7.3 Knocking Badly

[1320Cummins]

We were cruising @ 2,500rpm on flat ground today headed back from a job when she let go.
Out of the blue a loud rhythmic knock started. I pulled over and started cracking injector lines, found no real changes in noise.
My buddy was following me in my 95 with tractor and trailer in tow. He says there was never any smoke. We hooked up to the truck and headed home.
When we got home I started the truck and noticed a decent amount of grey/white smoke, I never noticed this when we were on the side of the road.
We started cracking injectors again, smoke is gone when #6 is shut down. So pulling the injector was the obvious first move. After pulling and inspecting I found nothing. I installed a spare injector and fired her back up, more smoke, crack #6 line, no smoke.
Tomorrow I will be performing a compression test, and most likely pulling the head and maybe the oil pan. What a PITA!!!
I am bidding on a bus with a DT-466, but I dont know if I will win.

 

[hesutton]

The compression test sounds like a good idea. Might pull the valve cover and see if there is anything amiss with the valve train.

DT466 eh? Sounds fimilar.

Heath

 

[snicklas]

DT466 eh? Sounds fimilar.

Heath

Heath, but his DT466 will fit a bit easier, I believe by looking at his sig, it will be going into a S-1600 Medium Duty IH Truck......

 

[hesutton]

Heath, but his DT466 will fit a bit easier, I believe by looking at his sig, it will be going into a S-1600 Medium Duty IH Truck......

Stop reminding me of how much work it's going to be.........

Heath

 

[1320Cummins]

Well, no bus (sigh) http://www.renebates.com/cgi-bin/mnlist.cgi?bates55/7648
$2,350.00 is a bit rich for me right now, so user 1959 got the bus. I went all the way to $2300 but but the other bidder just would not quit.
I watch that site alot and connot recall a bus of that age and mileage going for so much. I think the issue might be that its been a while since I have seen a 466 equiped bus on there, so that might have a bit to do with it.
For now I am going to fix the grumpy old 7.3. I still have not finished the compression test, so ill report back on that later.
And yes, it was the S-1600 + 4 yards of crushed concrete still in the bed (8 yards full, Ill withhold the weight at 8 yards and yes it stops very well).

FYI, I had a friend bench test a Ford spec DB-2 today. The pump produced 60cc before turning it up and 80cc after, and fueled hard to 3700rpm.

 

[1320Cummins]

I was only able to get results from the left bank before my tester took a dump. Good news is, that was the bank in question anyhow.
#2-390psi
#4-400
#6-400
#8-290

I followed up with a leak down test, and found #8 to have no pressure retention. Cylinders 2,4, and 6 hissed for a good 8 seconds after turning off air supply. I also found the glow plug wet, and the nozle of the injector had a coked oily coating. I am thinking cracked piston.
Just great! Cant wait to see what it looks like inside. Lets all hope for no block damage;p

 

[david85]

Wouldn't you have very high pulsing blowby if you had a cracked piston? We have seen some head gasket failures that result in a knocking like this. Just saying that it might not be the worst.

 

[1320Cummins]

Well, it is the worst. Besides having a hole in the block. I have the head off and found what looks to be a broken wrist pin. Either way broken pin or not the wrist pin clip came out and allowed the pin to dig into the side of the block. I am wanting a 466 in a bad way right now!
I guess we will pull the motor tomorrow and tear it down. If the pin is broken I am finding some turbo rods or a DT466. Any one have some turbo rods?
Worst part about this job is that I have to do 90% of it all by myself. Makes for a slow job that needs to be done yesterday.

 

[hesutton]

Man that really sucks! Do you have another block already?

I hope you can get your rig up and going soon.

Heath

 

[1320Cummins]

No good blocks. Only a block that needs a serious case of line boring, I dont even know why I keep it I already had #6 sleved when I built this motor, so thats how I would go for #8.
I have located a complete DTA-466 with air compressor, P-pump, and an allison auto, within a couple hours of me. The guy is asking $1800 for the pair.

 

[1320Cummins]

Looks like its a go for the 466/Ally combo I just got back from looking at it and am pretty happy but afraid at the same time. I asked him his bottom dollar and he told me $1500. I am thinking when I roll in there on monday or tuesday to get it ill hagle a bit more. Yes, I am one of "those" people.
I asked him about starting it and he told me that if he had to help me start it the price was $1800. He also said I have to provide the oil, fuel, and battery. I pulled an oil sample from what was left in the pan, so im most likely going to send that off on monday. Plans also include a compression test and a check of the cranking oil pressure. I dont need his help if I dont fire it, and even then I would just want to support it with his fork lift.
So.... I need a dog house, radiator hoses, new drive shaft, TV cable and modulator, shifter and cable, trans cooler, power steering reservoir, down pipe, and I am sure plenty of other things. I shoulda got the bus!

 

[dyoung14]

How come so many peoples engines let go like this one, not being abused or anything, just turning 2500 rpm, i have turned mine 4400 a bunch and never done a single thing to it

 

[1320Cummins]

How come so many peoples engines let go like this one, not being abused or anything, just turning 2500 rpm, i have turned mine 4400 a bunch and never done a single thing to it

It gets its share of abuse! You must keep in mind that this truck sees 25 - 34,000 lbs on a daily basis, and makes far more torque than your N/A 6.9.
I think this is a lesson for anyone that wants to build a powerful IDI for heavy hauling. Use TURBO RODS!!!
Any of yall need some IDI parts? I also have a SPICER 5spd with a nearly new $600 Eaton Road Ranger clutch.

 

[dyoung14]

It gets its share of abuse! You must keep in mind that this truck sees 25 - 34,000 lbs on a daily basis, and makes far more torque than your N/A 6.9.
I think this is a lesson for anyone that wants to build a powerful IDI for heavy hauling. Use TURBO RODS!!!
Any of yall need some IDI parts? I also have a SPICER 5spd with a nearly new $600 Eaton Road Ranger clutch.

what all parts do you got that you want to get rid of?

 

[1320Cummins]

I am not 100% positive as of right now. I am keeping the HX-35 that I am positive about. I will post a thread in the classifieds when I decide if I am going to part it out. I have all kinds of goodies if I decide to part it out, including some brand new Sealed Power standard rings and a brand new Airtex lift pump.