clutch slipping

[cadetchris]

just done a nice trip to lincoln and back, i noticed that at times when i wanted to accelerate hard (i.e, over take a lorry) the revs of the engine increased as did the noise, but the speed only slowly increased. i was thinking this might be due to the clutch plate slipping.

any ideas?

[katy]

If you still have that oil leak at the rear of the engine, you probably have oil on the clutch, causing it to slip. If the oil leak has been fixed the slipping clutch should clear itself - eventually.

[cadetchris]

well i had fixed the oil leak, but its reapperard from a different location. i am starting to think that bmcecosse was right and i have somehow pressured my crankcase and the venting method isnt quite right.
ill whip off the tube from the rocker to the filter and see if that cures it. IF it dosent, i am at a total loss as to where its leaking

[bmcecosse]

Tube from rocker needs to go directly to the carb intake - little tube on the side. On the filter is hopeless. If there is oil now dripping from the little split-pin hole in the base of the gearbox bellhousing - then yes - that's oil on the clutch, coming from the rear crankshaft scroll.

[Alec]

Hello Chris,

while it might be oil, it is worth checking that there is free play in the release mechanism?

Alec

[MarkyB]

Seconded, oil from the crank goes onto the other side of the flywheel from the clutch and get spun off into the bell housing.

[bmcecosse]

But it soon spreads into the clutch plate too. But Alec is right of course - it may simply need adjusting - here's hoping! I'm a terrible pessimist........

[cadetchris]

i have been meaning to just back off the clutch mechanism a bit, as i had the whole lot out when the engine and gearbox came out, so i might of over adjusted it so its partially engaged all the time.

as for the rocker cover to carb pipe, my carb dosent have the little brass pipe on one side, would be nice to have one, but its absent. ill run it for a day or two without the pipe on the top and see if that does anything

[bmcecosse]

NO - don't do that! That will be worse! Get a later type carb .......... asap.

[cadetchris]

not quite understanding this whole carb business. the car was designed with one type of carb, and the engine breathing worked fine. with this new carb (bearing in mind how much a new carb is), i cannot see it making any difference except drawing any fumes back into the engine.

i cannot afford a new carb all for the sake of creating abit of suction in the engine case, i wont buy an old one as i have learnt that these are always more hassle to faff around with and rebuild,

so, back to the initial question, without spending over £100 for a new carb and without taking the engine out for the 5th time this year, how can i stop the oil leak?

[Alec]

Hello Chris,

does your engine have a side breather also, if so make sure it is clear\clean?
Personally I see no reason why the air filter breather is not OK. So many cars (with S.U. carburettors) do it that way.
I would check that the rocker cover is not caked with old oily crud inside where the pipe stub enters. (there is a little plate over the hole so it can get blocked)
Make sure the oil level is not over high (Don't check just after switching off the engine, give it plenty of time to drain.)

Alec

[MarkyB]

so, back to the initial question, without spending over £100 for a new carb and without taking the engine out for the 5th time this year, how can i stop the oil leak?

Take the inlet manifold off, drill and tap it as for a servo take-off but only have a 1/8 hole so there isn't too much suction.
Connect the breather to that instead.
Alternatively, drive the car more gently.

[cadetchris]

now i didnt think of the manifold idea, that would certainly solve a few problems. ill do it tomorrow morning

[linearaudio]

Are you sure it's not breathing since your rebuild? You say its not producing fumes- have you checked by taking the oil filler off, or just basing your judgement on the exhaust pipe?

[cadetchris]

well i have taken off the filler cap and their is no smoke, fumes etc evident coming from the engine, it dosent even smell either.
strangely the same was happening before my rebuild, so i am honestly at a total loss to what is causing the leak.

my new oil pressure guage (which i have now become obsessed with) starts off at 60psi when cold and when warmed up it stays around 40psi when doing the speed of many gazelle. HOWEVER, this does drop to around 20 and then down to 5, even though i have a full sump, so i am very confused to what my oil pressure is doing and what the gauge is upto as well.

i do have a nice shinny spin on oil filter, which dosent leak, but this shouldnt cause the the oil to pour out the back of the engine.

so, i am lost and confused about this leak.

[linearaudio]

5 PSI!!!!!!
Thats horribly, horribly low!

[cadetchris]

i know that, but it still maintains oil (ish) in the sump and its a new oil pump, as well as cylinder rings and bearings. so unless the engine is totally US, then i am at a loss

[linearaudio]

At a long guess, I would say your rear main bearing journal is worn, causing a serious loss of oil pressure, and slinging a lot of oil around so some that of it is getting past the rear scroll "seal" and onto the clutch.
Gloomy prognostication, but it would answer both problems

[bmcecosse]

The 1/8" suction hole on the manifold works well - I 'cured' a rather heavy breathing 1340 Mini engine that way! No more leaks - no more nasty smells - and much less blue smoke after 'over-run'. Your 5 psi - is surely not when the engine is running at speed ? Even that 40 psi is horribly low. If it is 5psi when running at say 50 mph - it's truly knackered - and as LA points out - the rear bearing will be flooding the scroll with oil which it can't possibly contain

[cadetchris]

i thought that the oil pressure was erratic to say the least. i have had some faith in the engine until i put a oil pressure guage in and thats kind of preoccupied me. i am inclined to think its the gauge than the engine its self