87 replies to this topic

[jamie_t]

I wouldn’t put it in my engine.
I can’t really afford ‘good’ oil. I use Halfords 15w/40 Enhanced Mineral Oil. Only £16 for 5L

[Sprocket]

i was stating what i had been told and read in various articles and by various engine builders. Im pretty sure the article i was thinking of was written by Keith Calver and it went in to oil additives etc. For a fresh engine build things require wear to bed in so when the oil is full of additives things like cams bearings and rings dont settle and glaze over and for cams if they dont work harden then they go flat in no time.

Just a couple of things I find difficult to understand here

Firstly cam bearings or mains/ big end bearings for that matter do not 'wear' in, they 'bed' in. Big difference. Oil should seperate the cam bearing journal from the babbit, the journals sort of float on a layer of oil, that is the point of lubrication, to prevent metal to metal contact, and as such, prevent wear. Same goes for the big ends and main bearings. If the journal is in contact with the babbit to cause wear, there is something fundamentaly wrong; excluding starting, where short periods of metal to metal contact may occur; that is not exactly breaking the engine in is it.

Secondly, the cam and cam follower (tappet) are already case hardened. Work hardning is a process of 'working' the material at low temperatures to its plastic region which means, that once it has deforemed to a point, it does not return to its original shape. This would be undesirable in a mechanical part such as a cam and follower and highly unlikely under the pressures that cam is exposed to. These parts do wear on initial engine start up. The high idle breakin does two things. It knocks off the high edges of the cam and followers(desirabale) and it then builds up the thin protective layer of the ZDDP. If there is not a high concentration of ZDDP in the engine oil, this protective ZDDP layer is not thick enough to protect the cam or the follower and wear continues at a slower rate (undesirable). This is pretty much why performance cams are wearing out much sooner with the modern oils that lack ZDDP. Standard applications are also suffering. When you next change your oil, look at the tree of metal filings that is stuck to the sump plug magnet. Where do you think that metal has come from? Its from your cam, cam followers, the rings and the bore. Its also from the gearbox, which is where the high ZDDP also protects.

Propper running in oil has no friction modifiers and little detergents to help the rings bed in, but is loaded with ZDDP to protect the cam and followers in the first crittical hours of engine break in.

Edited by Sprocket, 21 December 2009 - 07:26 PM.

[GreaseMonkey]

Slightly off topic

But what is the best oil to run an engine in with?

[Dan]

Err,

Propper running in oil has no friction modifiers and little detergents to help the rings bed in, but is loaded with ZDDP to protect the cam and followers in the first crittical hours of engine break in.

Proper running in oil (usually labelled running in oil), or a basic oil with few advanced detergent additives.

[In-a-mini]

i set bed in??? yes i said wear too but was talking about cams in the same sentence you can rip anything i say apart but my opinion will stay the same. supermarket oils are basic oils which are good enough for standard mini engines that are regularly serviced if you have a race engine then use an oil that is more advanced. as i say the price of the oil is not really related to if its best for your mini. i tried giving my advice and opinion from a guy in the car trade but everyone else has there opinion and is willing to push it at all cost.

Edited by In-a-mini, 21 December 2009 - 07:56 PM.

[GreaseMonkey]

Proper running in oil (usually labelled running in oil)

Sorry Dan

Was looking for a reccomended one, have seen the Penrite running in oil

Never mind

Edited by GreaseMonkey, 21 December 2009 - 08:26 PM.

[bmcecosse]

I've used the ASDA and Morrisons 20W50 oil for years - it's fine! Just don't expect it to last for ever - but it has never caused my engines any problems - including a fancy 1340. I wouldn't use it in a modern engine where 0W40 is specified - but only because it's not 0W40 - it's 20W50, and it's fine for an A series!

[Surfbluegarage]

i have 2 friends who jusy run asda or wilkos 20w50 in there mini and scamp... 2 reasons for this... A. its cheap and B. both the mini and scamp do an oil change on themsleves pis out on the floor) so it wld cost a fortune to run decent oil until they fix the leaks. theyve never had any problems and as far as i know both engines are doing well... just my 2 cents worth.. not sure if id use it in my 1380 S though...

Edited by mini_mad_daps, 21 December 2009 - 09:15 PM.

[Sprocket]

I'll continue with my snobbery

[mini13]

I wonder how many people running cheap oils measure their cam profiles during a rebuild.

[bmcecosse]

The ones I have looked at are all fine - no change in valve gaps - and the followers have always been fine too!

[Dan]

Was looking for a reccomended one, have seen the Penrite running in oil

Yes Penrite is a good running in oil but it's expensive, or it was last time I bought any. And it smells odd. Unipart Green has always been considered a good running in oil, although that's not what it's intended for.

[mini13]

well neither of those show up lobe wear do they....

The ones I have looked at are all fine - no change in valve gaps - and the followers have always been fine too!

[Darkscamp]

I ran Shell Helix Mineral or Texaco Havoline Mineral 15w40 oil in the scamp.

On the last engine rebulid i found minimal wear and the cam lobes were fine when compared to a brand new cam.

I'm currently running Motorfactors special price Comma Mineral Oil until i can stop the oil from *peeing* out the gear selector seal.

[1984mini25]

To bring this old topic back, have asda stopped selling their 20/50 oil? Or is it a cunning ploy for me to go find out they don’t have it and then have to buy fuel anyways.

And before anyone starts I need to do two oil changes. One on the standard, 64k 998 in the 25 (probably has all of 35bhp on a good day) witch should have had time for the new crank bearings and gearbox to settle in after the gearbox broke up and trashed the pump. So not really related to what oil was being used, as I’d only done less than 30 miles on the asda stuff, just bad luck and timing.

And the second is to dump in the freshly re-build engine, just so it can be run and set up, bedded in and then swapped for some slight more expensive stuff.

Just don’t fancy having to pay £40 odd qwid only for the halfords stuff (only one local that I can get asap) oils to be drained back in only a few hundred miles.