Oils and running in

[fool73]

Hi
In the next couple of weeks I will be refitting my engine after a rebuild. I would value any tips and advice as to oils and procedure to to use for running in as I've never run an engine in before.

I was intending to use three lots of oil. I have a can of Halfords classic 20/50 which I intended to use for the first several minutes, and then drain and refill. Then after a few hundred miles change it again. Does anyone have any advise as to whether this is the correct way to go, and if so which oil would you use for the second and third fills and where would you get it for the best deal.
Any other non-oil related running in tips and gotchas also gladly welcomed.
Cheers

[marshman]

If the engine has been rebored and has new pistons and rings I would use a proper running in oil for the first 500 miles, then change it for a good quality 20W50.

Basically you don't want too good an oil for the first few hundred miles as you want the rings to bed in to the bores to form a good seal.

I think Millers make one - there are several others as well.

http://www.camskill.co.uk/m1b42s28p69075/Millers_Oil_-_Running_In_Oil_-_5_Litre_-_5L_

Finally don't be too gentle with the new engine - too light a use can be worse than too heavy as the rings don't bed in properly.

Roger

[mjb67]

There was another running in thread quite recently... Let's see if I can find it...

Ah here we are:

http://www.stag.org.uk/forum/showthread.php?22964-Running-in&highlight=running

Interesting stuff. I certainly didn't know that you were supposed to use a variety of throttle openings.

[Ian Durrant]

There was another running in thread quite recently... Let's see if I can find it...

Ah here we are:

http://www.stag.org.uk/forum/showthread.php?22964-Running-in&highlight=running

Interesting stuff. I certainly didn't know that you were supposed to use a variety of throttle openings.

A race engine builder told me once that you shouldn't run it at a constant speed as that glazes the bores before the rings bed in. In fact he said it was good to accelerate then overrun repeatedly as the vacuum caused on overrun tends to pull oil up into the bores and prevents glazing by cooling the surfaces.

[Nambo]

Dont labour it, keep it revving, and give it some stick!
A higher combustion pressure gets behind the piston rings and pushes them against the bores, in the bike world the word is "ride it like you stole it".
I friend of mine, (female), would only use her Bonneville going to rallys, ie mainly A roads and motorways, she wouldn't go above 60, in the end it seized up as she hardened the rings before they wore into shape, then blowby gases heated the pistons till they seized.

[GDPR]

Never run an engine in in my life! Use a reasonable 20/50 and let the engine rev freely and not slog it in high gear with low revs.

Personally go to 4500 for the first 100 miles, 5000 for the next 100, change to a good oil, then occasional trips to the red line thereafter - not blown one up yet, and most people will tell you I very frequently go to 6500 with my TV8....

Every brand new car I've had over the last 30 years had been past 100mph on collection with delivery mileage - all then did over 100k and never knocked or burnt oil before being sold or killed....

[StagnJag]

When Favershams rebuilt my Engine Trevor told me to stay away from motorways and avoid driving at constant speed/revs which corelates with Ians comments above.

I also chanced mine on the rolling road at one of the nationals after around 3500 miles so it was briefly red-lined on that occasion. I didn't tell Trevor that though. (I can say it now, it is out of warranty!). It hasn't done it any harm, it runs sweet as a nut. I did pass comment to Trevor that I used Halfords Classic in it and he wasn't impressed with that saying he wouldn't put that in one of his engines! I think that is what is in there at the moment, but I have a can of VR1 lined up to go in at the next change.

Regards

Dave

[Steve JP]

I think all Trevor's engines run as sweet as a nut, mine does as well, I followed his advice, then after the second oil change did 2000 miles around the Alps and back just to make sure.

[mjheathcote]

Defo running in oil...just drive it normally without any boy racing.

[wilf]

I would always use VR1, especially for running in, when that anti-scuff additive will help on the cam lobes. I just would never use a modern synthetic, as that can stop the rings bedding in. Is why I always "push" a new modern, since they have synthetic in from new, and if you don't give them some major throttle openings from day one, they will guzzle oil forever.

What are the specific characteristics of a "running in" oil?

[GDPR]

What are the specific characteristics of a "running in" oil?

The viscosity and lubricity of an elderly Yaks urine...

[Motorsport Micky]

Couple of points, when you build a race engine the tolerances are deliberately adjusted so the engine is on the "well worn" side.

This allows it to develop maximum performance within a very short space of time, (200 miles norm) because if you build a race engine to last 5 years then you don't win ! With 10 or 15 races a year this will give a competition mileage of between 500 and 1500 miles (depends on tracks) after which the engine is broken back down and clearances checked and the rings and bearings changed. However there are certain similarities within the "bedding" in period of the components.

Whether on race engines or units built for normal road use there are well documented concerns regarding early camshaft failure in engines which have large bucket type cam followers (or flat head tappets like a Stag or TRs). This has been put down to the modern oils having a lack of ZDDP additive which has steadily been reduced to help vehicles comply with increasing emissions. Many engines now have roller rockers and cope with the reduction of the oil additives in modern lubricants. The ZDDP additive helps prevent high pressure areas of the engine (tappets are a good example) breaking down the oils and causing excessive wear within very short life spans. There are additives available which can be bought which will help your oil achieve the ZDDP levels needed for our older "flat tappet" engines.

Linking with the wear characteristics is the critical early engine use where the engines require revving OVER 2000 revs for the first 20 minutes or more of use so that camshafts provide the correct scuffing action on the tappets and helps reduce the pressures in that engines components. Like Kryten I use any reasonable 20-50 (but with a ZDDP additive) when I first start the engine after its rebuild and after a initial couple of minute check for fluid leaks I complete a 40 mile bedding in run with emergency toolkit, oils water and mobile phone on my prescribed test route left with the wife.
It's carried out totally at OVER 2000 revs and up to 4000 revs which sometimes calls for a little juggling of gears and trying to avoid too many red traffic lights where a plus 2000 revs maintained on the engine cause curious looks from onlookers. After the initial bedding in period I take the engine up to about 200 miles varying the throttle openings throughout the rev range, and with especial care taken to fully expand the piston rings (at BMEP*) with full acceleration maximum load running at the engines maximum torque area, after that it is used completely as the engine should throughout it's full engine range.

*BMEP is Brake Mean Effective Pressure which is where the engine develops most compression throughout it's power stroke commonly found in the area of maximum torque. This helps fully expand the piston rings and helps them bed into the cylinder walls correctly giving the best compression and avoiding glazing of the bores.
On road engines even on my daily driver (Ford S Max) it's not bad practice to use this same technique once a month if the car has had lots of short runs or easy use applications, alternatively I tow a 1700 kg caravan around 6 times a year and that sorts it lol.

Micky

[wilf]

Interesting Mickey. On yank V8s with flat tappet cams the cam break in procedure is as you say, revs held over 2000 for at least 20 minutes. Made me appreciate roller cams, I can tell you.

I wasn't sure if the same procedure was necessary on an OHC engine due to the much larger diameter of the followers aka buckets.

[Nambo]

A very interesting article:- http://www.mototuneusa.com/break_in_secrets.htm

[Motorsport Micky]

Hi Wilf,

Well I've never compared the profiles of the Stag cam against TRs or others and as you say the follower size is more generous on the OHC engines, however the important characteristic is the used surface area of the follower by the cam.
I'd theorise that the bigger OHC cam followers merely give a more stable follower action being a bigger dia, whereas the swept area of the cam may not be markedly different from the surface area used on the narrower followers used on the TR or Rover V8 engines. My money would be on using ZDDP additives to ensure whatever "scrubbing" action the cam employs it's countered by the boosted oil used, belt and braces Wilf.

Micky