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MG MGA - engine rebuild break-in

So far I've put about 350 miles on my rebuilt 1500. The other day I took it up to 85 without a hitch. Any idea when it will be fully broken in, or how it should be driven to break it in, if at all? In the old days I remember recomendations like not over 50 for the first X miles (500?) and never at a sustained speed for longer than x. I've also heard people say break it in the way your going to drive it. Nowadays I don't think new cars come with such recommendations.
brucep

Just had my 1800 rebuilt and was told easy driving for the first 300-500 miles with a max speed of 50 using 10W30 oil. Change oil and filter to 20W50 for next 300-500 miles with speeds up to 60ish. Change oil and filter again to 20W50 then all should be fine.
I'm sure there may some different suggestions but they should be pretty much the same.
Kris
Kris Sorensen

Hi Bruce. After and engine rebuild, I drive the car very gently for the first 200 miles. No full throttle, or high speed driving at all. I do vary the engine and road speed speed considerably however. Short bursts of light acceleration followed by backing off the accelerator is good. This helps load the piston rings, and helps to bed them in, and also sucks oil into the cylinders, for extra lubrication. After 200 miles, I gradually increase acceleration, and top speeds, for very short periods of time. Around 450 miles, I start pushing the engine a bit, with higher (but not redline) RPM's and higher road speeds for relatively short periods of time. Around 500 miles, I start driving the car "normally", that is using higher revs and road speeds on a regular basis. Around 500-600 miles I change the oil and filter. I still use "conventional" motor oil and run 20 W 50. After another 1000 miles, I again change the oil but then switch to synthetic, which I swear by! Cheers! Glenn
Glenn

My engine rebuilder gave me running in / cutting in oil which is very thin (Castrol No 2)for the first 500 miles, no high speed high rev driving, change oil to 20/50 after this.
Dave

How does one justify dyno tuning a new engine if brake in is required?
brucep

Bruce, that's what I've been wondering, as I am about to have my tired old 1600 engine replaced with a rebuilt one. How much revving is safe during the break-in period - 3,000RPM?

Regards,
M.D.
'57 Coupe
M. D.

You can break the engine in on the dyno. I have seen this in engineering areas.
mike parker

This thread was discussed between 15/06/2005 and 16/06/2005

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This thread is from the archive. The Live MG MGA BBS is active now.