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MG Midget and Sprite Technical - Running in? they can't both be right

I'm currently running in my new engine. I checked the archive before doing this and there seems to be two opposing arguments.

There are quite a few of the "take it gentle, nothing above 3500 rev's for the first 500 miles" belief. However there are also some very strong supporters for the "climb in drive it like you normally do" (but don't labour the engine a low rev's). This side of the fence includes several chaps that are held in high regard on this site.

They can't both be right.

BTW, my first 100 miles has generally been around town but with a couple of blasts up to high ish revs and 80 mph.

??????????????
T Wainwright

hi,
there was a big discussion about this on the Lotus Elan forum I used to be involved in..
Amongst the racers there was a strong belief in a different method.
start the car...
the drive it to somewhere straight..
then do 4-6 cycles of full throttle to near redline then decelerate on a closed throttle to idle...
The idea is that the increased cylinder pressure forces the rings out so that they bed into the cylinder walls.
It was thought that the worst thing to do was to take it too easy as it leads to glazing of cylinder bores.
Tried it on my lotus twincam, and it seemed to work.
runs will, no oil vapour on the back!
Tim
T Dafforn

>> However there are also some very strong supporters for the "climb in drive it like you normally do" (but don't labour the engine a low rev's).

That's what Standard Triumph used to recommend in the 1960s.

Roly
Roly Alcock

nop it's almost like religion you can never be sure what to believe.

Here is how i did it

1st start
adjust timing and carbs and check for leaks
then fix leaks

2nd start
get in drive 300miles using moderate revs (not above 4000) after 100 miles 1 or 2 dashes to 5500 do not let it labour

Then drive until you have done the first 650 miles.
Try to make the runs as long as posible (making sure the oil gets hot) just drive normaly not like a elderly not like a hooligan.
I did not pull it over 5000.
Change the oil

Then refill the oil and just drive it normaly and increase the rev limit over the next 650 miles.

After that i figured that it was run in and started giving it hell ;)

worked fine
Onno Könemann

I am very similar to Onno

Religion is not hard to eveluate the age of the Earth is in the region of billions of years, the bible states a few thousand now commonsense therefore helps to evaluate which book is accurate and which is not.

Here with the engine commonsense prevails. Just run the engine normally without making the engine struggle and without making it scream it's heart out. A few thousand miles sounds about right simply to bed everything in.

Just one more thing, it is commonsense to use a cheap oil so that the bedding in process can actually occur. Modern synthetic oils are so good that when used the bedding in process is prevented. after a few thousand miles the quality of oil can be increased and the engine made to work harder. IMO. :)
Robert (Bob) Midget Turbo

looks like you've already chose against the "nothing above 3500 revs" by doing 80 mph

and you may (only may) have been labouring the engine if you've been at very low revs round town

Personally I'd now say you want to vary your speeds and revs, take it easy without laboubering the engine (generally around 2,500 - 3,500 revs) for the next 400 miles ay least then the following 500 miles built incramentally

cheap oil for first 500 then change oil and filter (filters are so cheap)

and I'd change the oil and filter again at 1,000 and put in good quality

oil and filter change then at the next 6 month/6,000 miles and again

oil and filter change at the 12 month/12,000 mile service

And I personally would use flush on the oil change from cheap to good quality oil
Nigel Atkins

The Advice I got from some really good people on here on the BBS was to find a country road about 3 miles long with hills and curves

warm the engine to temp...put the car in 3rd gear (ONLY) and drive up and down the road at 30-50 mph for 300 miles watch the oil level and the gauges

havent gotten there yet but soon, basically you dont want to treat to gentle as that will glaze the cly and the rings wont bed in, but you dont want to race to 12,000 rpm ither

you want "load" on the engine for the rings to work and bed in

3500 rpm at stand still in the drive way is apperantly way differant then 3500 rpm in 3rd gear flying down the road at load.

Prop
Prop

I hope you all bed your new cams in at 2000 rpm for at least 10 minutes? That is the first step once the engine has started. as Bob says modern oils can prevent the rings bedding in correctly.The best bedding in should occur at max torque when the highest ring prssure will be exerted per cycle. Damage occurs when the piston rings cannot reject heat fast enough during bedding in, ie too much load at low rpms torque heat and too much high speed bhp build up of heat. Labouring the engine in a high gear is daft as is seeing how fast the engine will go in the higher gears. The best way imo is to use the new engine hard in first and second up to 5500-6000 (depending what the engine is)to bed the rings then reasonable use in the higher gears to get from a to b, a couple of hundred miles should be more than sufficient. I build engines with an extra 1/2 thou " clearance to allow a little safety if someone is over exuberant with running in. When I do the initial bed in of a race engine I bed the cam, set the timing to near optimum then start building up the bhp. On an MGB I load the engine to say 60 at the wheels and wait for the temp to rise above normal, let it cool then go to 80 etc etc once I have run at 120 at the wheels I notice the heat build up becomes significantly slower therfore I guess the engine is run in and ready to race! Time taken 40 minutes including cooling. Typical Race clearances are 3 1/2 thou over the piston as opposed to 2 1/2 thou for road.

Incorrect running in, too gentle or oil too posh prevents the peaks from the honing being worn off the bores, they bend over and form hooks, this allows oil to collect in the troughs which burns beautifully, you might not see the oil smoke but the oil will disappear down the dipstick as if by magic. The other problem is bore glazing with combustion product varnish which will cause a visibly smokey engine.



Mr Wainwright

As Nigel said you seem to have chosen already?

Peter
P Burgess

Bob

Just a thought re the Bible, I reckon Man wrote the bible (then decided what should be included in it and what should not) not God so careful about making such glib assumptions. Working out the bible is not correct in terms of genesis etc does not mean God does not exist that is a sylogistic argument and does not compute Captain.

Peter (thought for the day) :)

P Burgess

Thats 6 votes for the "run it as you normally do" and non for the "pamper it for 500 miles". Where have they all gone.

On the oil thing I thought all old MG's like ours needed to run on mineral oil as the good book says (Haynes). I've used that thick green classic oil from Halfords. Has a picture of a sprite on the can smells nice too. I'm using the basic mineral oil for the run in, red bottle from Halfords. Should I go for a part synthetic after this?
tm wainwright

Hiya

The semi stuff seems to work well, also getting good feedback with midgets on castrol 10/60 edge oil.

Don't forget we aren't in the 60s anymore in terms of fuel, oil, driving conditions etc etc.

http://www.castrol.com/castrol/productdetailmin.do?categoryId=9014074&contentId=7027067

Peter
P Burgess

I am very much with Peter on this one. A good quality oil is more than welcome. I remember having a conversation more than 20 years ago with the people at Oscelli. They had tried running a fresh engine on Shell Helix (Full synth) and when they stripped it down they could see every machining mark meaning the engine had not bedded in correctly. It also meant that the oil was extremely good at its job of protecting and lubricating.

So a cheap oil for bedding in and then quality for future long life protection. Must admit I use a semi syth simply for economy as I like tinkering and therefore tend to change my oil each year on very low mileage.

Pete

Can't argue with that logic, it seems spot on to me, just because the bible can be proved to be incorrect on so many occassions does not mean a God does not exist? It simply means that it can not be relied upon as being accurate information.
I totally agree.
Bob Turbo Midget England

I ran mine in according to the engine builders instructions (which I forget exactly..).

I did bed the cam in. I think the first 100 miles was at 3,500 rpm on a motorway. After that I think I progressively used more rpm. I've never worried about giving a run-in engine 'short bursts'.

Who built the engine and exactly what work was done in the build? Stock road engine?

I also gave the engine an early oil change after either a 100 miles or 500 or a 1000 - can remember which it was.
Daniel Thirteen-Twelve

Hi Daniel

I cannot see how doing a 100 miles cruising at 3500 on the motorway beds an engine? Modern cars seem to need no bedding at all why is that? I reckon the engines are started and worked briskly and functions tested on the rolling road then out to the new owner. With a rebuilt engine if the clearance in the bores is correct then bedding should be a minimal process. All the other component bedding in is pretty instantaneous once the engine starts. I reckon the 1,000,000 mile running in period was initially from reconditioners who built the engines on a wing and a prayer and hoped gentle use would do the trick and stave off warranty claims.

Peter
P Burgess

Peter,

I would expect one of the reasons modern engines require little or no bedding in is the use of plateau honing of the bores.
David Billington

Plateau honing usually only takes a couple of up and down strokes and only takes a smidge off the high spots, we stopped plateau honing some years ago and went for a rougher stone finish under piston manufacturer guidance, this gave us better oil consumption and bedding in.

Peter
P Burgess

Peter,

Maybe the devil is in the detail, IIRC plateau honing has been used by the engine manufacturers for a few decades at least, for the same reason you don't use it. A mate used to work at LandRover and showed me around the engine line including the rather expensive new plateau honing machines they had recently installed early 1990s IIRC. I'll ask another mate what the score is with the OEMs these days as he works for Ricardo doing engine design.
David Billington

We found the plateau honing via flex hone was not good as it could do more harm than good, a very posh oem machine on the other hand....we had also experimented with old fashioned cork for plateau honing.

Peter
P Burgess

Im using break in oil by comp. its made esp for breaking in new engine...

I just cant belive how freaken expensive the stuff is...anyone know where I can get it cheaper...check out the price tag in this advert...


http://www.tognottisautoworld.com/parts-lookup.aspx?i=4746641&source=googleps

Yeah uh HUH! I think NOT! LOL. Hope you get a free oil filter for that price

seriously I am using a break in oil But I only paid about 8 dollars a qt. NOT the price tag above

Prop.... you get what you pay for?
Prop

Hi Prop

we struggle to get mineral oil running in oil. It used to be straight 30w with no additives but I am told the oil companies are phasing out mineral in favour of semi and fully synthetic.

Peter
P Burgess

In response to TM: I used to run re-bored engines in gently; I wasn't so much concerned about the occasional zip up the rev-band, more to preventing the engine sustaining too much power for a few 100 miles in deference to the extra friction and resulting heat.

There may have been good reasons some years back, but the evidence here seems contrary to this practice.

So next time, I'll do as prescribed here.

I did about 15K (some competition) in a 1293 A-series some 10+ years ago. When I sold it, the new owner took it apart for a check and told me he could still see hone marks on the bore... so clearly not run-in enough!

A
Anthony Cutler

I use running-in oil with a cam lube additive (Crane) and the method as described by Peter B. I almost cry when I have to discard the oil and filter after only half an hour of use.
I wouldn't treat a std road engine to that expense.
Mike Allen

What's the best way to break in an engine? RUN IT HARD!

See www.mototuneusa.com/break_in_secrets.htm
JM Morris

I am in the process of running in our 1380 after a complete rebuild, finished yesterday. Bores deglazed by Peter B, new Omega pistons, new crank bearings, new cam Piper 270 this time, replacing a Kent 276, and new followers etc.

Went for the Piper as Peter May told me that their billet version has cross-drilled cam lobes, pressure fed from the centre cam bearing. A previous experience with a Kent 276 billet cam bought last year wore the lobes away in about 2,500 miles. Had been bedded in and same oil regime. Any similar experiences?

Did the usual 20 minutes at 2,500+ to bed in the cam, then re-torqued the head before a 30 mile country road trip just to make sure everything was OK. I subscribe to the 'no heavy load, and restricted rpm for 500 miles' school of thinking, so today have just got back from a funeral in Bognor Regis, a round trip of 220 miles, using 3,500 rpm as a max, but tried to vary the speed and the load. So about half the running in done in the last 24 hours. No smoke and oil consumption of about 3mm down the dipstick, which seems to bode well!!

Once it has done about 500 miles, I will change the oil to Castrol Edge 10w/60 (synthetic), plus change the filter of course and then hope to have a few years good use from it.

Richard
Richard Wale

Peter,

I spoke to my mate that works at Ricardo yesterday, at the pub with a few beers, and he said that plateau honing is the industry standard for bores and he added that getting the right result is quite tricky and left to specialists in the field and their equipment. A lot of research having been done into what's required and how to get the result consistently, that would be important for an OEM.

He also mentioned laser honing as a new process but not production yet. It was a brief mention but I think it was using the laser to produce a well controlled cross hatch. I can ask further if required.
David Billington

This thread was discussed between 26/07/2010 and 29/07/2010

MG Midget and Sprite Technical index

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