"Breaking in Big Block"

[derek fletcher]

Hello,
Just getting finished up on 383 break-in on 67 Dart.

Did two 2000-2500 rpm pulls bringing water temp up to 150 then cool.

Thing is probably only have about 15 min runtime so far.This time drained water and oil while hot. Surprised at what the oil looks like already.

Questions are: How many more pulls? how about new filter now before a few more pulls? change oil now, then run 500 miles?

The isky rockers are quite noisy, lashes set at 28 and 32 can these rockers be tightened up some?

this is an F-284 mechanical (solid) lifter Crane camshaft from the late 1960's. It's a single pattern camshaft with 284 degrees advertised duration,

and 241 degrees duration at .050" tappet lift. Lobe lift is .302", gross valve lift with 1.5:1 rocker arms is .453". Lobe separation is 112.5 degrees.

Recommended valve lash at operating temperature is .028" intake, .032" exhaust.


What does the jury pool suggest?

Thank you for any suggestion,

Derek

 

[1968rt]

Im running the Mopar .528-284 and it has the same lash specs. I readjusted them to .018 and .022. Sounds much better and lumpier.

 

[t.flatt]

What do you mean by you're surprised at what the oil looks like? A new filter and oil is never a bad idea. You can cut the old filter open and see if there is anything nasty in there.

 

[Rishi]

how dirty (or build up of carbon) can the oil really get with 15 minutes of runtime? Nick's Garage (of youtube fame) run their break-ins at constant RPM for 20 minutes before hammering 'em on the dyno.

 

[Don Frelier]

What do you mean by you're surprised at what the oil looks like? A new filter and oil is never a bad idea. You can cut the old filter open and see if there is anything nasty in there.

The oil might just have assembly lube mixed in.
Unless you're running super rich?
Make sure timing is really advanced during break in.

You should be fine running it anywhere between 100-500 miles.
But I agree cutting open the filter is a good idea.
(Use a good filter, wix, Baldwin, fleet guard or Mopar)

 

[ckessel]

Central coast huh? Yo from Osos.

 

[PlymCrazy]

That 383 oughtta be fun when done in that Dart.
And welcome from NY.
Let's see some pics of the car!