Waukesha VGF H24 GLD Bogging down under load

[Danandersen]

Hi guys,

Im running a couple VGF H24GLDs one of them was recently serviced, new head gaskets, wastegate, plugs, coils, oil ect.

but now I seem to have lost power in the engine. It bogs down and won't maintain speed at 500 amps while it it rated at 616 amps. (throttle fully open)


I have checked my O2, gas over air pressure, timing, firing, air intake and filters, compression and valve lash. I have checked for air leaks and exhaust leaks and I have little to no pressure drop from leaving the turbo to the Intake manifold and I am now out of ideas of what could be wrong


Compared to logs from before the service and last year, I seem to have about 5-6 psi lower intake manifold pressure at the same load.
I am suspecting maybe there is something wrong with the wastegate? despite it being new and not adjustable (like the old ones)

Any ideas?

Thanks in advance!

Dan

 

[Danandersen]

Hi Mike. This is a little over my head, But I'll answer the best I can;


I dont know if I run HCR or LCR, the comp is 11:1

Serial: c-94371/1 on the engine (what is BOM an acronym for?) I was thinking I might have gotten a wrong wastegate - but I didn't know that there were several kinds etc. So I didn't pay much attention to it.

As for psi and Mercury, I have no data.. my gauge measures PSI, that's all I've ever used. But I can hook up a an HG probe if needed.

As for my O2, I did the test running the engine under load, but not overloaded and it was running at 60.00 hz, so the O2 readings should still be ok, right? I can see how the O2 getting off if I overload it.
It is a draw-through carb as well, so gas over air should be proportionate shouldn't it?

How do I get a hold on the BHP/INT calculating spread sheet?


Thanks to the both of you!


Dan

 

[ivymike]

..you can convert psi to inches of HG, they're just different units of measure like centimeters and inches ... just type it into google

http://www.convertunits.com/from/psi/to/inch+of+mercury+[0+°C]

 

[ivymike]

oh, and BOM is bill of materials (parts list)

 

[gruntguru]

From Mike's post your boost should be 31 or 33"hg ie 15.2 or 16.2 psi. If the wastegeate is cracking at 10 psi as you said earlier, that is your problem - wrong wastegate.

je suis charlie

 

[Danandersen]

Yes, Wrong wastegate, I put the old one back in and it worked fine. My question is now, I dont see any other part numbers for other wastegates, and I cant adjust this type. so
how can i have ended up with a wrong one?

 

[Lou Scannon]

Your engine rating plate *should* be a guide to getting the correct wastegate. Failing that, by hook or crook you will have to find a way judiciously to increase the preload on the one you have. If the preload you end up with is higher than the spring in your wastegate is designed for, it may have a shortened life expectancy. Be wary too, of coil bind at full power, causing overboost, turbo overspeed & possibly other consequences.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[MikeHalloran]

More response from my Waukesha expert:

{
Let’s answer his questions in order.

11.1 is a high comp ratio.

A BOM is a Bill of Material which shows how the engine was built (AS BUILT) when it left the factory. Based on the s/n of his engine here is the 3 main parts I pulled from the BOM.



Piston 300304K

Turbocharger 305866

Wastegate 305810





The gauge readings are only important when we know which scale we are using. We can convert PSI to HG and back. This way we are talking in the same language.



His O2 reading may be where the problem is. The AFR is being controlled by the adjustable orifice (Load Screw) at the higher loads. If you are not giving the engine enough fuel to reach the higher loads it won’t.



If you adjust the AFR to its lean setting before the engine has reached full Continuous Duty Load it will be too lean to reach full load. To normally adjust an AFR you need to run slightly rich (less than 7.8% O2) to make the BHP necessary for full Cont/Duty BHP. Once you are running at Full Rated load you then start leaning the unit out to the specific O2 readings. This is what I was saying earlier that the natural tracking of the carburetor goes from rich to lean. If you set up the O2 at a lesser BHP then when you need the Greater BHP you don’t have the proper air to fuel ratio to make the necessary BHP. The engine is set too lean. To see this happing all one has to do is start removing load and watch the O2 start to track rich (start dropping from 7.8% to say 6%).



If the parts are correct then the adjustment of the AFR is not correct based on his load and power demand.


}

Mike Halloran
Pembroke Pines, FL, USA

 

[Danandersen]

Mike,

Thank you for your answer.

About the O2, I understand and it makes sense.

The wastegate Part Number your tech provided is correct, that is what I ordered, and that is on the invoice too. However, if you read ealier as well

I had the old wastegate out laying next to the new one I hooked up compressed air to them both, and I saw that the "new" wastegate would open at a significantly smaller psi then the "old" one - Obviously then bypassing exhaust at a lower load.

So I put the old one back in, and my problems stopped. Engine running at rated load with no problems.. O2 readings are perfect too.. So it must be the new wastegate. I just cant figure out why? as I said, it is new?

As far as I know, I cant adjust the wastegate aside for the few 0.001" on the power piston for altitude adjustments - which by the way is exactly like the old one.

Dont really know what to do about it. It feels like $1900 down the drain. ( I know, I know... spare parts.. but yeah..)

 

[Lou Scannon]

I would pursue your warranty replacement options with the new wastegate. Evidently it is defective.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[gruntguru]

As I said in an earlier post, changing the preload on the WG spring (by adjusting the pushrod or crushing the muscle unit housing) is not the way to go if more than 1 or 2 psi adjustment is required. The spring itself must be changed.

je suis charlie

 

[MikeHalloran]

So, did you receive the correct new wastegate, or did you receive the wrong new wastegate in the right box, or did you receive a correctly marked wrong part with some bullshit assurance, or what?

Parts counter personnel have been known to swap parts and boxes in an effort to save their job after they screw up, and to keep doing that and similar evil until the inventory is irrevocably tangled.

I'd say a $1900 screw-up justifies a polite call or ten to your parts supplier, and maybe a few less polite bonus calls.


Mike Halloran
Pembroke Pines, FL, USA

 

[Tmoose]

"Yes, Wrong wastegate, I put the old one back in and it worked fine. My question is now, I dont see any other part numbers for other wastegates, and I cant adjust this type. so how can i have ended up with a wrong one?"

============

Are there any identifying mumbers on the two, old, working OK wastegates?