Turbo/wastegate test

[Larry3570]

Hi,

I have an 8.3 300 hp in a '94 Kountry Star. How do I verify if the tuebocharger is working OK?

Also, how do I verify if the wastegate is working OK? I was lubing the PacBrake exhaust butterfly and tried to manually move the wastegate control arm, but I couldn't move it at all. Is it sprung so hard that manual operation is impossible? Or could it be stuck? And if so, how does it get un-stuck? Actually, on this type of engine I don't even know what causes the wastegate to actuate.

Thanks,
Larry

[Ray,IN]

If the turbo is not working you have low power, lots of smoke on hard acceleration and steep grades. I don't think the wastegate can be moved by hand, but I'd stop in an authorized Cummins repair center and ask some questions. The Cummins repair center I used was eager to discuss my engine when they had time.

[Flagelpater]

My butterfly valve is stuck as well. I have tried penetrating oil but it has not worked so far. It will be a week or so before I can get to it. Please let me know how you make out. If anyone has suggestions to free it up it would be appreciated.

[chasfm11]

Flagelpater, have you tried disconnecting the linkage to the air cylinder? It would be interesting to find out if your butterfly was seized at the pivot points on it or in the push linkage for the air cylinder. I haven't had your problem but I do use the Pacbrake lubricant (it is specially formulated for high temperatures and, IMHO, is safer than other types) on everything that moves on the exhaust brake and linkage.

I was, too, was worried about whether the turbo was operating correctly, Specifically, I was concerned about leaks in the Charge Air system between the turbo and the intake manifold. I bought VMSpc, an chassis monitoring application that runs on a laptop with the intent of monitoring turbo boost pressure. I figured that, at a minimum, I would get a mental baseline picture of boost pressure versus engine load. I now know what I can expect to see boost wise under most conditions and hope that I would recognize the situation if a turbo problem developed.

[Flagelpater]

chasfm, Thank you for your help. I will not be able to get to it for a few more days. I could not tell if it was just the pivot points that are seized. I too have always used the Pacbrake to keep it functional. I did not lubricate it as parked it this winter. We actually stayed in the coach as our new home was being built. I made the mistake of running the coach and moving it back and forth as little several times. Obviously this never moved the Pacbrake or got the engine up to operating temperature, big mistake I find out now! I also do not understand why they designed the linkage with such a small angle between the pivot points. Has anyone found a "Magic Solution" to free up the linkage or butterfly?

[chasfm11]

I have no experience so this is just opinion. Faced with your situation, I might try to remove the exhaust brake completely and see if I could work it loose on the bench, assuming that disconnecting the linkage to the butterfly valve did not solve the problem. Given the work involved in the removal, however, I might be tempted to replace the exhaust brake with the new style. I do admit that it might take some changes to the exhaust system and that those changes might not be easy to do.

[Larry3570]

Thanks Ray,
I used a compressor to put air to the wastegate diaphram and although the diaphram output rod is trying to move it can't make the wastegate shaft move. I'm soaking it with Liquid Wrench and I'll try Vice-Grips on it. I don't see that I have much to lose. Might heat it too.


Chasfm,
Flagelpater,
I have no problem with my exhaust brake and have never worked on it other than to apply the PacBrake oil every year. My problem is with the wastegate.

[Flagelpater]

Chasfm11: I removed the PacBrake today. The linkage at the end of the air actuator and the butterfly shaft are completely seized. I put it on the bench and had to drill out the clevis pin. I was hoping that it was all that was holding the butterfly, but that was not the case. I have shipped the unit off to my son to overhaul.
The inside of the valve looked real clean, no buildup at all. The design of the linkage set-up leaves a lot to be desired. There is almost no mechanical advantage at the link point. There is almost no angle when the valve is wide open. It would seem to me that there should be at least a 45 degree angle there. Also, the clevis pin should have a slot in the end so you can rotate it while lubricating it. I may have my son install this type of pin, or a bolt so I can turn the head. I think I actually caused most of the problem. It was working as I parked the coach for the winter, we stayed in the coach here in PA as they built our new house. I ran the coach every two weeks for 20 minutes, at idle. This probably caused the linkage to seize. I will let you know how I make out.

[chasfm11]

Sorry, Larry, I didn't mean for us to highjack your thread to talk about his exhaust brake problem.

[Flagelpater]

Larry; If I committed an error I am sorry. I thought the INFO about my problem would help you with your stuck PacBrake.

[chasfm11]

What Larry is trying to tell us is that his wastegate on his turbocharger is stuck. While it has some of the came characteristics as the mechanics on an exhaust brake (an internal valve controlled by an external mechanism), it is a very different setup. You got your exhaust brake apart fairly easily and can see the valve without much of a problem. The wastegate inside of his turbo, assuming it is a Holset turbocharger, will be much more difficult to free up.

Here is a link explaining it. I don't envy him the task.
http://www.holset.co.uk/mainsite/fil...-wastegate.php

[Flagelpater]

Boy, I missed that completely! Sorry, I thought you were talking about the PacBrake being stuck and wondering about the Wastegate. Thank you for the link. My experience with wastegates were always stuck Open or Closed. Wouldn't this show up as overboost or underboost? Can they just be slow to move? Couldn't we see it just on the Boost Gage or would we need special instrumentation?

[Larry3570]

Chasfm,
Flagelpater,

Please don't apologize, I just didn't you making helpful suggestions about a problem I didn't have. Luckily my PacBrake works great.

I did some more research and found out the (Holset) diaphramic wastegate actuator can withstand 50# PSI, and I had been blasting everything with Liquid Wrench a couple times a day, so I jacked up the regulator to about 45# and slowly it moved. After about 75 air pulses and lots of LW now it's just fine. So I've oiled it well and hopefully that's it.

Thanks,
Larry

[Flagelpater]

What symptoms did you have that made you go looking? What type oil did you use after you got it moving?