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Turbo/Haltech V6
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Discussion Starter · #1 ·
My mechanic sent me these pics, and he told me that it looks like there is a little bit of pitting on the middle cylinder. When I went to look at it, they had sanded it down a little bit so the affected area was smooth but there was still very little holes left in that spot. My question would be: whould this affect the performance of my car at all?

These pics are from before he sanded it.



 

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My snail is bigger!
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As long as the holes have no sharp edges, then you'll be okay. I would, however, get the head dye checked to check for any developing cracks before putting it back on the car.
 

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Stage 1 SDS @11+ psi
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I had the same thing in my quench areas. Greg said it wasn't a big deal. They get filled up by a layer carbon eventually.
 
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Premium Member
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Might fill in, or might be a lot of nice little peaks that get hot and melt and burn and continue to erode like they already have been doing.

I'd be curious why it's there to begin with.
 

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Stage 1 SDS @11+ psi
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I didn't think they were much of a threat. You can get peaks and such just from carbon build up. Let's see if Greg can join in for further explanation.


PM sent.
 

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Turbo/Haltech V6
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Discussion Starter · #8 · (Edited)
The guys installing the heads said.
Possible cause: maybe part of the plug broke off in the cylinder and was smashed into the head buy the piston. Then it smashed out the end of the plug, so when they went to take the plug out it partially stripped the threads. Just a best guess.
I forgot to mention that the spark plugs threads were a little bit stripped also on this cylinder. The only one that can answer why they were there is Ryu since I bought the heads from him. After they sanded down the affected part they were pretty confident that it wasn't going to cause any problems.:)
 

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Turbo/Haltech V6
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Discussion Starter · #9 ·
You could get hot spots that'll cause pre ignition. I've seen plenty worse than that and they didn't even attempt to fix it and everything is still good now.

The guys working on my car said the same thing. This is why they decided to sand it down.
 

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Resident Asshole
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I really don't need to say anything as it appears to have already been all said but I'll probably ramble on anyways. ;) I've seen these heads in conditions with the surface smooth as glass to so pitted and mangled that the heads become good only for valve train parts and mockups. The general consensus from all the machine shops I've used along with my personal experience says that as long as it's minor and it's been lightly sanded or machined to remove the rough and raised spots, the head should be fine for use.

As to what causes this, there are several possibilities. Foreign objects in the combustion chamber can definitely do this. The heads that normally turn to junk are the ones that have had fo's banging around in the combustion chamber for a bit. Pieces of piston embed themselves into the soft aluminum and normally not only destroy the outer ring of the head's surface in relation to the bore, but also the valve seats and bowl areas. Smaller pocket marks can be made by detonation and excessive exhaust temps. I've literally seen heads where that outer ring on the head's surface for each cylinder bore has been burned and disintegrated from high temps working it's way from the bowl outwards. You can always see that in the valves too.

I think one of the biggest things that can't be overlooked is that the castings these heads are made from aren't exactly the best. I've seen a good number of 6g72 heads have bubble areas below the main surface. This normally only becomes evident after having the head's surface milled, ie decked. I've seen these bubble areas which really do look very much like detonation marks in all surface areas of the head, even areas that aren't directly over a bore but just the block deck surface.

Good luck!
 
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Stage 1 SDS @11+ psi
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Thanks for chirping in, Greg. Well, I guess it is "buyer beware". Watch that tune!
 

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Turbo/Haltech V6
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Discussion Starter · #13 ·
One of the valves looks pitted too.
No, the valves seemed to be in perfect condition. They were just dirty on those pics. They put the heads on yesterday, so I guess I will find out if everything is good when I get the car running. Thanks for the inputs.:bigthumb:
 

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stupid booster
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Im willing to bet if you think something happened to those heads then most likely something did, LOL. Ive seen that engine in person and i never thought it would run
 
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