rebuilt engine - what oil changes?

[tinman123]

so we all say and do, run the rebuilt engine for a few short periods on new oil until you get up to the normal intervals.
its the done thing.

but my curiosity needs to ask why?
why do so if an engine is built in a clean environment with washed parts, new parts and everything set correctly.
is it something that was done back when oil mightnt of been so great and therefore needed it, todays good quality modern oils are a long way ahead, so why change in short intervals a couple of times after a rebuild?

im doing a perkins engine here at the mo, a full rebuild with nothing spared, it will get mobil delvac 15w/40 mx engine oil and off he will go.
ill advise to change the oil at half the normal time for the run in and go back to normal after that, but i wouldnt think it imperative he do it either tbh, its a diesel i know and id be more firm about doing it on a petrol engine but i dont work on them.

petrol or diesel, why is it specifically done?

 

[Chris Stevens]

Big big mistake to use anything other than running in oil on a properly rebuilt engine, as this can mean glazed cylinders, which will mean engine strip to rectify.

 

[lexi]

I agree with the ordinary bedding in oil first and all the rest of advice. Tell me this though. Honda build new engines and coat the piston rings and skirts with Moly D at the factory. The sumps are filled with 0/20 fully synthetic. Where is the bedding in getting done?

 

[brightspark]

I agree with the ordinary bedding in oil first and all the rest of advice. Tell me this though. Honda build new engines and coat the piston rings and skirts with Moly D at the factory. The sumps are filled with 0/20 fully synthetic. Where is the bedding in getting done?

easy . the machining tolerances are so good as well as the materials. this 1000 mile running in like the old days isn't needed

 

[The_Yellow_Ardvark]

@lexi
When it is sold to a punter, with instructions on how to drive it.
Then go back after 500 miles for a free service.
15% of engines used in Swindon were binned as not meeting specifications. That is in build and "on arrival" QA testing.
They then were sent back or robed for warrantee parts for main dealers.

 

[daleyd]

@lexi
When it is sold to a punter, with instructions on how to drive it.
Then go back after 500 miles for a free service.
15% of engines used in Swindon were binned as not meeting specifications. That is in build and "on arrival" QA testing.
They then were sent back or robed for warrantee parts for main dealers.

I've had a couple of new cars and never had anything other than a service after 12 months (not Hondas but a couple of VW s, a Mazda and a Nissan )?

 

[lexi]

Yes Brightspark, those are my thoughts. I don't think the engine rebuilders have the machining and metallurgy that Honda have. For ordinary cars, not much beats factory spec.

Interesting that Ardvark. I can't see by Honda engines really, though every modern engine can do the miles now. I think Honda are the largest actual engine unit manufacture in the world now.

 

[brightspark]

the 500mile free service is just a free quick check there's no servicing involved

 

[Bill Edwards]

so we all say and do, run the rebuilt engine for a few short periods on new oil until you get up to the normal intervals.
its the done thing.

but my curiosity needs to ask why?
why do so if an engine is built in a clean environment with washed parts, new parts and everything set correctly.
is it something that was done back when oil mightnt of been so great and therefore needed it, todays good quality modern oils are a long way ahead, so why change in short intervals a couple of times after a rebuild?

im doing a perkins engine here at the mo, a full rebuild with nothing spared, it will get mobil delvac 15w/40 mx engine oil and off he will go.
ill advise to change the oil at half the normal time for the run in and go back to normal after that, but i wouldnt think it imperative he do it either tbh, its a diesel i know and id be more firm about doing it on a petrol engine but i dont work on them.

petrol or diesel, why is it specifically done?

People probably do overdo it these days, but some of it still stands.

No matter how much time and effort goes into cleaning parts and keeping the work environment clean the typical workshop is a dirty place when it comes to engines. Unless you're in almost laboratory conditions with super clean tools and the right clothing etc you will gets bits you don't want inside an engine.

But what's probably at least as important is that you are installing parts together and even with decent parts if you look at things on a microscopic level you will still (to a degree) have high and low spots, when you put things together you can expect a few bits to wear quickly until things mate.

So I would say that even if it's just the cheapest oil available you want to put in something to flush the dirt, metal particles and any leaked gasket sealants out to keep things clean.

 

[The_Yellow_Ardvark]

Edit to my post
Double checked with my Friend who worked in Swindon in The QA.
It was 15% of the drive train components.
The QA would reject parts for wrong paint to parts being correct to specs
Some engine and gear box's were striped to have internals inspected.
Sorry for any confusion.

 

[brightspark]

the last engine I built for racing was done in my dining room white sheets all covering the floor no one was allowed in and door kept shut. all parts blasted and power washed . rebuilt with all the best materials it was run on a test bed for 2 hours before fitting in the car then ran about 5 miles then raced it flat out . it lasted 3 years with no probs and I sold it on still a good runner had it on the dyno and it was only 10hp behind a professionaly built redline racing engine and half of the price

 

[tinman123]

People probably do overdo it these days, but some of it still stands.

No matter how much time and effort goes into cleaning parts and keeping the work environment clean the typical workshop is a dirty place when it comes to engines. Unless you're in almost laboratory conditions with super clean tools and the right clothing etc you will gets bits you don't want inside an engine.

But what's probably at least as important is that you are installing parts together and even with decent parts if you look at things on a microscopic level you will still (to a degree) have high and low spots, when you put things together you can expect a few bits to wear quickly until things mate.

So I would say that even if it's just the cheapest oil available you want to put in something to flush the dirt, metal particles and any leaked gasket sealants out to keep things clean.

il agree that some of it stands.
altho when id build an engine all be it in the workshop but its pressure washed, run through the parts cleaner and blown off, i dont expect to have any surplus gasket sealant as i dont use any bar shellac and its going nowhere.
there would be nothing else going on in the workshop when its getin built so apart from what im breathing and the dust off myself there shouldnt be anything to worry about imo.
its not ferarri standards but its close enough for a massey engine.

as for anything that might be left i think the filter would get it and in the case of a diesel 50hrs run in would be grand and then back to the 250hr service.

what you say about uising cheap oil is right, thats what run in oil basically is, an oil that dosent have as good a lubrication as a quality oil and thats why its used, to let those microscopic pieces level out but i still think there is no need to be anal about it.

 

[lexi]

Did old bodgers not used to put a dash of Vim in for running in?

 

[steveo3002]

Did old bodgers not used to put a dash of Vim in for running in?

isnt that for when the rings didnt bed in

 

[tinman123]

Did old bodgers not used to put a dash of Vim in for running in?

ive heard of that trick being done with some washing powder not so long ago, they reckoned it id take the glaze off the liners.
my jury would be out on it tho.

 

[brightspark]

old wives tales

 

[tinman123]

old wives tales

i know the lad that did it, in a agri garage.
now he is a fairly clued in kind of guy at the repairs in fairness so i dont know, but like you id have my doubts.
if it was that easy we would be all at it.

 

[The_Yellow_Ardvark]

So adding a heaped tea spoon of valve grinding paste to a rebuilt engine, for when the cheque bounced for the second time would be a bad or good idea?



Questioning Vark.

 

[dannyp]

for my golf an oil filter is £5 and 5ltr of cheep 10/40 semi syn is £10. the first change is to flush the crap out as it wasent built in a lab, and make sure there isn't scary amount of nastyness in the oil. the 2nd change after 1000 miles of running that oil ( probaly only 100 miles of full throttel in that ) as it should have setteld by then and its time for the proper oil 10/50 fully syn ready for playtime