No oil pressure and loud knocking

[s3ndo]

Hi guys,

1275 Marina engine

Was driving to work this morning, started hearing a knocking sound and then it suddenly got quite loud and I noticed I had no oil pressure. I pulled over, grabbed the oil out of my boot and went to fill it up, full of oil...

I left it where it was and walked to work. Any ideas?

Cheers

[philthehill]

1. Big ends or main bearings failed.

2. Oil pump failure leading to loss of oil pressure resulting in big end/main bearing failure.

Take the sump off and remove a big end cap and see what you find. Do the same with the centre main.

Sorry to say that the prognosis does not look good.

[bmcecosse]

Does sound like oil pump failure - assuming there isn't a massive leak... Could be broken crank - although that usually leaves 'some' oil pressure -to have absolutely none indicates a pretty drastic failure somewhere along the way. Even a stuck relief valve would leave some pressure showing... It's definitely full of 'oil' and not water with some oil floating on top...?

[s3ndo]

Well I've only gone off the dipstick. There was a level up to above the max (where I topped it up as I thought it was empty before realising). It could be water, it's currently stuck in a narrow country lane, AA will be my friend here I think. Currently on a 24 hours shift so can't get back to see it till tomorrow morning.

Big end I suppose will mean new engine?

[s3ndo]

I sneaked out of work for a quick look. It looks like it's oil in the pan, but there is a very slight bit of emulsification under the cap. Hardly anything though.

[bmcecosse]

With such a drastic drop in oil pressure - it will need a pretty major rebuild...

[philthehill]

If the crankshaft is shot there is a brand new Marina 1275cc crankshaft for sale on 'e' bay at a starting price of £175. It has already been relisted at least once so may not go for much more than the £175.
See 'e' bay ityem No: 251691308178.

[bmcecosse]

The last two I bought were only £50 each..... about 8 years ago certainly....

[s3ndo]

Fingers crossed then I don't mind any expenditure tbh, just want her back to normal or better

[bmcecosse]

Here's the crank - but I do feel the price is a rip..... but there are no others that I can see.... http://www.ebay.co.uk/itm/NEW-MORRIS-IT ... 3a99f89492

[s3ndo]

If it's not the crank and instead something even worse, what engines could be a straightforward easy swap?

[bmcecosse]

It's highly unlikely to be a broken crank - although pretty sure it will need a regrind. This may be one of these cases where the oil pump drive shaft has spun in the rotor.... Another 1275 would be the straight swap (but I don't see any on ebay..) failing which a 948 or 1098 engine will go straight in -provided you have a Minor 4 speed gearbox ??

[s3ndo]

It's a 4 speed gearbox but unsure if it's still a minor one? I don't foresee it having been changed.

[s3ndo]

Just an update. Sat in car waiting for aa. Thought I'd give it a quick turnover. Oil pressure is back and knocking noise nearly gone but still a little bit audible.

[bmcecosse]

When you say 'oil pressure is back' I assume you are reading this on a gauge - not relying on the light?? If only the light - then it simply indicates that your engine has died....it's far too late a warning of impending problems. With cold oil - the pressure will have struggled up enough to put the light out (anything from 8 to 15 psi) but that doesn't mean the problem has gone away. However - all not quite so black looking now - a crank regrind and new oil pump should see it 'good as new' in that department at least... And if you don't have an oil pressure gauge - put it top of your Santa list !

[s3ndo]

This is from a gauge not the light, aa turned up turned it on declared it big end failure and dropped me off at my mates garage. He's going to have a look later.

[s3ndo]

Phoned the girlfriend and told her the bad news to which she replied when she was using it recently it was knocking at bit at certain revs, mid range... why didn't she tell me!

[panky]

Just a thought, does the Marina engine have a mechanical fuel pump?

[s3ndo]

So I might be able to source a 1098 engine, however there are some modifications to my car eg a mg metro carb, large bore exhaust with 3 branch exhaust. I know thanks to bmcecosse that I need to check to make sure it's the original minor gearbox, will the 3 branch transfer across or will it need to be modified?

[bmcecosse]

You can use it all just as is. Only possible fly in the ointment would be if the gearbox and /or clutch operation have been modified away from standard.