Break-In. How Long?

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eekvonzipper said:
New Cam/Lifters/Chain, Fresh Rings. Rebuilt '65 273, Cam Break-In done...
Started Driving it over the weekend. Haven't Revved it passed 3000 rpm yet.
How long should I be nice to it before I can Floor-It and Shift at 5000?
Click to expand...
What was your procedure in breaking in the cam?
 
Engine running-in is another area that has done a back flip over the decades. And nothing to do with iron rings. Even with Moly rings back in the day, the idea was to be gentle, creep up on the engine speed over a lot miles.
Modern thinking is that loading the engine forces combustion pressure behind the rings to force them out against the bore & bed-in more quickly.
Take your pick!
 
I think there should be a new name for the phenomena of forum paranoia overkill overload.....
I've seen everything from the most expensive builds blow up on the runstand to the cheapest builds rev to the moon forever....
Boy I've watching people spend some money trying to make their conscience feel good....
 
Best is on a dyno so some load can be added, with 20 minutes of cam / ring brake in, we cycle the throttle between 2000 and 3000 and some steady spots in between with some load added after about 10 minutes and cycled with and without load. Let them cool down for a few hours then warm them back up and do some full power pulls. Will say, that the first power pull is the hardest to watch, especially when the red line is 9800…. Just pulled a motor off the dyno on Monday for a car going to Laguna tomorrow.
 
Scody21 said:
Best is on a dyno so some load can be added, with 20 minutes of cam / ring brake in, we cycle the throttle between 2000 and 3000 and some steady spots in between with some load added after about 10 minutes and cycled with and without load. Let them cool down for a few hours then warm them back up and do some full power pulls. Will say, that the first power pull is the hardest to watch, especially when the red line is 9800…. Just pulled a motor off the dyno on Monday for a car going to Laguna tomorrow.
Click to expand...
I was watching a 410 sprint car deal on a dyno and at 8800 my butthole puckered up. And it wasn’t even my engine. That thing went to 9400 and didn’t complain. Very cool to watch/hear.
 
Tom Nelson built a small cube LS with twins for a boat and ran it on the dyno at full throttle, full load, and full boost for multiple 5 minute runs.

 
I fixed a Performance Issue with a Ballast Resistor!
The First Time I gave 'er the onions it revved well up to about 3 1/2 r's and started to stumble and miss...
Runs Well at W.O.T. to 3 1/2 r's and then runs like s**t,
I've thought about this all day... wondering what did I change that caused this?
I got a Halifax Distrib, Accel Wires, NGK Plugs and an Accel Yellow Coil. I tried to match the Coils resistance with an Equal Resistor @ around 1.6ohms (Too Much!)
I put My Old Resistor (.7 - .8) back in there tonight, changed Nothing else and Bam! She Runs Like a Striped-A**-@pe!
Now I just have to summon the nerve to run it passed 4xxx R's... 3rd gear at 4000 rpm was about 75mph and Loud! Lol Too Much Fun!
 
If the bore finish is right and you have a quality ring package. They are pretty much seated by you turning the motor over by hand as you assemble it. I break in the cam and change the oil and have at it. Change oil again at 500 miles. Has worked for me. My guess is that most ring seal failures can be traced back to fuel washing the cylinders or bore condition at start.
 
best advice i ever got was from Terry Zeke Maxwell he built my 440 and told me once cam was broken in try to kill it , beat it from day one and drove that truck for 700,000 miles over 13 years never had a problem with the engine . Do the same with all my cars either they last or they don't
 
Nat said:
best advice i ever got was from Terry Zeke Maxwell he built my 440 and told me once cam was broken in try to kill it , beat it from day one and drove that truck for 700,000 miles over 13 years never had a problem with the engine . Do the same with all my cars either they last or they don't
Click to expand...
Pat Musi says the same thing. Break the rings in on the first burnout. Then run it like it owes you money.
 
eekvonzipper said:
New Cam/Lifters/Chain, Fresh Rings. Rebuilt '65 273, Cam Break-In done...
Started Driving it over the weekend. Haven't Revved it passed 3000 rpm yet.
How long should I be nice to it before I can Floor-It and Shift at 5000?
Click to expand...

I had my '65 273 professionally rebuilt at an engine shop, and they told me 1,000 miles before it's fully "broken in." I am sure you know this, but you also need to use something like Valvoline VR1 racing oil if you plan to run readily available premium unleaded. Love our '65!
 
Not sure what fuel choice has to do with oil choice, but with a flat tappet, you should be running a high zinc oil. I run VR1 with my flat tappet. No issues.
 
eekvonzipper said:
I fixed a Performance Issue with a Ballast Resistor!
The First Time I gave 'er the onions it revved well up to about 3 1/2 r's and started to stumble and miss...
Runs Well at W.O.T. to 3 1/2 r's and then runs like s**t,
I've thought about this all day... wondering what did I change that caused this?
I got a Halifax Distrib, Accel Wires, NGK Plugs and an Accel Yellow Coil. I tried to match the Coils resistance with an Equal Resistor @ around 1.6ohms (Too Much!)
I put My Old Resistor (.7 - .8) back in there tonight, changed Nothing else and Bam! She Runs Like a Striped-A**-@pe!
Now I just have to summon the nerve to run it passed 4xxx R's... 3rd gear at 4000 rpm was about 75mph and Loud! Lol Too Much Fun!
Click to expand...
eek,
I'd make sure you know how much mechanical, and vacuum advance the distributor is giving by using a dial-back timing light. If there is too much full total advance, it could cause missing at 3500 rpm and maybe damage. Make sure the distributor has the right advance curve. Do not assume it is right.
 
eekvonzipper said:
New Cam/Lifters/Chain, Fresh Rings. Rebuilt '65 273, Cam Break-In done...
Started Driving it over the weekend. Haven't Revved it passed 3000 rpm yet.
How long should I be nice to it before I can Floor-It and Shift at 5000?
Click to expand...
what rings di u use? the break in of the rings r more important to mr
i used molly steel rings , i used a very pacific patern
first i ran it @ idle till it warmed up then ran it @100-1500 for 30 minutes, then we drove it up to 3000 rpm . for 30 mins then up to 5000 then back ti idle . & it was done . now i had 70 lbs of oil pressure the entire time . i have 30k on the rebuild & no oil usage @ all . now my motor is a rb (440) not a la small block but the rings break in would be tye same
 
kbakewell said:
I had my '65 273 professionally rebuilt at an engine shop, and they told me 1,000 miles before it's fully "broken in." I am sure you know this, but you also need to use something like Valvoline VR1 racing oil if you plan to run readily available premium unleaded. Love our '65!
Click to expand...


If it took 1k to get the rings in it was worn out before it hit 1k.
 
kbakewell said:
I had my '65 273 professionally rebuilt at an engine shop, and they told me 1,000 miles before it's fully "broken in." I am sure you know this, but you also need to use something like Valvoline VR1 racing oil if you plan to run readily available premium unleaded. Love our '65!
Click to expand...
I started it the 1st time with a VP Racing Fuel called C-9 (Non Ethanol)
Then I started using a Recreational Pump Gas called Premium/Premium (Blue Handle) It's a 91octane Ethanol Free and I put some Lead Additive in it (1/2oz per Gal)
For Oil I run a Rotella T-4 15w40 with a zddp additive in it (1/2oz per qt I think)
 
Richard Sweet said:
eek,
I'd make sure you know how much mechanical, and vacuum advance the distributor is giving by using a dial-back timing light. If there is too much full total advance, it could cause missing at 3500 rpm and maybe damage. Make sure the distributor has the right advance curve. Do not assume it is right.
Click to expand...
I've assumed nothing. It Is right, Rebuilt and Dialed-In for My Car by @halifaxhops. Low teens initial and low 30's total.
I fixed an issue with the Resistor swap, It's a Non-Issue now.
 
Last edited:
Martin Koiryohann said:
what rings di u use? the break in of the rings r more important to mr
i used molly steel rings , i used a very pacific patern
first i ran it @ idle till it warmed up then ran it @100-1500 for 30 minutes, then we drove it up to 3000 rpm . for 30 mins then up to 5000 then back ti idle . & it was done . now i had 70 lbs of oil pressure the entire time . i have 30k on the rebuild & no oil usage @ all . now my motor is a rb (440) not a la small block but the rings break in would be tye same
Click to expand...
Post #23 "It is Old Iron, w/ Cast Rings, Reground Cam, Honed-Finish No Re-Bore.
New Pump and Bearings"

Post #27 "20 minutes @ 2500,
Set Idle and Timing,
Revved to 3000 a couple times
Changed the Oil"
 
Juts FYO Inver trust a analouge dial back timing light they are almost always wrong at advance ue a digital or a timing tape.
 
As best I can remember this, more or less, is written in a dog eared early70's era mopar performance engine bulletin.
Follow camshaft break in procedure, cool engine to dead cold.
Re-start and check timing and idle adjustments, when warmed up make 10 half throttle pulls in second gear from 1500 to 4500 rpm, coasting in gear each time. Cool to dead cold.
Re-start, make 10 full throttle pulls in second gear to 5500 RPM, cool to dead cold.
Change out break in oil.
Race!
 
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