Engine/Transmission (1998.5 - 2002) 3 Melted Pistons

[Partyat33]

Had the head taken off for an O-Ring job last weekend and surprise surprise. Three pistons had signs of damage on the top. I have been told that the spray angle was incorrect and therefore not spraying into the bowl. That certainly looks like what happened. The other three pistons and cylinders looked perfect after 110,000 miles. The cylinder walls of the three affected cylinders had the cross hatch marks worn off but no signs of 'real damage'. The good news is the head was flat and I got the O-Ring completed. There was a crack in the head between two exhaust valves but it did not extend into the valve seats.



Now I got a lot of work to do !!!!





Dennis

 

[Bob Wagner]

are you switching injectors?

 

[Partyat33]

I will definetly be switching injectors, Bob.



Not sure what else yet !!!

 

[Gary - K7GLD]

Outta curiosity, which pistons were damaged?

 

[jtisdale]

Gary,

I believe it was 1, 3, and 5. I could be mistaken though.



As I understand it, there was no forewarning whatsoever. The possibility exists for anyone of us to be running around with melted/damaged pistons, and not even know it.

:--)



















I am glad to hear that the o-ringing went well. Did you re-use the stock head bolts, or go with studs?

Jim

 

[Partyat33]

No symptoms at all. Only reason I had to the head off was for an O ring. Good thing we caught it when we did.



Dennis

 

[Royal]

What kind of injectors were you using? Where they modified ones and where did you get them?

 

[csevers]

As every body likes to see a "train reck" do ya have any pics of the damage that we can study??



Thanks

Craig

 

[Partyat33]

I know it might seem hard to believe but I am not totally sure whose injectors they are. I bought them used. I was told one thing and in trying to confirm it now I am not sure. I don’t want to make a false statement.



Yes, I do have pictures. Aron has pictures too.



Dennis



PS. I am not much of a mechanic. If anybody has any suggestions, they would be appreciated.





Dennis

 

[jaybigboy34]

Where did you buy your injectors?

 

[RustyJC]

Were the piston cooling nozzles still in place in the block on the cylinders with the toasted pistons?



Rusty

 

[Jim Fulmer]

If the spray pattern was hitting the edge of the bowl(lip) then those injectors would make a good set of cores for say some EDM's, if the melting is in the bowl are were it's suppose to be then your staying in it too long. Running these engine at high EGT's like in a 1/4 doesn't do that, running them high like pulling a long hill will though.



Jim

 

[Gary - K7GLD]

Personally, I'm sorta curious - if the affected pistons ARE 1-3-5, if that somehow correlates with the VP-44 fueling order?

 

[Partyat33]

The melted portions are outside the bowl and not necessarily centered. No damage in the bowl.



Dennis

 

[TBeckman]

1-5-3-6-2-4

 

[Partyat33]

1, 5, 6 from the photos. Don't have it pulled yet. After talking to people in the know, my suspicion is that the pop off pressures may not have been correct and they were dribbling. They have quite a few miles on them, do injectors wear out ?

 

[Scrappy]

dribbling?

if they are dribbling, then wouldn't the damage be located in the piston bowls because the injectors are centered in the combustion chamber?

 

[jtisdale]

Whats your plan Dennis? New pistons or run her till she blows?

 

[Partyat33]

I bought an engine stand and a engine hoist. Starting to take it out this weekend. I don't think anything else is damaged, so I will rebuild it now. I am hoping its just pistons, rings, crank bearings, and a hone of the cylinders.



This will be a VERY long weekend. I hope I can get it out by Sunday.



Dennis

 

[Gary - K7GLD]

Optimist... .