minor 1000 engine

Post by **stevep007** » Tue Nov 13, 2007 8:50 pm

hi, does anybody know if an A40 1098 engine has the same gearbox mounting plate as the minor? will it bolt straight in or will the plate have to be swapped over?

Post by **bmcecosse** » Tue Nov 13, 2007 11:12 pm

Yes - it has the same backplate (if that's what you mean) and will fit directly to your existing gearbox IF it is a 1098 'ribbed case' gearbox!
If you are intending fitting this 1098 engine to an earlier 948 'smooth case' gearbox then you will need to swap over the flywheel assembly and the backplate from the old engine, because the 1098 engine has a larger diameter clutch which will foul on the casing of the 'smooth case' gearbox.

Post by **stevep007** » Wed Nov 14, 2007 7:23 am

thanks for the info. i have a 1970 minor 1000 so it should have the later ribbed gearbox but i will check this evening. other than that, are there any other issues to worry about, ie; will the A40 1098 be high compression and would it have used the same dyno and oil filter mounting arrangements?

Post by **dunketh** » Wed Nov 14, 2007 3:46 pm

There arent really any other options for mounting components on the engine.
The bolt holes for the dyno mounting plate are only present on one side of the block and the oil filter can only fit in one place.

The heater tap may be different but its no show stopper.

Post by **stevep007** » Wed Nov 14, 2007 6:06 pm

thanks for all the info. the reason i'm thinking of swapping the engine out is because at the higher end of the rev range and under load (acceleration) there is definately a vibration from the engine. it almost sounds like a growl and i cant really pin it down. possible main bearings or camshaft. take your foot off the throttle and the noise/vibration goes. there is no vibe at lower revs under load. it starts to come in at around 45+mph in 4th. i think i would have to recon the whole engine to be sure of a cure and it would be cheaper and quicker to replace it with a known good used engine.
if anybody knows what this noise could be, i would be grateful for any ideas before laying out for a replacement.

Post by **MoggyTech** » Wed Nov 14, 2007 6:44 pm

Worth checking before you rebuild/replace engine

Engine Mountings loose or worn (New mounts tend to cause roughness for a while, then they soften up a bit)
Gearbox steady wire too taught.
Gearbox mountings loose or worn.
Water Pump excessive play on pulley, or fan blades bent out of alignment
Engine tie bar too tight or bushes worn.
Head Gasket leaking
Exhaust manifold gasket leaking
Unlikely to be camshaft or cam bearings, they last forever.

You could try a damper type crankshaft pulley from a mini/metro.

Any idea what the oil pressure is? If 60 psi above 30MPH and 40 PSI at idle, unlikely to be main bearings.

Post by **stevep007** » Wed Nov 14, 2007 7:42 pm

oil pressure is around 45 at idle and 60 ish at speed when warmed up. around 50 odd at idle when cold. engine front mounts new but vibes were there before. slackened off steady and wire but no difference. rear mounts appear good. there is slight play in water pump pulley but it is a new pump and again the vibes were there before it was replaced. i suppose i could try it with no fan bolted on, just to test it. this has got me stumped. i think i would get it at all engine speeds under load if it was bearings but this is only as you go up the rev range. if it was fan imbalance it should happen even when not under load.

Post by **stevep007** » Wed Nov 14, 2007 7:43 pm

forgot to mention, there is a slight oil leak from the head gasket but would this cause vibes?

Post by **bmcecosse** » Thu Nov 15, 2007 7:44 pm

Vibration like that is normally associated with worn main bearings - they rumble. Only difference with the Austin engine is that it will have a mechanical fuel pump - you can either use it or remove it and blank off the hole where it fitted. TBH - the mechanical pump is more reliable and no hassles with fuel vapour problems because it is low mounted on the engine.