What to do first?

[h2odrx]

Ok,
I found a 84 6.9 that runs, (bad knock?) i didn't have time to hear it run, but the man said he would not get close to it? $350 so i guess i'll get some parts?
Should I
1. pull gp's and injectors to see what i find? :Sly
2. or just take the heads off and apply to my block?
3. or run real fast?

what do you think?

dwight

 

[hoodshauler]

pull the valve covers and take a look. Start at top and work your way down

 

[towcat]

Actually, if the knock is not deep down in the motor like down in the oil pan, loosen the injector lines one at a time and see if the "knock" goes away. Then start tearing in deeper. keep in mind though, there isn't much interchangability in the body parts between your truck and the knocker truck.

 

[h2odrx]

so the injector lines will tell me what?
i'm just getting the motor not the whole truck, he will not sell the truck?

 

[sle2115]

so the injector lines will tell me what?
i'm just getting the motor not the whole truck, he will not sell the truck?

When/if you find one that makes the knock less or go completely away, you will have identified the cylinder with the knock and can begin to diagnose that cylinder.

 

[towcat]

so the injector lines will tell me what?
i'm just getting the motor not the whole truck, he will not sell the truck?

for starters, a weak injector will fire earlier than the others therefore causing a early ignition and a "knock" will result. many IDI's have been condemmed due to weak injectors. min pressure needs to be at 1400psi but if one is weaker than the others, the result is the same. let's say most are popping at 1800psi and one pops at 1500, the weaker one will cause the cylinder to "knock".

 

[Diesel JD]

I'd say for that price buy it, and you can almost make your money back in parts and scrap metal if it turns out to be junk. Its a gamble to be sure. You'll want to visually inspect those heads and also have them pressure checked and magnafluxed. Don't let the guys machine them. If they are out of the warpage limit post here for advice. If they are milled out of specs, they are basically boat anchors. They can be milled a slight bit, but the guy better know his stuff and not take them below minimum thickness.
J.D.

 

[h2odrx]

the coolant looked great and full, not sure how long it has been setting? i'll stop by in the morning to talk with him, i wanted the whole truck but he said no. i'll try and get what i can, he said IP was replaced not long ago? so that in its self is $150? with other parts i might be ok? what is the bad casting numbers on the early models? it's an 84 so i wonder if i find other problems?

 

[Full Monte]

This is the voice of embarassed experience talking here. Once I pulled the heads off my 85 6.9 due to a knock that I was told by an expert was a glow plug tip rattling around in a cylinder. It was one hell of a knock. It turned out to be a failed injector that was ******* fuel into the cylinder, causing it to try to compress a liquid. Do the simple stuff first...or join the embarassed experience club.

 

[h2odrx]

Update boy this is funny?

I went and paid my deposit on the engine today. and got the history of the truck? said he had two just alike, (construction bussiness) and stopped the insurrance and tags on one, well he got the wrong one so they took his tags until he could clear it up? then he parked it at a friends and some one stole it? a few years go by and a freind called an told him he had his truck in his yard (what was left of it) lots of stuff stripped off it and said it was blown up? i asked if it was a low end knock and he said yes must of ran it with no oil? I don't think he knows what he has? oh yea he said it was a F650? they didn't make them in 84 did they?

 

[fx4wannabe]

I don't think he has a clue what he is talking about. Is he sure its even a diesel? Back then the heavy duties were called F-SuperDuty and I don't think that came out till late 80's or early 90's.

 

[h2odrx]

yes it is dieselI looked, but if it was a 650 it would have a different cab? it looks like a F250 to me I'll try and get the vin, he said he wanted to keep the truck to make a wreaker out of it? will a 460 bolt to a diesel trans?

 

[fx4wannabe]

Don't know about the tranny swap but if its a 250 it will have the D50 indepedent front end. 350 would be solid axle D60.

 

[h2odrx]

cool i'll look

 

[sle2115]

Could also have a D44.