Running in a new engine

[Ben]

Searching the net for answers and it seems half the answers suggest being very gentle and the other half suggest giving it a good thrashing!

I understand that the idea of running it in is to bed in the new piston rings, and I understand why people say to give it a good thrashing. However, while this would bed the rings in nicely, would it not make the bores very smooth, due to the new rings having nice sharp edges?

Also, if you were going to take it for a hard drive, you wouldn't be able to let it idle and warm up first?

[Ricky]

I would try not to keep the revs the same for too long, so take the country roads or something. Also use engine braking a lot.

[darrenjlobb]

In the middle is what you want to do, certainly don't be gentle all the time, that's the last thing you want to do...beat thing is to give it bursts of load / boost, then few minutes gentle, then load it up again, try to vary revs and avoid cruising for long periods at same speed... Only thing to avoid is high revs for first part of run in, so just load it up until 4k ( if derv ) and not much more till its bed in a bit more, but not to long, its important to bed the full travel of cylinder from day 1, and you need rpms to do this.

[Ben]

Ricky - Yeah this is one of the running in methods I've been reading about, do you not let the engine warm up before doing this though?

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Darren - Thanks for the reply, Take it you try not to let it idle for to long before taking it out then? And for how long would you drive it like this?

Only other problem I have is that I was going to fit a new clutch to the engine. Am I likely to damage a new one during the running in of an engine?

[darrenjlobb]

New clutch from day 1 will be fine, and as for how long, I normally do 50 miles of country driving / as above, then change the oil, then another 50 miles allowign for a few more revs, then drop oil / filter again, and then do few hundreds miles giving it abuse / more rpms but not RAPING it, just load / ease off etc.... or at least thats what i always set out to do...

In reality it see's 50 miles at 25psi, change the oil, try out 60psi @ 6krpm, and thats the way it stays from then on, but at least try

Main thing is dont be to gentle, or itl blue smoke its tits off / not start very good forever more!

[Ben]

Oki doke cheers for the advice, ill hopefully be running it in in a couple of weeks so ill report back with how it goes!

[strictly_perv]

What spec is the engine? I remember you saying over PM your hoping for 150bhp so its sounding promising.

[Ben]

It's an xud with hdi rods, new rings and a fully rebuilt head with valves cut at a slightly different angle for better flow. I've got a td04 to go on, refurbed injectors and I'm going to refurb a pump because the one I'm using atm isn't that great. Hoping for 160-170 bhp, but anywhere over 150 will be good fun. I'll do a project thread at some point, probably after all the works done, then ill just do a massive write up all at once!

[Dave]

Even if you were to ra*e it from minute 1, the only real effect would be your head could become warped. Modern engines (I say modern in the last 30 years) have become amazing really and will drive fine with the oil pressure through the roof, its just not good practice, and can leave other areas starved of oil if you've talking sub zero temperature. Dont be gentle that they glaze, done be too harsh that nothing has time to expand properly, and as said change your oil as good measure because you're effectively chipping the bores/rings away at each other.

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It's an xud with hdi rods, new rings and a fully rebuilt head with valves cut at a slightly different angle for better flow. I've got a td04 to go on, refurbed injectors and I'm going to refurb a pump because the one I'm using atm isn't that great. Hoping for 160-170 bhp, but anywhere over 150 will be good fun. I'll do a project thread at some point, probably after all the works done, then ill just do a massive write up all at once!

150hp can be achieved with a big blower alone.