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RBL · Posted: Thu Apr 28, 2005 5:25 pm Post subject: Running in engine

I've rebuilt my engine (8v 1.7) with everything other than new pistons and hydraulic tappets.

What's the best way to run it in? I've read a few different theories. In my ignorance I've already started it a few times to check everything and get it up to temperature and do the timing. However before I go any further I think I need to run it at 2,500 to 4000rpm for 15 minutes to properly bed in the piston rings.

Is this correct? Anyone have any definative ways of doing it? (I want to do it this weekend because a mechanic is coming round on Tuesday to properly balance the carbs and tune it.)

Thanks, Rich

Ian M · Posted: Thu Apr 28, 2005 7:05 pm Post subject:

Just running it gently to tune wont hurt it but to run it in properly I would suggest you need to do about 500 miles at no more than about 3500rpm.
Thats how I do it anyway
Ian
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ChrisC · Alfa Sprint Joined: 13 Mar 2003 Posts: 152 Location: Frome

has it actually been rebored or just new rings?
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Bellamachinna · Posted: Fri Apr 29, 2005 4:16 pm Post subject:

Hi...

In my opinion, in the first 1000 Km`s, you should run it gently avoiding to go above 3500 Rpm. Keep always an correct gear ratio for each ocasion, to avoid forcing the engine to pick up from low revs.
After this 1000 km´s, and till the 3000 km`s you should start using 4500/5000 revs, keeping always the correct gear ratio. During this part, you can start to push it a bit (never till the red line, and never in first gear), to ensure that you dont get an "lazy" engine.
For me the runing in period is divided in two parts:
-Till 1000 Km`s (beding)
-After 1000 km`s, and till 3000Km`s (freeing)
After the 3000 km`s, change oil and filter and "PEDAL TO THE METAL"
Hope this helps
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alexj · Posted: Sun May 01, 2005 5:23 am Post subject:

What do people think of this page....

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

gritsop · Posted: Sun May 01, 2005 9:16 am Post subject:

Hi,

His advice sounds OK with good arguments but I would prefer to follow the workshop manual since it has been written by the mechanics that actually built the motor and their knowledge is applied on it.

Just my opinion.

Regards
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Bellamachinna · Posted: Sun May 01, 2005 11:36 pm Post subject:

Hi...

Guest · Posted: Mon May 02, 2005 10:14 am Post subject:

taken from 'four stroke performance tuning 2nd ed - by Graham Bell'
The initial bed-in of rings is acheived by giving the car a full throttle burst for a few seconds, followed by snapping the throttle shut and coasting for a few more seconds. This should be repeated at least 12-15 times with the engine at normal operating tempreture. Accelerate the vehicle in top gear from the slowest speed it will pull in that gear. By givving the engine full power, the high gas pressure forces the rings out against the bore wall. snapping the throttle shut causes a vacuum in the cylinder, which draws up extra oil. This and low engine speed minimises the risk of glazing and allows the ring to face and cylinder wall to cool. After the rings a initially bed in, the engine can be opperated at up to 80% of rev/power potential, but constantly vary the speed. If this is not done, the rings may still glaze. After about half an hour of this on the dyno or the race circut, the rings can be considerd run in. A road engine with crome rings should be run in for about 200 mile, prefferably in one session. Again, constantly vary the enginespeed and include heavy acceleration for short bursts as for initial bedding in. avoid constant high speed untill the engine has done 500-700 miles. good luck with the new engine!

ps. change the oil after 50km or so as most of the intial wear occours in this period - dont leave it till 3000km.

Guest · Posted: Mon May 02, 2005 10:19 am Post subject:

Guest · Posted: Mon May 02, 2005 2:43 pm Post subject:

Thanks for the replies guys. You can see the reason for my question - there are many theories!

(Chris. The cylinders have been honed but not rebored.)

Thanks Alexj, I've read this site: http://www.mototuneusa.com/break_in_secrets.htm and it makes most sense but is contravercial and goes against owners manual instructions. It is similar to what the previous person (guest) has said in that high pressure is needed to force the rings out. Otherwise, with gentle running, they will never be properly bed it and carbon deposits will build up and you'll lose some HP.

RBL · Posted: Mon May 02, 2005 2:45 pm Post subject:

Sorry, that was me (forgot to login)

Thanks for the replies, Rich

Bellamachinna · Posted: Mon May 02, 2005 3:46 pm Post subject:

Hi

James Granger · Alfa 33 Joined: 10 Apr 2003 Posts: 302

RBL · Posted: Wed May 04, 2005 3:47 pm Post subject:

Thanks James, I think that is what I'll do.

Had it crypton tuned yesterday. I'd done it myself and it was 15degress advanced - no wonder it didn't sound good! He's done it properly now and the emmisions is 2.9% HC at idle. (He said 3.4% was the maximum allowed at the test). I won't run it now till it's ready for the road (a couple of weeks) then I'll try those break in proceedures.

I'll let you know how it goes.