Engine Rebuild

[silloyd]

Jury's out on the oil plugs, I want to do this rebuild once and thoroughly.

That aside, I thought earlier in this post that the consensus was that the cam was OK?!?

[bmcecosse]

Sorry - can't remember -so many threads to follow! But followers like that could maybe have damaged the cam lobes....

[silloyd]

..and there was me thinking you were the all knowing oracle ( )

This has developed into a bit of a long post though, here are the photos

[bmcecosse]

Hahaha.....they do look ok, but it could be a fine chance to upgrade to a slightly better cam! MG Metro - or '266' as sold by many. Big improvement on all the later cams is that they have 1/2" wide lobes - so don't damage the followers so readily.

[silloyd]

Not sure if the budget can stretch to that.

Would any 1275 cam with wider lobes be an improvement or only the MG Metro/'266' version?

[MikeNash]

That timing cover that was pictured earlier - what's it off? (Roy'll know 'cos he sold me an engine that's got them on!) And why cut off the timing marks? Won't they line up with your new damper pulley? They do on mine and its much easier to use than the usual 1098 ones for which you need to get under the car.
And another question for Roy; there's more "pointers" on these timing marks than the usual 1098 ones. Are they the usual 5 degrees apart? Regards, MikeN.

[bmcecosse]

Other 1275 cams are not worth having from a timing etc aspect - but are 1/2" wide -so worth it from that point of view. Actually - (unless you get the 'low power' cam) - the timing is same as the 1098 engine BUT it is advanced by 5 degrees which was found to improve torque and economy - so yes - worth having, but not by much.... The MG / 266 cam is much better!
Timing cover from 998 Mini. Extra marks - sorry no idea -I never time anything using the 'marks' - there's no point(sorry about the pun..). I think the ref was to cutting off the timing location fitting - which has no known use in service, but was possibly used to set up the timing on the production line.....

[silloyd]

Much time passed...... (Doing stuff on the house for SWOTBO!)

In between other things I've thoroughly cleaned everything and repainted the block, sump, timing chain cover, etc. Re-assmbly begins.

I've installed the reground crank and main bearings, including the new bearing shells and thrust washers. After torquing the main bearing bolts, the crank turns smoothly but is quite stiff - needs two hands to turn it, one on the drive flange and one pressing fairly hard on one of the legs of the crank. I only have the original well worn bearings to compare with and they were much less tight, so is this normal until the bearing surfaces bed in a bit? (Before you ask, yes I lubricated with lots of engine oil).

Next question. The bolts that hold the big end caps to the con rod do not have lock tabs (they were not present when I took the engine apart). That said they have 12 point heads (see pic) and I therefore can't see how lock tabs would work anyway. Again is this correct? What keeps them from working loose, apart from being torqued up properly in the first instance?

[frame][/frame]

[bmcecosse]

Hmmm - the crank should spin round easily in the mains...... Does any one main cap make it tight? Double check the centre main is right way round - can't go wrong with the others....The big ends will be fine - use the correct socket - and I always degrease bolt and rod thread - and apply a spot of Loctite to the bolt thread.

[silloyd]

thanks for the reply.

No single cap is causing the tightness - I've tried releasing/tightening each in turn and have tightened each pair of bolts progressively. Centre cap is on the right way around. It seems a tad looser after re-oiling each bearing and rotating a few times, I guess it will bed in with use(?)

Thanks for the pointer on the big end bolts, hadn't thought of that.

[silloyd]

Next problem...a crack in the back plate:
[frame][/frame]

Just appeared when reassembling, didn't think I was being rough in handling it and it was sitting flat against the end of the block before I tightened the bolts, i.e. no obvious stresses (!?!)

Even though this is outside the area that seals against the block, I'm assuming it either needs to be welded (I have no facilities for that) or I need a new back plate(?)

[les]

Play safe, change it.

[bmcecosse]

Not an unknown problem. Weld it or change it.

[silloyd]

Next questions:

I'm not sure I fully follow the instructions for inserting the distributor drive in section AAA.4 of the workshop manual. It says "...holding the drive gear with the slot just below the horizontal and the large offset uppermost, enter the gear. As the gear engages with the camshaft the slot will turn in an anti-clockwise direction until it is approximately in the one o'clock position".

If I start with the roughly slot horizontal I get this:
[frame][/frame]
which I would call two o'clock

If I insert it one tooth anti-clockwise, then I get this:
[frame][/frame]
which is more 'one o'clock' but that means starting with the slot not in a horizontal position.

I know that this can be accommodated to some degree when setting up the dizzy but which is roughly right to start with please?

Next, how tight should the Mini type timing chain tensioner be? Does this look about right
[frame][/frame]
(sorry, engine was upside down when I took the pic)

[MarkyB]

The second picture does look more like 1 o clock but it isn't that critical and can still be changed with the engine in so don't sweat it.
Can't comment on the timing chain as I've not used this set up.
However everything looks very dry, schlep some oil on all bearings as part of the rebuild.

[silloyd]

Thanks MarkyB.

Bearings have loads of engine oil and took these pics before oiling the chain, sprockets and tensioner so that they would be clearer.

[welshrat]

The second picture does look more like 1 o clock but it isn't that critical and can still be changed with the engine in so don't sweat it.
Can't comment on the timing chain as I've not used this set up.
However everything looks very dry, schlep some oil on all bearings as part of the rebuild.

You are right that the dissy drive can be changed with the engine in, however, I recently fixed the sump as the motor was upside down, turned it over and attempted to fit the drive, had a bolt fitted as recommended but still managed to let go of it and it dropped into the bottom of the newly fitted sump. Only way of getting it back was to remove the sump, thankfully I had not filled it with oil, fitted the drive with sump off then refitted sump, all good fun.

[philthehill]

The chain tension is OK.
I have the same arrangement on my engine.

[bmcecosse]

rat - you should be glad it wasn't a Mini!! And yes - the Mini tensioner looks about right - don't make it TOO tight or it may rip the rubber block to shreds....

[welshrat]

Good to have you back BMC, how's the tan? And yes very pleased it was not a mini!