Running a rebuilt engine

Post by **youngun** » Mon Sep 24, 2007 9:23 pm

After ive rebuilt the engine and its back in the mog, seems like a long way off!! Whats the best way to go about running it, i.e. oil and fuel wise??

YG

Post by **bmcecosse** » Mon Sep 24, 2007 10:13 pm

Just take it easy - don't hammer it. Can't remember what's been done - is it re-bored/new pistons ?

Post by **d_harris** » Tue Sep 25, 2007 12:38 pm

Just use normal fuel, and norwal 20w50 then change the oil and filter after about 500 miles.

Also, be really sympathetic to the engine

Post by **MoggyTech** » Tue Sep 25, 2007 3:11 pm

Don't hammer the poor thing, and try NOT to drive at steady speeds for too long, but vary speed a little. Then oil and filter change after 500 miles. Also do not use any oil additives, just a quality 20/50W

Post by **bmcecosse** » Tue Sep 25, 2007 6:50 pm

Why not drive at steady speed ? Where on earth is the logic in that idea ?

Post by **MoggyTech** » Tue Sep 25, 2007 7:13 pm

bmcecosse wrote:Why not drive at steady speed ? Where on earth is the logic in that idea ?

Well known fact from earlier engines. Varying speeds mean the bearing loads vary slightly, leading to better running in of bearing shells etc. This was drummed into me by every mechanic during the 60's and 70's

Still used today in a slightly modified form.

http://www.mototuneusa.com/break_in_secrets.htm

Post by **youngun** » Tue Sep 25, 2007 7:24 pm

I see, its just good to know what to do once its done....pretty much the same do's and dont's as that of motorcycle engines!!

Post by **MoggyTech** » Tue Sep 25, 2007 7:31 pm

youngun wrote:I see, its just good to know what to do once its done....pretty much the same do's and dont's as that of motorcycle engines!!

Yes indeed. While being fairly gentle on a new engine is standard practice, the odd burst of speed, and high rev over-run does more GOOD than HARM if the engine was rebuilt to a high standard. Too much gentle cruising for extended periods from the get go, can result in poor piston ring bedding in, and an engine that uses a fair bit of oil, even after it's run in. I wouldn't advise doing 'burn-outs' but a bit of fun will give a smoother engine in the long run.

Oh and the way to kill a new engine is letting it labour through the gears. NEVER EVER do this in an attempt to keep the revs down. In fact, don't do it to any engine, run in or not.

Post by **dalebrignall** » Tue Sep 25, 2007 7:48 pm

i drove mine with a bit of sympethy i did not thrash it but i varied my revs did not stay at the same spped too long and i did regular gear changes so the engine did not get put under strain,i think its ok oil pressure 60 on the motorway at 60 mph when warm just dont go mad with it.

Post by **MoggyTech** » Tue Sep 25, 2007 7:52 pm

dalebrignall wrote:i drove mine with a bit of sympethy i did not thrash it but i varied my revs did not stay at the same spped too long and i did regular gear changes so the engine did not get put under strain,i think its ok oil pressure 60 on the motorway at 60 mph when warm just dont go mad with it.

Yup, that's the way to keep a new engine happy for ages.

Post by **bmcecosse** » Tue Sep 25, 2007 10:09 pm

Err - bearings don't need ANY running in - it's just rings and bores you need to worry about! There is absolutely no logic in avoiding 'steady speed' running - just don't hammer it till the rings bed in to the bores.