is off.
Again - just smear the gasket with grease - no need for blue gasket goo.
It is good that you have found a source of crankshaft dampers.
Could you please post a web link to the supplier/part.

[svenedin]

Much appreciated as always Phil. I thought as much. A bit more work but as you say, I'd be annoyed if I took the front of the car off and did the timing cover only to find it still leaks.

I bought the AHU1878 from here. It is a bit more expensive than from Minispares but they have stock and Minispares do not:https://www.minisport.com/ahu1878-crank ... ulley.html

Stephen

[philthehill]

Thank you for the link.
I have been to Minisport at Padiham in the old T.A. centre several times back in the day.
They always had a very good selection of S/H tuning parts to peruse and buy but last time I went the S/H side of the business appeared to have been discontinued.
They replaced a valve seat in a 940 head whilst I waited so very good service.
You will find the 1098cc engine a lot smoother with the damper fitted.

[svenedin]

The job is not yet urgent but the oil leak is increasing. I am gathering together the tools and parts that I need to do the job properly. For example, I have had to order a flywheel locking tool and a big 1 5/8" (second hand) ring spanner. Parts are gaskets, locking washers, camshaft thrust washer, a damped pulley etc. I have spare shims for the crank sprocket in case that needs the end float correcting. My usual way of approaching a job that requires quite a lot of disassembly is to try to do as many other jobs at the same time. The starter motor needs to come out so I will put back a fully refurbished one and then refurbish the old one etc. I need to refurbish a spare timing chain cover and I might as well swap the fan and fan pulley for refurbished parts when the access is very good with the front off the car. Hopefully, when this is done the oil leak will be cured and the mechanicals will look a lot nicer too. I have a breather rocker cover I refurbished years ago and I am going to experiment with a slightly different breathing system with a Y-piece from the tappet chest meeting the pipe from rocker and then the single pipe to PCV valve. In theory this will be a better breathing system and the engine even less likely to leak oil. The absolute ideal would be a breather timing belt cover, with the squashed oil separator that does not catch the fan but that would need a different front plate as well. The breather timing chain covers with the recessed bit and flattened can seem hard to find....That would not only improve the engine breathing but that kidney shaped timing cover has a better neoprene gasket and it enables a chain tensioner to be fitted so there would be significant advantages.

Phil do you happen to know what the part number is for the later, kidney shaped timing cover that has the oil separator can recessed so it will not catch the standard Minor fan? Is it LJR10168? Also if I found one, what front plate would I need? I am going to take the front plate off anyway to change the gasket behind it.

Stephen

[philthehill]

You do not need another front engine plate to accommodate the kidney shaped timing chain cover. Just drill the extra holes in the Minor front engine plate.
If you fit the tensioner you will also need to drill a hole in the front engine plate to accommodate the head of the tensioner pivot pin.
Some advocate fitting the pin from the front of the tensioner but that style of fitment of the pin is subject to risk of coming loose. Better to fit the pin it as BMC/BL designed/intended.
The hole for the pivot pin has to be larger than the pin head so as to allow for adjustment of the tensioner. I will dig out a modified front engine plate later and confirm the size of the hole for the pin head.
As regards the timing chain cover - All the timing chain covers with breather have little to no clearance between breather and fan when fitted to a minor. There are various thicknesses of spacer available to go between fan blade and water pump flange which may help.
If your block has the aperture for a mechanical fuel pump I would fit the breather to that aperture and use the later kidney shaped timing chain cover without breather.

Breather 1.JPG (1.09 MiB) Viewed 867 times

If you use the kidney shaped timing chain cover you will need to remove the timing sensor bracket (if fitted and the dimple below it). Also any deflector plate inside the timing chain cover will need to be removed if using a duplex chain/sprockets.

Timing cover 2.JPG (1.3 MiB) Viewed 873 times

[svenedin]

I had another look under the car this morning. The leak is actually not just oil. It is watery oil from the front of the engine. I am not quite sure where it is coming from. It seems to leak when cold and sitting in the garage. I have not been able to see it drip when the engine is hot. The drips drip off the timing pointers. I removed the radiator and the fan pulley and tightened all the water pump bolts (not too tight of course). I checked all of the hoses and the bypass hose and I checked all of the timing cover bolts. Some of the bolts did tighten a bit. I have put everything back together and will monitor. If it is the water pump gasket this is annoying. The water pump was only replaced about 2 years ago and it has not been disturbed.

Stephen

[philthehill]

To confirm - the diameter of the hole in the front engine plate to accommodate the head of the tensioner pivot pin is 11/16".
It has to be that large as the tensioner when applied pivots around the holding bolt so moving the tensioner pin in an arc.

[svenedin]

To confirm - the diameter of the hole in the front engine plate to accommodate the head of the tensioner pivot pin is 11/16".
It has to be that large as the tensioner when applied pivots around the holding bolt so moving the tensioner pin in an arc.

Thank you.

After my running repairs this morning I ran the engine up to temperature and no sign of any drips of water or oil. That's a good thing of course but if it still leaks when sitting cold then I remain puzzled! I cannot say exactly where it was leaking from. The oil I think was being washed off an oozing timing cover by water leaking from either water pump gasket or bypass hose. We'll see in due course......

Various parts are being stripped and de-rusted at the moment.

Stephen

[svenedin]

The new damped pulley arrived and I am impressed with the quality. Having never handled a damped pulley it is pretty heavy!

Phil, how do you mark a damped pulley with a timing mark? I have thought of two options. Either put the old pulley on top of the new pulley with the keyways aligned and transfer the timing mark in Tippex or set the engine to TDC, lock the flywheel and then mark the new pulley once installed. I am a bit worried that Tippex (or paint) is not really good enough or permanent enough. I am tempted to use a sharp cold chisel to make a small notch as per the original pulley. What do you think?

Edit: there is actually a small notch in rim of the v-pulley. Whether that timing mark will be correct for the Morris with the timing marks below the pulley (rather than the later Minis with the timing pointers above) I do not know yet. I could very easily make a new notch and paint it with white paint.

Stephen

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[don58van]

You might consider installing Declan Burns' design for the stationary timing marks above the damper.

Don

[svenedin]

You might consider installing Declan Burns' design for the stationary timing marks above the damper.

Don

Thank you. I must have missed those posts from 2020 but I found them by searching. I was rather busy during the Covid period!

I think I will probably just copy across the timing notch from the old pulley. I have an old engine that I may be able to get the pulley off so I don't have to wait until I am actually doing the job. It is a nuisance getting under the car to see the timing pointers but it's not something I have to do very often so I don't really mind. I know people say time by ear and no need for a TDC mark etc but I do like to check with a strobe that I haven't done something crazy when I set the timing.

Stephen

[philthehill]

The first thing you are going to have to do is remove the timing disc from the rear of the pulley. Just drill out the rivets . You can then tap the old rivet holes as they can then be used with a puller (as below) to remove the pulley if required. Using a 2 or 3 leg puller can damage the damped pulley.

Damper puller.JPG (873.97 KiB) Viewed 787 times

As regards timing marks - I have just timed the engine and painted marks on the timing chain cover and pulley where I can see them. No need for special timing marks etc. You do not have to stick with the original timing marks/positions.