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Drooling Piston

compounds and an exhaust brake??

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I built a small set of towing compounds with the HX35 over a He351VGT.

They are working fine and giving me what I wanted which was quick spool up. With my 13spd tranny I really benefit from the quicker spool up.

Anyway, The VGT has an exhaust brake feature in it. When I use it, it seems to cause oil to spew out of the HX35. I took the HX35 out and had it rebuilt at ADP, in Kent.

I just came back over Chinook pass with my 11,000lbs camp trailer and there is an oily mess again.

Has anyone ever experienced something similar ?

Can anyone enplane why this might be happening?

Is there, Something about slowing the flow & increasing the back pressure, of the exhaust gas, through the HX35 while still force feeding it some (even though small) amount of air from the VGT, lets oil blow through the seals?

Thanks 

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Do your turbo oil drains go in above or below the oil sump level? I’m betting above, at least for the HX35. Also what do you have for crankcase ventilation? I’m betting you have a lot of crankcase  gasses when the brake is being used that is causing the oil to back up in the HX35.

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18 minutes ago, Torque Monkey said:

Do your turbo oil drains go in above or below the oil sump level? I’m betting above, at least for the HX35. Also what do you have for crankcase ventilation? I’m betting you have a lot of crankcase  gasses when the brake is being used that is causing the oil to back up in the HX35.

 

Yes, the oil drain goes back into the oil pan above the oil level. Actually, the top turbo (the HX35) drain, is plumbed into the stock drain port, in the block.

I have not done anything with the crankcase ventilation, so it is just the stock, road draft tube, that drops down, near the left rear of the engine.

When the trailer is pushing me down the mountain, and she is revved up to about 2,000 RPMS, and the exhaust brake is on, the exhaust back pressure can hit 50+ psi of exhaust pressure.

 

I understand your working theory here, and it is only one that makes any sense to me. So, what can I do to . .  

measure crank case pressure? 

drill and tap a valve cover and move one of my boost gauge sending units there so I can monitor it while driving? then I can put a 1/8 pipe plug in it when I''m done. or maybe I can drill and tap the #10 JIC 45* elbow at the bottom of that oil drain line, put the sending unit there, then I would see the difference, in oil pressure, in that return hose, with and without the brake on.

 

provide extra venting/breathing?

drill a valve cover and put a gas engine style breather on top?

 

and why just the HX35? its drain hose is longer since it is the top turbo. Why not both turbos? 

 

I has thought about trying to secure a Go Pro style camera, under the hood, pointing at the turbo, to see if I can get evidence of where the oil is coming from. The spray patterns (and shadows of them) suggest its coming from the center section of the HX35 but I can't recreate it in the driveway. Even if I was sure of where it is coming from, I didn't have a clue as to the why? Especially after having that turbo resealed and rebuilt.

 

Thanks for the reply! it gives me something to think about.

 

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It’s tricky for sure. Probably what I would do it degrease the area the best I could then take it for a spin and set the exhaust brake at high rpms. Try to recreate the trailer behind the truck the best you can. See if you can see where the oil is coming from. Maybe the drain is leaking near the center section. If it were coming from the ring seal in the exhaust side the only way you would know is blue smoke out the exhaust. It has to be an external leak in the center section. Maybe a crack that was missed?

 

putting you boost gauge on the valve cover isn’t a bad idea at all.

 

you could run a 24v type draft tube on the front of the engine along with you current vent if needed. Just add a valve cover with the oil fill cap.

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I got everything cleaned up.

figured out a way to secure an inexpensive boroscope, with its own lights, under the hood pointing at the turbo. This scope has a WiFi transmitter. My son sat in the passenger seat, looking at my I-pad while I drove and put the truck through different scenarios.

The oil is coming out of the exhaust side of the turbo and wetting the center section. It seems to be happening under all, higher RPM deceleration, conditions.

When consulting the very wise Google. The new working theory is, I need to reduce the volume, of the oil supply to the turbo. There were several threads, on car forums, about this same scenario, happening on deceleration.

I used #6 sized hydraulic hose and fittings for the supply and #10 for the drain. Those other forums said when they reduced the size of the supply line down to a #4, the oil leak disappeared.  

On my build thread, there was discussion about using a "T" or not on the supply line. Since I did use a "T", where 1 port is divided to supply oil to both turbos, I never considered the possibility that I could still be over oiling this turbo.

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12 minutes ago, Drooling Piston said:

I got everything cleaned up.

figured out a way to secure an inexpensive boroscope, with its own lights, under the hood pointing at the turbo. This scope has a WiFi transmitter. My son sat in the passenger seat, looking at my I-pad while I drove and put the truck through different scenarios.

The oil is coming out of the exhaust side of the turbo and wetting the center section. It seems to be happening under all, higher RPM deceleration, conditions.

When consulting the very wise Google. The new working theory is, I need to reduce the volume, of the oil supply to the turbo. There were several threads, on car forums, about this same scenario, happening on deceleration.

I used #6 sized hydraulic hose and fittings for the supply and #10 for the drain. Those other forums said when they reduced the size of the supply line down to a #4, the oil leak disappeared.  

On my build thread, there was discussion about using a "T" or not on the supply line. Since I did use a "T", where 1 port is divided to supply oil to both turbos, I never considered the possibility that I could still be over oiling this turbo.

 

When the vanes on the VGT close to create the exhaust brake function does it pressurize the cavity in the exhaust housing (wheel and shaft) or just the volume leading into the housing and back into the exhaust manifold?

 

Have you pulled the oil cap to see if you gain any significant crank case gasses when the exhaust brake is on?

 

I know on the turbos I've worked with (HX40, HX35 and HT3B) the drains are significantly larger that the hole in the top that feeds oil in.  I believe the intention is that the oil is pressurized into the bearing cavity and keeps it flooded but just gravity drains out. I think it's more likely that you have some sort of restriction on the drain side be it case pressure or hose restriction than an over supply of oil to the turbo.  The hole in the top of the housing and the hole in the top of the turbo and in the filter housing (at the oil line ends) would be the flow restriction, not the hose feeding the turbo.  I had a 3B leak on the compressor side at high RPM and boost, it was a result of restriction on the drain side, the bend in the 3/4" hose (or 1"?) was too tight and reduced the ID down to about 75% opening.

 

If you didn't just have that thing rebuilt I'd have sworn the shaft seals in the turbo gave up but I guess that's not likely the case.

 

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22 hours ago, stroketeck said:

was that the reason you had it rebuilt?

 

Oil leaks, both exterior and inside the compressor housing, putting oil into the boost pipes

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23 hours ago, Woodenhead said:

 

When the vanes on the VGT close to create the exhaust brake function does it pressurize the cavity in the exhaust housing (wheel and shaft) or just the volume leading into the housing and back into the exhaust manifold?

 

Have you pulled the oil cap to see if you gain any significant crank case gasses when the exhaust brake is on?

 

I know on the turbos I've worked with (HX40, HX35 and HT3B) the drains are significantly larger that the hole in the top that feeds oil in.  I believe the intention is that the oil is pressurized into the bearing cavity and keeps it flooded but just gravity drains out. I think it's more likely that you have some sort of restriction on the drain side be it case pressure or hose restriction than an over supply of oil to the turbo.  The hole in the top of the housing and the hole in the top of the turbo and in the filter housing (at the oil line ends) would be the flow restriction, not the hose feeding the turbo.  I had a 3B leak on the compressor side at high RPM and boost, it was a result of restriction on the drain side, the bend in the 3/4" hose (or 1"?) was too tight and reduced the ID down to about 75% opening.

 

If you didn't just have that thing rebuilt I'd have sworn the shaft seals in the turbo gave up but I guess that's not likely the case.

 

 

I've never thought about it and don't know for sure, but I would assume there is pressure inside the exhaust housing as well as back upstream for the whole exhaust.

The VGT is not what is leaking though.

 

No, I haven't tried to watch what might come out of the oil filler cap while driving.

 

you mentioned a 3/4 or 1 inch drain line, I used a #10 hydraulic hose and fittings. They are a 5/8 ID. The adapter, that bolts to the bottom of the turbo, and has a #10 male JIC fitting, Looked to be about 1/2 inch ID. The drain hose from the turbo to where it enters the block is nearly a straight fall, with just a slight bend. 

So, the adapter, on the bottom of the turbo, may be my restriction, at only 1/2" ID.

 

https://www.amazon.com/dp/B07SG495ST/ref=sspa_dk_detail_3?psc=1&pd_rd_i=B07SG495ST&pd_rd_w=uY2jY&pf_rd_p=8a8f3917-7900-4ce8-ad90-adf0d53c0985&pd_rd_wg=MQfmV&pf_rd_r=3BJ3WXMDJGXWXS8RPXXR&pd_rd_r=c379e2f0-8ddb-11e9-bd2f-f9fbdb80feb9

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1 minute ago, Drooling Piston said:

 

I've never thought about it and don't know for sure, but I would assume there is pressure inside the exhaust housing as well as back upstream for the whole exhaust.

The VGT is not what is leaking though.

 

No, I haven't tried to watch what might come out of the oil filler cap while driving.

 

you mentioned a 3/4 or 1 inch drain line, I used a #10 hydraulic hose and fittings. They are a 5/8 ID. The adapter, that bolts to the bottom of the turbo, and has a #10 male JIC fitting, Looked to be about 1/2 inch ID. The drain hose from the turbo to where it enters the block is nearly a straight fall, with just a slight bend. 

So, the adapter, on the bottom of the turbo, may be my restriction, at only 1/2" ID.

 

https://www.amazon.com/dp/B07SG495ST/ref=sspa_dk_detail_3?psc=1&pd_rd_i=B07SG495ST&pd_rd_w=uY2jY&pf_rd_p=8a8f3917-7900-4ce8-ad90-adf0d53c0985&pd_rd_wg=MQfmV&pf_rd_r=3BJ3WXMDJGXWXS8RPXXR&pd_rd_r=c379e2f0-8ddb-11e9-bd2f-f9fbdb80feb9

 

I have a few fittings and turbos laying around, I could measure the ID this afternoon (if I remember) and see what they are.  The reason I asked about what gets pressurized with the VGT exhaust brake is I was wondering if it was pressurized around the turbo shaft seal as you mention it leaks when the brake is on.

 

 

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i have drained with -10 for a long time, i also have built alot of trucks with twins and exhaust brakes and have not had any issue, also never seen a hx35 leak oil without a broke shaft. i believe there is a crack in the centre section of the hx35

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Quality of rebuild ever suspected ? 

Seal not in place correctly, buggered up on install , correct kit used ... just throwing out there for noodling 

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I don’t leak often but my housing is definitely cracked.

 

Sorry for slight derail

 

😀

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Well I decided it was time to do something. Good or Bad

 

I had a smaller oil feed line made up with #4 hose and the #6 fittings to mate up with everything else I had already plumbed in there.

 

After a few short test runs, all looked fine, no oil leaks and it didn't smoke the turbo due to a lack of oil.

 

I thought about asking on this forum if anyone needed something hauled over the pass, but, what if I had a break down or whatever was being hauled wasn't very heavy, so I didn't post anything but took off on a test run by myself with no other time constraints or expectations.

 

Sunday morning I put tools, coveralls, boost boots, hoses, clamps, jacks etc in the truck, loaded 3 yards of sand into the dump trailer and set out on a test run.

I stopped at the Federal way truck scale on I-5, about 6am, while they were closed, and weighed my truck & trailer. combined gross weight was 17,780lbs.

up hywy 18 over Tiger mountain, up I-90 over snoqualime pass, the other climb out of Cle Elum, I think its called Rye Grass, turned south on hywy 82 for Yakima, with 3 more 2500ft elevation climbs, back to the west on hywy 410, over White pass to I-5 and back to Tacoma.

I pushed her hard and didn't let her get under 60mph up each climb and 65-68mph everywhere else (that I could, depending on traffic), using the exhaust brake on the way back down those hills. The trip was about 360 miles.

The only trouble I had was a tire blew out on the dump trailer.

 

Reducing the volume of oil, to that one turbo, fixed its oil leak issue.

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Awesome! I’m glad you solved it.

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