petrol in the oil

[timwilks13]

Driving home last night I had a sudden loss of power and a horrible knocking sound from the engine. Popped the hood and by removing CT leads found she was only running on two cylinders,thought its the head gasket again but that wouldnt explain the knocking sound. Checked the oil and it was very runny and stank of petrol. I'm doing some exploratory surgery tonight but thought I would ask first to see if anyone has had a similar thing?

[twiss]

Ooooh well that definitely doesnt sound good! Id probably compression test it right away if you can

[kiwizook]

that sounds real bad to me. probably some leak in the engine forcing air/fuel mixture past the pistons, and get through to the oil? pressure test sound like the first thing to me, if you find out the problem with the two cylinders, it might then explain the petrol in the oil

[turbo-tom]

Whip the plugs out compression test in and then go from there as they can tell most things

[Jordi]

My initial thought was nothing serious.

If it was only running on 2 or 3 cylinders id have said no spark on the other pots and the unburn fuel was running into the sump.

How ever, as per our conversation if it is sparking on all 4 plugs it is more serious. Seen as its the two cylinders next to each other its either the gasket or block.

Knocking / rattling may be a valve or piston ring?

As suggested compression test it, although i'm not hopeful about good results.

[juncopartner]

Have you checked the fuel pump? I saw this happen on my mates V8, there was a split in the diaphram so the fuel was pumping into the sump. The bottom end sounded like a bag of hammers due to the sudden lack of lubrication. Mind you when he changed the oil it stayed clean for ages afterwards. I think he used a couple of gallons of fuel going from the car park at Robin Hoods bay to the bottom of the trials site less than half a mile!!!!

[twiss]

/\

thats a good point!
im on a facet pump anyway so this wouldnt really apply...

[Jordi]

There was a 410 at Bridlington on ebay a few times. If it comes on again i might have for parts. Its dismantled already.

So if you need bits may some cheap ones!

[timwilks13]

Ok so I haven't been able to get a compression tester but all the vales are fine so can rule out dropped valve, the knocking sound turned out to be a loose engine mount that only started knocking when the engine was running on two cylinders so I'm hopefull it could just be the head gasket gone that's letting too much water into the cylinders which would explain why its not firing? Not sure how to explain the petrol in the oil yet though.

Jordi that sJ in brid if its the one I'm thinking of (red with exterior roll cage?) The reason it keeps coming on is the Guy ants £300 for it so takes it off when it doesn't get that.

[Jordi]

Thats the one. I may go to £300 for it. Depends if the cage is any good.

The petrol will be the unburnt fuel form the cylinders that aren't firing running into the sump.