Morris Minor Owners Club

Hi guys/girls

I am think about gettin my morris 1098cc engine upgrade with 80 thou overbore though Jonathon JLH. Just want to see if any one else has had is done and what it is like.

Cheers
Seb

80though will go through the liners into the block

Liners ?

could be talkin crap but have herd maybe on here or in the visard book who noes that the best to go is +40. +60 tends to lose power by making the bores flex. was looking to do this myself and stumbled onto this info just thinking if +60 is bad news +80 cant be good.

I assumed it had liners as you can put liners in excuse my technical ignorance

I think i mean you may uncover an oilway or waterway Luke is correct its in the vizard book.

As far as I know, oversize pistons are available upto +0.040". However, if JLH is offering to do an +0.080" overbore then it is obviously posible and maybe then liners are used ???
I'm sure Jono will be along to explain all

My view - the increase in power from this modification will be neglible (the power limiting factor on this engine is the head/cam/manifolds & carb- NOT it's capacity) certainly will be v poor in terms of bhp/£ value. Far far better to start off with a 1275 and go from there. But the 1098 can be very easily and cheaply encouraged to give 65/70 bhp anyway - without any v expensive reboring.
There are +80 and even larger pistons (+100 and +120 I believe) becoming available from Australia. They are not cheap - and it's not clear if they are really for 998 Mini engines and so will stick out the top of the block with a 1098 crank - and so will have to be machined down - which may weaken them somewhat, to say the least. However - I believe the 1098 engine was popular (in Minis) in OZ - so maybe they are the correct height. I'm also fairly sure these pistons will require the later 998 Mini press fit rods. Hopefully JLH will elucidate - there's nothing on his website about this - that I can see.

Here in NZ ive heard a few stories of bedford pistons being used in the a-series blocks. I dont know what the bedford pistons are out of though as all the piston diameters in a catalogue here are much larger than the 1098cc's bore.