As a 30 plus year machinist I concur with racerxxx. If you are concerned flip the head over and use a precision straight/knife edge and check it with an 0.02mm feeler gauge for flatness.Looks like they cut the domes as well to keep the compression stock I'd assume. Nothing looks out of the ordinary to me. I see those machining lines all day long at work.
I would and I do on my engines. Can’t hurt.Glen at Perry Performance Group said I need to re-torque the head. I checked SD manual and on the Di, it is never needed. Should I re-torque the head?
Since you have many years as a machinist, I have a question. PPG began the process of making the head SMOOTH. Then QUIT before finishing the process. Why would anyone do that?As a 30 plus year machinist I concur with racerxxx. If you are concerned flip the head over and use a precision straight/knife edge and check it with an 0.02mm feeler gauge for flatness.
I enlarged the image. It looks clear enough to me, but I dont know if you are seeing the same image as I am.I’m with mikidymac. I don’t understand what you are showing. The only thing I am seeing is a empty spark plug hole, fuel rail with no air injector but some kind of spacer in its place.
Since you have many years as a machinist, I have a question. PPG began the process of making the head SMOOTH. Then QUIT before finishing the process. Why would anyone do that?
The bottom area is very smooth, the top is rough (arrow pointing up) (from the resurfacing table?) There is a RIDGE you can feel that steps up from the smooth area to the rough.Can you show a picture if the markings/evidence of smoothing the head? I see a few marks, some are tool marks. Bad machinists are often "skilled" in the art of camouflage.
If you can visually identify a milky white fluid running down the cylinder wall then chances are your headgasket is leaking. Usually the result of an improper torque sequence. Ide pull the head off and reinstall with some copper coat as added protection.I enlarged the image. It looks clear enough to me, but I dont know if you are seeing the same image as I am.
The red rectangle is around the spark plug hole. inside the hole is a horizontal line, which appears to be where the head bolts to the cylinder. there is fluid running down from that point on both cylinders. the question is whether or not the head gasket/head is leaking. I had some moisture on the RAVE valves when I pulled them out 3 minutes after I shut the engine off so I removed the plugs and found this.
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I don’t know the answer to that as the head is not in front of me and I was not there, but I think you have to take it a step further and QC the surface using a precision straight edge with an 0.02mm feeler gauge to determine if the head is in fact flat, or if it has high/low spots. If it does, is it within acceptable criteria. I personally would not machine half a head if that is in fact what was done, but again from you picture it is hard for me to tell if it is half machined or just a machining mark from making two passes with a smaller cutter. The dome machining is obvious to me.Since you have many years as a machinist, I have a question. PPG began the process of making the head SMOOTH. Then QUIT before finishing the process. Why would anyone do that?
Thank you for your input! which side of the ridge do I put the straight edge on?I don’t know the answer to that as the head is not in front of me and I was not there, but I think you have to take it a step further and QC the surface using a precision straight edge with an 0.02mm feeler gauge to determine if the head is in fact flat, or if it has high/low spots. If it does, is it within acceptable criteria. I personally would not machine half a head if that is in fact what was done, but again from you picture it is hard for me to tell if it is half machined or just a machining mark from making two passes with a smaller cutter. The dome machining is obvious to me.
Also anytime you machine the sealing surface from a DI head you need to machine the domes deeper as to not reduce the squish of the cylinders too much.
The main thing I am trying to convey to you is flatness. It can be the prettiest machining in the world, but if it is not flat it is useless.