ciscohusker

As some of you may have been reading my posts I bought a wrecked 94 4 x4 and am in the process of getting it going. It seems like everything I tear apart on this thing is in need of some TLC. It has 122,000 on the odometer but they must have been hard miles or it was disconnected. Anyway I pulled the head off after finding a bent push rod and got a nice look at what wrong injectors can do to the pistons. Notice that #3 has the most damage. Where is the best place to get some pistons and since I will be replaceing the pistons is there anything I should look at to upgrade to while I'm in there. This truck will have it's share of mods on it when I'm done with a goal of 500 to 600 hp. Thanks

Geico266

OUCH! Pretty much lets the "My EGT's can go to 1,700F " crowd what a cooked engine looks like. There is a reason Cummins dummies down the stock engine, and this is why.

Txwelder

What were the "wrong" injectors?

ciscohusker

Wrong spray angle for example a 370 injector was not designed for a stock 12v piston to spray into the bowl correctly.

signature600

You using 370's then?? How much timing?

Chris

Txwelder

Really, how many trucks have had failure or damage due to 370's? Might be a set for sale here before too long.

ciscohusker

I have never driven this truck I bought it wrecked and am getting the pleasure of fixing everything the previous owner didn't maintain no oil in tranny, axle seals out, low oil in transfer case, Ujoints out, power steering resivoir dry, and much more. But I'm not complaining I bought the truck right and will know everything about it when I'm done. As for what injectors it was running, the old owner put some stockers back in and pulled all his gauges before the insurance company took possesion so who knows I was using the 370's as an example. I have heard as to how some injectors don't spray into the stock piston bowl well and have got the oppurtunity to see first hand what happens now. I just didn't get the pleasure of doing the damage myself.

pvkj454

Wouldn't that damage be caused more by high EGT or detonation than the wrong spray angle? The dome inside the bowl looks badly damaged and fuel should not have been spraying on it.

Fueling around

I cannot find my photos of a 370 injector spray pattern on a stock piston. It does not focus in the bowl, but on the lip of the bowl. It does NOT produce a random splatter over the piston

The damage in the photos reminds me of dribble from bad tip or blown poppet.

Crimedog

I think I know what photos you are talking about John, at least I saw some on here a while back that I can't find now. They were of some 370's that had many miles on them and you could barely see some "cleaner" spots on the pistons where the spray pattern was. It was certainly not as far out from the bowl as the pictures in this thread are.

Wouldn't fuel hitting the piston actually cool it to a certain extent? Maybe I'm wrong but that's just a thought I had while typing...

ciscohusker

I don't know if I would call this a random pattern due to the fact that all the pistons have damage in the same locations. If you are looking from the front of the truck it would be in the 10 to 1 O'clock on all pistons. #3 had the worst damage. It may not have been a 370 I have no idea what the previous owner had in it since they put stock ones in after they wrecked it and it was totaled. That is the most frustrating part of the work is I have no Idea what was all done to this thing.

jlipskoc

I don't think it was wrong injectors, I think it was a bad driver/bad maintenance. Either a screwed up timing, or EGT's thru the roof, or the dude was running NOS and propane.

Jim Fulmer's 700+ hp truck ran 370's for years on end like that on #2 only, drag racing and more, he pulled the head and shown pics on TDR a while back the pistons look like new, there was no visible difference.

I've personally never heard of 370 problems with people that use them everyday, if they do have issues, there either abusing the truck, don't have the common sense like most of us here do with our trucks, or there doing some homebrew horsepower magic.

ciscohusker

I do believe that Jim was running something other than a stock piston so that it would match up with the 370's patteren.

jlipskoc

I wasn't aware of that or known that he had different pistons, hmmm interesting.

I've been running 370's for a long long time, this is the first I've heard of this. Hope I don't regret putting them in after all this time.

I guess the person to get on this thread is Don M, maybe someone should send him a PM and have him look at that picture of the piston bowl above, maybe he's see it before.

gunracer1

i had over 60k miles on my 370's when i pulled the head. the timing was between 16 and 20 the whole time. the egts were over 1500 many, many times. and all my pistons looked great, no pitting or signs of high egt's.