Mini tensioner mod timing marks

[stevelemoir]

I'm trying to install the mini timing chain tensioner but have found that the timing marks on the mini cover are miles away from the dimple on the crankshaft pulley.
The dimples on the sprockets are in line....tensioner not fitted

IMG_0636.JPG (2.38 MiB) Viewed 1730 times

The dimple is way out with piston 2 at TDC.
Do I have to grind off the existing one then make my own pointer and weld it in position on the mini cover?

[RobThomas]

Morris timing mark on the pulley is for when the timing mark is at the bottom. You need the matching Mini pulley which has the timing mark at about the 10 o'clock position. That pulley isn't the greatest design so maybe best to just get the Mini one and be done with it?

[stevelemoir]

Thanks for the reply.
Any idea of mini part number for the pulley and a supplier? The engine is a 948cc.

Would it be logical to file a new dimple in the existing pulley?
I have a dial gauge so could set piston one at 1.83mm BTDC to get the 5 degree position.
Piston one to keep it the same as currently. I know the mini set up would use piston 2.

[philthehill]

What I would do is bring No: 1 piston to TDC - mark/dimple the existing pulley relative to TDC No: 1 on the new timing cover/marks, paint the new dimple with white paint and thereafter use the revised marking.

No expense incurred and you have the timing marks which can be seen from above - beats having to crawl under the car to check.

The multi-piece pulley in your photo is not the most reliable in that the rivets have a tendency to loosed and the pulley fall apart.

The better pulley to fit to your engine is the harmonic damper type which can be treated in the same way as regards timing marks.

The timing cover with the facility to accommodate the tensioner - have you removed the internal baffle - it may well foul the duplex timing chain as the baffle was meant for use with the tensioned simplex chain.

Timing cover 2.JPG (1.6 MiB) Viewed 1703 times

How are you fitting the tensioner to the front engine plate?
If fitting ex factory style - the front engine plate needs to be drilled to accommodate the head of the tensioner pivot pin as per photo of the modified 1275cc Midget front engine plate shown below. The hole (11/16") needs to be large to accommodate the swing of the tensioner pin head when setting the chain tensioner. Setting the locking bolt halfway along the slot seems to work well.
The front engine plate can also be drilled to accommodate the additional timing cover bolt.
I used a 'A' Plus front engine plate as a pattern when setting out and drilling the additional holes.

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[Declan_Burns]

Here's how I added the new timing marks. A simple aluminium bracket bolted to the cover and as Phil mentions just line it up with no. 1 Piston at TDC and file a notch and add a dab of paint (still to do in the photo).
Regards
Declan

[stevelemoir]

The mini cover i’m using (CAM 4904) doesn’t have the internal baffle.
I’ve drilled a blind hole for the pivot pin large enough to allow full adjustment of the tensioner.

I’ve just found out that the original oil thrower (948cc) is to big for the mini cover so I’ve ordered the later oil thrower 12A1148 which I believe will fit.

I’ve been using the owners club technical tips document on timing chains. Perhaps this could be amended to include the following:

Need the mini crankshaft pulley to use the timing marks on the mini cover (using cylinder 2) or make a new notch on the existing pulley. Use the cylinder of your choice but using cylinder 1 seems logical.

Could use existing sprockets without the rubber tensioner rings. However the mini sprocket will be lighter. (I’m not sure whether this is correct. Initially I was going to use the minor sprockets. I’m now using mini sprockets)

The 2 set screws needed to fix the tensioner may have to be shortened to fit.

Only the later oil thrower (12A1148) fits the mini cover.

Who can I contact to get the technical tips document updated?

[philthehill]

Oil thrower 12A1148 is the correct oil thrower to use with the later timing covers with neoprene lip seal.

No: 1 cylinder TDC should be used for the timing mark.

The original Minor simplex sprockets can be used but you may find that they are worn. The Minor cam sprocket is heavier as it has to accommodate the two tensioner rings.

The two set screws do not need to be shortened.

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[stevelemoir]

I had to shorten the set screws I got as part of the tensioner kit from Mini Spares.

[philthehill]

I find it strange that you have had to fit new bolts and shorten them.
I have fitted several of these tensioners and have used the existing timing chain cover bolts which have never needed shortening, my 1380cc motor though uses high tensile Allen headed screws where possible as per the picture below.

http://www.minispares.com/product/Class ... o%20search

The tensioner is used with a vernier adjustable steel duplex set up.