The day after a rebuilt heads & gaskets R&R, (a what if question)

[Brad S.]

Have not done this yet, but I need to ask this.
IF my rings are bad, extra compression from rebuilt heads, and no visible cracked heads.
What are the chances that blowby will be worse afterwards???
Just wondering if anyone else had this problem after a rebuilt heads.

Also are there any problems of rotating the engine, while the heads are off, to check out the cylinder walls????

 

[91idi]

No problem rotation of engine other than lifters need bleed down. I have rebuilt many heads on idis an never had more blow by afterwards

 

[RLDSL]

Your heads do not have a dome in the combustion area like a gas burner. THis is a diesel. Even if the head is milled, your compression is not going up. THe only relief cut is where the valves recess slightly into the seats and that changes very slightly, not enough to make enough difference to worry about at roughly 21:1 compression or whatever these critters are pushing. Only way compression would go up is if the guides were so hammered the valves werent seating, but it would have been coughig some still.
Only thing to worry about is if you do get heads milled, make sure to get your intake manifold matched or you are going to have trouble getting it mounted, just bring the manifold in to the machine shop and they will know what to do ( the bolt holes are all going to be a touch too high with milled heads ) Granted, new rings are nice, but rings do last a pretty good long time in these things if you just keep them clean

 

[icanfixall]

What Robert is saying about the intake manifold not fitting is this... when the heads are milled some the intake ports become closer to the center line of the crank. So does the mounting area between the valley area. So the intake will be wider than that and need to be cut back some. If 5 thousands is taken off both heads the amount taken off the intake manifold is not 5 or 10 thousands. Its a mathamatical calculation that needs to ne made for the correct amount taken off both sides of the intake.

 

[Brad S.]

Thanks guys about intake. After I read those posts I remembered that from gas engine stuff.
And glad to hear that others have done the heads without other problems.
If I have a bad head gasket on that side and I fix it, thats were I figured the extra compression would come from.
For me another big part of the head gasket fix is making sure there are no cracks or holes etc.