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I'm confused... oil

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I am confused about which oil I should be using... 1986 318i M10B18

I went to Page and asked for the right oil for my M10. I assumed they would know what was right. Later on I looked at the receipt, it says they sold me 10w30.

Now if I understand right, 10w30 is a low viscosity oil for low temperature operation, so its not right for the car.

I asked another specialist and they said 20w50 is what I should be using. So I ask my cousin, another mechanic to hook me up with some 20w50. He comes back and says na na what you want is 15w40, and the 20w50 is only really used on motorbikes.

I also consulted the bentley manual and the table in there indicvates 20w50 is what I need

This makes tastic very confused! I have 4 different yet reputable sources telling me different things. Can someone clear this up for me? What oil should I be using??

Cheers

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AS I said in my PM...the 20W50 is the correct oil. However 15W40 will be fine but dont use the 10W30

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Righto. Hopefully Page will give me a refund. I paid $62 for 4 liltres off them, my cousin can get the same amount for $35 :)

Feedback appreciated.

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Hmm what would make the M40 different in terms of oil requirements? Does it run a higher CR?

My findings for the day..

I ended up scoring 5litres of 15w40 for $36.

Page refunded me, but said they have been using 10w30 for years (in the m10b18).

Glenn recommended 20w50 and I am sure that is sound advice and I don't want to offend, but it was interesting to note that the people at central Ford/Mazda (where my cousin works and got me the deal on oil) said they don't use 20w50 in cars, and that it is more suited to motorbikes and other higger compression applications?

Cheers all.

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there sure is alot to choose from when it comes to oil these days

it sorta also depends on how many k's you engines done and if it burns any oil. if your k's are high and it burns a bit of oil then your spose to use a thicker oil (25w60 or 20w50)

20w50 mineral would be the best choice due to the cars age i rekon. 15w40 mineral would be fine also. 10w30 does seem a little thin but ive heard of ppl using 5w40 and even 0w40 in older cars with good results

my 2cents.

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when it comes to m10s, oil is oil..im sure they can't die!

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I've run mine on mine on both 15w40 and 20w50, pressure gets a little low with the extra heat so I switched to a 20w50, but as gus said for an old M10 oil is oil, any name brand should do the job fine.

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Glenn recommended 20w50 and I am sure that is sound advice and I don't want to offend, but it was interesting to note that the people at central Ford/Mazda (where my cousin works and got me the deal on oil) said they don't use 20w50 in cars, and that it is more suited to motorbikes and other higger compression applications?

And they probably dont work on 1986 vehicles anymore either, not many franchaises do

Your original PM to me was "they sold me 10W30" I gave you the correct answer "20W50"

If you had asked me what else I could use I would have said 15W40 because that is what we use on the older cars

Its got nothing to do with compression ratio. Most modern engines run higher CR and thinner oils. Its all to do with clearances, loadings and flow rates of the oil in the engines. And climates too, recommendations also vary with climatic conditions.

Edited by botanymotorworx

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What about the correct oil for a M40B18?

Would it just be the same, 20W50?

Use a well branded 15W40

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Ok,

what would i be need to use or better worded to start off with?

new engine,cam ground pistons,bored block,new bearings,rather tight wrist pins etc.?

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Ok,

what would i be need to use or better worded to start off with?

new engine,cam ground pistons,bored block,new bearings,rather tight wrist pins etc.?

I would take a recommendation from your engine rebuilder, either SG or SH rated oil 20W50 for 1,000km then switch to a 15W40, to allow the rings and other components to bed in. This was recommended by Engine Rebuilders Ltd

Edit: I hope you put molly grease on your cam lobes. Run engine at about 1,500RPM for at least 15 minutes. Dont let it idle. Then let it cool down (cold) and readjust your valve clearances. Am I right in assuming this is an M30 engine ??

Edited by botanymotorworx

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20 50 would be to thick imho,esp in winter.I would rather burn a bit of oil and get protection at start up..20 50 is reserved for my motor mower!.The stuff that Page sold you Max was that castrol magnatec??I am pretty sure thats what they use in my car.

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20 50 would be to thick imho,esp in winter.I would rather burn a bit of oil and get protection at start up..20 50 is reserved for my motor mower!.The stuff that Page sold you Max was that castrol magnatec??I am pretty sure thats what they use in my car.

Thinner oil on a fresh engine allows too much oil in the ring lands and prevents the rings from bedding in. Thinner oil after bedding in is fine though

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Valvoline put out a very good running in oil..not sure of the viscosity though

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Edit: I hope you put molly grease on your cam lobes. Run engine at about 1,500RPM for at least 15 minutes. Dont let it idle.

why not let it idle? So that oil pressure stays very high??

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why not let it idle? So that oil pressure stays very high??

Yes and to keep the camshaft velocity up on initial start up

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why not let it idle? So that oil pressure stays very high??

So the cam lobes get plenty of oil during the critical bedding in process.

For BMW Weapon, I'd have thought once it's up and running you'd want something which can maintain oil pressure under duress (it'll be turbo, right?).

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i read an interesting article on this the other day....apparently pressure on the cam lobes is most at idle (slowest rpm, so makes sense the rockers have more time to pressure the lobes). keeping it at a decent rpm means the cam has time to wear in

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i read an interesting article on this the other day....apparently pressure on the cam lobes is most at idle (slowest rpm, so makes sense the rockers have more time to pressure the lobes). keeping it at a decent rpm means the cam has time to wear in

Thats correct...all new cams come with a run in stage warning about this

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What are brands to steer clear of?

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