"Breaking In" A Rebuilt Engine... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Canadian694x4** · 09-02-2005, 02:27 PM

What's The Proper Way To "Break In" a Chevy Small Block? I have a rebuilt engine and wanted to know the proper procedure in breaking it in.

GMC71k20 · 09-02-2005, 02:39 PM

did you rebuild your307?

Purs · 09-02-2005, 02:40 PM

you'll get many varying answers on this one.... here is one guys opinion.

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

A long time hot rod buddy of mine (who has rebuilt hundreds of engines) says he runs them wide open for 30 seconds, that's it. He says, and I quote, " if it's gonna blow, it's gonna blow in my driveway!".... Personally, I've never had the courage to do it that way...

dubie · 09-02-2005, 02:56 PM

i heard mixed feeling towards breaking in an engine. I tried to baby it for the first while but my foot got itchy and I just couldn't scratch it in time. I now have about 900 kms on the rebuild and she's still nice and tight. I say break it in like you would normally drive it. Some say baby it and don't take it over 40mph, some say run the hell out of it, so I went half way and drove the baby to hell and back

*FormerMember* · 09-02-2005, 04:04 PM

I break them in like I drive them. Have 100k miles on one of my own rebuilds.

Same with any new truck. I break it in like I drive them.

70short/step · 09-02-2005, 04:06 PM

You need to "break in" the cam and lifters like the manufacture says. After that drive it like you are going to drive it. If you are gonna drive it hard, then go for it.

But I would not do the Wide Open the first 30 seconds! You wont even have the oil circulating yet!

**Canadian694x4** · 09-02-2005, 04:32 PM

I had my 283 (that the P.O. put in the Truck) Rebuilt, been driving it today. Haven't been pushing it by any means. Just wondered if there really was a "strict" way of doing so.

Thanks everyone.

Brian

Purs · 09-02-2005, 07:04 PM

Quote:

Originally Posted by 70short/step

I would not do the Wide Open the first 30 seconds! You wont even have the oil circulating yet!

I've never known anyone (that new what they were doing) that didn't "pre-oil" their engine with a drill for several minutes before firing it for the first time.....

70short/step · 09-02-2005, 07:10 PM

Quote:

Originally Posted by Purs

I've never known anyone (that new what they were doing) that didn't "pre-oil" their engine with a drill for several minutes before firing it for the first time.....

Me either. but I have never known anyone (that knew what they were doing) That would fire up an engine and run it wide open throttle for 30 seconds!

Old Yeller 1970 · 09-02-2005, 07:23 PM

Quote:

Originally Posted by 70short/step

Me either. but I have never known anyone (that knew what they were doing) That would fire up an engine and run it wide open throttle for 30 seconds!

My engine builder is an old circle track racing legend from around here. He never would run it wide open for the first thirty seconds but he used to race with a guy who did.
His friend would say he wanted it to blow right then and there if it was going to do it and run the motor right out to 8000 RPM's, though maybe not for thirty seconds. It still makes my engine builder wince when he talks about it. Said he figures it would take off 2-3 races from the life of the engine doing it that way.
My engine builder said to be sure to prelube the engine by turning the oil pump with a screw driver or an old distrubutor with the camshaft gear removed before ever cranking the engine.
Car mags say you should then run it at fast idle for about 20 minutes before driving it.

mplex2000 · 09-02-2005, 07:54 PM

Get some good highway driving (50-70mph) after your initial cam break-in. Helps the rings seat!

86swb · 09-02-2005, 08:09 PM

Just drive it like you always do. I do not know about that 30 second thing? I would not do that myself.

Purs · 09-02-2005, 08:26 PM

Quote:

Originally Posted by 70short/step

Me either. but I have never known anyone (that knew what they were doing) That would fire up an engine and run it wide open throttle for 30 seconds!

relax, if you read my post then you noticed that I said I didn't have the balls to do it myself either. I was just passing on some info from a guy that most likely has forgotten more automotive knowledge than me and you know put together. BTW, he picked that bit of advice from his father who was nicknamed "stroker" (yes and ex-circle tracker too) and his other son was some sort of national champion circle track racer a year or two ago....

am I recommending it, no, but it seems to have worked for them....

cheers!

70short/step · 09-02-2005, 08:42 PM

Quote:

Originally Posted by Purs

relax, if you read my post then you noticed that I said I didn't have the balls to do it myself either. I was just passing on some info from a guy that most likely has forgotten more automotive knowledge than me and you know put together. BTW, he picked that bit of advice from his father who was nicknamed "stroker" (yes and ex-circle tracker too) and his other son was some sort of national champion circle track racer a year or two ago....

am I recommending it, no, but it seems to have worked for them....

cheers!

Oh I am "Relaxed". I just didnt want a guy asking advise on how to break in an engine to try and do something like that. Sorry if you though I was personally 'attacking' you or something.

Purs · 09-02-2005, 09:17 PM

no problem dude

keep on truckin'

Musclerodz · 09-03-2005, 12:02 AM

First remove the distributer and pre-oil the motor until you have pressure. I have always used straight weight oil for break-in. Fire the motor and you want to run it 2000 rpm or above to properly break in the cam and lifters. This is not a real big issue if you have a roller valve train. After that be easy on it for a couple hundred miles. Pull the filter and cut it open to inspect for metal particles. If everything looks good it should last a long time. I have never had any issues on any motor I broke in following this procedure.

Mike

EDIT: I meant to say run in at 2K rpm or above for 20 min. Also if you have a high rate springs, remove the outer spring for break in only. Do not drive without the springs installed.

FRENCHBLUE72 · 09-03-2005, 08:35 PM

I have built 2 engines in my short life time and have always broke in the cam for 20 minutes then drained the oil,put some good oil in it and drove it like I was gonna drive it and both motors were assembled by me a 1st timer and they are still running today....

86swb · 09-03-2005, 08:40 PM

Quote:

Originally Posted by FRENCHBLUE72

I have built 2 engines in my short life time and have always broke in the cam for 20 minutes then drained the oil,put some good oil in it and drove it like I was gonna drive it and both motors were assembled by me a 1st timer and they are still running today....

Well first timer, sounds like you did a good job putting the engins together. I would not know where to start.

09-02-2005, 02:27 PM	#1
Canadian694x4 Born To Lose Club Join Date: Feb 2003 Location: Calgary, Alberta/Oxenden, Ontario, Great White North Posts: 13,307	"Breaking In" A Rebuilt Engine... What's The Proper Way To "Break In" a Chevy Small Block? I have a rebuilt engine and wanted to know the proper procedure in breaking it in. __________________ Brian Smith - "Born To Lose" 1969 Chevrolet K10 LWB Fleetside - Proud Owner For 22 Yrs - 1 of 208 Built & Sold In Canada!- 283 V8/350TH/NP208, 2" All Spring Lift, 32" Good Year MT/R's. 1972 GMC K2500 Custom LWB Fleetside - Proud Owner For 3 Yrs - 1 of 571 Built & Sold In Canada! - 350 V8/SM465/NP205, 4” Rough Country Lift, 33” Interco TSL Thornbirds 2007.5 GMC Sierra SLE 2500HD 4x4 - Proud Owner For 17 Yrs- 6.6L V8 Duramax Diesel/Allison 1000, 2" Lift, 33" Mickey Thompson MTZ's. 2008 Yamaha Raptor 700r - Proud Owner For 15 Yrs - ITP Mud Lites. 2015 John Deere 1025R - Proud Owner For 8 Yrs - 24HP Diesel/H120/54D/260B/SB1154.

09-02-2005, 02:40 PM	#3
Purs Got Big Block? Join Date: Apr 2000 Location: West Texas Posts: 1,510	you'll get many varying answers on this one.... here is one guys opinion. http://www.mototuneusa.com/break_in_secrets.htm A long time hot rod buddy of mine (who has rebuilt hundreds of engines) says he runs them wide open for 30 seconds, that's it. He says, and I quote, " if it's gonna blow, it's gonna blow in my driveway!".... Personally, I've never had the courage to do it that way... __________________ "Experience is what you get when you didn't get what you wanted."

09-02-2005, 02:56 PM	#4
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,853	i heard mixed feeling towards breaking in an engine. I tried to baby it for the first while but my foot got itchy and I just couldn't scratch it in time. I now have about 900 kms on the rebuild and she's still nice and tight. I say break it in like you would normally drive it. Some say baby it and don't take it over 40mph, some say run the hell out of it, so I went half way and drove the baby to hell and back __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

09-02-2005, 04:06 PM	#6
70short/step Registered User Join Date: Dec 2003 Location: Stockton, CA Posts: 1,579	You need to "break in" the cam and lifters like the manufacture says. After that drive it like you are going to drive it. If you are gonna drive it hard, then go for it. But I would not do the Wide Open the first 30 seconds! You wont even have the oil circulating yet! __________________ For every person with a spark of genius, There are a hundred with ignition trouble. 70 Short/Step

09-02-2005, 04:32 PM	#7
Canadian694x4 Born To Lose Club Join Date: Feb 2003 Location: Calgary, Alberta/Oxenden, Ontario, Great White North Posts: 13,307	I had my 283 (that the P.O. put in the Truck) Rebuilt, been driving it today. Haven't been pushing it by any means. Just wondered if there really was a "strict" way of doing so. Thanks everyone. Brian Attached Images __________________ Brian Smith - "Born To Lose" 1969 Chevrolet K10 LWB Fleetside - Proud Owner For 22 Yrs - 1 of 208 Built & Sold In Canada!- 283 V8/350TH/NP208, 2" All Spring Lift, 32" Good Year MT/R's. 1972 GMC K2500 Custom LWB Fleetside - Proud Owner For 3 Yrs - 1 of 571 Built & Sold In Canada! - 350 V8/SM465/NP205, 4” Rough Country Lift, 33” Interco TSL Thornbirds 2007.5 GMC Sierra SLE 2500HD 4x4 - Proud Owner For 17 Yrs- 6.6L V8 Duramax Diesel/Allison 1000, 2" Lift, 33" Mickey Thompson MTZ's. 2008 Yamaha Raptor 700r - Proud Owner For 15 Yrs - ITP Mud Lites. 2015 John Deere 1025R - Proud Owner For 8 Yrs - 24HP Diesel/H120/54D/260B/SB1154.

09-02-2005, 02:39 PM	#2
GMC71k20 Registered User Join Date: Aug 2002 Location: mass Posts: 1,277	did you rebuild your307?

09-02-2005, 04:04 PM	#5
FormerMember Account Suspended Join Date: Feb 2004 Posts: 3,051	I break them in like I drive them. Have 100k miles on one of my own rebuilds. Same with any new truck. I break it in like I drive them.

09-02-2005, 07:54 PM	#11
mplex2000 Registered User Join Date: Jul 2005 Location: DFW Posts: 463	Get some good highway driving (50-70mph) after your initial cam break-in. Helps the rings seat!

09-02-2005, 08:09 PM	#12
86swb Born a Chevy Man Join Date: Apr 2005 Location: Navarre, Florida Posts: 10,221	Just drive it like you always do. I do not know about that 30 second thing? I would not do that myself. __________________ John or 86 (Viet Nam combat Vet-BIG RED ONE) '65-'66 1986 Chevy SWB Silverado 1984 Chevy Longbed Silverado New Kia Sportage (Wife's car and she loves it) CHEVY, American made w/pride! If you can read this, YOU NEED TO THANK A TEACHER! If you can read this in ENGLISH, PLEASE THANK A SOLDIER! GOD BLESS AMERICA AND BLESS OUR FIGHTING TROOPS

09-02-2005, 09:17 PM	#15
Purs Got Big Block? Join Date: Apr 2000 Location: West Texas Posts: 1,510	no problem dude keep on truckin' __________________ "Experience is what you get when you didn't get what you wanted."

09-03-2005, 12:02 AM	#16
Musclerodz Senior Member Join Date: Aug 2005 Location: OKC, OK Posts: 2,364	First remove the distributer and pre-oil the motor until you have pressure. I have always used straight weight oil for break-in. Fire the motor and you want to run it 2000 rpm or above to properly break in the cam and lifters. This is not a real big issue if you have a roller valve train. After that be easy on it for a couple hundred miles. Pull the filter and cut it open to inspect for metal particles. If everything looks good it should last a long time. I have never had any issues on any motor I broke in following this procedure. Mike EDIT: I meant to say run in at 2K rpm or above for 20 min. Also if you have a high rate springs, remove the outer spring for break in only. Do not drive without the springs installed. __________________ Mike Redpath Last edited by Musclerodz; 09-03-2005 at 11:37 PM.

09-03-2005, 08:35 PM	#17
FRENCHBLUE72 PROJECT 7DEUCE Join Date: Dec 2002 Location: GRANTS PASS OR Posts: 21,606	I have built 2 engines in my short life time and have always broke in the cam for 20 minutes then drained the oil,put some good oil in it and drove it like I was gonna drive it and both motors were assembled by me a 1st timer and they are still running today.... __________________ GO BIG GREEN GO DUCKS MEMBER #6377 72 k-5 daily driver 6'' lift 35'' 350-350-205 slowly getting rust free. Project "7DEUCE" check out my build http://67-72chevytrucks.com/vboard/s...d.php?t=267665 Tim Powell..R.I.P EastSideLowlife..... R.I.P..



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