Break In Procedures

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LJS30

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Well guys I finally got my Dart back and the freshly rebuilt 318 sounds nice. However I want to know what is the proper way to break in an engine after a rebuild? On a previous rebuild I just babied it a little for about two thousand miles and changed the oil at that point. What do you gents do for a proper break in time?
 
Did you break the cam in on the first run? 2500-3000 for first 25 minutes of run time?

Break-in depends on who you ask.
 
Cam is broken in and changed the oil/filter???

Go drive it as hard as you like. This isn't the 60's with sloppy machining and tolerances.
 
Safe to assume the cam is broken in? If so, drive it like you stole it.
 
According to the 1972 Dart Owner's Manual:

"A long break-in period is not required for the engine in your new car. Drive moderately during the first 300 miles. After the initial 60 miles, speeds up to 50 or 60 mph are desirable. While cruising, brief full-throttle accelerations within limits of state and local traffic laws contribute to a good break-in. Wide open throttle accelerations in low gear can be detrimental and should be avoided for at least 500 miles...."

In order to get things to seat properly in the engine, the sources I have read say to vary engine speed every 4-5 minutes at most during the first 300 miles.
 
X2 what 2 darts posted. After cam breakin on dads 273 he put maybe 100 more miles on it then we changed oil. Went on a weekend trip to Moparfest, which was about 300 mile round trip. Ran like a champ, no issues.
 
After the cam is broken in run her like Mopars were made to run. Hard and Fast !!!!!!!
 
crackedback said:
Cam is broken in and changed the oil/filter???

Go drive it as hard as you like. This isn't the 60's with sloppy machining and tolerances.
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X2, and if you have a roller cam you can just seat the rings real quick and then go beat on it...even easier. :D That is what I did with my 410 stroker motor, and 4 years later with hundreds of passes down the 1/4 mile and thousandths of street miles, its still doing fine.
 
Some of you need to get out of the 60's... :)

Cast rings, sloppy bores, poor piston wall clearances... none of which should be happening today with quality machine work.

I can't think how much pump/race fuel I'd have to go through to get 300-500 miles on an engine. Cam got broken in, oil, change, idle got set and it was beat the daylights out of it.
 
UOP said:
Did you break the cam in on the first run? 2500-3000 for first 25 minutes of run time?

Break-in depends on who you ask.
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Yea my friend broke it in before I picked it up. I guess the consensus is to drive the heck out of it. That shouldn't be a problem. :D
 
Guys dyno engines all the time. Do you think they baby those after the cam is broken in. How many hours on the dyno to simulate 300 miles? Never gonna happen to run it for 5 hours at 2500-3500.

Once they are broken in and maybe an oil change, they get flogged!

My last one got the rings broken in and got treated to about 40 pulls, 38 in excess of 6K rpm... :)
 
Yes but not everybody tears apart their engine each season and replaces the bad stuff.

Some of us street guys like to get over 50,000 miles before popping off even a valve cover
 
and that meant what? I have had several stock, except for cam and valve springs 340's spin 7000 all day long.
 
dodge freak said:
Yes but not everybody tears apart their engine each season and replaces the bad stuff.

Some of us street guys like to get over 50,000 miles before popping off even a valve cover
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This makes no sense....absolutely NO sense!
 
crackedback said:
Cam is broken in and changed the oil/filter???

Go drive it as hard as you like. This isn't the 60's with sloppy machining and tolerances.
Click to expand...
x2 they don't baby any kind of race engines.if the cam is broke in correctly ,hit it!if its gonna come apart it will.
 
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