7.3 idi cavitation

Va_Mike

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I'm heading to look at a engine today and just wanted to know what cylinders tend to suffer from cavitation more? Going to do a compression test on a few cylinders and want to make sure I check know problem ones.
 

79jasper

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Compression test wont show you anything about cavitation, unless it has gone through a cylinder wall. Even then, it could be such a small hole that you may not see it by the numbers.
Just look for equal-ish numbers.

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Garbage_Mechan

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More telling on cavitation that has pinholed the cyl wall is signs of moisture and white/ grey slime under the valve covers, oil filler cap or in the CDR valve. I’ve seen them run fine with a pinhole except the above symptoms till one day the piston ends up parked below the pinhole for a few hours. Hydrolocked.
 

chris142

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I think it's pretty rare really. In the past I have seen complete disaster cooling systems,completely clogged with rust and no holes in the liners.
 

Garbage_Mechan

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I’ve seen 2 IDI’s personally. One was a 1990 in 1994 with 100,000 miles. That one hurt my young pocketbook.
Had one DT466 do it in 3000 hours. ( Fresh rebuild, mechanic forgot the coolant additive.) Small and Big Cam Cummins always had pits in the liners when pulled. Sometimes through.
I’d think there may have been blocks that were more prone to it that were weeded out of the pool by now.
 

chris142

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I’ve seen 2 IDI’s personally. One was a 1990 in 1994 with 100,000 miles. That one hurt my young pocketbook.
Had one DT466 do it in 3000 hours. ( Fresh rebuild, mechanic forgot the coolant additive.) Small and Big Cam Cummins always had pits in the liners when pulled. Sometimes through.
I’d think there may have been blocks that were more prone to it that were weeded out of the pool by now.
Ya those 855's would get the block worm if the coolant and addatives were not kept up. My 1962 Nt280b was still going when I sold it in 2012.
 

ifrythings

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Well said. I also believe that most the cavitation incident blocks have shown up by now, you almost never see it happen any more.

Everyone says cavitation is so rare till it happens to you. #8 cylinder right in the center.
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Thewespaul

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Everyone says cavitation is so rare till it happens to you. #8 cylinder right in the center.
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Looks like the piston skirts were eating into that side of the cylinder wall which doesn’t help it, when was that?
 

ifrythings

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I’m guessing those holes were there before I rebuilt the engine and had 20 thou taken off. Didn’t realize it at the time but when I broke down the engine and a gallon of clear water came out before oil started draining would of been a good clue on the health of this engine. I was told by people that if it made it past 100k it would be fine, this had just over 400k so I didn’t even look for problems like this, didn’t know much out diesels or idis at that time.

Machine shop was very helpful with all the problems I had with this engine and they sleeved #7 and #8 for free. If I were to do it again I would definitely consider sleeping every hole or at minimum #7 and #8 hole.
 

Thewespaul

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I’m guessing those holes were there before I rebuilt the engine and had 20 thou taken off. Didn’t realize it at the time but when I broke down the engine and a gallon of clear water came out before oil started draining would of been a good clue on the health of this engine. I was told by people that if it made it past 100k it would be fine, this had just over 400k so I didn’t even look for problems like this, didn’t know much out diesels or idis at that time.

Machine shop was very helpful with all the problems I had with this engine and they sleeved #7 and #8 for free. If I were to do it again I would definitely consider sleeping every hole or at minimum #7 and #8 hole.
Yeah with 400k I would sleeve the whole thing too. I like finding engines with around 150k for builds, not much wear but enough to ring out the bad blocks.
 

Blackascoal

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Yeah with 400k I would sleeve the whole thing too. I like finding engines with around 150k for builds, not much wear but enough to ring out the bad blocks.
Is it safe to say if you make it to 150k without cavitation you’re probably not going to encounter it? I’m right about there with my 94.


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Thewespaul

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Is it safe to say if you make it to 150k without cavitation you’re probably not going to encounter it? I’m right about there with my 94.


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I wouldn’t worry about it. We’re much more likely to get hit by a drunk driver than to experience cavitation issues. I’ve had more casting flaws lead to premature rod failures in na blocks than I’ve seen cavitation in a ****** bore blocks, and even that’s a huge minority.
 

IDIoit

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the only way to "check" cavitation is by sonic testing.

I have recently been on the wrench with 3 different blocks.
I was looking to put a solid runner together for a project I am working on.
I bought 3 different blocks for 1-200 a piece.
out of 6 heads, 3 were cracked."
one block, which was a turbo block, had a bent rod.
the other 2 short blocks were pretty nice after you cleaned the sludge out of them.
all bearings were within spec.
I had a freshly set of machined heads on the shelf.
made 1 solid engine
all new gaskets, injectors and a pump is on its way.
the other good short block, is getting a set of the uncracked heads.
lapped the valves, and checked the guides.
checked the valve recession...
just waiting on studs!

moral of the story.
treat every block you buy, as a "core"

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