engine breakin

[67 plymouth]

I am getting ready to fire up my rebuilt motor and want some recommendations.Its a 360 bored 30 over with K/B pistons, Edelbrock heads, Mopar hyd. cam .430/.450 lift, Performer manifold w/750 carb. Comp 10.5
Need details on engine breakin.
Oil, time, RPM,etc.

After breakin what about synthetic oil?

[This message has been edited by 67 plymouth (edited July 27, 2000).]

[rb77413]

I had a 383 built by Dan Dvorak, and He said to use 30 weight first, start it up. Make sure it starts right up, don't grind on the starter or U will be replacing a cam, like I did. The only thing good about that is that after 150 miles the cam went flat. Actually it was a bad cam. Only one lifter and lobe went flat. But I got to step up to a bigger cam. OK Start out on 30 weight. Vary the RPM from about 1500 to 3000 for at least 30 min. Drain the oil, Then drive it. Dan also said to take it up it second gear, then let up on it to build lots of vacuum. I did this, and if there wasn't a bad came I had no problems, 'cept I sitched from manifolds to headers, so I had to do all this on open headers. My ears are still rining. Godd luck, and make sure all is right beofre trying to start it. It helps since my wife worked the throttle and I kept an eye on things under the hood.

[sublime70]

1. Pre-oil it, pre-oil it, pre-oil it!

2. Have it ready to fire and run continuously for 30 minutes, without several stops & starts. A big fan can help keep it cool. The new valvesprings will take a "set" the first time the engine is run, so don't go over 3000 rpm or so, and let it completely cool down after cam break-in.

3. I may be stepping on some toes, but as an aircraft mechanic and longtime gearhead, I have found that if an engine is built right, it is not too sensitive to the type of oil used for break-in. But if it's not built right (ie., cylinder walls too rough or smooth, bad ring fit, bearing bore misalignment, etc.), it doesn't matter what oil you use, it's gonna have problems. I like to use a regular 10/40 for the cam break-in and then 300 miles or so on a good 20/50, followed by a good synthetic (Red Line, Mobil 1 15/50) for the rest of the engine's life. I have witnessed several hot street engines broken-in COMPLETELY on 5/30 Mobil 1 without any problems, so I ignore the wive's tales concerning synthetics and break-in.

4. When you get it driving, load it down ASAP, full throttle at reasonable rpms in second or third gear. It all depends on your ring type and cylinder wall finish. This is one area where the Mopar Engines Manual is actually helpful, for a change.

Good luck and busted knuckles to ya.

[sublime70]

1. Pre-oil it, pre-oil it, pre-oil it!

2. Have it ready to fire and run continuously for 30 minutes, without several stops & starts. A big fan can help keep it cool. The new valvesprings will take a "set" the first time the engine is run, so don't go over 3000 rpm or so, and let it completely cool down after cam break-in.

3. I may be stepping on some toes, but as an aircraft mechanic and longtime gearhead, I have found that if an engine is built right, it is not too sensitive to the type of oil used for break-in. But if it's not built right (ie., cylinder walls too rough or smooth, bad ring fit, bearing bore misalignment, etc.), it doesn't matter what oil you use, it's gonna have problems. I like to use a regular 10/40 for the cam break-in and then 300 miles or so on a good 20/50, followed by a good synthetic (Red Line, Mobil 1 15/50) for the rest of the engine's life. I have witnessed several hot street engines broken-in COMPLETELY on 5/30 Mobil 1 without any problems, so I ignore the wive's tales concerning synthetics and break-in.

4. When you get it driving, load it down ASAP, full throttle at reasonable rpms in second or third gear. It all depends on your ring type and cylinder wall finish. This is one area where the Mopar Engines Manual is actually helpful, for a change.

Good luck and busted knuckles to ya.

[67 plymouth]

Thanks for the help.
will let you all know the results