low compression engine

[ijs1968]

Hello,

I'm a new member trying to help my lad restore a 1967 2dr. We have one seized engine in the car and also a second spare engine that came with the car but is a low compression version from a van we think (10v). The 10v engine looks easier to rebuild as it seems in better nick but has some sticking valves after taking the rocker cover off. Also this engine is supposedly a closed circuit breather type.

Does the low compression engine differ that much in performance from the high compression version ?

Also , not knowing much about the breather system i feel more confident in trying to take parts from the original engine and try and mimmick what's already there but is there anything internal in the engine to worry about or is it just a case of swapping over the rocker cover and changing the cover plate on the side to the one with the breather pipe ?

Or would it be better to forget the van engine and just start from scratch with what's already in the car ?

Any suggestions would be gratefully received. As you can probably guess , I'm not experienced in the ways of anything mechanical so any advice would be most welcome.

[bmcecosse]

Why do you think it is a 'low compression' engine? Have you run a compression check? And you should KEEP the closed circuit breather etc - it's a great system for preventing oil leaks and nasty smells......... And make every effort to unseize the first engine. Pour diesel fuel down the bores - leave for a week - then gently rock the crankshaft back and forth until you can turn it.. Then strip and clean!

[JOWETTJAVELIN]

A low compression engine is designed to run on really poor quality petrol of an octane rating a hell of a lot less than standard 95 RON fuel on sale in the UK.

Technically (and I am not advising you to do this!), you could dilute the petrol with other, cheaper fuels and the engine would run perfectly happily.

Of course the power output would be lower as you cannot take advantage of premium fuels and why would you want to in a van? They were workhorses, used and abused, flogged, battered and belted for 10 years before being either retired or crushed.

Years ago a friend who had a Marina (with a much higher compression ratio than the van engine) accidentally filled up with diesel instead of petrol. Despite this it ran (protestingly), it just smoked and smoked and was much louder.

[ijs1968]

Thanks for the responses. The engine plate on the 10v engine indicates that it's a low compression version and the top of the pistons are dished. We'll take the the original engine apart at the weekend and decide after that the best way to go.

Thanks again

[bmcecosse]

What part of the engine plate indicates it is 'low compression' ? the 10V does NOT in itself mean low compression. And all (Minor) pistons are dished........ I'm not even sure there ARE any low compression 1098 engines......

[les]

How can the CR high or low be found out if the engine is complete and in the vehicle?

[bmcecosse]

He knows the pistons are dished - so I suspect it's not complete......

[mike.perry]

Military Travellers and GPO vans had low compression engines. The Travellers had to manage on BOAR low octane petrol which even made Land Rovers pink (not the colour). When I took my TA Land Rover 55 FM 40 on exercise in Germany it ran perfectly well on Shell petrol in UK then pinked like mad for 2 weeks on BAOR fuel and was perfect when filled up in UK with Shell.
Back to Morris engines, engine number 10MA-U-H or L = High or Low Compression. L/C pistons are very dished. As for performance you could just about wind a L.C. Traveller up to 70mph on a UK motorway

[bmcecosse]

So -1098 engines were made in Low Comp form ??

[les]

Roy, I was asking the question for myself (whilst on the subject) as I wanted to find out regarding my project. Maybe I could have worded my post better.

[bmcecosse]

I honestly thought Low Comp engines were just in the 948 range. But happy to be corrected!

[M25VAN]

My van had a LC engine when I got it, there was an L in the lettering on the engine block plate. Pistons were indeed deeply dished. I seem to remember running it on 2star petrol.
Mr BMC, have a look at General Data page 11 in the owners manual, I think you have a copy.

[bmcecosse]

Oh well..... So - does the engine number in THIS thread have a L in it??

[ijs1968]

Hi All,

The engine plate is 10V/189E/L64997. I assumed it was low compression after a bit of google searching on the code and after taking the engine apart , noticed the pistons were dished a lot ? When we take the other engine apart we can compare pistons so will know one way or the other.

Really appreciate the assistance and at least have a year a bit to figure things out and get it on the road !! by the time my lad turns 17.

Going to try and muddle through with our limited skills for the moment.

Ian

[brucek]

Can you post pictures of the dished pistons? - not many will have seen these wheras many will have seen the standard high comp pistons. We'd be able to tell you very quickly if there is a difference and before you have to pul the other engine down The engine number does indicate a low comp unit though

[ijs1968]

sounds like a good plan. i'll take some photos later in the week.

thanks

ian

[welshrat]

Found this recently, thought you may be interested in the code breaker information.[frame][/frame]

[liammonty]

Some of the cars had low compression engines as standard too- I've just bought a 1968 2 door that's been off the road in storage for 30 yrs, and that has the original low comp engine. It even has a factory plate under the bonnet saying 'this vehicle fitted with low compression engine'. It was first sold to Hertfordshire County Council- maybe they thought the power of a high comp 1098 was too wild for their staff!!!

[mike.perry]

Cheaper running costs on 2 star.

[POMMReg]

Engine dates to late '70,early '71 - from a civvy LCV in the 300xxx chassis range.

Should be green too.

Hope this helps.
POMMReg