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Hi,

Need a bit of advice;

About to attempt the first start of my 850 engine in around 30 years and I'm wondering what oil will be best suited. The head has been removed, cleaned, skimmed and rebuilt with the rest of the block remaining as it was. I've not got any experience in this, so looking for guidances.

Many thanks,

Joel

Use cheap mineral oil 20/50, get oil pressure first then get it going. Run it unto temp checking for leaks etc, then dump the oil and inspect it.

I agree with Smiffy!

If it's just had the head off, there could be all sorts of rust/crap
buildup on the inside of the rest of the engine. This could do with
being flushed out.

Think about the water system as well...

I normally run for a couple of hundred miles with the cheap oil,
then put some better stuff in. I do a "First Service", changing the
oil and re-checking the rockers etc.

I use "Millers Classic Mini Oil" which I get in 25 litre drums...

Ian

I'd actually suggest using a mid-range quality Diesel lube oil, these have superior detergents in them to Lube Oil for Petrol Engines, but I'd only leave it in there for about 100 - 200 km then go over to something really decent.

I would also suggest that you remove the banjo bolt that connects the oil feed pipe from the block to the filter housing.
You can then pour some oil down into the block.
Then, gently rotate the engine "backwards".

This will put oil in the oil pump and prime it, so when you start to crank, you will pull up oil quickly and get oil pressure almost straight-away.
(Don't forget to put the banjo bolt back in.... )

-You will, of course, crank the engine over with the spark plugs removed, to get oil pressure, before you try and start the engine

Ian, I just noticed this in your post;-

ianh1968 wrote:
I use "Millers Classic Mini Oil" which I get in 25 litre drums...

Ian

Sorry for possibly going OT here, however, most oils or more so the additives in them, have a shelf life, I don't know if Millers is one of these, but maybe worth looking in to, unless you're using that drum up in 12 months-ish. This shelf life varies, from what I've seen, from 6 to 12 months, this is why in most car service shedules they list an engine oil change at X miles (or km) or Y months, however the gearboxes and diffs (in conventional cars) don't require such a scheduled change (as well as them not getting contaminated in the same way that engine oil will).

Sorry to hijack this thread, but I'm in process of building a new engine for my MGB. It's an Oselli 1950 full race spec unit and I was thinking it best to run it with Castrol R (or whatever the modern day equivalent is). Would this be a sensible option or would standard 20/50 mineral oil (such as Millars or Halfords Classic) suffice? I'm guessing prob best to run with the cheap oil to begin with and then a full oil and filter change on completion of running in.

Am I right in saying that once an engine is using racing oil it has to keep using it??

I'd use cheap 20/50 and change it regularly.

If you're talking something with mega forces involved, you might want something which provides residual lubrication (MoS2). For what we're talking about, it's just an old standard engine. Cheap 20/50 will provide the lubrication and if you change it regularly, there shouldn't be a buildup of anything nasty. If there are substances which need to be emulsified, this will happen under normal conditions.

The only problems start when people like my mum think that as long as the oil light doesn't come on, it's good to go. That's when you get a huge crap buildup and the oil is so "loaded" that it can't dissolve more crap.

I ran a whole series of Morris Minors and always used "trago" oil. (Cheapest 20/50). Kept an eye on everything and it was faultless. When I had the engines to bits, they were fine.

With more exciting engines, film strength comes in, particularly with the gears, cam followers (more pressure) and big ends. This is where you need to carefully consider your choice.....I choose castor, purely because I'm on top of it and the film strength is second to none. For a more of a fit and forget solution, I'd look at more expensive oils, but unless you are talking synthetics (weasel piss destroys gears) you are looking at basically 20/50 cheap oil with some fancy additive pack in it. These have a range of snake oil in them, but generally, it's a combination of a residual lubricant and some sort of detergent to emulsify any condensate. If you are only doing short runs and the engine doesn't get up to temp, it might be wise to have something to do this.....however, it's a better idea to give it a good blast to clear it.....and change it regularly.

The modern view is that you don't have to change your oil, you can just fit some Castrol Magatex Intelligent Magnetic Molecules Eco Oil and leave it in there forever. People don't even change their tyres anymore.....I doubt most people would know how to drain their oil!!!!

A part of classic car ownership is continual maintenance. Cheap 20/50 is fine as long as you keep on top of it. There is no point having super helical intermolecular chelating magnatex semi synthetic polyols in your fricking 850!!!!!! Just as you wouldn't fuel it on 180 Octane Avgas!!!!

Shed. (Chemist)

If you really feel you need a racing oil, you'd be much better using a mineral based one. Rather than a castor based oil such as Castrol R. Personally I don't think the smell is worth the hassle.

the other thing to consider with castor oil is that it has a whole load of really nasty stuff in it, I got a load on my skin years ago and it did me no good at all

Speaking as someone who runs Castrol R in one of his road cars. I am happy to admit that it is never a sensible decision. "R" takes more looking after than normal oil, and once it's in you are committed. That said, it does protect very well & smells great.

However you MUST use castrol R to build your engine, you can't use normal engine building lube & then fill with castrol R, the mineral based build lube will form sludge in the bottom of your crank case & can cause bug problems.

The reason my Terrapin had seized before I bought it was that someone had mixed mineral & vegetable oil in it!

Running "R" is NOT impossible, but it is certainly NOT SENSIBLE either.

The big benefit of R is in the 'box - for an MGB with separate gearbox oil I wouldn't see the point.

Smiffy, the only which might be better than Castor Oil is a carefully synthesised castor oil, or something which uses similar functional groups on a molecule to achieve the same film strength.

The central problem is that the functional groups which promote the film strength also promote crap formation.

If you're running a serious set of valve springs, a silly camshaft and straight cut gears with a higher point lode, film strength is your friend. Molyslip is horrible shit. For want of better words. It's cheating on a chemical level. It also stinks when it burns.... (Think of the smell of EP80 and Valvoline "stink" oil).

A good way to ensure it runs probably would be to reduce the pressure in the crankcase via an evacusump. When I put shed together, I'm going this route.....encourage water to vaporise and pull it out. I suppose, if you were feeling sporting, you could recycle your oil by chucking a drying agent in it and then pulling it through a filter with a vacuum. If it was a bit runny, you could throw a solvent in it and evaporate it off afterwards. Lots of ways of cracking a nut.....or you could just wear your gearbox/cam out quicker. I've seen lots of pitted S/C gears.

Good anecdote. I had an old Suzuki SJ van. I used to utterly thrash the shit out of it to keep up with everyday traffic. It would scream it's tits off. 970cc ally engine. If I was going at in a mad shagging frenzy of craziness, I could get 70 out of it. That was an utterly mental driving experience on big knobbly mud tyres and loose suspension. It was like a cross between a bubble and a hovercraft. Anyway, I was feeling rich one day and chucked a thing of molyslip in the engine. It instantly sounded more sweet. I was thrashing it along the same bit of road, same weather, pressure temperature, etc and got 80 out of it!!!!!! It is the equivalent of crack cocaine for your engine though.

That reminds me, the carbs were problematic on those and the solution was to take off the air filter, rev the shit out of it and when it was at the orgasmic, about to blow up limit, you'd whack your hand over the carb and it would suck all the filth out of the jets.

I do miss my SJ. It had it's own suite of problems like the mini!

In the shed wrote:Smiffy, the only which might be better than Castor Oil is a carefully synthesised castor oil, or something which uses similar functional groups on a molecule to achieve the same film strength.

Didn't say anything was better, if thats what you mean.

In the shed wrote: The central problem is that the functional groups which promote the film strength also promote crap formation.

If you're running a serious set of valve springs, a silly camshaft and straight cut gears with a higher point lode, film strength is your friend. Molyslip is horrible shit. For want of better words. It's cheating on a chemical level. It also stinks when it burns.... (Think of the smell of EP80 and Valvoline "stink" oil).

A good way to ensure it runs probably would be to reduce the pressure in the crankcase via an evacusump. When I put shed together, I'm going this route.....encourage water to vaporise and pull it out. I suppose, if you were feeling sporting, you could recycle your oil by chucking a drying agent in it and then pulling it through a filter with a vacuum. If it was a bit runny, you could throw a solvent in it and evaporate it off afterwards. Lots of ways of cracking a nut.....or you could just wear your gearbox/cam out quicker. I've seen lots of pitted S/C gears.

Good anecdote. I had an old Suzuki SJ van. I used to utterly thrash the shit out of it to keep up with everyday traffic. It would scream it's tits off. 970cc ally engine. If I was going at in a mad shagging frenzy of craziness, I could get 70 out of it. That was an utterly mental driving experience on big knobbly mud tyres and loose suspension. It was like a cross between a bubble and a hovercraft. Anyway, I was feeling rich one day and chucked a thing of molyslip in the engine. It instantly sounded more sweet. I was thrashing it along the same bit of road, same weather, pressure temperature, etc and got 80 out of it!!!!!! It is the equivalent of crack cocaine for your engine though.

That reminds me, the carbs were problematic on those and the solution was to take off the air filter, rev the shit out of it and when it was at the orgasmic, about to blow up limit, you'd whack your hand over the carb and it would suck all the filth out of the jets.

I do miss my SJ. It had it's own suite of problems like the mini!

The rest is exactly just like I said, not worth the hassle imho.

Thanks for the help. Think I've got an idea what to use and will try the banjo bolt trick as not thought of that! And don't worry, I won't be going over the top with spec as I know this is an 850. Standard 20/50 with constant monitoring, changing and maintenance.

Cheers all.