Improper engine break in.

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alpha13

alpha13

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Hey guys, I've been milling it around in my head for about a week. Long story short. I helped a friend rebuild a mild 350 chevy. (I need Mopar Baptized!) After we broke in the cam for the 30 minutes, I mentioned changing the oil. He insisted that it didn't need changed for at least 50 miles. I told him otherwise but he drove it anyway. We drove the truck around for about 50 miles and changed the oil using the zinc additive. I told him about the 500 miles of lightly driving to break in the rest of the engine and he agreed. Then he sends me a video of him doing burnouts and romping on it with just over a few hundred miles on a fresh built engine.:banghead: I told him to go easy on it for a while after I saw the videos. Anyway, my real question is, How much damage could actually have been done to his engine? I would assume his rings might suffer a little and some internals might have a harder time mating. Do you think it will live if he baby's it for the rest of the break in cycle? I don't know everything, I'm just curious to know some opinions or experiences.:prayer:
 
I mean he's being redeemed a bit since it's mild, hopefully gave him a little slack. Still something I sure as hell wouldn't do with my fresh build. I'd be keeping a close eye on any shimmer in that next oil change. At the least I'm sure those lifters aren't too happy.
 
Put a new engine in my 73 Duster...fired it up and broke in cam....drove it around block to make sure the trans shift....changed oil .....load it on the trailer..head to the race track...

made two passes....next TNT is may 1...hope to make alot more passes....

sort of like what he did...
 
My 340 was broke in mild...for about a week,,,,,since then I beat the $hit outta it for the last 8 years and it runs sweet (knock on wood) lol :burnout:
 
Built my 360, broke in the cam, changed the oil, stomped the living crap out of it (300ish miles). Pulled the engine to paint engine bay and checked it out for ***** and giggles. Looks like I just built it. haha. Fun times. I believe once you get the rings to seat and cam broken in, it's fair game. Haven't had one come apart on me yet, maybe i'm lucky.
 
Well if it was my daily driver with stock parts and was planning on hundreds of thousands of miles of dependable service ? Well, yes everything you where saying. BUT , if he bought expensive high quality high performance parts and is really only expecting 20-30,000 miles with lots of fun track days? He's fine.:burnout:
 
oh crap man I forgot he was talking about a Chevy that thing could blow at any minute! It's not like a Mopar that can take abuse!
 
Built hundreds of engines all the same way assemble correctly. Break in cam if its flat tappet. Change oil, then beat on it. Give back to customer. Have a very good success rate so far.
 
So the majority says he is alright. Good to know. I had another friend who blew 3 chevy engines. I got tired of messing with them so I just wanna make sure I don't have to tear this thing apart again soon. I've heard of guys long ago not even breaking in cams and never had a problem. Just putting it together and driving the hell out of it.
 
You don't see them professional Pro Stock, Funny Car and Top Fuel boys breakin stuff in for 500 miles. They rebuild um in the pits bust um off to make sure they're right and then put the fire to it. Same in NASCAR.

Once the camshaft is broken in, IMO, it's Katy bar the door. Because if it's gonna break, it's gonna break anyway so you might as well find out.
 
My main concern is not changing the oil right after the cam was broken in. IMO $20 for a good filter and 5 qts. of oil is real cheap insurance. As far as romping on it right after it's assembled it really depends on how tight the bearings and pistons were. If it's just a re-ring, no new pistons and crank it should be loose enough that going straight out and letting it rip won't hurt any more than it would 500 miles down the road. Brand new cars when assembled needed a little time to loosen up because the engines were built with real tight tolerance's so they'd last 100,000 plus miles. That's why they recommend a break in period
 
If it doesn't leak, or knock, make funny noise; was assembled properly, go out and stand on it just as hard as you can, not gonna hurt it.
 
LMAO...broke my 416 in running it down the 1/4..no problem,we build them to beat on..
 
RustyRatRod said:
You don't see them professional Pro Stock, Funny Car and Top Fuel boys breakin stuff in for 500 miles. They rebuild um in the pits bust um off to make sure they're right and then put the fire to it. Same in NASCAR.

Once the camshaft is broken in, IMO, it's Katy bar the door. Because if it's gonna break, it's gonna break anyway so you might as well find out.
Click to expand...

Well also though, those top fuel cars destroy themselves in one pass... They have to rebuild it after every run because they are so powerful. They have a one speed transmission and the clutches actually weld themselves together on the way down the track because of the intense heat. It's actually pretty cool.Lol.
Alright, so older engines have looser tolerances so the break in period isn't as strict. Lots of good news haha. I will let my friend know he is alright. Thanks for the advice guys!
 
Break the camshaft in, Change the oil and filter. And drive it like you STOLE it !!
 
They don't baby them for 500 miles when they run them in on a Dyno. This is 2015, not 1945.. Modern engine materials and technology reduce run in time and run in problems.
I don't change the oil either right after the cam is run in.. why would I? If the engine is clean when you assemble it, what would you expect to find?? I just check to see if there is any sign of metal in the oil.
 
Break it in like you're going to drive it! If he's going to beat on it, then beat on it all the time!!

Read a story some time ago....Greg Rager bought his 69 Roadrunner 4 speed, took it off the lot, immedietly changed to Wolfs Head oil and set out for about a 200 mile trip! He was told by some knowledgable builder of Mopars to get it up to speed, then drop it in 3rd and maintain that speed and watch the temp guage climb! When it tops out and starts to come back down, that is the point that the motor is broken in! Arrived at his destination and immedietly went to the track! Strong runner still to this day!! Geof
 
I'm glad everyone has shared their stories and experiences. Most everything I own has a ton of miles so I have never had to worry about a break in period til now.
JBurch, that was an interesting article. It really does make sense. I now know i won't break a new engine in lightly. Also I.definitely won't be using synthetic Rusty. Lol
 
Hi Guys, just put in a newly built 70 - 340, 40 over 10.5 -1, balanced crank, 2.02 J heads with roller rockers w bee hive springs, air gap, holley 750 DP, comp cam 20-670-4... 474/474 lift with a duration @ .050, 233/240, hooker headers.....factory 4 speed with 3.55's.....has about 100 miles on it so far....been running through the gears up to about 4K rpm....city / rural driving
THOUGHTS re break in ...keep it up... more of the same or vary?
 
The best way to seat the rings is a couple of burnouts. But not changing the oil after cam break in is rediculous for a flat tappet cam engine. Roller cam, no big deal.
 
All these 500-mile break-ins? LOL it's funny to see what I said 5 years ago.,..
I was supposed to break in my motor for 500 miles and I was supposed to break in my transmission for 500 miles and I was supposed to break in my clutch for 500 miles and I was supposed to break my rear end in for 500 miles... LOL...
All of which made it to the quarter mile track before 50 miles lol... Five years later she's doing fine...
 
One guy i knew wanted to run up his 454 crate engine at idle for a few hours before driving it.
Said he blew one up in his driveway during the cam break in.
I give her the 1500 rpms for 1/2hour and he changed oil. Still good as far as i know.
Cant putt them around,
 
As I understand it the higher RPM at break-in is to get the cam saturated with oil... My engine builder did say to drive it kind of easy for 50 miles or so or like an hour of driving around town with the brake and oil in.. change the oil and let it have it..
I assume when you're changing the oil you're getting rid of any of the metal to metal breakin contaminants... Which I would hope there wouldn't be much....
Once that cycle is over I fail to see any reason the motor can't be taken to its potential...
 
Shayne Dysart said:
Hi Guys, just put in a newly built 70 - 340, 40 over 10.5 -1, balanced crank, 2.02 J heads with roller rockers w bee hive springs, air gap, holley 750 DP, comp cam 20-670-4... 474/474 lift with a duration @ .050, 233/240, hooker headers.....factory 4 speed with 3.55's.....has about 100 miles on it so far....been running through the gears up to about 4K rpm....city / rural driving
THOUGHTS re break in ...keep it up... more of the same or vary?
Click to expand...
Keep increasing the RPM's and the load more and more.
 
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