"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

 

[Newbomb Turk]

New oil and filter. Let it get up to temp. You are killing the oil.

 

[BSB67]

Yes, you can run the lash tighter. But doing that simply to make it quiter is odd to me.

My guess is that motor with a street friendly compression ratio will run best in every meaningful way with the recommend lash.

Maybe consider a hydraulic cam if the noise is the concern.

 

[MOPAROFFICIAL]

Hope you broke the cam In for 20 min at least. Otherwise it sounds like you should put fresh oil in if you haven't and drive it.
I wouldn't take more than .004 out of it.

 

[92b]

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
View attachment 1716462313

Could you be more specific about how you did your breakin? Not sure what you mean by pulls. Is it on a dyno? Am I right in assuming this is a used and already broke in cam and lifter set? If so did the cam and lifters come from this motor?

 

[jbc426]

For the last 10 years or so, I've been running Jomar 100% No Bypass oil filters on my hotrods. It saved one of my motors from oil passage contamination when I lost some rocker arm needle bearings due to valve train harmonics taking them out.

Another thing I've been doing on fresh engines for a while now is installing a section of screen in the top radiator inlet before running the motor for the first time. It's just a 5 inch square of screen that I shape into a sock type shape, insert it into the radiator nose bung, and wrap the edges over the outside of it. I then slip the hose over that. It's amazing how much stuff it catches from the inside of the block's water passages. I remove it shortly after it stops catching stuff that would otherwise end up inside the top radiator tank blocking the tubes.

Kindly overlook the current wiring mess, that's my last step before it's running again.

 

[burks440]

make schure the oil holes on rocker shaft is facing down and also make schure the shafts are placed as should be the notch at end of shaft should be right rear.

 

[middleagecrisis]

I'm confused by why you wouldn't do a normal cam break in cycle and would shut down the motor when it just started getting up to operating temp. Sounds like a good way to destroy a cam early to me and induce premature wear into the motor.