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Old 03-03-2008, 08:04 PM   #26
Billla
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Re: crank case pressure HIGH!!!

Quote:
Originally Posted by Sport/Truck View Post
Then you won’t agree with this…….. http://www.mototuneusa.com/break_in_secrets.htm
s/t
Hmmm: "Although the examples shown here are motorcycle engines"...

Otherwise, it's just a big collection of crap IMHO - I don't see any "secrets". This guys credentials are...what? Some of the comments are OK - but they're well-known and nothing magical.

The best break-in for a GEN I, after cam break in is complete if required is to follow the guidance in the shop manual - cycles of acceleration at about 60% throttle and then letting off to "compression brake" the engine. With current ring technology and a machine shop that knows how to make the right surface for them the engine can be considered fully broken in after about 300 miles. I've pulled enough broken rings out of engines that were beat on in the first 20 miles to disagree with the "just do it" approach.

Note that racing engines are different; they're typically running forged pistons with relatively loose clearances - maybe even .005+ - vs. the hypereutectics with .001.

This is a little rambling, but the bottom line is that street engines aren't race engines and require a different technique.
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Old 03-03-2008, 08:52 PM   #27
Sport/Truck
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Re: crank case pressure HIGH!!!

I thought I'd throw it out there just for the controversy. It did make some good points, and is applicable to all 4 strokes.
s/t
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1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe.
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Old 03-03-2008, 08:57 PM   #28
Billla
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Re: crank case pressure HIGH!!!

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Originally Posted by Sport/Truck View Post
I thought I'd throw it out there just for the controversy. It did make some good points, and is applicable to all 4 strokes.
s/t
Absolutely - any critical tone in the message was directed at the website, not at you

Which points did you believe to be good?

The guy that posted the web noted that it was applicable to all 4 strokes...athough as noted he has never "tested" it with anything other than motorcyle engines. Again - this guy has absolutely no creds that I can see - is his name, engineering background, shop afiliation - ANYTHING posted anywhere? If he's built 300 (motorocyle only) engines and used this "with no problems", where is the long-term follow-up?
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