Need opinions on gap in valve seat.....

I can see why you are concerned. From the marks on the unmachined portion of the combustion chamber, and the gap, it really does look like something bounced around in there.

Personally, I would want to see the area around the valve seat welded up, remachined, and the seat properly pressed in. However there may be a reason the shop chose not to do that.

the potential is for the seat to drop out of the head and interfere with the valve...and you can guess that happens after that.

Is the gap just on the edge, or is there clearance all the way to the base of the seat? If just around the outer edge its less of a concern.

 

looking at it again, did they weld on the head at all before the three-axis operation? it almost looks as if the gaps are where they didn't put in enough material

 

Not really thrilled with the workmanship.

 

I called my machinist and described the situation. Obviously he's not able to hold it in his hand and inspect, but he said not to run it with any gap. Its not worth the risk.

He thinks that maybe the seat shifted somehow and when the new one was installed, it didn't sit true in the deformed pocket. Ideally it should have been welded and re-cut before the seat was pressed in.

This is just his and my .02, but I agree with him.

 

Subscribing out of interest.

I'm very surprised that you've received your head back from a trusted machine shop in this condition. I share your concern as regards continuing the assembly with this apparent problem.

Best of luck and please do let us know how this develops.

 

That sure looks like a lot of "hoping" going on.....

 

frighteningly bad, in all honesty..
that doesn't mean it wont function as required-the question is... for how long?

If the car is going to be towed on and off of trailers, at car shows, for the next 25 years....and run for less than 10-20 hours on a hobbs meter, you might be OK..might...

I would not expect it to survive for any significant length of time if you were to run the car, under load, for ANY protracted period of time...in my opinion..

machine this stuff every week for a living..I have a real world perspective...but, it is truly amazing how bad something might look, yet how well it might last-let alone how well it might perform...
Performance and longevity being two completely different outcomes in this life...

 

Yikes!

 

If the problems were on the inlet valves, I would have less concern. I can't see any way that there isn't going to be a real hot spot on those seats where they cannot transfer the heat to the head.

 

Damn sloppy work. At the very least that is a hot spot waiting to cause detonation.

 

Agree...
A time-bomb in the making.

 

Quite apart from the valve seats themselves what's going on in this whole area?

I presume it was damaged and then built up before machining back down but the finished product is extremely coarse looking. Surely this isn't a desired result?
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Also, is that a crack in the upper right port or something else?
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Speaking as a retired tool & die maker, the work that was done is very poor. Not enough weld and the combustion chamber profile is crude. The milling cuts should have been closer together and each one blended into the other to form a smooth surface. Each one of those ridges is a potential hot spot for detonation. Looks to me like someone was in a hurry. Just my two cents.

 

Gaps around a valve seat in an aluminum head.... ahhh, No!

Best I can tell, those heads (is it 'Those' rather than 'the') were milled about .030"..... yet another fopaux. There should be a 1MM deep, flat squish area surrounding the valves and combustion chamber. Maybe the photo just has the wrong lighting and I am not seeing it clearly.

 

Have it redone properly or you will not sleep at nights. Looks like a hand grenade to me. Sorry, but this is not something to be overlooked just to get the car back on the road.

 

Geez Jon, what did they machine it with......a hammer? I think they (or someone else -- hint, hint) could sharpen their pencil (and tooling) a bit more there.

Do they feel that "it is good enough" or that "it cannot be done any better" ?? I don't want to pass judgment without knowing all the details of the before condition and what they had to work with and any applicable limitations.

Frankly though, if their attitude is the former, I would say well, "better is the enemy of good enough" .

 

Sorry but this is terrible work, welding and machining looks like it was done in shop class by a student who would rather be in the math class. I would not accept it and would not use the heads in this condition.

 

Good eye there!

My guess is it is a residue track or perhaps a scratch ---- looks a bit too clean and linear to be a crack. But, it is DEFINITELY something to verify.

 

Not sure..... but, it is "faux pas", though ........just razzing you Dave hope all is going well out there with everything

Incidentally the guy (R. S.) who called and likely wasted a bunch of your time a little while back ---- he ain't no friend of mine..... guy is a total jackass, in fact.