Refurbished engines

[A500leroy]

If a high mileage engine is taken apart, all the parts checked, whatever is worn is replaced, un worn parts put back in, is that as good as a brand new engine?

[GreenV8S]

A500leroy said:

un worn parts

Not sure what you think that would cover.

On a high mileage engine all the moving parts are likely to be worn. That means all bearings, pistons, bore, valve train and so on. Unless you do a nut-and-bolt rebuild incuding a full top and bottom end rebuild complete with new bearings and bores, it is not like new.

[KingGary]

Every part is designed and built within tolerance, if it’s outside, it needs replacing. There’s no new or old about it, unless it’s a new engine. It’s fine to inspect and refit old parts if they aren’t considered worn.

[Vsix and Vtec]

In short, no. However that does a disservice to the whole truth, that being that whilst it will never have as little wear on it as a new engine, in the main it just doesn't matter. A reconditioned engine will have the parts that matter in good order, and will be serviceable for many years to come. The fact it has a sump that's not "as new" or block, or cam cover, makes almost no difference, so long as the used items are within tolerance. The lower cost is due to this factor, but that's not to say the reliability is less.

Put it this way, the biggest factor on reliability isn't usually how new it is, it's how well it's treated.

[E-bmw]

A500leroy said:

If a high mileage engine is taken apart, all the parts checked, whatever is worn is replaced, un worn parts put back in, is that as good as a brand new engine?

Simple answer is an obvious no.

Doesn't mean it won't give good service for many years/miles.

[kestral]

A500leroy said:

If a high mileage engine is taken apart, all the parts checked, whatever is worn is replaced, un worn parts put back in, is that as good as a brand new engine?

It depends what you mean by 'as good'.

If an engine is rebuit properly it will do exactly the same as factory supplied brand new engine.

If the engine is rebuilt to a high spec it will be an improvement on a factory supplied engine.

[Richard-D]

I've had such poor experiences with reconditioned engines that I either rebuild myself or fit a 2nd hand engine from a breakers. A reconditioned engine should be a safe bet but on the 3 occasions I've gone this route (over about 25 years) it's been a resounding fail.

[Megaflow]

A500leroy said:

If a high mileage engine is taken apart, all the parts checked, whatever is worn is replaced, un worn parts put back in, is that as good as a brand new engine?

That is entirely dependant on how you are defining what is worn.

Material properties can degrade over time due to thermal and mechanical fatigue, so unless you perform a full range of mat lab tests, you can't be sure the material is the same as when it is no. An example is the Rover K series, it know for annealing it's head when it over heats and once they get to a certain hardness the head casting is scrap.