[ds968]

Ok, now that I managed to "break" the valves [img]style_emoticons/<#EMO_DIR#>/rolleyes.gif[/img] , how do I break in the new ones ? I hear new valves require some time to settle in just right ( I'll have new lifters and new guides as well ) so for the first 100 or more miles the speed at which I'm driving should vary as much as possible and that I should even put a bit of stress on the rpms from time to time, but absolutely not go over a 5krpm level... is this correct, or is there a commonly accepted wisdom for what exactly it is that I should do ?

Guidance is appreciated !

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[xrad]

avoid high rpms (above 5000) for first fifty-100 miles or so, but vary rpms, not a straight 50 miles at 60mph. that should be about 250,000 to 500,000 cycles...more than enough. They are not as sensitive as rings....

then change the oil.

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[flash]

"break them in on the track" - that's what we always said

or was it "break them into pieces on the track"?

i can never get that one straight

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[ds968]

<!--quoteo(post=73539:date=Jun 8 2009, 05:20 PM:name=xrad)-->QUOTE (xrad @ Jun 8 2009, 05:20 PM) <{POST_SNAPBACK}><!--quotec-->then change the oil.<!--QuoteEnd--><!--QuoteEEnd-->

Why ? ( BTW, I have fairly new oil in there now )

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[S_Cal968]

What xrad suggested is more for seating piston rings and bearings in a fresh engine. Typically a cam & lifters break-in after 20-30 minutes of operation. I 2nd changing the oil after ~1000-1500 miles...

re: oil cahnge; with any newly machined parts, there's always the chance of metal particles, which is rather undesirable for obvious reasons. Also if assembly lube was used when installing the lifters [I hope they use it], it's best to get that out too.

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[ds968]

<!--quoteo(post=73554:date=Jun 8 2009, 07:18 PM:name=S_Cal968)-->QUOTE (S_Cal968 @ Jun 8 2009, 07:18 PM) <{POST_SNAPBACK}><!--quotec-->re: oil cahnge; with any newly machined parts, there's always the chance of metal particles, which is rather undesirable for obvious reasons. Also if assembly lube was used when installing the lifters [I hope they use it], it's best to get that out too.<!--QuoteEnd--><!--QuoteEEnd-->


noted. will change the oil as indicated.

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[xrad]

The above is what I tell anyone else to do for break-in. For my engines personal rebuilds, I tend to run them in hard over the full rpm range after 20 miles with at least 2 oil changes before 100 miles. I like to start with non-synth for older engines and synth for newer. I have inspected the cylinders and valves on several of these engines and they were in excellent shape.

After measuring tolerances and making everything as clean as possible, I have not had any problems

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