17 replies to this topic

[minidan]

ok guys i think we have a major problem on our hands now, the 1380 in the Minus is losing a lot of oil every day.

and its not leaking out the bottom of the engine either. I have absolute proof that its pumping out of the breather hose on the rocker cover.
check out the picture attached. That is 2 journeys totaling about 25-26miles. about 13 each way . i passed the rocker breather hose into the passenger footwell and put it into an empty coke bottle this morning. The oil in the bottle is what has come out just today . and it does this every day.
The oil smells heavily of petrol.
the oil on the dipstick is always clean because of the frequent topups. but i havent noticed any 'milk' in the oil.

what the hell is going on??

so far the engine seems to be producing all of the 100bhp it was nearly two months back on the RR, and NO smoke comes out of the exhaust.

im a bit worried about it to be honest.

hopfully someone can shed some light on this.



thanks for reading,.

[Rhys]

Hi ya mate, i have never heard of this but this link may be helpful!

http://www.thumperta...p/t-234892.html

Good luck!

Rhys

[Kerrin]

Is the oil too full on the dipstick. if no sounds like too much compression is leaking into block and pressuring oil out of the breather.

if yes and you say it smells of petrol in oil

Is the fuel pump diaphragm split and leaking petrol into the engine (this is worth trying first)

Is it overfueling?

Possibly float needle is stuck open or float is split and has sunk.

or fuel pressure is too high if using electric fuel pump etc.

[minidan]

Is the oil too full on the dipstick. if no sounds like too much compression is leaking into block and pressuring oil out of the breather.

if yes and you say it smells of petrol in oil

Is the fuel pump diaphragm split and leaking petrol into the engine (this is worth trying first)

Is it overfueling?

Possibly float needle is stuck open or float is split and has sunk.

or fuel pressure is too high if using electric fuel pump etc.

1.the oil is usually low on the dipstick before we top it up
2. it has an electric fuel pump mounted in the boot, but i dont know what the pressure is for the pump.
3. if the float needle was stuck open fuel would pour out of the chamber . (this has happened before) and we fixed that.
4 . i dont know if the float has split but i cant see how this could make 1/4 litre of oil pour out every day.

the engine has done 3000 miles since new, and never had a problem till now. if the incorrect fuel pump waqs being used wouldnt there have been a problem from the start ?

thanks for your help .

Edited by minidan, 06 November 2007 - 07:31 PM.

[ian]

sounds like crankcase pressure, is it blowing out of the dipstick hole too?, how have you got the breathers set up, are they clear?

[minidan]

i dont think its blowing out the dipstick hole. although im not 100% sure of this. i would say no but will check it.

the breather hoses are as follows:

one breather hose coming out of the top of the rocker cover going across left and down to just below the subframe level and one other breather hose on the clutch case and it goes up and over and down to the subframe again. both hoses are nicely laid out, no kinks / not being squashed etc . they can breathe freely.

I just this minute took the car out for a very short drive to check the performance. (as its not my car i don't drive it). its running sweet as a nut and has just as much power as always. this engine has done 3000 since being built.

[mk1leg]

Hi..!..check see if head gasket was put on right way round looks as if oil ways could be blocked and oil does not drain down to g/box quick enough....good luck.........

[minidan]

Hi..!..check see if head gasket was put on right way round looks as if oil ways could be blocked and oil does not drain down to g/box quick enough....good luck.........

yea we will check at some point , but again , ... how could you do nearly 3000 miles before it becomes a problem???

[m1n1]

hmm. mine is similar to yours.

is it coming out as a mist, then condensing into drops and filling the bottle?


i used to have by breathing system linked to the carb, but on overrun the oil mist would be sucked into the inlet manifold and upon pressing the accelerater would have a nice puff of smoke. Now i have gauze breathers on either side of the engine; when its running hot i can see mist coming out of them. more so at the rear of the engine.

[The Matt]

crankcase compression. You've either not got enough 'breathing' on your engine so it's pushing internal pressure up and causing it to leak out.....

Or, there's a ring gone/worn out.....

I'd do a compression/leakdown test to be honest.

[Jammy]

Stig had a very similar problem on the way to the Nurburgring this year. Although at times we were getting great plumes of smoke from the back of the car. Whether this was oil dripping on to a hot exhaust, or oil being burnt through the exhaust we weren't sure.

He had a cracked head. Sounds like this might be the case with yours too. If its only a very slight crack it could let the air/fuel mix into the oilways making it smell of petrol, but not enough oil into the chamber and cylinder to great a smoke cloud big enough to see out the back.

I don't think the oil smelling of petrol has anything to do with your carb or the mech pump diaphragm. For a start if the float was stuck you'd be flooding the cylinder and you've had fuel flowing out the overflow. If the diaphragm was split you'd see lots of little bubbles on the dipstick, and I believe the fuel would seperate from the oil in your bottle.

[minidan]

well thanks for trying to solve to problem guys but we took it to Classic cars of Kent near us (thats where we did the rolling road session) and they did some tests to check for possible headgasket failure.

all the compressions were fine. and he checked the coolant to see if combustion gases were leaking into it. that was fine too. but he still suspected a head gasket problem.
They took the head off today to find a much bigger problem .

it turns out that whoever built the engine bodged the head by skimming too much off and exposing one of the oil ways. and had tried to braze it? dunno exactly what that means but its failed meaning water is very slightly leaking into the block.

bottom line is we need a new cylinder head so a £250 headgasket change is now ££££ ?

cant believe it.

dont spose anyones got a decent head for sale ???

edit* , just found this on ebay ebay
does that look ok? (looks a bit manky to me but what do i know...)

Edited by minidan, 12 November 2007 - 06:17 PM.

[mk1leg]

Hi..!..check see if head gasket was put on right way round looks as if oil ways could be blocked and oil does not drain down to g/box quick enough....good luck.........

yea we will check at some point , but again , ... how could you do nearly 3000 miles before it becomes a problem???

I was pretty close

Edited by mk1leg, 12 November 2007 - 11:38 PM.

[minidan]

found this on ebay ebay
does that look ok? (looks a bit manky to me but what do i know...)

anyone know what a decent cylinder head should look like? does the one in the link look ok to fit?

[Scottym]

found this on ebay ebay
does that look ok? (looks a bit manky to me but what do i know...)

anyone know what a decent cylinder head should look like? does the one in the link look ok to fit?

I do ...... One that doesn't come from EBAY.

Simple as that. You may as well be spending 250 quid on a lump of pig iron, the head could be scrap, have a bad history or even problems like you have here.

I can only reccomend what I have done in the past is, and go and see the guys at ML motorsport in Higham Kent. They will be able to sort you something for your spec.


scott