Hi,

What is good quality oil for an A series motor?

I think I have just had a bad expierence with 5W-30 synthetic oil. Motor is being checked after premature wear on number 4 big-end and number 3 main bearings. The machine shop suggested that the thin oil was escaping from other bearing before getting to these bearings.

Could be some other reason but I thought I'd see what others have been using.

Most oils seem to be designed for the multivalve jap motors. Where does this leave us Mini owners?


Cheers,

Dave

Here you go: http://www.ausmini.com/forums/viewtopic.php?t=10257&highlight=oils

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Roads need more corners
A Deluxe(CG13DE), 2 Clubbies(998 and 1275) and 2 Morris 1100Ss

Read through the Thread That Fuzzy has mentioned...DON"T USE SYNTHETIC"S

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Stop Licking the Dog...I Don't Care Who Started It

yikes, that oil is way too thin.. and synthetics are not recommended!
use penrite Hpr-30 or
50weight or 60weight oil

Minis only have 3 main bearings, and the middle one feeds both #2 and #3 big ends- so yes like yours probably, you can have it too thin. In our climate, anyway.

You can't really go wrong with a good 20W/50. Any name brand will do. I've had good results with Valvoline SF 20W/50, and it's cheap at $10 for 4L.

As said (if you want to spend more...) Penrite HPR30 is good, also Castrol Formula R 25W/50 (Watch it- there are 4 Castrol Rs, and the other 3 are synthetics).

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

You can't really make the mistake with the other 3 Formula R's. I mean, the right one for Mini's is $30, the others are lik $60+!!!

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i have some Castrol Formula R ready to go in JAM

IIRC 5w-30 is ok according to the workshop manual, but thats most likely for very cold climates. I'm using 15w-50 synthetic redline oil at the moment and its going fine so far but its VERY expensive so I'm not sure if I'll use it again - I just wanted to satisfy my curiousity about whether it would be ok. Next I might try some cheaper synthetics (maybe caltex havoline 10w-50 - support ambrose & ingall's sponsor )

Geoff

Yep Im using Castrol Formula R 25W/50 as DrMini suggested in Granny ..

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Opinions expressed by me are of my opinion only and are copyrighted to Kinkabell Corporation? 2006.

Hi,

More news from the original poster...

Reading about synthetic oils on the web has highlighted a couple of issues.

First it appears synthetic oils may have a tendency to "clean" the oil galleries and perhaps dislodge carbon build-up. Not sure if this happened in my case but there were some score marks on the bearings.

Also I read that if the oil is too thin it doesn't provide a sufficient "buffer" to prevent metal on metal contact. I guess in a Mini motor the bearing tolerances are a bit more than on modern cars allowing the thin oil to escape before it can build up this layer.

The crank isn't cross-drilled and regularly spins at 6000+ rpm so maybe the lighter oil has more of a tendency to centrifuge away from the mains.

What also seems to have contributed to my problems was a un-balanced flywheel which would have put a bit of extra stress on the number 3 main.

The strange thing is that the car only gets used at motorkhanas (and driving to and from) and as such has only done about 1000kms since the last rebuild. The motor is a 1380 running 10.5:1 CR and a MG Metro cam, so it's not that hot.

I would be interested in hearing if anyone else has had an actual engine failure possibly contributed to by using too light an oil.


Cheers,

Dave

i can't imagine oil doing that alone, not when the motor has done 1000kms

Hi All,

Thanks for contributing to this thread.

Well hopefully it was the oils fault, because the motor's just come back from the machinists and they could find anything that would cause the failure. I guess I'll find out after the next few Motorkhanas.

BTW is was Castrol R 10W 40 that I used. I thought that the thin oil would flow better and put less strain on the oil pump and hence more power to the wheels....WRONG.

I'll be using 25W-50 from now on !!!

I did read up about synth oil and Mini gearboxes and apparently there isn''t much of an issue there.


cheers,

Dave

Yesterday I came across a Castrol GTX "For older engines", it was a 25W-60. Has anybody had any experience using this?

Am I right in assuming that the "60" would mean better protection for the gearbox, especially with summer coming up?

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One should never skimp on the zip ties.

I have been using BP Corse Plus 25W 60.Very happy with oil pressure.
Have recommended this Brand to other Mini owners,and also
happy with results.
Don't know about Castrol brand-but GTX got a bad name for itself
when Mini's were racing at Speedway's......

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I'm a synthetic convert.
A few years ago I was racing the 'S' in an 8 or 10 lap race at Phillip Island on a hot day, towards the end of the race the oil temp guage started to enter the red zone and oil pressure had dropped to under 50psi at 7000rpm (usually sits at 80). On the slow down lap the pressure was very low at normal revs and dropped to zero at idle. Water temp was OK and stayed around 200 F. Oil temp recoved before the next race and no obvious engine damage had occurred. I was using Penrite HPR 30 or 50 with the normal 'S' type oil cooler, straight cut gearbox and lsd. Phillip Island is a high speed track with much of the lap at full throttle and high rpm.
Penrite examined the problem and recommended their 10 tenths 25 Competition engine oil which is rated at 25W-60. It's either fully synthetic or semi-synthetic but costs the same as most fully synthetic oils ($$$$). It's able to withstand extremes in heat better than their other oils, maintaining it's viscosity and therefore oil pressure under these conditions.
I've been using it in 3 competition cars since then and have had no problems with engines, gearbox or diff.
It's probably a bit over the top for road use, but it's cheaper than an engine rebuild.

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Curly
'64 Cooper 'S' (Group Nb spec)
'67 Mini Marcos GT www.mm7056.wordpress.com