11 replies to this topic

[homemademini]

Hi everyone,

Is it needed to set camshaft timing again when replacing the timing chain?

or is it OK everything is replace as it was?

Additionally, anyone having feedback about the S-CAN 3D Timing Cover kit? quality, easy to fit, etc.

Any other alternative I should consider?

 

Thanks,

 

Olivier

Edited by homemademini, 19 June 2026 - 06:57 AM.

[DeadSquare]

Yes.  The Cam Shaft timing must be set correctly.   If the timing is not correctly set, it is possible for a valve and a piston to hit each other.

 

 

Please forgive me, if this is what you have done.

 

When replacing the timing chain, with the engine in the upright position, before dismantling the Sprockets, it is important that the Crank is rotated until the key way in the Crank Shaft is in the 12.00 "O" clock (Top Dead Centre) position.  For simplicity, it must remain through out, unmoved, in this position.

 

By contrast, the Cam Shaft keyway is about 2.00 "O" clock.

 

Look closely at the Sprockets, each has a "Dot", a small shallow hole, on their coreference, and the sprockets must be positioned with the chain round them, in such a way that the dots are in a straight imaginary line between the centre of the Crank Shaft and the centre of the Cam Shaft;  ie Crank, smaller sprocket dot, larger sprocket dot and Cam.

 

Remembering to refit any shims and wishing that you had three hands so that the chain is kept taught, slide the smaller sprocket a little way onto the Crank Shaft until its key way engages the Crank Shaft key.

 

Ensuring that the Crank Shaft does not rotate, carefully bring the larger Cam Shaft sprocket in line with the Cam Shaft spigot and slide the smaller Crank Shaft sprocket further on to the Crank until the larger Cam Shaft sprocket just begins to fit on the Cam Shaft spigot.

 

Using a "Straight Edge", check that the two dots line up with the centre lines of the Crank Shaft and the Cam Shaft.

 

If they don't line up, the larger sprocket must be eased off the Cam Shaft spigot and one tooth at a time the chain must be repositioned until you are absolutely sure that the dots are correctly in line.

[Spider]

Some may say otherwise, but to me, a new chain also means new sprockets. As the chain wears, the pitch of it increases and in doing so, loads up less sprocket teeth leading to more rapid wear of them.

 

So, new sprockets will mean at the very least, checking the cam timing.

I've been tempted but not tried the after market timing chain cover kits like the one you've mentioned. While they do appear well made and I like the way the seal, the thing that puts me off all that I have seen is that they all have deep sides to enclose the sprockets, fitted with a more or less flat cover. At a routine chain / sprocket change, like you are doing, how do you get the sprocket off the crankshaft ?

[absx2]

Unfortunately the dot to dot method can be way out on aftermarket sprockets sold by our mini parts suppliers these days so a timing disc and a DTI is a must if you want the best out of your mini. 

[homemademini]

Thanks for all your answers.
I think Spider's comment is a good point. Future maintenance might be more challenging with the shape of this timing cover.

Regarding the sprockets, any recommended good quality ones?

I initially wanted to change the backplate because two of the cover screw thread are loose and the backplate gasket might also be partly responsible of the leak.

Any other timing cover and backplate alternative on the market that anyone could recommend?

[Ethel]

I've run belts & looked on the new chain setups as an attempt to get the best of both with access to adjust the timing without disturbing the crank end. I dare say you could design in sprocket removal with a strategically placed boss & maybe a cranked lever to use off it. No idea if any of them have anything like that.

 

I reskon Spider could be onto something. If they've "chainified" a belt kit there's no dry compartment needing an extra cover join. Just make a more rigid version of the tin cover, with an access hatch

[Spider]

Regarding the sprockets, any recommended good quality ones?

 

The standard cast sprocket are actually not too bad and last quite well. When I'm after something a bit more up market, these are quite good, just quite a bit dearer than the standard sets;-

https://www.minispar...-with-evo-chain

 

 

[Shooter63]

I've just fitted the MED version of the alloy back plate and cover, and found two issues, one small, one a bit larger, first issue (small) the supplied bolts don't come with washers, if you fit them like that they will bite into the soft alloy, second and bigger issue, the bottom hose kinks when you try to fit it to the rad end, I  think its because of the extra depth of the casing and the fact it's square edged not rounded like the original, I had to trim the hose down a bit.

On to timing gears

Over the last few years I've fitted both standard and lightweight steel versions, the standard ones fit on no bother but if you time by dot to dot they set the cam retarded at around 112 degrees, if it bothers you is up to you.

The lightweight steel ones are really tight to get on both the crank and camshaft, the camshaft being the worst offender. I actually put the cam wheel in my lathe and eased them with a bit of fine cloth. If you go dot to dot with these ( non adjustable version) they go in very tight as in around 104 degrees.

 

 

Shooter

[DeadSquare]

I've just fitted the MED version of the alloy back plate and cover, and found two issues, one small, one a bit larger, first issue (small) the supplied bolts don't come with washers, if you fit them like that they will bite into the soft alloy, second and bigger issue, the bottom hose kinks when you try to fit it to the rad end, I  think its because of the extra depth of the casing and the fact it's square edged not rounded like the original, I had to trim the hose down a bit.

On to timing gears

Over the last few years I've fitted both standard and lightweight steel versions, the standard ones fit on no bother but if you time by dot to dot they set the cam retarded at around 112 degrees, if it bothers you is up to you.

The lightweight steel ones are really tight to get on both the crank and camshaft, the camshaft being the worst offender. I actually put the cam wheel in my lathe and eased them with a bit of fine cloth. If you go dot to dot with these ( non adjustable version) they go in very tight as in around 104 degrees.

 

 

Shooter

Just Before Easter, I went to help someone change his Cam, and was presented with MED back plate, cover etc.  

 

I used to be able to swap a Cam in 1/2 a morning, and exchanging the tin chain cover for something different, is as daft as fitting steel suspension springs.

 

 

I learned something else, there won't be a next time.  If there was, the first thing I'd do would be to try the sprocket on the Cam spigot.

[Spider]

I've found just about all the Steel Gears, from all suppliers, out of the packet, to be tight, too tight, fitting and all have needed some dressing to get a snug fit. Personally, that doesn't bother me, as I can match them to the shafts. I set them just a wee bit tighter than stock gears, these I feel are not quite tight enough, this is evident after they have had some use.

[floormanager]

Wrong post

Edited by floormanager, 21 June 2026 - 05:45 PM.

[Earwax]

No recommendations on backplate as such - just some information

 

A couple of types of alloy backplate  ( some bespoke copies of aftermarket ones - were available a few years ago on different mini forums)

 

- some (as suggested above) are bulky where you don't want   

- some have metric not imperial bolts on the back 2 hard to reach ( changed from a bolt to a post so you dont have to get behind)

- nearly all need to dress the countersunk bottom 2 spaces- and one I had to outsize a hole due to subtle fit differences.

 

Basically - as with nearly everything these days - don't assume it will fit perfectly.

 

The other thing to consider depends on your block - if you have cleaned/rodded your oil galleries and replaced bungs with small grub screw - most backplates will cover/partially cover this . 

 

Just as it is prudent to take a little grind to the engine mount/ lower radiator bracket - to allow a new fan to pass through  - it is worth considering whether a little grind off the back plate to gain access to the oil plug is worthwhile to assist if an oil seep occurs at this place.

       

Also worth pondering , if you have the Pretensioner type cover - changing over to the later tensioner type and  adding the chain tensioner - is IMO a good option - but needs planning beforehand