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

 

[ivymike]

Does the boost figure you measure at the manifold match the performance spec?

 

[ivymike]

oh, and is the wastegate actuating when you load it up?

 

[Danandersen]

I do not know if the boost matches specs. I don't have them. But Boost is 5-7 psi less then previously.

hmm, I did not check the wastegate lever when I initially loaded the engine up, I'll check that. But I do not see any movement during load changes. Mind you, the changes are also not huge.

 

[gruntguru]

If the wastegate is not opening check wastegate valve is not leaking/stuck open. Check for exhaust or intake restriction. Was the timing drive disturbed/replaced - if so check valve timing.

je suis charlie

 

[Danandersen]

-(Update)-


The wastegate is not stuck open, just checked, it seems to open up when right after the heavy load has been applied and is evening out. But at around 10 PSI it opens (not fully) and at that point
too much exhaust is bypassed so I don't get sufficient boost in the intake to run at a higher load.


So I took out the new wastegate and had it laying next to my old wastegate, I hooked up some low pressure air, and I see that on the new wastegate it is very willing to open up, while on my Old
wastegate it takes about twice the psi before it moves. So I installed the old wastegate again and the engine runs just fine, even at almost max load, I have great boost and all is happy and dandy.

So seemingly the old wastegate works fine while the new one doesn't? they should be the same models.. unless there is a different wastegate for the G's, GL's or VHPs which is more sensitive?

 

[ivymike]

is the wastegate tension adjustable? (I'm assuming there's a screw and spring on there somewhere)

 

[Danandersen]

Nope, Not adjustable. There is, however, a limit screw that will limit the valve from opening. But I don't feel like playing around with that. I don't want my generator to overshoot the speed during load changes because the turbo don't react fast enough.

 

[gruntguru]

Wastegates are designed to control boost to a range of settings. This usually requires a spring change. Just swap the old spring into the new wastegate.

Wastegates with a seperate "muscle unit" and valve can sometimes be adjusted (slightly only - a few psi) by adjusting the push/pull rod length.

je suis charlie

 

[catserveng]

Is it this type of wastegate?

If so, does the "old" and "new" have the same number of spacers?

If so, there were about 5 different internal spring groups for these, three single spring and two double spring. They all look similar, and ran into a number of problems with wastegates when customers used aftermarket suppliers that built both CAT and Waukesha wastegates, springs, internal shims and spacers would get mixed up.

There was a shop in Midland TX that used to rebuild and supply new assemblies and parts, can't find their info anymore (been quite a while since I directly dealt with that stuff).

I don't either CAT or Waukesha ever published actual bench testing specs for wastegates, we used to take a known good wastegate for an application, then apply air pressure to the inlet in 2 PSI increments and measure the valve position with a depth mic, then record it on a spreadsheet. A shop I worked with many years ago (now closed and everyone moved on) had built a test bench with a long reach dial indicator and built up their own test sheets.

Hope that helps, MikeL.

 

[Danandersen]

Yes, The only problem is that Waukesha made a new model of the wastegates that cannot be opened without breaking the casing. I could break the old one open, but wouldn't get the old spring into the new
one and get it working again.

I asked my Rep that exact question and he told me that people had in the past messed around with the wastegates to get more power out of there engines and thus ruin their engines, even under warranty. So waukehsa, getting tired of having to pay for it over and over, made new wastegates that can't be opened or really done anything to.

 

[Danandersen]

No, doesn't look anywhere near those. I'll get a picture later on tonight. You'll know when you see it, nothing can really be done to ones I have.

Good idea about making that sheet with the measurements, no I just need a pressure regulator that is precise enough to actually read such small increments. I really only have centralized air in my shop.

 

[Danandersen]

 

[gruntguru]

Waukesha should be able to give you a boost pressure spec for your engine. If it is only 10 psi, you are stuck with the lower power unless you are content to modify the boost setting. This is easily done without a spring change.

You can make small changes by adjusting the length of the muscle unit pushrod.

For larger changes you can fit a "bleed tee" in the pressure line to the WG. This involes a restriction in the line from the manifold followed by a branch bleeding air through a second restrictor back to the turbo inlet. The easy way is to mount both restrictors in the tee piece itself. Make the in-line restrictor about 0.80", 2mm diameter. The bleed will probably be smaller. Equal size bleed will roughly doulble the boost. Start small and incrase the bleed size until the boost is right.

je suis charlie

 

[catserveng]

I think Turbonetics make these for Waukesha, probably an OEM product but you might get someone there to give you some ideas.

One thing to look at on this style is the rod adjustment. You can affect the opening pressure by stacking gaskets (not recommended) or readjusting the rod if you can.

The flapper looks like it is seating evenly, how does it mating surface look?

If it was me I'd get a small air regulator and a good gauge and see how much stroke you get for a given range of pressures and compare. If they have gone to a "fixed" wastegate then to meet differing power and emissions ratings and altitude they would need to offer more than one. I know the local Waukesha guys are griping because after being bought by GE they are going thru a number of pains with parts supplies, differing distribution paths and apparently lots of old documentation disappearing as systems are "updated".

Your best bet may be to find a shop in the patch that has a good turbo guy who may be able to get you some better help.

MikeL.

 

[Danandersen]

Gruntguru; I'll have to get with the factory or something for the pressure spec. I don't find it in the manual nor does my rep know. I wouldn't necessarily want to modify the boost setting myself. I think i might then move into an area that's a bit over my head. I like your idea about the Bleed tee. I'll look into that, Thanks a bunch.

Catserveng (Mike) ; The rod is adjustable, according to the manual I have, Im only really "supposed" to change it because of altitude differences. and only by .04 of an inch per 1000 Meter elevation.

The mating surface is clean and smooth, the flapper sits fine. Yeah, I'll have to do the comparison over the weekend when the engine off.

Didn't know that there was a problem with parts and supplies. My distributor hasn't mentioned anything. But nice to know.

Thanks

 

[Lou Scannon]

Don't know if this the case for your situation, but if you run an engine above its designed power rating, among other things you may exceed thermal loading limits on the exhaust side: exhaust valves, turbocharger and exhaust manifolds; beyond that, maybe even the piston crown and top ring (to say nothing about knock, which I assume is being guarded against at any rate).

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[MikeHalloran]

The engine you should be measuring, carefully, is the one that's _not_ bogging.


Mike Halloran
Pembroke Pines, FL, USA

 

[Danandersen]

Hemi; No, Im not running at higher power rating than designed. In fact I always run at max 95% - equipment just seems to last longer that way.


Mike; Of course, it's the only one I know for a fact to be a good one.


Thanks

 

[MikeHalloran]

Comments from my Waukesha expert:

Let this guy know that WED does have a BHP/INT Manifold pressure calculating spread sheet. He is not giving much information on the engine such as High (HCR) or Low (LCR) comp ratio. I would start with the parts replaced first. The VGF GL/GLD has 4 different turbos which could mount. It also has 2 different Wastegates, and there is the possibility of 3 different comp/ratio pistons which could fit. The wastegates are not like the VHP which we rebuild all the time and WED had released information on how to set them up for the different engines. He also needs to be correct in his stating the intake manifold pressure as Inches of HG and not PSI. The calculated Int/Man pressure for the VGF HCR is 31inches HG and for the LCR engine 33 inches HG. You could see that with a 6 PSI drop you would see approx. 12"HG loss so he is probably seeing a 6"HG loss of pressure.
1) Get his S/N and I can run a BOM of the engine how it left the factory so he can compare parts.
2) To prove it is not the wastegate, just remove the signal or pressure line and plug it so the wastegate cannot open.
3) The natural tracking curve of the AFR is to go from Rich to lean and if he is measuring O2 at 7.8% with a 6" HG loss he may be set lean. Verify the O2 sensor fuel cell is stable sampling open air and if it is good then make a small adjustment rich on the carburetor load screw and see if he get his power back. Only do this after making sure all the parts are correct.

Mike Halloran
Pembroke Pines, FL, USA