Why do IP heads go bad?

[Parker2]

I just had to change th IP head out on my Duece. I am pretty sure that is not the first time it's been done on this truck. The engine has very low hours and I just cant see that it's from wear. I am suspecting dirty fuel and filters.
Like the title says - why do they go bad? I want to make sure that it doesnt happen again.
Also can these heads be repaired?

 

[scrapman]

No, to the repair question.Machining tolerances are less than .005. The actual hours on the engine is really a guess at best. The hour meters go bad and are replaced just like any other part, sometimes a little sticker is applied but, none of the previous operators really cared if the meter was accurate. The same reasoning applies to the mileage too.

 

[Divemaster920]

IP's, usually the condition of the fuel.
There are always some that are connected to a mechanical failure, but then that is usually connected to condition of fuel. But not always.
That is what I have been told by someone that His only Profession is rebuilding IP's and injectors.

 

[m-35tom]

tolerances are .0001 or less...........dirt in fuel, running out of fuel will kill one if it is already worn.

 

[cranetruck]

Parts of the IP/FDC are lapped to within a couple of microns. A rusty fuel tank is very very bad....

 

[Michael_Golden]

I just had to change th IP head out on my Duece. I am pretty sure that is not the first time it's been done on this truck. The engine has very low hours and I just cant see that it's from wear. I am suspecting dirty fuel and filters.
Like the title says - why do they go bad? I want to make sure that it doesnt happen again.
Also can these heads be repaired?

Where did you find a replacement head, if you don't mind my asking?

 

[Rattlewagon]

if the IP head is shot, would it be a safe assumption the injectors are not far behind it?

 

[Michael_Golden]

if the IP head is shot, would it be a safe assumption the injectors are not far behind it?

My IP head appears to be cracked. I don't think that would have any bearing on whether the injectors are good or bad.

 

[Keith_J]

if the IP head is shot, would it be a safe assumption the injectors are not far behind it?

Depends. There is a fine strainer on the nozzle holders to protect the needle. These are easy to fix but you need a clean place to take the nozzles off, back flush, pull the needle and clean. Only remove the nozzle, the other end has the spring preload section and if taken apart, it might need recalibration for proper cracking pressure. Specification is 2800 PSI. Any diesel injector shop servicing Bosch should be able to service them.

The needle can become stuck to where removing it for cleaning is difficult but if the engine has been running, it should come out.

This isn't a job for the shop, you need a clean room. Just the smallest bit of dust can cause problems. The needle fit in the nozzle is within 0.0001", fingerprints can influence the fit. NEVER INTERCHANGE NEEDLES! They fit only one nozzle.

The nozzles are keyed to the holder, they only fit one way.

 

[gimpyrobb]

"Why do IP heads go bad?"

Because you touch yourself. If your not carefull, you'll go blind too.

 

[54reo]

 

[Parker2]

Where did you find a replacement head, if you don't mind my asking?

I bought a 5 ton injector pump from greengemdepot for $100.00, but then I decided to just swap out the heads instead of doing the entire pump install.

 

[kaiser2help]

My pump appears to be good but that damn center plunger bolt in the middle weeps fuel. This is the bolt in the IP head that is in the middle of all the injector lines.Damn!

 

[cranetruck]

My pump appears to be good but that damn center plunger bolt in the middle weeps fuel. This is the bolt in the IP head that is in the middle of all the injector lines.Damn!

1) Clean top of hydraulic head.
2) Clean top of hydraulic head.
3) Remove plunger bore screw.
4) Wipe surfaces clean.
5) Re-install and torque to 50 to 55 ft-lb.

 

[Massm35a2]

This is why I've been running John's adaptors and spin on secondary and final filters. I run a NAPA 3336 6 micron secondary and NAPA 3626 2 micron as my final filter. Deuce runs great. I've had a fuel pressure gauge on the dash since before the spin on's and the pressure has not changed, 32 PSI idle, 70 at 2500rpm Deuce runs great! have been running these filters since April with no issues.

 

[rizzo]

My pump appears to be good but that damn center plunger bolt in the middle weeps fuel. This is the bolt in the IP head that is in the middle of all the injector lines.Damn!

mine is leaking around the bottom. I don't even have to start the engine, just turn the fuel pump on. it looks like it is coming out of the bolt holes that hold the head on. maybe there is a crack i cannot see somewhere. I am not sure what to do. I guess replace the head.

I am searching for other threads now to see if I can find some answers / ideas.

 

[tmbrwolf]

Another issue is the military for the most part uses JP-8 aviation kerosene instead of diesel, JP-8 doesn't have the lubricity of diesel and does cause some accelerated wear in the IP head and other components that require the lubrication of the fuel, NATO testing for the "one fuel on the battlefield" concept determined a 10% loss in life expectancy in using JP-8 over diesel. For the military that was an acceptable tradeoff for not having to supply several different fuels during combat operations. Bottom line is use a fuel that will properly lubricate the components and make sure it's CLEAN!

rizzo: I get the leak problem several times a year with fire departments, I can usually repair them by removing the IP head and replacing the 2 O-rings, problem is usually solved!

 

[res0wc18]

again cant stress fuel filtration to at least 2 microns. Add some tcw-3 two cycle smokeless ashless oil to the fuel mix about half ounce per gallon and it will solve any lube problems.

 

[stumps]

I just had to change th IP head out on my Duece. I am pretty sure that is not the first time it's been done on this truck. The engine has very low hours and I just cant see that it's from wear. I am suspecting dirty fuel and filters.
Like the title says - why do they go bad? I want to make sure that it doesnt happen again.
Also can these heads be repaired?

I was just reading through the maintenance comic books on the old site, and one of them listed a bunch of failures, including broken IP heads, as being caused by defective engine mounts. They show the fix being to replace the mounting bolt with a new grade 8 bolt and washer.

They didn't say how the engine mount bolt caused broken IP heads, but maybe the old bolt breaks, allowing excessive engine vibration, and that shakes the IP head until its mounting tabs stress fracture?

Check your engine mounts.

-Chuck

 

[rizzo]

rizzo: I get the leak problem several times a year with fire departments, I can usually repair them by removing the IP head and replacing the 2 O-rings, problem is usually solved!

where do I get the o rings? any o ring supply store?