What oil to use?

[spoonza6]

Hi guys,
my starlet is finally ready to be started up after the engine has had a fresh rebuild using forged components etc. What sort of oil should i use when running the engine in?

Thanks

[Bazda]

Pennzoil have a special run in oil.

[sergei]

If you can't find special run-in oil (I believe it is only meant to be used in first 500kms or so), just use any non-synthetic 10w40(30) or 15w40.

Make sure you load the engine (but not thrash it, and not at idle) on the first run.

[.:O4AGTZ:.]

As above, first start up should be quite a high idle.

[spoonza6]

ok sweet, i got my mate whose a diesel mechanic who will be with me for running it in so he knows all the do's and don'ts. Will look for the oil tomorrow. Thanks for the info.

[Dell'Orto]

Penrite do a 15w40 running in oil too

[loose_unit]

Yeh I used the Penrite stuff to run mine in

[spoonza6]

where would be the best place to buy the oil

[Dell'Orto]

Repco should carry it, not sure if Supercheap still do?

[loose_unit]

Nar we dont carry the running in stuff on shelf anymore, dont think it sold well when we did carry it.

[Dell'Orto]

Yeah pretty sure I'm the only one who's bought it

[Py7h0n]

Whatever cheap and nasty you like.

I normally dump cheap nasty at 200km and run more again till 500 then dump it again and then switch to something a bit better till 1000 then move to my normal synthetic.

If turbo just becareful as the cheap nasty stuff does not like turbo core heat at all.

[Heylin]

I found this article quite helpful it applies to motorbike engines, but pretty sure ive seen this method reccomended for cars as well.

http://www.mototuneusa.com/break_in_secrets.htm

Basically the run in process doesnt take nearly as long as the old school thought of babying the motor for 1000 kms.

Seat the rings then drive it hard as the rings need to be forced into the freshly honed walls in order to seal effectively.

[Py7h0n]

Yes but you need to be careful too - Rings take no time to bed in - Bearings however do take a little while.

[Vertigo]

interesting. id really like to know which is the best way before i drop in my first engine build. think ill do some investigating.

[allencr]

Engine bearings do not break in, there is rod & main clearance & they do not touch as long as there is oil pressure, and would never touch or barely show any wear marks at all if the engine hadn't been started dry & cold, ingested dirt, or been detonating or being lugged.
Rings & cyls., valve stems & guides, cam lobes & followers do rub against each other without the benefit of pressurized lube.

[Dell'Orto]

Yes but you need to be careful too - Rings take no time to bed in - Bearings however do take a little while.

Interesting, I've always thought the opposite, as advised by my engine reconditioning customers. The bores have peaks and troughs that the ring needs to bed to, the bearings have a smooth surface.

[Py7h0n]

Bores have peaks and troughs that the rings bed into. This process takes very little time (less than 20km normally) and requires accelleration and decelleration to create pressure on the rings to force them into place. All of my 2JZ's which I have built have had boost (no more than 5psi) within the first 10km to assist this and all of them have had fantastic compression / ring seal.

Bearings on the other side are put into place by hand and do not move as you say. Big end bearings on the other hand do get very great forces applied to them at the top and bottom of the piston stoke. These forces on a new engine are a lot greater as the bearing clearances are at their tightest (least oil flow). When you start an engine the oil pressure is not up and you get contact on the bearings which is what causes older bearings to have shiny spots (wear). This increases the clearance and in my opinion is how a bearing beds in.

Everyone has an opinion and a way of running cars in. I would recommend motoman's side for the rings but also run the engine for about 500km before hard tuning or road racing to ensure that everything else has had it's time to completely bed in.

[Dell'Orto]

When you start an engine the oil pressure is not up and you get contact on the bearings which is what causes older bearings to have shiny spots (wear). This increases the clearance and in my opinion is how a bearing beds in.

When you start a rebuilt engine for the first time you should always prime the oil system first anyway, I use a pressure primer and feed it in at 30psi. Subsequent starts ought to build oil pressure quickly, and by that stage the bearing will have residual oil cover.

[allencr]

What sort of oil should i use when running the engine in?

I's almost difficult to get the wrong oil.
Don't get anything that says gear, hypoid, GL-?
Don't get anything that says synthetic
Don't get anything that has a number over 20
I'd stay away from any multi-viscosity
Some still like Non-Detergent
Good luck