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03 Kia Sedona
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17 Posts
Discussion Starter #1
the valves left about 2mm indent on piston tops. can i replace valves and run motor with grooves in pistons?
 

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2004 Carnival, 2.5L KV6 / GV6 / K5 engine
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99 Posts
Can't say for sure on the Kia 3.5L, but some years ago a friend had the timing go out on a Nissan and had broken valves & dented pistons. He had it back together before I had a chance to see the damage myself so can't comment on the depth, but he said he just replaced the valves, cleaned up the piston tops to check for fractures & cracks, and just dressed out some of the sharper edges with a Dremel to avoid any chance of hotspots. Would be 5 years ago, and I know the thing was still going 18 months ago.

Others wiser that I may care to opine, but given the work to change them, may be worth just running with the indentations & see how it goes.

Edit: Spoke to him this evening and he recalls the depth being mostly about 1mm or so, maybe close to 2mm in places. Its still going strong, was 7 years ago (yikes).
 

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03 Kia Sedona
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17 Posts
Discussion Starter #3
thanks. i am going to find out the thickness to make sure. scraped with pick found no fractures
 

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2004 Carnival, 2.5L KV6 / GV6 / K5 engine
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99 Posts
View attachment 12606 are the grooves too deep
Hard to say from that photo. And I guess whats 'too deep' is going to be pretty subjective. Kia would say any indentation at all is 'too deep' and sell you 3 new ones. My friend (who gets all his parts from wreckers) would probably say if you can't see through the indentations into the crankcase then they're usable :D.

But am I seeing that metal may have lipped & flowed upwards around the outer edges of the impact crescents? I think that's what he was indicating should be gently dressed out with a rotary tool.

Might be worth Googling for others experiences, I don't think it necessarily needs to be with the Kia engine which seems to be a fairly generic contemporary design (unlike the somewhat 'adventurous' engineering in our K5 engines here).
 

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2009 F350 FX4
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1 Posts
Well as a Hyundai/Kia tech let me start off by saying that most likely you will never damage a piston with a valve. Its the other way around. The valves are weak, tiny pieces of metal that will easily bend when the force of the rotating assembly pushes against it.

What you see in the top of the piston is far too perfect to be valve damage. What you are looking at is valve reliefs. These are pockets machined into the surface of the piston to make room for the valves. The valves actually open up into these reliefs. 999 times out of 1000 you will never do any significant damage to a piston from valves hitting.

You will be ok reassembling that engine with a simple valve replacement.

Good luck.

BTW, here is what a Brand new piston from a 3.5L Sedona looks like.

 
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