hey guys,
ever since i rebuilt my motor (1098cc, had it acid cleaned, re-bored the block, grinded the crank, replaced cam bearings, new gudgeon bushes and pins, new pistons and rings to fit new bore size, new main brgs, new big end brgs, new cam brgs, new thrust washers, timings chain, all new gaskets, and new clutch) iv been burning oil.. i guess thats the only way i could be loosing it coz i have no leaks.. i ran it in for around 700miles doing no more than 80kmph on long runs, used all the gears when accelerating so i didnt rev the engine hard but and didnt change to early either.. bassically iv tryed to make the run in as smooth as possible and still havent given it a real thrashing and its now done just over 1700kms now and its still using oil.. Is this normal? do all minis always use oil? or will it eventually stop burning oil.. i havent managed to see any smoke blowing out the exhaust.. the oil i used to run it in on was a organic shell 20w-50 dumped the oil afta 500 miles as advised by the blokes at minicentral over here in wa and am going to dump it every 5000.. anyone have any answers?
cheers Gus

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Drive it like you nicked it.

by the way the engine runs beautifully but gets a bit hot (up to 3/4s on the temp guage) on long trips eg: 2hrs 30 mins down to our farm.. i always slow down to let it cool down tho to look after it... i dont like the idea of running the motor that hot for ong periods.. maybe a bigger radiator is needed..

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Drive it like you nicked it.

What oil are you useing, synthetic or mineral?

Blue

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Keep shiny side up

still using mineral shell 20w-50 which was what i was advised... i researched the synthetic stuff and found that to be bad for the type of engines that minis have.. coz the lube properties r to good and the oil is also to thin.. something about the piston rings wouldnt bed themselves in properly if i used synthetic to run it in on

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Drive it like you nicked it.

synthetics are cool to lube the motor what it dont like is synthetics in the box chews out baulk rings
makka

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shouldnt run hot, check for blown head gasket maybe,
check your valve stem seals, thats the most common way minis burn oil,
on my fresh rebuilt motor it did use oil, but not very much

oh ok cheers for that info makka... can you explain y im still loosing oil.. do u think the oil will stop dissappearing the more the motor gets run in or will the motor always use oil? because i was gentle with the run in so i assumed that it wouldnt use oil afta itd been run in..

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Drive it like you nicked it.

head gasket is fine.. it maybe the stem seals.. i didnt have the head reconditioned.. maybe thats my problem.. how do they effect the oil consumption.. ino what they are just need explaining about how they cause oil loss when they r worn..

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Drive it like you nicked it.

maybe you ran it in too gentle, not allowing the rings to bed in properly, just shooting in the dark here.

in terms of oil consumption they stop oil from running down into the combustion chamber

if you had all the other stuff reconditioned, getting the head done too would be a good idea

its easy to tell if the engine is burning oil, cos the exhaust will smell oily and be a little bit more smokey

You seem to have done all the right things. Areas I would look at in order are:

Under bonnet
Has it got a coating of oily film under the bonnet or on the engine? could be losing oil in a fine mist and not see any drops persay.

then Engine:

Colour of plugs to see which is sooting up (could be one cylinder)
Compression test to see if the rings were gapped and installed properly
Run the breather into a tin can filled with S/S scouring pads and see if you have oil being circulated this way.

Seems like the head was off... did you reco it?
Could be sucking oil down the valve guides, I'd make sure the stem seals are new and the guides are not to warn. Normally you'd get smoke out the tail pipe under heavy accel and off the mark.

Could be a poorly installed head gasket..failure to retension the head after run in
Were the surfaces perfectly clean should use prepsol to clean them
Was the gasket new and untouched - oily fingerprints can blow the gasket
The head stud thread holes should be counter sunk/bored upto 3mm / 120thou this reduces localised swelling and blowing the head gasket.

Pull it apart again and look to the signs of oil passing or fouling areas.

Havent solved your problem you? take it to a engine reconditioning factory. these guys dont fix cars they build engines and will know their stuff.

gus is the exhaust pipe sooty ???? black ...... if so that means one of two things rich mixture or oil getting into the combustion chambers
makka

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Worn valve giudes & valve stem seals when worn will cause the exhaust to blow
blue smoke on the overrun (when you back off)
This is because the oil is sucked into the combustion chamber on the inlet stroke
Valve stem seals are normally only fitted to the inlet valves, but can be fitted
to both
Usually the exhaust guide gets pretty hot & makes the seal go hard after a while
Try & fit the seals with a little contraction ring on them, I've found these the best

Are the spark plugs oily?

Blue

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Keep shiny side up

makka the exhaust is a bit sooty to be honest but i think thats due to rich mixture the carby needs a service i'm sure.. im averaging about or just under 200kms to a tank around the city.. i havent re-tourque wrenched the head since i put the motor back in yet.. i think i should check that.. i rekon you migh be on the money with the valve stem seals because like i said i didnt recon the head just cleaned it up all nice and got rid of the carbon build up from when the motor kiked the bucket originally... i cleaned all surfaces with petrol before putin the motor back together the bloke gaped the ring right for me so ino its not that... yeah i rekon it may be the valve stem seals cos it doesnt blow smoke out the pipe and if it odes its very little coz ive had friends following me and not rported any smoke to me... im sure i didnt run it in to gentle i was aware of that as i was running it in so im sure i did it right.. thanks again for all your help guys maybe i just need to take it to minicentral and get them to have a look at the valve stem seals... i need to adjust my tappets also, this wouldnt have nething to do with it? i dont c how..

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Drive it like you nicked it.

how much is it useing .... just out of curiosity ???
makka

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