347 oil weight

[Machran]

What oil weight should I run in my 347? I have a sheet from the short block builder that mentions 20w 50 for break in. Should I stay with 20w 50?

 

[carkrazy]

every engine builder has there own methods and theories. I have built two engines with renowned engine builder Ronnie Crawford. one was a mod motor the other a push rod motor and he gave me the same break in procedures for both. basically buy regular non synthetic 10w30 and run it for 500-600 miles. After that drain it and add your preffered synthetic oil. I used Amsoil 10w40 on my push rod 418 stroker that makes 500hp to the crank. The theory behind the non synthetic is it will allow the rings to seat/break in faster than if you used synthetic. I'm a little more anal and did this procedure twice before switching to synthetic. All I can tell you is that it work very well for me. hope this helps you out.

p.s. by the way the 418 is my avatar

 

[Toasty]

every engine builder has there own methods and theories. I have built to engines with renowned engine builder Ronnie Crawford. one was a mod motor the other a push rod motor and he gave me the same break in procedures for both. basically buy regular non synthetic 10w30 and run it for 500-600 miles. After that drain it and add your preffered synthetic oil. I used Amsoil 10w40 on my push rod 418 stroker that makes 500hp to the crank. The theory behind the non synthetic is it will allow the rings to seat/break in faster than if you used synthetic. I'm a little more anal and did this procedure twice before switching to synthetic. All I can tell you is that it work very well for me. hope this helps you out.

p.s. by the way the 418 is my avatar

Its not a matter of synhetic taking longer to break in - its the fact that if you put synthetic in a brand new engine your rings will likely never break in at all.

Do not use sythetic oil at any time during engine assembly or during the breakin period. Synthetics are just too slippery and you get highly inaccurate torque readings if you use it as an assembly lube. Always use an SAE 30w oil (10w30 is fine) for engine assembly and breakin.

 

[Toasty]

What oil weight should I run in my 347? I have a sheet from the short block builder that mentions 20w 50 for break in. Should I stay with 20w 50?

The thicker the oil, the more parasitic loss you will have.

HOWEVER, depending on the bearing tolerances that your builder used, a heavy weight oil like 20w50 may be appropriate. The best person to ask is your engine builder.

 

[mystical]

Its not a matter of synhetic taking longer to break in - its the fact that if you put synthetic in a brand new engine your rings will likely never break in at all.

Do not use sythetic oil at any time during engine assembly or during the breakin period. Synthetics are just too slippery and you get highly inaccurate torque readings if you use it as an assembly lube. Always use an SAE 30w oil (10w30 is fine) for engine assembly and breakin.

Agreed, although I always wondered about those cars factory filled with synthetic (vette, viper, imports etc.):shrug:

 

[carkrazy]

its not a matter of synhetic taking longer to break in - its the fact that if you put synthetic in a brand new engine your rings will likely never break in at all.

Do not use sythetic oil at any time during engine assembly or during the breakin period. Synthetics are just too slippery and you get highly inaccurate torque readings if you use it as an assembly lube. Always use an sae 30w oil (10w30 is fine) for engine assembly and breakin.

exactly!

 

[Toasty]

Agreed, although I always wondered about those cars factory filled with synthetic (vette, viper, imports etc.):shrug:

engine broken in before it leaves the factory