break in of rebuilt engine

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long1776

Member
Joined
Apr 22, 2011
Messages
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Location
sweden
My Car
de Tomaso Longchamp
My 351 C has been torn down and rebuilt with quality parts. Break in was done on a dyno and I've only 10 miles since then, never going above 3000 rpm, had some starting issues in the begining. Now to my question, should the heads be retorqued? If yes, when? and how much. Should I first loosen them and then retorque?

 
You shouldn't have to re-torque the heads. If you just want to, don't loosen them. Just re-torque to the same specification. I do suggest checking the intake bolts again.

Chuck

 
I would check the intake manifold bolts. One item in Ford's 'pre-delivery' to do list is to retorque the intake bolts. This is done when the car is delivered to the dealership. Another item on the list is 'wash the car'.

mike

 
Yeah, head gaskets don't need retorquing these days, particularly the MLS gaskets (Cometic). +1 on headers and intakes bolts, though.

 
This is definitely true these days as well. If you're running moly rings, the rings will seat within the first 15 minutes of runtime!

 
Was it broken in with non-synthetic motor oil? Did you add some type of zinc addititve? The flat tappet cams shouldn't be broken in with synthetic motor oil and a little extra zinc doesn't hurt.

 
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