Had a trawl through old posts, and can't turn up much about running in an engine following rebuild... discussed briefly here: running in but no definitive answers... so:

 

How many revs for how many miles?

What oil/ frequency of change?

Revving without load good to bed rings?

any other useful info??

 

If we can keep it to proven methods it's be good, and could probably make a good FAQ.

 

Rich

I saw a guy nurse a brand new Mitsubishi Sigma years ago and at 40,000 KM was still smoking like a train. Bores got glazed and it was all over.

 

I've never tried the hard run in method but then haven't had an engine recon lately either. Back when we did do motors (some 18 years ago), the run in method was to treat them fairly gently with varying loads and speeds.

 

Some years ago they used to make things like Protec rings where you crank the motor over by hand for 20 revs and 80 percent of the work is done. These were designed for quick fixes though.

 

I don't know what today’s technology is like in comparison but I'd say it would be a lot better than that mentioned above.

 

I think I would tend to be a bit harder than the old days but not quite as hard as the link where he is dealing with new engines with probably some amazing machining work.

 

Just my 2 cents worth (is that 1 penny over there?)

when I were a lad.....not so long ago, we used to run in any rebuilt engine or new vehicle for about 1000mls, with what was called running in oil.

 

Never heard of anything for years that uses running in oil. cars are now dropped of at dealerships brand spanking new, taken out on road test by the apprentices and thrashed, no oil change, no run in, and the motors dont blow up.

 

Better materials, design, build, and lubricants have made the old style running in on most motors a thing of the past. this may be different on specialist engines such as racing etc, but for most of us I think as long as you are sensible and dont redline before every gear change you wont do much harm.

 

30yrs ago when they used to go on about running in all the time, your car was considered nearly scrap if it had done over 100,000mls now they say a VW needs to do 80,000 before its running at its best

machine shops work to tighter tolerances than manufacturers.

machine shops work to tighter tolerances than manufacturers.

except nissan's bearings :wack: :p

Well I was at this point a few months back, I never thought the point of doing a 1000 miles to run it in was valid, work out how many times the pistons will have traveled up and down in a 100 miles never mind a 1000.

 

Its personal choice mine got 20 miles a gentle ish a trip to Jae then 16psi

machine shops work to tighter tolerances than manufacturers.

 

the place I served my apprenticeship had its own machine shop :) and engine shop, gearbox shop, fuel injection shop, body shop fook come to think of it the only thing it didnt have was a corner shop.

 

I found the tolerances depended upon how much beer had been consumed by the engineers the night before :D.

my engine was run in hard like in the motatune link posted earlier , Car now dosent use oil and results are more than impressive !

:( ive got all this fun to look forward to next week. cant decide what's best to do

my car is now running after a full rebuild... i did about 300 miles of random driving in it yesterday and 'sensibly' ragged the pants off it! up and down gears spreading the load but didnt red line it. she lapped it up and had a big smile on her face!.. similar to the smile i had :D

 

my advice is, set it up for life, drive it like you stole it!

I risked it totally and after a full rebuild took it down to LeMans and back. Didn't drive it hard at all as I don't really, but took it through the gears and lightly brought it on boost. Luckily, the roads to get there are a mixture of long straights and then towns /villages, so the engine always had a spread of revs. I tried not to labour the engine, but kept the revs up just to allow things to bed in, but don't drive it like a pansy.

 

Incidently, my car didn't miss a single beat on its first run. By the time I'd gotten back, I'd done nearly 500 miles. :)

:( ive got all this fun to look forward to next week. cant decide what's best to do

 

Yeah same here.

 

I've been set a limit of 4k to not go over but i can rag it upto that set rev limit.

 

Also running it on a cheap shite oil so there are no protective stuff in there.

 

So many different opinions though make you wonder don't they. oh dear.

That mototune artice is pretty much what all engine builders I've spoken to have said too. Also is the same advice given by Graham Bell in his books. Only other thing to remember is if you have changed the cams or had them reground then you have to keep the revs > about 2000 for the first 20 mins or so to harden them properly.

Only other thing to remember is if you have changed the cams or had them reground then you have to keep the revs > about 2000 for the first 20 mins or so to harden them properly.

 

Hmmm... didn't know that! So what if you've got new rings and new cams... 20 mins for the cams to harden & the bores will have glazed :confused: :confused: Arse!

That mototune artice is pretty much what all engine builders I've spoken to have said too. Also is the same advice given by Graham Bell in his books. Only other thing to remember is if you have changed the cams or had them reground then you have to keep the revs > about 2000 for the first 20 mins or so to harden them properly.

 

more than 2000 revs, no problem :rofl:

Ah - completely mis-read that one...! Cool - that certainly won't be a problem!!

Engineering quality and materials? Sorry but you obviously don't understand the purpose of running in... When a block is prepared there is a process called HONING which puts a rough surface on the bores for the rings to 'bed-in' to. No boring process is perfect, as much as no rings are perfectly round, so the two must wear to the shape of each other. The whole running in process is to make the rings fit the bores perfectly. The ultimate running-in process puts enough pressure on the rings without wearing the honing surface away. Do too many miles without enough load and the honing will get worn away before the rings have shaped - this also applies to using an oil with high sheer properties... Use a basic mineral oil for running in and give it varied load and varied revs for the first 250 miles, change oil and filter, then give another 500 miles with increased load but same rpm (not more than 5500). This will make the most of the honing without damaging anything. FYI bottom end bearings are NOT part of the running in process, any metal-metal cotact here will result in major failure.....

 

On the contrary it's you that does not know his engineering. Honing, which uses graded stone heads, is used after a rebore to smooth and refine the surfaces further. On a used engine where the bore is polished by the piston ring over time, this glazing requires to be removed using a 'glaze buster' which is no more refined than emery cloth attached to flexible rubber paddles driven by a drill. And 'mineral oil' in an engine with a turbo ? you must be joking.