Bit of engine porn, and a few questions!

[TomLS]

Hi all,
I've been stripping down the new engine I bought, and I have a few questions - with pictures, if you would be so kind.


1) Hole above crank:
I'm not sure if this is meant to be here, as I haven't stripped an A-series before. It looks pretty ragged, but could just be 'rough cast'.

Mog Engine upgrade by TomHBP, on Flickr


2) Cam number:
A Piper 270 cam. I would very much like to keep this if possible! I also have an (apparently very rare) A+ version of the old 2A948 MG Metro cam lying in the garage, with 3 x 1/8" rings between lobes 3&4 (VERY slightly surface rusted, but nothing that won't clean right up - now well oiled). The specs are vastly different to the 270 - but advice about which would be better for fast road is appreciated.

Mog Engine upgrade by TomHBP, on Flickr


3) Scored cam bearing:
Not so good news - the cam bearings look pretty scored. Not deep, but can be felt. I assume these will need changing, and need to be done by a machine shop with a press?

Mog Engine upgrade by TomHBP, on Flickr


4) Cam lobe and lifter wear:
I nearly didn't remove this lot, it's just by virtue of the cam number being stamped on the rear that they got removed, and as you can see - they're KNACKERED. I have a small question about the new lifters I already have - see below.
The only downside to this, is that there's slight unevenness noted on the cam lobes associated with the shafted lifters (5 in total), the worst one being shown. There is a slight 'flat spot' on the midpoint of the lobe at this point, that feels less rounded than perhaps it should.
Is there any way this cam can be saved? I have a feeling that if I put it back in now, that it will kill the new lifters in comparatively short order.

Mog Engine upgrade by TomHBP, on Flickr


5) Front plate screw heads:
This is an interesting one - these screw heads were apparently sitting more proud than they should be! I have new ones, and it will be relatively easy to countersink the front plate by a further 1mm or so, BUT...

Mog Engine upgrade by TomHBP, on Flickr


6) Nicked timing chain:
They appear to have kicked the back of the duplex chain. There's no other damage to the chain, and it looks good as new. The nicks seen in the center of the pic, and one above are the worst present. Should I replace it with...

Mog Engine upgrade by TomHBP, on Flickr


7) Surface rust timing chain:
This one that I bought a while ago. My garage is apparently quite humid, and it has a very slight amount of surface rust on the sprockets, but none on the load faces of the teeth, or the chain that I can see. Scrap it, fit it, or keep the old one??

Mog Engine upgrade by TomHBP, on Flickr


Cam lifter hole discrepancy:
Finally on to the question about my new lifters. The old ones had a single small hole that is angled up to the inside of the seat. Is this to allow oil in to the pushrod knuckle, or out of it, and is it necessary either way?!

Mog Engine upgrade by TomHBP, on Flickr


That's it for now. Tomorrow night, we get to see if the bottom end holds any nasty surprises...

Cheers all,

Tom.

[MarkyB]

1st job is see why the oil isn't being filtered properly.
Cast hole is fine, I think.
I think the cam is knackered (see above) the hardening is very thin and yours is worn through.
I believe you can put the cam bearing in but then they need to be line bored or some such.

[bmcecosse]

What size engine is this ??? Yes - that cam has been ruined - probably by not fitting new followers when it was fitted. The 2A948 cam is NOT from the MG Metro - it was only used in the 997 Cooper engine - and as such is a very slight upgrade from the AEA300 camshaft which was fitted as standard to the 1098 engines. So - we need to find out what cam you have. That cam bearing will be fine - but as les points out - it is an indication that unfiltered oil has been going round the engine..... so check the filter. The cam chains etc look fine. If your 3 rings are between the 3rd and 4th lobes - then indeed it is the 'rare' cam version AC Dodd lists as possibly having been fitted to early MG Metros - however it is still not a very exciting cam (252 timing)- you would do better to find a genuine MG Metro cam (252/268) if you can. Oh and don't worry about the lack of oil hole in the new followers. The oil hole you show simply tells me these followers are VERY old - which is why I suspect they weren't changed when the 270 cam was fitted......

[TomLS]

This is the (hopefully) 2" mains 1098 I picked up last week (The machining receipt lists 1275 main bearings any way). It also has a 12G940 with the bigger inlets, harmonic balance and a pocketed block to boot.

The oil filter was upgraded to a mini spin-on one a few years ago, so I suspect the damage occurred before that was done, but I'll make sure to flush it well any way.

It's a real shame that cam is knackered - I can't justify £180 for another! I've seen a video of the A35 that used to contain this, and my god was it quick!
I got the details of the '3-band' cam off the printout that came with the cam when I bought it, which lists this website:
http://www.mlmotorsport.com/forum/index.php?topic=11.0

Glad the chain looks okay - are you referring to my slightly rusted one, or the nicked, already fitted one.

Looks like I'll have to start looking for another cam then! Considering the head, higher revving abilities of the engine, HIF44 (I can make a decent one from my 4 spares!), and the near future addition of an LCB, would your cam recommendation change at all? I was thinking Kent 266, as they really aren't that dear, and are easier to find than the MG metro cam (and apparently very similar?).

Thanks again.

[bmcecosse]

Yes - the 266 will be nice in that engine. Not too revvy - good torque.

[TomLS]

Okay, 266 it is!

I pulled the sump today (should have re-drained it first... That was MESSY) and removed the center main. No major worries there - the bearing had a small patch of copper showing, and the journal itself was virtually unmarked. There was no scoring at least!
The thrust spacers are barely marked! (std).
I may as well replace the shells while i'm there though (+0.010). What is the best brand to buy? As its 2" mains I guess I need a set from a 1275. Just out of interest, is it the same crank as a 1275, or are they different strokes?

Cheers,
Tom.

[bmcecosse]

Same stroke - different crank. beware the later (and better) 1275 mains have no groove in the cap shells. To fit them - you would need to machine (file??) a centre tag location in the caps.

[TomLS]

Okay, thanks for the info.

Are the con-rod big end bearings the same as a standard 1098, or a 1275? I can't find the info anywhere!

[bmcecosse]

Ahhh- now that I don't know for that engine. Are the rods split horizontally - or at an angle? Best to measure the big ends.

[chrisryder]

It might be worth sourcing your shells from an MG supplier. Tell them it's a 1098 '10CC' midget engine and they should supply you with the right ones!