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MG MGF Technical - Minimum break-in distance

Hi all,
Car: 1996 MGF 1.8i, 63,000 km
Replaced parts :
Valve guides, valve seals, piston rings, cylinder liners, full overhaul gasket set, timing belt, water pump.

ATM, driving in town areas is not a problem but in the highway its such a bore. I have to constantly look at the tachometer to keep track of engine speed. What is the minimum distance I should drive below 3000rpm before I can really enjoy driving my F again?


I can well imagine that would be a real bore Dani!!!

IIRC the rpm limit can be slowly increased from about 500 miles, enabling you to use almost the full rev range from about 800 - but I'm sure someone with access to their owners handbook will be able to sort you out with the official figures. :o)
Rob Bell

The mgtf book, which should be pretty much the same given it's the same engine, says <3000 revs for 600 miles. There's no mention of slowly increasing engine revs or anything like that as far as I can remember.
However, the general feeling on the BBS was that revs should be increased by 1k revs every 100 miles thereafter, so the full range should be available at about 1000 miles.
I'm at about 550 in the TF and can feel it loosening up, so I'm now more confident about occasionally hittling 3500-4000 revs. For those who have already been through this torture, is there a noticable surge of power on a VVC (160) engine at around 4k revs like on the MPI? Presumably the VVC mechanism will have more of any effect around that point?




Yes, the VVC engine comes into its own above 4000rpm. It then goes on, up to max rpm. Enjoy!

Bruce Caldwell

Hmmm, minimum break in distance eh? I'd say about 0mm, you need to be in contact with the car to break in.


SF <--being facetious

Thanks to the replies. Have driven it for 400+km already. Can't wait to reach the 600km mark (to be on the safe side).

Happy motoring to all.


When running in it is probably more important to vary the revs and not labour the engine than sticking rigidly to 3K revs. You should not keep the rev counter at 3K, if you are driving, say, on the motorway. Vary it up (yes up) and down. The biggest sin is to labour the VVC engine. I found with both the F and TF that I was driving at around 3K revs but changing gear at 4K revs to keep the revs up.

Just don't go mad when you hit 600 miles as this engine takes a lot of running in. My TF has done 9K miles and now feels that it has arrived.


Michael Williams



We are talking miles and you are talking kilomtres. It is 600 Miles to run the car in. This is around 900 klms!


Patrick Beet

Michael, I'll keep that in mind. Thanks.

Patrick, thanks for the warning. In my eagerness, I mistook the miles for km. Planning a 200km drive this weekend, gotta bring along things to keep me awake :) Anyway, as long as its on the road again.


This thread was discussed between 01/10/2002 and 02/10/2002

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