running a C20LET engine in

[NOVA-LE67]

hi im in the process of rebuilding my C20LET and i am unsure on how many miles and what RPM range to use to run the engine in? when looking for information everyone says different thing. i know this will probably be the same hear but hopefully you guys will give information based on past experience.

thanks alot

[Stuart]

Spank it.

[Southie]

If the engines been built right then running it in shouldn't be a major issue, I've usually done about 200 mile steady away with revs upto about 4k, then as Stuart says let yourself go and enjoy it lol

Make sure you do a oil drop after about 500 miles to get rid of any fresh new build metal that will have been lying around ;)

[MK999]

Low RPM, full power runs, steadily increasing RPM on each. If you do it on a rolling road you can actually watch the power increase as everything wears in, and it's usually done after about 45 mins.

Unless it's for a race and needed in the next 10 minutes, then the usual procedure is to sit at 6k in the pits for 10 minutes before qualifying lol

[Benn]

Unless it's for a race and needed in the next 10 minutes, then the usual procedure is to sit at 6k in the pits for 10 minutes before qualifying lol

It amazed me watching guys do this on oval track cars.

[MK999]

Works fine tbh, it's not ideal as the rings don't get flexed quite as hard under next to no load, but the whole 'run it for 3000 miles at 15 mph and 1500RPM max' died out when we started making bearings that are actually round and not shaped liked a corrugated roof. Cam manufacturers seem to still like a slow run in, never had chance to ask them why but I know a lot of the lower market don't chamfer the edges on their profiles, so there's probably a few sharp spots around the castings? Might just be a PR thing in that people don't like being told to spank their shiny new engines and they'd rather bumble around for 4000 miles.

I always liked Geoff Goddards advice on warm up procedure on a Cosworth F1 engine, "minimum RPM at minimum mechanical clatter" i.e, rev it til the gears stop clouting together and it sounds like it's got oil pressure lol

[Benn]

Oh i know it works, just crazy to watch. I know i'd never do the 1k gently run in thing again. Worse month of my life...

[mowgli]

i love mk999's comments, as they match what my mate & i used to do to brand new hire fleet cars fresh off the transporter, taking them to get fuelled up......lol

i've always been told, run it in like you plan to drive it.. once its warmed up for the first time, it isn't suddenly going to do anything different, it will be running & that's it.

i'm not even sure the 500 mile thing is relevant these days, as you are not going to leave swarf in an engine if you have lavished hours of care assembling it, as opposed to [cough cough]mass production methods...

[Stuart]

30miles or 30 mins on the engine production line ftw.

[NOVA-LE67]

cheers for the help guys ill let you know how it goes :)

[mowgli]

i found some running in info in Motorsport mag. from Mike Costin, 1/2 of Cosworth. its the 'running in' spec ford made them do when they were making the YB. they would randomly grab an engine off the line & do a test.

'we were allowed 15 seconds to get the oil pressure up, then we had to run it at 7000rpm from cold, like someone abusing a cold car on a winter's morning. then take the hot water out, put cold water in, do it again. then take it to bits and there wasn't to be any scuffing, anywhere.'

there were a lot more abusive tests done. ie a 300hr test, where the engine was run at full power for a set time, followed by a set time at max torque, then tickover, then stripped to check for wear. then only using new gaskets, reassemble it & do another 300hrs non-stop.

bearing in mind the yb was based on a cortina lump it sort of shows what an engine can put up with & makes a slow running in look a bit redundant.