13 replies to this topic

[AlexMozza]

I have finally got my mini on the road, after 3 years and there are the usual few issues,

Firstly, Timing, with a Timing light, it looks like the timing is out judging from the marks on the crank pulley, can this be corrected by rotating the dizzy unit? I think I saw my Dad do it to correct it before, if so how is it done?

Secondly when going from partail throttle to off throttle the engine seems to build up revs, before the revs decline as they should, this also happens when stopping, the revs will rise to around 2k, and hold at above 1.5k. I was thinking this could be due to a sticky butterfly, but im not so sure?

Final issues is I feel quite serious.
When I am driving normal speeds, well at any speed i get no warning lights, however after I have been driving for a while and the engine is nice and hot, around 30 mins, if i stop and the engine is on tick over, I get an orange light between the dials, Am i correct in assuming this is oil pressure.
I have checked the oil level, plenty there and checked the rockers, oil is getting to the top of the head so no massive blocks.
When i build up the revs, the light goes out, but returns when at tick over. This only happens when the engine is hot though. I was thinking could this be more of a pressure sensor issues than actual loss of pressure?

Its a 1984 998.
Thanks,

[BennerW]

Definitely sounds like the Oil pressure light. I'm not sure at what Oil Pressure the Oil light comes on but when the Oil is getting hot its easier to squeeze through the holes which create the pressure. As the engine revs increase the oil pump rotates faster moving more oil and therefore pressure builds again. Get an Oil pressure gauge hooked up and that will tell you if you've got safe oil pressure and the sensor is dodgy or you have very little pressure which may cause a problem.

Did you get a new Oil Pump when you rebuilt the engine?

[AlexMozza]

Ok, I have an oil pressure guage, how do you wire one in, do you just connect it to the wire coming from the sensor from the block.
The oil pump was left as far as I know, its been a long time!

I was thinking of just getting a new one to be safe, where is the pump located on the block?

[BritishRacingGreen]

when you say running in, is this a rebuilt engine? if so you definitely shouldn't be getting oil pressure issues, it's only going to get worse, and although a new oil pump and checking the engine breathers are clear may help it is very unlikely to be them. Normally low oil pressure is caused but the gaps between the crank journals and the crank bearings is too large. Not something you'd expect on a rebuilt engine..

[BennerW]

The Pump is underneath the Flywheel housing towards the back of the block.

The Sensor is next to the distributor on the front of the engine. Not sure what type of gauge you have but you can just swap out the and replace with the one from the gauge if its mechanical. Light will be on though so not a permanent job.

Edited by BennerW, 05 November 2012 - 05:30 PM.

[AlexMozza]

The engine was a partial rebuild, just head work looking at receipts etc
How much of a job is it to get to the pump as I can pick one up tomorrow morning.


So say gaps between the crank journals and bearings, What would need to be replaced, or is that essentially changing the big end shells?
Just had the car running now, I let the car get ward, upon idling there is no light.

[AlexMozza]

Oh and the engine has done around 90k. Surely oil issues would not happen until above the 100k, its been regularly serviced etc.

[BennerW]

Not an easy Job. Much easier when the engine is out of the car.

Depends How well it was built in the first place and how hard its lifes been.

[tiger99]

It is just about possible to change the pump with the engine in the car, but it is necessary to drain the oil, jack under the transmission, and remove the offside engine mount, clutch cover, flywheel and clutch assembly, and transfer case. There is then the problem of ensuring that the idler gear end float is correct on reassembly. It may be ok, if the new transfer case gasket is of the same material as the old one, and torqued up correctly, but it is preferable to split the engine and box, and do a partial assembly of idler gear and case to the box so that a feeler gauge can be used to check the end float. Realistically, that means engine and gearbox out, not to difficult, but it takes time and does need lifting equipment.

But get the oil pressure gauge connected first, to see what is really going on. Faulty oil pressure switches are common, and I had one fail, with the light on, with less than 10k miles on a new Mini. The best type are mechanical, and have a flexible tube which goes into the same place as the pressure switch, with a T piece.

[AlexMozza]

Ok, well I have ordered a new pump and gasket, but ill get a gauge wired up tomorrow.
Well, the wort that happens is I break something!

[AlexMozza]

Just though something else.... Big ends, I know on other cars such as Stralets and Celicas when they start to go, not in an about to fail way, but just life span, the oil pressure can drop.
Well I think if the pressure gauge shows that there is a loss of pressure then Ill do the Big ends too anyway.

[AlexMozza]

I did a Compression Test today just to check and I got good results on all four cylinders, Im also going to get a gauge plumbed in to get a real results,
but part of me thing that even if the gauge shows it is OK that I will take the engine out and check everything, new oil pump and big ends etc

[jaydee]

I have finally got my mini on the road, after 3 years and there are the usual few issues,

Thats the joy of rebuild a mini

Firstly, Timing, with a Timing light, it looks like the timing is out judging from the marks on the crank pulley, can this be corrected by rotating the dizzy unit? I think I saw my Dad do it to correct it before, if so how is it done?

Yes, you have to rotate the dizzy clockwise for more advance, anticlockwise to subtract advance.
Best way to do with a timing gun, is to have the marks on the timing covr pulley extended to 30°.
You'll see there are just a few marks, like 0°(+/- TDC, theyre not that accurate) 4°, 8° etc, mark your own 15° and 30°.
Now you can set maximum mech advace:
Raise idle speed to 3500/4000 rpm and disconnect vacuum pipe, now checking advance with the timing gun turn the dizzy until you get 30°.
Beware some dizzies cant reach 30°. If thats the case, dont bother with the timing gun, you're just wasting your time.
Once max timing has been set, drop idle back to 1500 rpm and see that you have 12°-16° advance, if more, you'll probably have problems with pinking so you must retard the advance back some degrees.
Adjust mixture to 3.5% CO if you have a gas tester.
Reconnect vacuum pipe and set idle speed to 900 rpm.
Now if you dont have a gas tester adjust mixture by ear..use the piston lift trick..
Test drive the car under load, take a slight uphill road and accelerate hard from 2k rpm in 2nd gear, if you can hear any pinking noise between 2000/3000 rpm, then you must retard the timing 2 deg back (turning anticlockwise) and retest.

Theres a shortcut to do it, advancing by ear and using the timing gun only to read the advance curve through the rev range, and not to set the timing.

Secondly when going from partail throttle to off throttle the engine seems to build up revs, before the revs decline as they should, this also happens when stopping, the revs will rise to around 2k, and hold at above 1.5k. I was thinking this could be due to a sticky butterfly, but im not so sure?

Sounds more like a timing/mixture problem or an air leak. Butterflies tend to stick wide open.. Remember, never ever put grease the accelerator cable!!

Final issues is I feel quite serious.
When I am driving normal speeds, well at any speed i get no warning lights, however after I have been driving for a while and the engine is nice and hot, around 30 mins, if i stop and the engine is on tick over, I get an orange light between the dials, Am i correct in assuming this is oil pressure.
I have checked the oil level, plenty there and checked the rockers, oil is getting to the top of the head so no massive blocks.
When i build up the revs, the light goes out, but returns when at tick over. This only happens when the engine is hot though. I was thinking could this be more of a pressure sensor issues than actual loss of pressure?

Its a 1984 998.
Thanks,

Lots of advice above about this, cant add anymore.

[Ethel]

Before you go ripping the pump out have a look at the oil pressure relief valve. A gauge will help a lot, the original sensor operates at 7-10psi, though there is an alternative one at about 20psi. If you are seeing less than 10lbs a full engine strip down is needed really.