Timing chain/water pump off - few questions!

[hanvyj]

Now I've got a modern (Sad day...) and i don't have to rely on the moggie to get to work, I've decided to start pulling the engine apart to try find the source of the rattle, oil loss and overheating problem.

I've come across a few things.

There seems to be quite a bit of some kind of white crystalline goopy stuff in the thermostat and water pump area. It doesn't seem like near enough to be blocking things up, but I was wondering if anyone has seen this before? It might be a bit of oil in the water causing mayonnaise? It doesn't show up on the oil filler cap or radiator cap - only noticed it since pulling bits off.

The timing chain, while it doesn't seem to be very worn, does look to have slack to me, but I'm not sure how much is likely to cause a rattle. Pics below.

I've decided, given this is pretty much a new duplex chain, to get a simplex and mini tensioner (already have the bulge in the case). Can I (and should I) use one set of the duplex gears? I'm assuming they are joined together and I'll need a whole new set of gears.

Should I replace the water pump or thermostat while I have it out? The pump seems bullet proof, being a single moving part and all, but does look a little old. I can't see anything that would have contributed to the cooling problem (other than a few bent fins the radiator is pretty perfect) so would considering replacing it with a higher-capacity pump like this be sensible? http://www.minispares.com/product/Class ... o%20search

Also, one of the oil leak sources may have been the timing chain gasket. It seems the felt type - A bit of reading says that I should use a rubber type gasket. Minispares don't list the material, but have two available:

http://www.minispares.com/product/Class ... |Back%20to

http://www.minispares.com/product/Class ... |Back%20to

Is the rover one worth getting? I don't mind spending an extra few quid if it's the rubber type that isn't going to cause a headache later on.

Thanks!

White goop:



Slack duplex chain:

[chickenjohn]

That chain does look a bit slack! Up to you whether you fit a new standard chain and new tensioning rings or go the duplex route.

As for the white deposits, partly alloy corrosion and possibly chalk, depending on your water in your area. Make sure you always run the cooling system with at least 50% blue glycol antifreeze all year round to minimise corrosion.

Also, a good idea to check the end of the water pump for play to see if it is worn.

[philthehill]

As regards the timing chain:-
The timing chain shown in you photo is rather slack and should be replaced. The teeth on the camshaft duplex gear look to be very serviceable and could be used again if the crankshaft duplex gear is of a similar condition. It is bad practice to replace just one gear only as it will lead to accelerated wear of the chain and gears.
You will have to have either a simplex or duplex set of gears you cannot split the duplex gears to make them simplex .
My recommendation would be to fit a new duplex chain and the Mini Timing chain tensioner assembly so that you get the best of both worlds.
The later timing gear cover gasket is of a a rubberised material and is Rover/Unipart No: GUG705550 GM / Mini Spares 12G2625. One side of the gasket is grey and the other side red and has a raised rubber sealing strip down the middle of the gasket on both sides. These are the gaskets I use and they are good. If you smear the faces of the gasket with LM grease they will come apart easily and they can be used again if required.
Make sure that what ever gasket you obtain is suitable for your timing cover as the pre 'A' plus had only 10 holes and the 'A' plus has 11 holes so your choice of gasket may be limited.

[IslipMinor]

Camshaft sprocket lock washer -

Have you undone the camshaft sprocket nut and removed the lock tab? If not I would fit one before replacing the timing cover!

I have run a duplex chain for many years and never seen one worn like that, but since you have the A-Plus cover, fitting a new duplex chain + Mini tensioner gives you the best of both worlds.

[bmcecosse]

Go with the Mini simplex system - I tried a tensioner on a duplex and it lasted all of 100 miles or so.... Yes you need new sprockets - but they are not expensive. But -MAKE SURE the sprockets are accurately aligned to each other...I suspect yours has been running slightly out of line. Also check the cam shaft end float... And a crankshaft damper is supposed to prevent crank whip - and to help protect the timing chain. No harm fitting one - if you can find one. People think Duplex is a cure for rattle - it is not - it has no tensioner effect built in - not even the dubious rubber rings of the original simplex set-up. As for the pump etc - as above - just clean them up and perhaps run some kind of cleaner through the system - perhaps Citric Acid - to remove any chalk and hard water deposits.

[philthehill]

Only if the tensioner is done up too tight will the tensioner fail whether fitted to a simplex or duplex chain system.
The tensioners and duplex chains fitted to my Minor over the years have lasted well, well, well past 100 miles!

[bmcecosse]

I don't think it was too tight Phil...but maybe - it wasn't yesterday. I'm surprised you would fit it to a competition engine - it's extra friction after all - and I can't imagine you would hear any slight rattle when hammering up a hill!

[hanvyj]

Only if the tensioner is done up too tight will the tensioner fail whether fitted to a simplex or duplex chain system.
The tensioners and duplex chains fitted to my Minor over the years have lasted well, well, well past 100 miles!

I didn't know you could fit a tensioner with a duplex chain, all the pictures I've seen have a single set up. Do you need to stack two, or space it out a little?

I'm looking at this to try figure it out: http://www.minispares.com/image.axd?typ ... SSK051.jpg

[bmcecosse]

Unless you are using a high lift cam and/or extra strong valve springs.......the Mini simplex is by far the best bet. It works...

[hanvyj]

I think that's the route I'll go down. Staying duplex saves me the cost of the gears, but simplex & tensioner seems the best all round solution.

It's done less than a thousand miles on this chain (since engine 'rebuild' ), so I suspect you are correct in that the teeth must have been slightly misaligned or something systematic that caused it. I've yet to read up on the manual on the process of replacing it, I'll try be careful to get it aligned correct.

"Have you undone the camshaft sprocket nut and removed the lock tab?"

- No, I don't think so. At this point all I had done was remove the parts external to the timing chain cover to get it off.

[bmcecosse]

Some chains sold these days are less than top quality...you may be surprised to hear.....

[hanvyj]

I'm not at all... every replacement part seems to introduce a new problem/unreliability. It's taking me a long time to get used to the idea that fitting a new part isn't a sensible thing to do...

[philthehill]

The Formula Junior solution was to fit gears instead of the chain whether duplex or simplex.
Brian Slark Racing is now producing a similar product for the ubiquitous 'A' Series.
http://www.slarkraceengineering.co.uk/engine-products/
I have been toying with the idea of fitting one of the gear drive kits but still have several new Kent Cams vernier adjustment duplex kits on the shelf so we will see.
As regards the cam drive on my engine yes it is certainly under extreme loading in that I have been running a Kent Megadyne 320 scatter cam, 1.5 ratio full roller rockers, high strength springs and larger valves etc, etc so I need all the help I can get to keep the timing correct and the tensioner I believe does help to keep it all together.
I agree timing chains are a varied bunch these day so I only buy the best I can get and the ones from Kent Cams seem to be the best and so far have not stretched and thrown the cam timing out and the engine has run to 10000 rpm at times without failure.

[bmcecosse]

10,000 on a 1275.......never heard of that before.....

[philthehill]

Well it is fully race prepared with all the goodies you could want attached and it is 1380cc with the Manx Racing 940 - 7 port head, fully balanced and held together with ARP fastenings and steel parts scattered liberally throughout the engine.
It was so free revving that it would reach 10000rpm with ease. But nothing under 5500rpm
Unfortunately 10000rpm is no good for the Quaife gearbox fitted which has a recomended limit of 7500rpm so now detuned slightly and fitted with a rev limiter set at 7500rpm.

[bmcecosse]

I've never heard of a 1275 being revved above a genuine 9000 - even the most modified of Mini engines.... and even then just momentarily... 970 engines - yes of course , maybe even 1070 engines, but 1275....... not even with the nitride EN40B cranks of the genuine S engines..... Why would a gearbox have a rev limit? It's all rotational - nothing reciprocating.......

[philthehill]

Then you have not come across the full race engines produced by Manx Racing! The proprietor and AFG940 cylinder head supremo W.(Bill)S. Quine ex Downton Engineering.
My engine was exactly the same spec as the racing engines he produced for Minis with an output in excess of 140bhp.
Whilst I would never run continuously at 10,000rpm it would reach those revs easily and as I said in my post above 10,000rpm is no good for me.
As regards the gearbox the Quaife S/C C/R clubman box is derived from a Ford RS 2000 one and uses the Ford main shaft which has a plain bearing. So Quaife only recommend using the box to 7500rpm. Quaife produce an alternative in the form of a roller bearing supported main-shaft but that adds considerably to the overall cost and the gearbox box now fitted was expensive enough when you add up the costs of the bell housing (CS Autoclassics), the Quaife SC/CR gear set, the Quaife alloy gearbox casing, the Quaife alloy top cover and the Quaife quick shift gear lever plus having the propshaft made/balanced.
The engine was built very nearly on the premise of b----r the cost lets just get it built and it is a beautiful engine and that 7 port head and twin 45 Weber carbs just draws the crowd.[frame][/frame]

[hanvyj]

1000rpm is crazy!

Timing gears sound like a great idea, but I dread to think the price. New baby on the way is forcing my budget low...

Checked, there is no locking nut at all. I'll order one. Does anyone know the size of the bolts I need to bolt the tensioner plate to the front plate?

Closer inspection of the water pump: There is a little play. I can 'rock it' but its an almost unnoticeable movement, just makes a slight clicking rather than moving much at all. Doesn't worry me much.

There a noticeable notch/hole in one of the veins though:



I'm going to test the thermostat by boiling it in a pan. There's no bypass hose, but it does have a single 3-4 mm hole drilled in the surround.

I managed to resize the photos to something more sensible.

[bmcecosse]

Ooooohhhh -that does need a good cleaning !