402BB engine break in ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Daves72'GMC · 05-27-2008, 11:29 PM

I'm almost done with the 2 1/2 year ground up rotisserie restoration on my 72' GMC and the 402BB engine only has about 50 miles on it and I was wondering is there a certain way for breaking the engine in and for how many miles?Thank you.

LONGHAIR · 05-28-2008, 04:07 AM

Cam "break-in" should be on the first start-up. If it was properly "assembly" lubed you might luck-out....
Other than the usual "don't lug it", "don't over-rev it" type stuff, there isn't much else.

**El Jay** · 05-28-2008, 04:43 AM

I'm thinking Longhair and I think along the same lines.

Right, or wrong, here's what I do: I run it in the driveway; never at a constant speed. Always above an idle, but never "screaming", maybe about 2500 RPM, max; constantly changing the engine speed. I know that sounds boring if you're the guy in the driver's seat.
After doing that for 1/2 to 1 hr., I shut it down; and change the oil and filter.
Then I drive it "normally" for about 1000 miles, and change the oil & filter again.

Yeah, I know, it's hard to keep your foot out of it when you got a new engine.

Hope that helped.

HoupPhotography · 05-28-2008, 06:24 AM

Why\how does the motor have 50 miles on it?

05-27-2008, 11:29 PM	#1
Daves72'GMC Registered User Join Date: Mar 2003 Location: Asheville, N.C Posts: 952	402BB engine break in ? I'm almost done with the 2 1/2 year ground up rotisserie restoration on my 72' GMC and the 402BB engine only has about 50 miles on it and I was wondering is there a certain way for breaking the engine in and for how many miles?Thank you.

05-28-2008, 04:07 AM	#2
LONGHAIR just can't cover up my redneck Join Date: May 2004 Location: Columbus OH Posts: 11,414	Re: 402BB engine break in ? Cam "break-in" should be on the first start-up. If it was properly "assembly" lubed you might luck-out.... Other than the usual "don't lug it", "don't over-rev it" type stuff, there isn't much else.

05-28-2008, 04:43 AM	#3
El Jay Gone to greener pastures Join Date: May 2007 Location: Gateway to the Delta Posts: 7,354	Re: 402BB engine break in ? I'm thinking Longhair and I think along the same lines. Right, or wrong, here's what I do: I run it in the driveway; never at a constant speed. Always above an idle, but never "screaming", maybe about 2500 RPM, max; constantly changing the engine speed. I know that sounds boring if you're the guy in the driver's seat. After doing that for 1/2 to 1 hr., I shut it down; and change the oil and filter. Then I drive it "normally" for about 1000 miles, and change the oil & filter again. Yeah, I know, it's hard to keep your foot out of it when you got a new engine. Hope that helped. __________________ '69 Chevy 1/2 T LWB Stepper: Daily Beater '72 GMC 3/4 T Fleet: Another Daily Beater '72 Plymouth Gran Coupe: ? "Ah women. They make the highs higher and the lows more frequent." Friedrich Nietzsche "Never kick a fresh turd on a hot day." Harry S. Truman GUN CONTROL: Never having to say, "I missed you." Always fire two warning shots into your attacker's chest area before putting a bullet between his eyes. Paraphrased from Louis Awerbuck

05-28-2008, 06:24 AM	#4
HoupPhotography Registered User Join Date: Feb 2008 Location: Phoenix, Az Posts: 1,204	Re: 402BB engine break in ? Why\how does the motor have 50 miles on it? __________________ R.I.P. Scott Kalitta

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