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 would take it very carefully.

 

I had my engine rebuilt at z-tech and ran it for 3000 rpm for 500 miles, then oil change.

4000 rpm for another 500 miles then another oil change.

 

After that it was meant to be fine to use but went bang after not even 1000 miles of normal use.

 

My advice DONT do what the garages tell you and run it in for about 60k miles with oil changes every 250 miles.

 

Then maybe... just maybe.. it will last.

:rofl:

hmmmmm... I might just keep it as a decorative piece of modern art in that case!!

I would take it very carefully.

 

I had my engine rebuilt at z-tech and ran it for 3000 rpm for 500 miles, then oil change.

4000 rpm for another 500 miles then another oil change.

 

After that it was meant to be fine to use but went bang after not even 1000 miles of normal use.

 

My advice DONT do what the garages tell you and run it in for about 60k miles with oil changes every 250 miles.

 

Then maybe... just maybe.. it will last.

 

Shortly after Jimmer rebuilt his engine with Wiseco pistons, 555 injectors and a set of larger turbos, he was on the rolling road knocking out 426 bhp and slipping down the M5 doing O my god miles per hour. He still drives it hard. If it rebuilt right, with todays engineering quality and materials, it don't need running in, but you do just need to keep an eagle eye out for any fluid leaks, just in case.

Shortly after Jimmer rebuilt his engine with Wiseco pistons, 555 injectors and a set of larger turbos, he was on the rolling road knocking out 426 bhp and slipping down the M5 doing O my god miles per hour. He still drives it hard. If it rebuilt right, with todays engineering quality and materials, it don't need running in, but you do just need to keep an eagle eye out for any fluid leaks, just in case.

 

Is Jimmer on here?? That sounds like exactly what I want to happen after I've put my engine back in...!

A morning set of runs on a dyno simulates a few hundred miles worth of cylinder wear - so will be bed those rings in nicely.

 

The Person who built my engine first time around said don't over-rev it, and don't load it up at very low revs. Basically drive it hard but don't go over 3,500 for the first few hundred miles.

 

Si.

Opinion is divided on this. I tend to stick with the traditional, take it easy,rev it a bit but don't load the engine for 500 miles (or until I get bored).

 

There is a school of thought that suggests you rev the spuds off it pretty much as soon as it's built, that way the rings/bores etc don't get time to work harden and therefore bed in very quickly before further wear takes place.

 

 

You may be interested to know that a new 350 doesn't even require it's first oil change until 9,000 miles !!!!! I could hardly believe it. Anyway, it's done nearly 70K now and at about 60K was spot on the factory bhp spec on a dyno ....

Did a quick google and came up with this.

 

http://www.aircooled.net/gnrlsite/resource/articles/engnbrkn.htm

 

Obviously some of it dosen't apply but the basics seem sound.

 

Good luck with it.

 

Darrell

Did a quick google and came up with this.

 

http://www.aircooled.net/gnrlsite/resource/articles/engnbrkn.htm

 

Obviously some of it dosen't apply but the basics seem sound.

 

Good luck with it.

 

Darrell

cool link :) id better get an account setup with opie oils for when mines running again!

I read on here somewhere that when running an engine in, one should use mineral oil. I believe it is because the anti-wear properties of modern synthetic oils inhibit the bedding in of the components.

 

Richard

I read on here somewhere that when running an engine in, one should use mineral oil. I believe it is because the anti-wear properties of modern synthetic oils inhibit the bedding in of the components.

 

Richard

I always use mono grade oil in my rebuilds with no additives.Pointless to rebuild an engine then fill it with oil full of anti wear properties.As regards to running in i dont.If you have faith in what youve built then start as you mean to go on,once hot drive it as you would normally just dont labour the engine or redline it.In my experience cars that have been nursed wont take hard driving later on.

mate of mine just had his subaru back from API after a rebuild. Their instructions are to not 'race' the engine for the first 1000 miles and keep the rpm under 4k. Then give it hell for a couple of hundred miles, then take it back for an oil change and mapping.

Shortly after Jimmer rebuilt his engine with Wiseco pistons, 555 injectors and a set of larger turbos, he was on the rolling road knocking out 426 bhp and slipping down the M5 doing O my god miles per hour. He still drives it hard. If it rebuilt right, with todays engineering quality and materials, it don't need running in, but you do just need to keep an eagle eye out for any fluid leaks, just in case.

 

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.....

Im not a believer in sticking to low revs and low throttle for XXX amount of miles. Varied RPM and loads is the key. Its worth noting that every 300zx was treated to a full speed run on a rolling road before it ever left the factory.

Yep load is certainly a big part of it - its cylinder pressure that pushes the rings against the bores to wear them. Cylinder pressure is directy related to load...

Yep load is certainly a big part of it - its cylinder pressure that pushes the rings against the bores to wear them. Cylinder pressure is directy related to load...

 

 

Well heres a cat going into the pigeons!

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

My brother did this on a massively overbored+ tuned bike.

No smoke, no leaks.Big power, compared to another conventionally run in motor, the only difference is he changedoil/filter after 20mile/100mile+500miles

LOL thats the link I was looking for to turn everything on its head :D Whether its the same for a relatively low revving car engine remains to be seen....

Heres a different view

 

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

When I bought my new motorbike I was told this:

 

1/4 of the rev band for the first 500 miles

1/2 the rev band until 1000 miles

(the rev band being up to and not exceeding the red line)

after that you can wind it up progressivly each time you ride it.

 

I cant see a high peformance car engine being much different?

I would take it very carefully.

 

I had my engine rebuilt at z-tech and ran it for 3000 rpm for 500 miles, then oil change.

4000 rpm for another 500 miles then another oil change.

 

After that it was meant to be fine to use but went bang after not even 1000 miles of normal use.

 

My advice DONT do what the garages tell you and run it in for about 60k miles with oil changes every 250 miles.

 

Then maybe... just maybe.. it will last.

Lol :slap: :rofl:

This is a very interesting post as mine will be ready to run in within a month.

 

Can this be made more idiot proof, horning? rabbits? loads?

 

In plain english for the simpletons on here, what is the best way to run a engine in? i'm running big mods and a basic map for running in on a Aem.

Its entirely up to you but you only get one chance.I dont nurse them in but drive them hard and have NEVER had any problems using this method.The link in another post on this subject is worth reading and makes perfect sense.just remember to use running in oil and if your rebuilding due to an engine failure metal particles will be left in your oil cooler so flush it out.

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

When I worked on the bedford truck engine line many years ago, if we had too many parts at a certain size they would be driven round the car park for a while, remaesured and thus we then had a different size. Yes engineering has come on a lot since then and new engines these days fit together much better. Unfortunately we are not talking about new engines on this thread, we are talking about a rebuilt one that possibly won't fit together as well. As andy has said the bore is not totaly smooth or round in this case and thus the rings need to wear them smooth and make themselves fit in the bore. (if that makes sence) Obviously this produces metal fragments in the oil, hence the need to change the oil, and hence it being pointless putting in low friction oil etc.

 

Hope that all makes sence. It did in my head.

 

Darrell

yes it made a lot of sense, appart from the mention of bedford their engines were all designed when Hitler was still in nappies, please dont compare them with anything thats been made in the last 40yrs :)