B7500HSD "knock" on the upper head area

[KubotaSchamota]

Hey guys..newbie here. I was hoping someone could chime in and tell me what could possibly be going on with my father in law's B7500HSD. We had a tractor mechanic come over and without even diagnosing where the sound was coming from he tore into the bottom end(a waste of 250 dollars) to find the rod bearings were just fine. Needless to say we didn't use his services anymore. Just by listening to the engine common sense would say it's something in the upper head area. I've uploaded a short vid so you fellas can check it out. Now whatever it is I'm sure it would require a professional but I just want some opinions and a starting point on where to look/what to tell the future mechanic. You can really hear it at start up and when the revs drop. I find it peculiar that there isn't oil squirting everywhere when he revs it up.

http://s197.photobucket.com/albums/aa287/mistercooldude81/?action=view&current=DSCI0232.flv

P.S. In the vid you'll hear my father in law rev the motor and I know some people would say that's probably not a good idea with the "knock" but there's just no telling him anything. He's the kinda guy that messes with things he shouldn't be messing with yet he gives up on the easy fixes and instead buys a new part/machine.

 

[Bulldog]

Does it have any oil flowing when its running? It's hard to tell in the video but I couldn't really see any.
How old is it and how many hours does it have?
What brand and weight oil do you use?
What brand oil filter do you use?

 

[Blkvoodoo]

Pull the injectors, take them to a REPUTABLE diesel injection shop and have them pressure and spray tested.
It sounds to me ( with all the other distortion ) like a possible fuel knock.

If an injector is not spraying properly the fuel dribbles out of the tip, and puddles in the pre-cup, which causes the knock you hear. dirty fuel, bad fuel filter, could be partly to blame.

I've seen many engines condemned as a result of this, yours seems to sound fine unless you apply fuel

 

[KubotaSchamota]

Does it have any oil flowing when its running? It's hard to tell in the video but I couldn't really see any.
How old is it and how many hours does it have?
What brand and weight oil do you use?
What brand oil filter do you use?

As far as I can tell there's no additional oil flowing into the rocker area. It's not totally dry by any means. The pool of oil that's already there doesn't increase or decrease when running the engine.
The tractor was bought back in 2000 and gets used at least 2,3 times a week. Not sure on the total hours. Hasn't really been maintained like it should. Gets a oil change whenever he gets enough time around the farm. Fuel filter is new.
From what I remember it's Rotella 15-45w.
Didn't really think to check the oil filter brand. I'll check later on tonight.

 

[KubotaSchamota]

Pull the injectors, take them to a REPUTABLE diesel injection shop and have them pressure and spray tested.
It sounds to me ( with all the other distortion ) like a possible fuel knock.

If an injector is not spraying properly the fuel dribbles out of the tip, and puddles in the pre-cup, which causes the knock you hear. dirty fuel, bad fuel filter, could be partly to blame.

I've seen many engines condemned as a result of this, yours seems to sound fine unless you apply fuel

Fuel filter is newish condition...just replaced a month ago. At first I thought it was because he didn't bleed lines after the filter install but it still doing that after the bleeding. I'm thinking it's the injection pump or injectors like you said.

 

[KubotaTech]

Maybe put an oil pressure gauge in it to see what the pressure is. If you can run it at constant speed and get it to knock, crack an injector line, and see if the noise changes with each injector cracked- one at a time. If it goes away, that may at least tell you where to go next. I agree, checking the injectors would be a good idea. Be sure you have good fuel supply to the injection pump.

 

[Bulldog]

It was hard to tell very much in the video but was it blowing white smoke out of the exhaust?
If so that does sound even more like a fuel problem. Raw fuel being dumped in will make white/light blue smoke and it smells strong most of the time.

The reason I asked about the filter brand is because I had a Fram filter stop up on my B 7100 one time and it made all kinds of strange sounds before I got it shut down. I changed the oil and filter and it did fine after that. Another thing is the lack of oil on the rockers. If I look in the valve cover on my L 3000 I can see all kinds of oil slinging around in there. I think if the valve cover was off it would shoot oil every where.

Keep us posted on this.

 

[KubotaSchamota]

It was hard to tell very much in the video but was it blowing white smoke out of the exhaust?
If so that does sound even more like a fuel problem. Raw fuel being dumped in will make white/light blue smoke and it smells strong most of the time.

The reason I asked about the filter brand is because I had a Fram filter stop up on my B 7100 one time and it made all kinds of strange sounds before I got it shut down. I changed the oil and filter and it did fine after that. Another thing is the lack of oil on the rockers. If I look in the valve cover on my L 3000 I can see all kinds of oil slinging around in there. I think if the valve cover was off it would shoot oil every where.

Keep us posted on this.

Yes..there is a bunch of white/blueish smoke. Very strong smell as well. I ended up taking out the injectors and I'll try to see if I can find a reputable injector specialist around my area.

 

[Bulldog]

Good luck with that and let us know how things turn out.

 

[KubotaSchamota]

well..Jack the injector guy said all three of my nozzles are bad. He tested them to 4500psi and they wouldn't even open. The valve part of the nozzle won't even come off. They're frozen..won't even spin freely. He's hoping I didn't damage my injection pump by running it in the condition that it was in. He said it could be algae since I mentioned there was black stuff coming from two of the injection pump outlet holes. So far he's instructed me to take off the injection pump and bring it to him for cleaning. He also told me to clean the lines and the tank but there's no way for me to reach in there and wipe down any possible contaminates. Does anyone know how to take off the gas tank and cover? Any pointers would be appreciated. If not then is there a product I can use to add to the diesel and allow it clean out the tank?

 

[Bulldog]

If it was me unless the tank had trash that was stuck in the bottom I wouldn't take it off. I would just remove the fuel line that goes to the fuel filter and drain it there. After I caught the fuel that was in the tank I would wash it out with a water hose dry let it dry out good. Then taker a air hose with a blower and blow some air in the tank to insure there was no remaining water. After that I would dump a little clean fuel in and let it just run thru just to make sure all the water was removed. Put a new fuel filter on and hook the line back up. Since you are going to have the injector pump off already I would flusk the line that is between the filter and the pump to make sure it is clean and you should be good.

As far as a fuel additive goes.
I use marvel mystery oil in my fuel at a 4oz to 10 gal. ratio. It will help to keep the fuel system clean and it treats te fuel as well. It will also add lubricity to the fuel and will help to keep your injectors and pump lubricated and will aid in keeping carbon from building up. For every day fuel treatment I use mercon dextron ATF fluid at the same ratio.

You probably will get a bunch of different answers to this question and some will say that Marvel won't do anything for you but I have been using it for over 30 yrs. and (knock on wood) have never had to work on any injection ststem on any of our diesel equipment.

 

[KubotaTech]

After you clean out the tank with an air nozzle, it prob. wouldnt hurt to maybe put a gallon of fuel in the tank and let it run out to kind of flush the tank out. At our shop we use an additive that has a water dispersant and is also used as a regular additive every time you fill up. I think it is an FPPF product. Sells for around 10 bucks. Bulldog was right, if you ask everyone here what to use as an additive everyone would tell you differently, just like what oil is the best to use.

 

[KubotaSchamota]

I got the injectors back. The guy did a great job of cleaning them up and replacing the nozzles. I asked for a quote on the injection pump cleaning it was waaay above my budget so he gave me some pointers on how to flush it out by gravity feeding it diesel and pushing on the bottom plunger assemblies(*gonna make your thumbs a lot stronger* as he said..hehe) I described to him how the tank was too small to clean by hand so he suggested a product called Stanadyne performance diesel additive. It's supposed to remove water from the diesel and a bunch of other stuff. Cross your fingers for me..I'll be out at my father in law's this monday to be putting it all back together.

 

[Blkvoodoo]

I got the injectors back. The guy did a great job of cleaning them up and replacing the nozzles. I asked for a quote on the injection pump cleaning it was waaay above my budget so he gave me some pointers on how to flush it out by gravity feeding it diesel and pushing on the bottom plunger assemblies(*gonna make your thumbs a lot stronger* as he said..hehe) I described to him how the tank was too small to clean by hand so he suggested a product called Stanadyne performance diesel additive. It's supposed to remove water from the diesel and a bunch of other stuff. Cross your fingers for me..I'll be out at my father in law's this monday to be putting it all back together.

My diesel shop recommended the same for the same reasons, a little goes a long way, the bottle treats like 60 gallons, OR, about 10-12 tank fulls in a baby 'bota, and it's cheap insurance.

As for the injection pump, keep a few extra filter 's handy, change them after a few tanks, you'll be dumping goo into the bottom as the fresh fuel and Stanadyne do their thing.

I run into the sludge/algae problem about twice a year on various pieces of equipment I repair, customer has replaced the fuel filter several times, but it still won't run, many of the forklifts I work on have fuel socks that get plugged up with the goo, when you run the engine, and accelerate, you can watch the primer pump suck down, it's a dead give away.

 

[KubotaSchamota]

YES! Everything is back to normal. The bad injector nozzles were the culprits. I even replaced the universal joint on the front drive shaft. The previous one was all chewed up looking..almost hanging on by a thread. I'm two steps from becoming a certified kubota tech. *pouring the sarcasm on* haha. Thanks to everyone that posted in this thread with your suggestions and advice.