Synthetic Oil Solves Turbocharger Problem
- Thread starter mormit
- Start date
- Status
>From "The Practical Handbook of Machinery Lubrication"
A construction equipment contractor was experiencing premature turbocharger failures when certain engines were operated under full-load conditions and used around the clock. Investigation through oil analysis and diagnosis of the failed components revealed that the failures were caused by coking of the petroleum base oil within the turbocharger oil passages, thus restricting oil flow and resulting in bearing failure.
The initial cause of the oil coking condition was excessive temperatures within the turbocharger housing. A fully synthetic diesel engine oil was selected of the same viscosity as the original petroleum base mineral oil and installed. Premature turbocharger failures did not reoccur and oil temperatures dropped by about eight degrees Fahrenheit.
A construction equipment contractor was experiencing premature turbocharger failures when certain engines were operated under full-load conditions and used around the clock. Investigation through oil analysis and diagnosis of the failed components revealed that the failures were caused by coking of the petroleum base oil within the turbocharger oil passages, thus restricting oil flow and resulting in bearing failure.
The initial cause of the oil coking condition was excessive temperatures within the turbocharger housing. A fully synthetic diesel engine oil was selected of the same viscosity as the original petroleum base mineral oil and installed. Premature turbocharger failures did not reoccur and oil temperatures dropped by about eight degrees Fahrenheit.
Turbo failure as such is caused by overfeuling by for example lugging an engine or a mechamical problem.
Agreed. The equipment in question was most likely over fueled and the EGT (exhaust gas temps) were through the roof. I'm guessing in the neighborhood of 1400 Deg+. This is either caused by plugged air filters or bad injection pump calibrations.
The true test of HP on a diesel isn't a snap dyno test. You can make a little 2.4L diesel crank out 400 hp for a short period. The true test is weather or not you can keep the temps in check and engine together at the rated HP levels for hours on end at full throttle.
Plow tractors on the farm are the best example. They will spend 12 hours strait running right at the torque peak pulling a large plow.
These engines are capable well above there stock rated Hp levels. Look at competition pulling tractors. there getting over 1,200-1,800 HP Out of a stock engine casting that was designed and rated for 200 HP max. You just cant keep that much power cool for longer than 300 feet without adding some major bulk.
Another less likely but possible in a distant world is that they were over speeding the turbo charger by forcing it to create more boost that its MAP range was designed for. Such as a pinched waste gate line. This usually causes a catastrophic failure of the turbo impeller though.
I assure you that the oil while it might have helped prolong the life of the turbo's was just a band aid for a much larger problem.
How about just riging up an independant oil system for the turbo. Give the turbo some thing like 7808, a turbine engine oil that is all most un effected by heat and does not coke?
While that would work. It would still be ignoring the underlying problems with the equipment.
I agree that overfuelind could certainly cause turbo failures. I generally see overfueling turbo failures in either the hot or cold sides of the turbo, not the cartridge (although there have been a few cartridges failed due to overfueling). A major problem with construction equipment is ambient temperatures. I've seen a lot of temperature related failures in off road equipment. The problem is most of the power generation equipment (engines, pumps, etc) is almost always enclosed in insulated compartments with little to now cooling air flow. Many larger pieces of equipment jacket water cool the turbo's as well as the cartridge oil supply.
I've seen the same problem with some of the equipment I worked on. A couple of us spent several weeks modifying the engine enclosures on a couple of test units. With the addition of cooling ducts to push heat out of the engine compartment we significantly reduced heat related failures.
In addition lugging the engine not only increases EGTs, but it is very hard on other components as lugging creates very high cylinder pressures, those are your enemy for long engine life.
I agree, Dualie, that the way people perceive HP is really not very accurate. What is even worse is the proliferation of dyno's and people's lack of understanding about them combine with their skewed understanding of HP and TQ. A diesel should also be run on a load dyno instead of an inertia (if that is what you were referring to as a snap dyno?) dyno like most race shops have.
I've seen the same problem with some of the equipment I worked on. A couple of us spent several weeks modifying the engine enclosures on a couple of test units. With the addition of cooling ducts to push heat out of the engine compartment we significantly reduced heat related failures.
In addition lugging the engine not only increases EGTs, but it is very hard on other components as lugging creates very high cylinder pressures, those are your enemy for long engine life.
I agree, Dualie, that the way people perceive HP is really not very accurate. What is even worse is the proliferation of dyno's and people's lack of understanding about them combine with their skewed understanding of HP and TQ. A diesel should also be run on a load dyno instead of an inertia (if that is what you were referring to as a snap dyno?) dyno like most race shops have.
yea sorry i was pretty tired when i made that post. For some reason i referred to a inertia dyno as a "snap" dyno. I don't really know what i was thinking there.
I have seen a couple of turbo Cartridge failures from pinched supply lines also. where the turbo is starved for oil.
Most true exhaust heat related failures show up in the form of warped shafts and distorted impellers.
I doubt any "major" construction company with full time bean counters could justify the ROI on a fully synthetic HD DEO.
Personally seeing a lot of good equipment destroyed in my day. The industry as a whole would be better served by better contamination control practices. THE WORST Culprits BY FAR! are the lube men them self's. I have seen very few lube trucks that i would even LET NEAR my equipment.
also to add what 1040Wreckerman said. Lugging is VERY hard on engines. It sends Cylinder pressures through the roof, Creates A large amount of added heat in the cylinder and in a diesel can lead to improper combustion where the Mix will continue to burn as it leaves the cyl. on its way out the exhaust. If you have ever torn down a Diesel engine that has been excessively lugged you can VISUALLY see the signs on the crank bearings and in extreme cases you can MIC the rods and they are actually shortened from the high loads placed on them.
And adding to my original post. Look at marine diesel variants of regular over the road diesels. For example the CAT 3406E 15.8L the highest Factory Rated HP out put for the OTR version was 625HP. The same motor with slight head modifications and higher flow injectors and a larger turbo to support it was rated to 900HP. They can do this because in a boat the engine is floating on the worlds largest radiator. With good sea water flow across the heat exchangers they will stay cool running at MAX torque for weeks on end.
I have seen a couple of turbo Cartridge failures from pinched supply lines also. where the turbo is starved for oil.
Most true exhaust heat related failures show up in the form of warped shafts and distorted impellers.
I doubt any "major" construction company with full time bean counters could justify the ROI on a fully synthetic HD DEO.
Personally seeing a lot of good equipment destroyed in my day. The industry as a whole would be better served by better contamination control practices. THE WORST Culprits BY FAR! are the lube men them self's. I have seen very few lube trucks that i would even LET NEAR my equipment.
also to add what 1040Wreckerman said. Lugging is VERY hard on engines. It sends Cylinder pressures through the roof, Creates A large amount of added heat in the cylinder and in a diesel can lead to improper combustion where the Mix will continue to burn as it leaves the cyl. on its way out the exhaust. If you have ever torn down a Diesel engine that has been excessively lugged you can VISUALLY see the signs on the crank bearings and in extreme cases you can MIC the rods and they are actually shortened from the high loads placed on them.
And adding to my original post. Look at marine diesel variants of regular over the road diesels. For example the CAT 3406E 15.8L the highest Factory Rated HP out put for the OTR version was 625HP. The same motor with slight head modifications and higher flow injectors and a larger turbo to support it was rated to 900HP. They can do this because in a boat the engine is floating on the worlds largest radiator. With good sea water flow across the heat exchangers they will stay cool running at MAX torque for weeks on end.
Good post Dualie, you are right on about lugging and what happens as a result. I just overhauled a NTC440 that was a low hour engine and I was suspect as to why it failed as early as it did. On inspection I found that there was fuel burning in the exhaust manifold and turbo. The small end of the rods were elongated about .009-.011", and the big end rod bearings were crushed. After talking to some other drivers that worked with the guy driving this NTC I'm sure the engine failed from lugging.
Another point about marine engines is the constant speed. Marine engines do not have to contend with high frequency acceleration and deceleration, which greatly improves rotating assembly life. This is why marine engines also tend to turn more RPM in many cases. The 3406E's were good engines, only real problem was that intermediate plate between the deck and head. For a while I had a truck with a 3406 that I put marine parts on, turned 2600 RPM and laid down about 770HP on the chassis dyno. A lot of fun to drive, but you had to keep an eye on things or you'd melt it down. When the shop was slow I didn't want to send anybody home, so I made work for them by driving that truck and tearing up trailers
Another point about marine engines is the constant speed. Marine engines do not have to contend with high frequency acceleration and deceleration, which greatly improves rotating assembly life. This is why marine engines also tend to turn more RPM in many cases. The 3406E's were good engines, only real problem was that intermediate plate between the deck and head. For a while I had a truck with a 3406 that I put marine parts on, turned 2600 RPM and laid down about 770HP on the chassis dyno. A lot of fun to drive, but you had to keep an eye on things or you'd melt it down. When the shop was slow I didn't want to send anybody home, so I made work for them by driving that truck and tearing up trailers
Going up a long steep grade and watching the pyro climb up and up and up and not down shifting.
What are you getting at Steve S? You just described lugging almost perfectly.
yep that's lugging. If you CAN use a lower gear when climbing a grade in a diesel, DO IT! The more rpm's the more AIR moving through the motor.
full throttle is full throttle. Your injecting the same amount of fuel with the pedal floored @1,300 Rpm than you would be @1,800 RPM. The only difference is your moving a lot more air though the motor to carry the heat away with it. More exhaust flow means MORE Boost. More Boost means more Cooling air charge. Provided that your Charge air cooler is effectively doing its job.
Now if your cruising flat lands you want to keep your RPM's low. Below 1,500 Rpm. Cat says to cruise there new ACERT motors @ 1,300 while Cummins says between 1,500 and 1,700 RPM.
full throttle is full throttle. Your injecting the same amount of fuel with the pedal floored @1,300 Rpm than you would be @1,800 RPM. The only difference is your moving a lot more air though the motor to carry the heat away with it. More exhaust flow means MORE Boost. More Boost means more Cooling air charge. Provided that your Charge air cooler is effectively doing its job.
Now if your cruising flat lands you want to keep your RPM's low. Below 1,500 Rpm. Cat says to cruise there new ACERT motors @ 1,300 while Cummins says between 1,500 and 1,700 RPM.
I wanted to be sure to explain what I meant. I think.
Years ago on sea trials we had a diesel generator on an oil tanker, that was improperly operated and gauges and alarms were ignored, run out of control. The fuel was shut off and it kept on running it was so hot. I was told it was using the lube oil as fuel. Dampers in the intake had to be closed and halon had to be shot into the intake ducting to get this engine to stop. The whole inside of the engine looked like it was attacked with a blow torch. The compartment was so hot inside it took your breath away just to be anywhere near the engine. It was determined that the wiring was installed wrong and no one caught the problem in construction. We sure found it on sea trials.
So, from what I have read here, an automatic transmission such as the Allison in my CAT powered diesel motorhome would make for long, cool engine life due to the auto transmission shifting down when climbing a hill thereby keeping engine revs above the lugging range........Am I correct?
I routinely use only moderate throttle and lower gear selection when pulling for long periods up hills. Otherwise, on level ground, my 28,000 lb RV gets 8.9 to 9.0 MPG...from what I can tell, this is rather good mileage.
I have never seen engine coolant temperatures approach the hot range. Unfortunately, I have no exhaust pyrometer. I can only judge engine temperatures from the water temperature and oil pressure gauges. Current oil is Delvac 15W-40 1300.
I routinely use only moderate throttle and lower gear selection when pulling for long periods up hills. Otherwise, on level ground, my 28,000 lb RV gets 8.9 to 9.0 MPG...from what I can tell, this is rather good mileage.
I have never seen engine coolant temperatures approach the hot range. Unfortunately, I have no exhaust pyrometer. I can only judge engine temperatures from the water temperature and oil pressure gauges. Current oil is Delvac 15W-40 1300.
with that good of fuel mileage I wouldn't touch Anything! 9MPG i wish my kenworth would get 6mpg and your getting 9mpg. Even with the Allison slush box.
Yes the Allison is programmed to best match engine speed to road speed and select the right gear. I would say 80% of the time let the Allison due its job.
Moderate throttle climbing hills is good. I always like to have a little throttle left climbing a hill. RARELY do i have any of my big HIGHER HP diesels Floored.
The only time i would manually force a down shift is if you starting to climb a hill and loosing speed and KNOW that your eventually need to drop into the next lowest gear. In most all of my trucks I know exactly when to downshift to be about 25RPM under the redline to keep the RPMS up.
Yes the Allison is programmed to best match engine speed to road speed and select the right gear. I would say 80% of the time let the Allison due its job.
Moderate throttle climbing hills is good. I always like to have a little throttle left climbing a hill. RARELY do i have any of my big HIGHER HP diesels Floored.
The only time i would manually force a down shift is if you starting to climb a hill and loosing speed and KNOW that your eventually need to drop into the next lowest gear. In most all of my trucks I know exactly when to downshift to be about 25RPM under the redline to keep the RPMS up.
What CAT motor and what Allison transmission does your motor home have?
Any time you don't have cooling issues in a diesel pusher your doing good! Their notorious for poor cooling. What year is your motor home? It seems to me i see more failures in Low mileage Diesel's with ELC that has never been changed.
If you don't see more than 75,000 miles a year i recommend a 4-5 year max life span for ELC before a flush and re-fill with distilled water and Fresh ELC
Any time you don't have cooling issues in a diesel pusher your doing good! Their notorious for poor cooling. What year is your motor home? It seems to me i see more failures in Low mileage Diesel's with ELC that has never been changed.
If you don't see more than 75,000 miles a year i recommend a 4-5 year max life span for ELC before a flush and re-fill with distilled water and Fresh ELC
CAT 3126B (7.2 L or 440 cu. in.) turbo, air to air intercooler pulling about 27,000-28,000 lbs. Allison 3000 series auto. I usually run the auto transmission in the economy mode that is selectable from the pushbutton transmission control panel (slightly lower RPM shift points) unless I’m in hilly country.
The CAT gets Mobil Delvac 15W-40 with CAT OE filters at 10,000 miles. The cooling system gets CAT’s long-life coolant with the extended service pack (changed by CAT at 40,000 miles). Air filter is changed when approaching the red range. Fuel filter will get changed this weekend along with the engine oil and filter. The chassis is greased with Shell Retinax. The hubs are oiled with Shell 90W gear oil.
Four 6-volt (series-parallel) deep cycle house batteries, two 990CCA 12-volt truck batteries (parallel), Onan 7.5Kw diesel generator with about 450 hrs, 2000 watt inverter, two 13.500 Btu heat pumps.
Belts, hoses and all other gear is like new. I paid $80,000.00 for the coach last September…..a pretty good deal, I believe.
The coach has only has 50,000 miles on it. It is a Holiday Rambler Endeavor 39 foot on a Freightliner chassis with a 1999 build date on the manufacturer’s nameplate, original Michelin tires. All the chassis components are in very good shape, brakes are antilock and work to perfection. The only complaint is occasionally, I must replace the 10-amp fuse for the turn signals. I suspect that this circuit’s current draw is exceeded especially if I use the turn signals shortly after starting the coach after a lay-up (slightly low battery voltage likely increases the current draw in the turn signal circuit). I will correct this by substituting LEDs for turn signal and side clearance/turn signal bulbs.
So far, excellent coach with reliable performance no oil leaks anywhere and very good mileage. I do have a light foot on the throttle.
This weekend, I need to check valve lash before changing oil.
You are correct, the rear engine motor homes with rear radiator placement (rather than side placement) can overheat especially with a tail wind. The secret is to carefully degrease and pressure wash the backside of the cooling system from the engine side. The CAT crankcase breather exits just at the lower portion of the intercooler. This breather does produce some moderate oil mist and can produce clogging in the lower portion of the intercooler and engine radiator lowering cooling capacity and causing high temperatures on the engine coolant temp gauge. The radiator and intercooler are clean along with the cooling fan. I am thinking of rerouting the engine breather however there is no evidence of any oil misting from this breather. I have seen no reduction of crankcase oil on the dipstick since 43,000 miles. I believe it is the Delvac that keeps oil where it belongs.
Any thoughts here?
the 3126B motor has a better reputation than its predecessor the 3116. Or the successor the C-7.
Personally i would dump some Fleetrite Anti-Foam Concentrate PN. CH1824392 in the oil at the 5,000 mile mark. Available from your local international trucks dealer parts counter.
In my own findings Delvac doesn't seem to hold up as well in HEUI motors. The best performers seem to be Regular old Delo 400, and the CAT 15-40 D.E.O.
The 3126 uses the HEUI injection system. Same as the 94-03 Power Stroke Ford diesels. This system uses the engine oil under high pressure (UP to 3,000 PSI.) to push down on the intensifier piston and compress the fuel charge for better atomization. Up to 21,000 Psi fuel pressure at the tip of the injector.
This puts a lot more strain on the engine oil that it really wouldn't see in any other diesel application. Anti foam properties are pretty important here. the performance of Delvac seemed to drop off at around the 5,000 mile mark in my power strokes, DT466E and 530E International's (also HEUI) and the Peterbilt 330 4 Door horse Trailer hauler w/3126 @ 350 Hp (34,000Lbs. combined)
When running the Delvac the fleetrite anti foam seemed to cure poor performance till the oil was drained in the bigger C.I. medium duty trucks. Which sucks cause normally I'm a big fan of Mobil products.
Since switching to Delo exclusively in everything we haven't needed to add the anti foam to the oil to cure poor performance. And our UOA's come back clean as a whistle.
As for the Allison auto in your application i recommend that you change the ATF to genuine Allison Synthetic AFT at 50,000 miles. then again at 125,000 miles. If you have your Allison transmission dealer do this ask them about extending the warranty on the transmission also. This is something they will do but ONLY when running there SYN ATF.
If this was my coach i would just go ahead and extend the RDT (road draft tube or crank case vent) as far as you can. I do this on all my equipment and trucks. I just keeps everything cleaner including the trailers. I usually run them from 3"-6" off the ground. This also keeps the wind from kicking the oil mist up the back side of your RV and off the front of your trailer.
Like i said above, Personally if I'm dropping road speed going up a hill i will force a manual downshift as soon as its safe to do so.
Normally the 3126's don't seem as sensitive to valve lash as other cat motors such as the C-10 and C-15. Which is contrary to what cat wants you to believe.
with them we usually just checked the lash at around 10,000 miles or first oil change, adjusted if necessary then re-checked and adjusted at 100,000 miles.
with the weights your pulling with that little 3126 i do recommend an exhaust pyrometer. Any small little thing could effect your EGT's when your working the engine to move that weight and fight the poor aerodynamics of the motor home.
Also if its not equipped with one an exhaust brake might be a worthwhile investment. most people think Texas is flat, but they haven't driven from El Paso to Houston up I-10
As i recall the only real major thing that put our 3126's in the shop was bad injector O-rings letting the engine oil bleed into the fuel side of the injector and getting pumped into the fuel tank.
Oh and Don't bring that thing to me If you need repairs! every coach i have seen didn't make engine access a high priority. Some seemed almost impossible to service.
I hope this is what you meant by any thoughts? I Just like giving information to people that are willing to listen. seems like that's a dyeing virtue.
Personally i would dump some Fleetrite Anti-Foam Concentrate PN. CH1824392 in the oil at the 5,000 mile mark. Available from your local international trucks dealer parts counter.
In my own findings Delvac doesn't seem to hold up as well in HEUI motors. The best performers seem to be Regular old Delo 400, and the CAT 15-40 D.E.O.
The 3126 uses the HEUI injection system. Same as the 94-03 Power Stroke Ford diesels. This system uses the engine oil under high pressure (UP to 3,000 PSI.) to push down on the intensifier piston and compress the fuel charge for better atomization. Up to 21,000 Psi fuel pressure at the tip of the injector.
This puts a lot more strain on the engine oil that it really wouldn't see in any other diesel application. Anti foam properties are pretty important here. the performance of Delvac seemed to drop off at around the 5,000 mile mark in my power strokes, DT466E and 530E International's (also HEUI) and the Peterbilt 330 4 Door horse Trailer hauler w/3126 @ 350 Hp (34,000Lbs. combined)
When running the Delvac the fleetrite anti foam seemed to cure poor performance till the oil was drained in the bigger C.I. medium duty trucks. Which sucks cause normally I'm a big fan of Mobil products.
Since switching to Delo exclusively in everything we haven't needed to add the anti foam to the oil to cure poor performance. And our UOA's come back clean as a whistle.
As for the Allison auto in your application i recommend that you change the ATF to genuine Allison Synthetic AFT at 50,000 miles. then again at 125,000 miles. If you have your Allison transmission dealer do this ask them about extending the warranty on the transmission also. This is something they will do but ONLY when running there SYN ATF.
If this was my coach i would just go ahead and extend the RDT (road draft tube or crank case vent) as far as you can. I do this on all my equipment and trucks. I just keeps everything cleaner including the trailers. I usually run them from 3"-6" off the ground. This also keeps the wind from kicking the oil mist up the back side of your RV and off the front of your trailer.
Like i said above, Personally if I'm dropping road speed going up a hill i will force a manual downshift as soon as its safe to do so.
Normally the 3126's don't seem as sensitive to valve lash as other cat motors such as the C-10 and C-15. Which is contrary to what cat wants you to believe.
with them we usually just checked the lash at around 10,000 miles or first oil change, adjusted if necessary then re-checked and adjusted at 100,000 miles.
with the weights your pulling with that little 3126 i do recommend an exhaust pyrometer. Any small little thing could effect your EGT's when your working the engine to move that weight and fight the poor aerodynamics of the motor home.
Also if its not equipped with one an exhaust brake might be a worthwhile investment. most people think Texas is flat, but they haven't driven from El Paso to Houston up I-10
As i recall the only real major thing that put our 3126's in the shop was bad injector O-rings letting the engine oil bleed into the fuel side of the injector and getting pumped into the fuel tank.
Oh and Don't bring that thing to me If you need repairs! every coach i have seen didn't make engine access a high priority. Some seemed almost impossible to service.
I hope this is what you meant by any thoughts? I Just like giving information to people that are willing to listen. seems like that's a dyeing virtue.
Get a pyro they're not really expensive .
- Status