Cummins Top-End work Reccomendation

[Jackman]

Looking for a recommendation for top end work on a Cummins 330B 6BTA. I think I have a valve or two that have decided to hangup after inspecting my sick engine this weekend. Two pushrods were slightly bent. Looking for a good place in Md or De or even Jersey (I live in PA).

I guess the goal is to remove the head in the boat and examine the surface of the pistons to make sure there is no damage that would require pulling the entire engine. If I see damage I'll bolt the head back on and remove the engine. If its just the head I'll rebuild it.

So has anyone had any luck with companies in my area of the country?

Jack

 

[oscarvan]

You can always try to put new rods in an a few quarts of Lucas Mystery Oil. I have unstuck many a sticky valve with it...... Worth a try.

 

[Boatsb]

Slightly bent rods? That's like only a little pregnant.

Pull it a do it right. If not you will regret it later.

 

[Jackman]

I can get the rods and replace them but even when I hand turned the engine after just trying to straighten the rod I could feel a rough spot like the valve was binding...maybe it dropped and the piston was contacting it. Lifter was working as we manually checked that it moved up and down. Engine turns fine without the pushrod in place...So its got to be the valves because when I put the rod back in it gives a little resistance and come of the rocker springs do not return the hole way up immediately as they should (uncompress)and are sluggish after opening the valve on two of the intake valves. I'm wondering if this is the residual effect of having a less than optimum Cummins exhaust elbow prior to switching over to the Tony Athens design. Maybe some water in the turbo? I did see some slight corrosion on the push rods.
I guess I can try the MMO...how exactly did you do it? Just add it or did you apply it to the top end directly?

Jack

 

[jim rosenthal]

Call T&S Marine Engines in Crisfield, MD. Pull the head and send it to them for a rebuild. And, yes, determining the cause is a good idea, too. They will be abble to help you figure that out. Ask for David.

MMO is great stuff but it isn't going to fix this kind of problem. .

 

[oscarvan]

I put it in the oil, but now agree with the previous posters that you may have more going on.

 

[Jackman]

Jim,

Thanks for the reference. I called and spoke to David. Seemed like a really nice and honest guy to. We discussed my situation and he recommended that I pull the head and examine the pistons and cylinder walls. If there is no damage he said replace the head with a new head. He does not rebuild them. I'm guessing sometimes the machining is not all that great and the valves dont seat properly. Best just to spend the extra bucks and buy it new.

I discussed the sticky valve situation that may have caused the bent pushrods and he said its quite possible to have sticky valves from corrosion which may have originated from the original posted issue of having the turbo pull in saltwater vapor and most certainly the poorly designed cummins exhaust elbow I had prior to updating with a custom riser from Tony Athens...When I pulled the pushrods I noticed some corrosion when I wiped them clean of oil...which I doubt is just from low hours over a short amount of time. I know its not from my aftercoolers or anything else because I do them EVERY season.

JAck

 

[whoover]

Hello, I was getting ready to order new mixing elbows from Tony Athens to redo the risers on my Cummis 903's. You now have me rethinking this decision. What is it that makes you think the mixers are less than efficient.

Thanks
Walt Hoover

 

[Jackman]

It's not about efficiency. I dont believe I said that but if I did I apologize as thats not what I meant. You might want to read Tony's many posts on these elbows. Its all about rise from the water level and how the water is injected into the elbow on the downhillside of the exhaust elbow. Maybe it works in your installation....but in mine it did not. I went through both turbos very early in the life of these engines because of salt water intrusion up the exhaust. My other issue is probably because of engine room ventilation. Your best thing to do is send Tony pictures that show how your engines are installed that are clear and cover the area of the exhaust and turbo very well.

Maybe you do not need the custom work...but I did. I only have 280 to 300 hours on my engines. Turbos should not be killed in that short amount of time. Mine looked just like his pictures of failed turbos because of poor exhaust system design.

 

[Boatsb]

Any repower needs to have the exhaust evaluated. Its not the off the shelf components fault. There is a specific height above the waterline and a slope that have to be met. Many repowers get custom risers for that reason.

About 50% of the repowers will not meet the Cummins specifications. Every time I do one it has to be inspected before Cummins signs off for warranty.

If you have to do 2 rods and the head why not pull the engine and make it easier to get to everything, clean and paint as necessary and reinstall a 100% sound engine.

 

[jim rosenthal]

FWIW, I would proceed one step at a time. You can absolutely trust David, these guys have sold and serviced and rebuilt both Cat and Cummins for literally decades. The first engines I had majored in that shop were DDs in the 1980s. Those 6-71s are probably still out there.

Pull the head and see what's going on.

You can also absolutely trust Tony. He has done MANY repowers with those engines and similar ones, and Cummins engineers always sign off on his work so that the warranty is in effect. If he built you exhaust systems, they are done right.

I don't know if you need to pull the engine entirely. Yet. I don't think you are at that point, but (and I hope not) you might get there. But I would do the head first.

 

[Jackman]

Bob...Two push rods were bent...not connecting rods as far as I know at this point. The exhaust was evaluated by the company I bought the engines from. The criteria of 10" from the waterline was met but may have not been enough..who knows. I think the water could have come from the elbow's water injection point as well. When I removed it to install Tony's engineered system I remember seeing a small hole in the jacket of the cummins elbow. Since the Cummins elbow may not have had the water injected downstream enough it could have backed up through the hole I found.

 

[Boatsb]

I dont remember what the 5.9 spec is but 12" and no 90 elbow comes to mind. It needs to go aft and down before making a turn that causes back pressure.

I see too many wrongly plumbed. Its a shame as the engines get damaged from an avoidable mistake.

 

[jim rosenthal]

Do you use surge tubes when you install these? Reason I ask is that my exhaust (done by Slane) has them, and I don't always see them.

 

[Jackman]

Jim,

I don't have surge tubes installed as I left the mufflers in place from the 454's. The exhaust system they installed when the boat was new was robust enough/set up for caterpillars even though the original owner put in 454's. When the back pressure was checked at install of the 330bs the installer said everything was fine as is. Tony's exhaust design was supposed to make things even better. No surge tubes.

 

[whoover]

Yes, I read your post wrong and confused the original cummins exhaust with your new design from seaboard marine. I feel good about my decision now. I do not have turbos but need to move the cooling water to the downward slope of the riser.

Walt Hoover

 

[Jackman]

SO I'm probably headed down tomorrow to remove the head on the port Cummins 330b 6BTA...First time doing this on a diesel. Figured I'd never have to do this since the diesel should outlast any gas engine I've ever had. True for my many land-based diesels. Gotta find out what went wrong.

Anyone have any pointers or suggestions? Things to avoid? Should not be that that. Just very heavy.

Jack

 

[Finalee]

You may want to reconsider just replacing the head. With such low hours the original head should be very rebuild able. If you do replace make sure its not Chinese junk. Lots of it out there. Rebuilding is a very basic operation on these..

 

[jim rosenthal]

If he obtains the replacement head from T&S it will not be junk, I assure you. I have no idea whether replacement heads are cast overseas. I believe they said that the cost of rebuilding it was not much different from getting a new one, but I may be mistaken.

 

[Jackman]

We started disassembly and with the custom exhaust off and turbo off we found somehow water got in there. Tony believes this to be from my travel lift operators not keeping the bow up to level when removing it Both the turbo and exhaust were installed new so I know its not lingering from the previous set up from the original install. I disassembled and cleaned up the turbo and it appears fine after being stuck. Tested the balance by looking at the blade spinning while using the shop vac trick. Seemed fine so I'm going to reinstall once the head inspection is done.

Purchased a cheap injector remover so I can move forward with the head. I'm hoping I see no piston damage. I looked using a boroscope just in cylinder 4 where the worst bent pushrod was and did not see anything notable. Just a bunch of soot. I remember when I removed all of the pushrods for inspection after seeing the bent one that the entire engine turned over very smoothly and I heard nothing out of the ordinary. No restrictions. When I put the rods back in their original location and hand turned the motor there was a binding in cylinder 1 like maybe a valve was stuck or bent. Thats why I am moving forward with removing the head. Will probably start Monday-Tuesday of the weather cooperates. I'm hoping i dont see something disasterous.