CatSkinner77V
Well-Known Member
- Joined
- Apr 14, 2007
- Messages
- 228
- Location
- Sperling, Manitoba, CANADA
- Occupation
- Earthmoving business owner
One work: TIMING
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Low power and lots of smoke(complete overhaul)D6H
- Thread starter Construct'O
- Start date
Auctioneerhere
Well-Known Member
Good luck & keep us posted.
Construct'O
Senior Member
A little update,not much
Got somethings checked ,but not much, had other issues that is taking up time.
Checked the hydraulic pump all the pressures was near spec.I'm having the hydraulic valve resealed and checked for issue while in there to see if spool is sticking.
Not really got to check the motor much yet ,but mechanic will start with the timing,then go from there.Didn't have time need to move on too a bigger problem .Sorry!
This really doesn't have to do with the smoke issue,but i was getting metal in the right final drive,so it is off and getting rebearing,seals, gears okay.When took off the final drive there was metal on the inter housing.
Checked transmission filter no metal to speak of in the rear filter (screen),so took the bellly pans off took out front magnetic filter small fine metal.
So i had the mechanic pull the rest of the right side where the park break is off.As it came out the thrash bearing fill off.The washer had broke still one piece but was flipping around on the inside on the plantery gears for the dif steer and break.So at least might have caught something here that could have been a major problem.So at least happy about that,not repair ,but would have been worse.
They came out with a newer updated cage for the new plantery gear,so the old cage they don't have ,so will have to find old or go new.The update is 3k for parts.
They found old cage ,but i would like to update so told them to look for update parts on a dead machine on the internet.They are searching.
More bad weather(5" of snow,cold) since torn down so will have to get my other parts back and on the machine before we can check the other issue.Will check the torgue convertor drain it and see if there is a issue with too much oil.Belly pan are off fast check there.I'm working on the list!!!!!!
So started ,but not much info except the above,with is a whole different problem,but one i knew needed taking care off.Later:usa
Got somethings checked ,but not much, had other issues that is taking up time.
Checked the hydraulic pump all the pressures was near spec.I'm having the hydraulic valve resealed and checked for issue while in there to see if spool is sticking.
Not really got to check the motor much yet ,but mechanic will start with the timing,then go from there.Didn't have time need to move on too a bigger problem .Sorry!
This really doesn't have to do with the smoke issue,but i was getting metal in the right final drive,so it is off and getting rebearing,seals, gears okay.When took off the final drive there was metal on the inter housing.
Checked transmission filter no metal to speak of in the rear filter (screen),so took the bellly pans off took out front magnetic filter small fine metal.
So i had the mechanic pull the rest of the right side where the park break is off.As it came out the thrash bearing fill off.The washer had broke still one piece but was flipping around on the inside on the plantery gears for the dif steer and break.So at least might have caught something here that could have been a major problem.So at least happy about that,not repair ,but would have been worse.
They came out with a newer updated cage for the new plantery gear,so the old cage they don't have ,so will have to find old or go new.The update is 3k for parts.
They found old cage ,but i would like to update so told them to look for update parts on a dead machine on the internet.They are searching.
More bad weather(5" of snow,cold) since torn down so will have to get my other parts back and on the machine before we can check the other issue.Will check the torgue convertor drain it and see if there is a issue with too much oil.Belly pan are off fast check there.I'm working on the list!!!!!!
So started ,but not much info except the above,with is a whole different problem,but one i knew needed taking care off.Later:usa
Construct'O
Senior Member
Dyno report and spec sheet
I meet with shop manger and customer service rep at DM ,Iowa Thrusday and got the dyno report and spec sheet.
Here is the dyno report and the spec sheet,i guestioned the torque reading while there,about the low torgue at mid range(25-30 minute mark).They said that was at stall.At the time it seemed low,not knowing what to ask wasn't sure what to reply.
Well when i got home and have had more time to go over the information.By the spec sheet and the report too me the torque(lb-ft) seem low on the test compared to the spec sheet.
I'm using the lb-ft on the spec sheet nominal is 668 on the test report the best it ever got was 578 at the 10 minute mark with the norminal on the dyno being more in the 480 range.What affects torque???
So what do you guys think(need help on this) is the torque low,by what what i'm seeing it seems to be:beatsme :usa
I meet with shop manger and customer service rep at DM ,Iowa Thrusday and got the dyno report and spec sheet.
Here is the dyno report and the spec sheet,i guestioned the torque reading while there,about the low torgue at mid range(25-30 minute mark).They said that was at stall.At the time it seemed low,not knowing what to ask wasn't sure what to reply.
Well when i got home and have had more time to go over the information.By the spec sheet and the report too me the torque(lb-ft) seem low on the test compared to the spec sheet.
I'm using the lb-ft on the spec sheet nominal is 668 on the test report the best it ever got was 578 at the 10 minute mark with the norminal on the dyno being more in the 480 range.What affects torque???
So what do you guys think(need help on this) is the torque low,by what what i'm seeing it seems to be:beatsme :usa
Attachments
special tool
Senior Member
If you are sure that you have zero slippage (TC, or otherwise),
next place to check if turbocharger performance.
Not NECESSARILY DO YOU NEED A TURBO.
If the tq is low and then comes up at redln this is spoolup characteristics of the turbo.
Lag can be cause by a number of things:
1.plugged exhaust (or catalyst, if equiped)
2.intake restriction (air filter dirty)
3.Overly LEAN mixture on a diesel during boost onset (rich on a gas job - opposite) - these remove heat energy from exhaust which is necessary to drive the turbine
4.air leaks on the cold side - this causes low HP (high end), not necessarily low TQ (bottom)
5.exhaust leaks between cylinder head and turbocharger - big lag culprit, seldom diagnosed correctly
If you are interested in my opinion, I would check the intake side for restriction first, then leaks. The smoke points you in the direction of low boost........
next place to check if turbocharger performance.
Not NECESSARILY DO YOU NEED A TURBO.
If the tq is low and then comes up at redln this is spoolup characteristics of the turbo.
Lag can be cause by a number of things:
1.plugged exhaust (or catalyst, if equiped)
2.intake restriction (air filter dirty)
3.Overly LEAN mixture on a diesel during boost onset (rich on a gas job - opposite) - these remove heat energy from exhaust which is necessary to drive the turbine
4.air leaks on the cold side - this causes low HP (high end), not necessarily low TQ (bottom)
5.exhaust leaks between cylinder head and turbocharger - big lag culprit, seldom diagnosed correctly
If you are interested in my opinion, I would check the intake side for restriction first, then leaks. The smoke points you in the direction of low boost........
NL1CAT
Well-Known Member
There are so much suggestions made i know.. but I'm curious ..
did you checked the vacuum line from the fuel pump that goes round the back of the engine (cabside)?
did you checked the vacuum line from the fuel pump that goes round the back of the engine (cabside)?
surfer-joe
Senior Member
You should have maximum torque at stall, and maximum turbo boost. The engine oil pressure seems to really drop off at stall if I'm reading the data right, I'm not sure that would have an effect on the low oil pressure solenoid at the injector pump or not. Engine oil pressure at low idle seems really low for this model engine. Engine RPM at stall seems correct. Fuel pressure at stall seems low. It's dropping a hundred foot/pounds of torque after running 55 minutes, that may indicate slippage and worn seals, or converter oil is finally at operating temp, but coolant temp seems to stay stable.
Just some observations.
Just some observations.
Construct'O
Senior Member
surfer-joe the top sheet is the actual dyno test sheet ,the bottom is a SPEC test sheet(from Cat.com)just for reference to compare the results too on the dyno sheet,so not sure if you understood that?
I thought the torque looked to be low also and the second line is boost i believe and it looked to be low at 22 bsi1(inHg) compared to on the spec sheet for norminal at 27.8.Not sure i'm reading this right ,but i think so.
Thanks for the reply anyone else?:usa
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This is what we are looking at; The first page is the actual data from the engine's dyno run. The second page is the spec sheet that the dyno operator uses. This contains the actual values Cat expects an engine set to this particular performance spec to make, hence a Nominal, Ceiling and Floor. For example, oil pressure can be 58 plus or minus 29psi, anything outside these figures and the operator would fail the engine.
Now the thorny question of Torque and Horsepower. The first thing to know is that Horespower is the English unit of power, Kilowatt(Kw) is the metric unit of power, so for now, we'll just call it "Power".
Power is a calculated figure, it can't be measured. The only things that can be measured are RPM and Torque. Power is calculated with the formula "Torque multiplied by RPM dived by a Constant" The constant depends on the units you are working in, in this case, English units so the constant is 5252. So HP = LB FT * RPM / 5252. The point I'm trying to get across is that 5252 only works for English units.
As you can see, HP depends on RPM, which is why motorcycle engine manufacturers can quote impressive HP figures. Their engines make only a modest amount of torque, but run at a zillon RPM so you can calculate a big HP.
Interestingly, note on the dyno run sheet that as RPM drops, the torque figures actually rise but HP falls due to the formula. Ever seen manufacturers quote "Torque Rise" figures? This is what they're talking about. It is calculated as a percentage. I can't remember the formula for this right now. In the real world it is felt as the engine's ability to "keep plugging away" as it comes under high load and the RPM falls.
I should point out that I'm no physics professor. This is only my interpretation based on what I've learned in my career (so far)
The problem we have is that the machine can't achieve full RPM but has lots of smoke under load. We can see on the dyno, the engine made RPM in the 1900's and the HP was within spec, allthough on the low side.
Constructo, I still think we're looking for a parasitic load or restriction on the air intake side. Have you tried running it with the air filter lid removed yet?
Keep us informed, this is getting interesting..........
Now the thorny question of Torque and Horsepower. The first thing to know is that Horespower is the English unit of power, Kilowatt(Kw) is the metric unit of power, so for now, we'll just call it "Power".
Power is a calculated figure, it can't be measured. The only things that can be measured are RPM and Torque. Power is calculated with the formula "Torque multiplied by RPM dived by a Constant" The constant depends on the units you are working in, in this case, English units so the constant is 5252. So HP = LB FT * RPM / 5252. The point I'm trying to get across is that 5252 only works for English units.
As you can see, HP depends on RPM, which is why motorcycle engine manufacturers can quote impressive HP figures. Their engines make only a modest amount of torque, but run at a zillon RPM so you can calculate a big HP.
Interestingly, note on the dyno run sheet that as RPM drops, the torque figures actually rise but HP falls due to the formula. Ever seen manufacturers quote "Torque Rise" figures? This is what they're talking about. It is calculated as a percentage. I can't remember the formula for this right now. In the real world it is felt as the engine's ability to "keep plugging away" as it comes under high load and the RPM falls.
I should point out that I'm no physics professor. This is only my interpretation based on what I've learned in my career (so far)
The problem we have is that the machine can't achieve full RPM but has lots of smoke under load. We can see on the dyno, the engine made RPM in the 1900's and the HP was within spec, allthough on the low side.
Constructo, I still think we're looking for a parasitic load or restriction on the air intake side. Have you tried running it with the air filter lid removed yet?
Keep us informed, this is getting interesting..........
j&d
Active Member
I am hesitant to comment cause this is not my area of expertise but I'll try to help and quickly defer to the mechanics on this site if I get in over my head.
According to the spec sheet full load power should be 179 at 1900 rpm's. Your engine maintains that hp at those rpm's throughout the times listed on the test. The torque check speed according to the spec sheet is 1400 rpm's. Your engine was only pulled down to this rpm once according to the dyno printout. That was done at the 10 minute mark. The torque at that time was 578 lb-ft. Yes the torque is low if I understand what I am reading. 43 lb-ft below minimum and 90 lb-ft below nominal recomendations. Should this have been enough to stop it from going out the door - I don't know but it does indicate a problem to me.
According to the spec sheet full load power should be 179 at 1900 rpm's. Your engine maintains that hp at those rpm's throughout the times listed on the test. The torque check speed according to the spec sheet is 1400 rpm's. Your engine was only pulled down to this rpm once according to the dyno printout. That was done at the 10 minute mark. The torque at that time was 578 lb-ft. Yes the torque is low if I understand what I am reading. 43 lb-ft below minimum and 90 lb-ft below nominal recomendations. Should this have been enough to stop it from going out the door - I don't know but it does indicate a problem to me.
j&d
Active Member
Please excuse the multiple posts. Its seems I get kicked out when typing a long post. I did three long ones earlier and lost them all.
Please take my comments with skepticism cause I am a farmer not a mechanic. The way I understand it your engine must be pulled down to check the torque. I am surprised your engine wasn't pulled down to 1400 rpm's on more occasions during the test in order to check the torque- or was it? Also the way I interpret things your question of low torque at the 25-30 minute mark has no merit because the torque check rpm's are 1400 not 1900.
RDG said it best in an earlier post when he said you can have all the fuel and air in the world but if it doesn't come together at the right time in the proper way you ain't got nothing. I stand by my initial post. I believe your engine is starved for air in some fashion. Or as Special Tool just mentioned the exhaust pressure may be low so as to not get optimum effect from the turbo. Both of these issues could be the result of improper valve function. Check Those Valves! For a couple hundred bucks max you'll have peace of mind. Yes check the timing'S first but to me that is to obvious to be likely. The parasitic load has merit but I've had experience with same symptoms as you on a D7G (same engine) with a fresh reman in it. After a new turbo and pump work the valves were the culprit. Its a long story perhaps I'll share sometime but the cat mechanic kept telliing us, "thats a new engine you gotta break that in". Sound familiar! My answer to him was, "horsehockey, I've run D7G's and this thing ain't right. I've never had to break an engine in and don't have trouble with our engines". Ours acted like we were wading around in two feet of wet sticky clay. Well we pulled our hair till we figured it out and I reckon thats what you'll do.
If your still looking for a common denominator for the same symptoms pre and post overhaul its the camshaft right? Whats the camshaft do???? Check Those Valves!
Disclaimer: The above advice could be a bunch of hooey. Remember I'm just a dumb lowly farmer. Shucks we could all be wrong.
Please take my comments with skepticism cause I am a farmer not a mechanic. The way I understand it your engine must be pulled down to check the torque. I am surprised your engine wasn't pulled down to 1400 rpm's on more occasions during the test in order to check the torque- or was it? Also the way I interpret things your question of low torque at the 25-30 minute mark has no merit because the torque check rpm's are 1400 not 1900.
RDG said it best in an earlier post when he said you can have all the fuel and air in the world but if it doesn't come together at the right time in the proper way you ain't got nothing. I stand by my initial post. I believe your engine is starved for air in some fashion. Or as Special Tool just mentioned the exhaust pressure may be low so as to not get optimum effect from the turbo. Both of these issues could be the result of improper valve function. Check Those Valves! For a couple hundred bucks max you'll have peace of mind. Yes check the timing'S first but to me that is to obvious to be likely. The parasitic load has merit but I've had experience with same symptoms as you on a D7G (same engine) with a fresh reman in it. After a new turbo and pump work the valves were the culprit. Its a long story perhaps I'll share sometime but the cat mechanic kept telliing us, "thats a new engine you gotta break that in". Sound familiar! My answer to him was, "horsehockey, I've run D7G's and this thing ain't right. I've never had to break an engine in and don't have trouble with our engines". Ours acted like we were wading around in two feet of wet sticky clay. Well we pulled our hair till we figured it out and I reckon thats what you'll do.
If your still looking for a common denominator for the same symptoms pre and post overhaul its the camshaft right? Whats the camshaft do???? Check Those Valves!
Disclaimer: The above advice could be a bunch of hooey. Remember I'm just a dumb lowly farmer.
Shucks we could all be wrong.j&d
Active Member
Upon further review I noticed your engine was a little weak on hp while on the dyno but still near minimum. What else concerns me is the low boost. I really don't know what that is but I assume its some measure of recovery or exhaust pressure or some such thing associated with the turbo. Your adjusted boost of 16 inHg at torque check rpm's (1400) and your adjusted boost of 20-22 compared to I assume full load speed specs indicate an engine starving slightly I think.
People make mistakes. Our valve adjustment with the reman engine was covered under warranty and I would hope when you determine the problem with your engine if due to human error it will be as well cause things just have'nt been quite right. I believe your dealer knows this.
We kept telling our cat mechanic our D7G was out of time. He checked and double checked both pump and engine. I know what I'd do and I think you may have it on your list by now. Perhaps I already mentioned it.........Check Those Valve Tolerances!
I'll shut up now. Good luck!
People make mistakes. Our valve adjustment with the reman engine was covered under warranty and I would hope when you determine the problem with your engine if due to human error it will be as well cause things just have'nt been quite right. I believe your dealer knows this.
We kept telling our cat mechanic our D7G was out of time. He checked and double checked both pump and engine. I know what I'd do and I think you may have it on your list by now. Perhaps I already mentioned it.........Check Those Valve Tolerances!
I'll shut up now. Good luck!
OCR
Senior Member
- Joined
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j&d, I am more than a little familiar with that frustrating event...
And then, you don't feel like... even if you can remember... trying to make a repost... happened many a time to me...
Did you see this?
https://www.heavyequipmentforums.com/Forum/showpost.php?p=144528&postcount=130
I does seem to work fairly well for those long posts... :cool2
OCR...
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NL1CAT
Well-Known Member
I had a stuck egr valve on a diesel once that gave a lot of smoke and lack of power. Since the 3306 hasn't got one maybe there is something going on that the intake air get exhaust gas in it?
J&D is quite right. Peak torque is low. I've just done some revision on the subject and I reckon that the torque rise is around 20% which is around a third lower than it should be. Torque rise is controlled by the FTS (full torque setting) adjustment screw and the torque spring, either of which could cause the low figure by restricting the fuelling.
However this doesn't (in my humble view) explain the problem. When it is installed in the tractor, the engine has black smoke and low RPM. This means incomplete combustion meaning either too much fuel or not enough air. It could also be explained, as suggested, by incorrect timing or a valve issue, but the engine is capable of making the correct torque and rated RPM (on the dyno) so I would suggest this eliminates valves or timing.
I think we need to look for something in the tractor which is causing the problem.
Also, don't get hung up too much on boost figures. They are a really useful tool for quick field tests when diagnosing low power, but the discrepancy in this case is only around 3psi. This possibly coincides with the HP being close to the floor.
As always, I'm open to contradiction on any of these points. I'm not a Caterpillar fuel system designer, just a heavy equipment mechanic.
However this doesn't (in my humble view) explain the problem. When it is installed in the tractor, the engine has black smoke and low RPM. This means incomplete combustion meaning either too much fuel or not enough air. It could also be explained, as suggested, by incorrect timing or a valve issue, but the engine is capable of making the correct torque and rated RPM (on the dyno) so I would suggest this eliminates valves or timing.
I think we need to look for something in the tractor which is causing the problem.
Also, don't get hung up too much on boost figures. They are a really useful tool for quick field tests when diagnosing low power, but the discrepancy in this case is only around 3psi. This possibly coincides with the HP being close to the floor.
As always, I'm open to contradiction on any of these points. I'm not a Caterpillar fuel system designer, just a heavy equipment mechanic.
Construct'O
Senior Member
I agree thats what noticed also!
What's the old saying been there done that ! So with that said i haven't been there done this before !!!!!!! That is why i keep posting and same goes for the dyno test so didn't really know what to look for at the meeting with the dealer shop manager.
After getting home and really studying the report and spec sheet i came to the same thoughts as you and others the torque on dyno and spec sheet using the 1400 rpm was the highest for torque,but lowest HP ,and boost, same as you noticed.It is low(578) compared to the 621 at even floor it didn't come up to spec there the way i read it.As stated in your post!
When i sked at the meeting they pointed out the highlighted HP and rpm at stall,which was why i mentioned that.So i say it in closer to the floor on HP(closer to 174 for the average then 179 the way i read it then tappering off to 172 below floor athe last part of then dyno)and actually below floor for torque.Meaning it was on the weak side before it left the the shop after the dyno.
Anyway i agree again with the valve check(it was on the list).So with that said and the issue of the old cam what is going on with the valves.Mechanic says the cam should miss if low cam lob,but unless it was really wore ,could you not have a miss if you have the valve adjust to tight? To compsate for wear?
So if valve is to tight on intake you could have fuel coming in as exhaust valve is opening those (smoke into exhaust not burnt.Those black smoke)Right ? Is this a sign of to tight valves?
If exhaust are to tight then there would be a miss.Right? (like if you have a burnt valve?
I'm i thinking right here.The valve train doesn't seem to be noise as in to loose,so why i'm leaning to tight but:beatsme Can you explain what you found on your 7G valve problem????
I do know they replaced some rocker stuff,but not sure what?
As for the savager we have checked the hydraulic pump( which also runs the dif steer) ,it has passed the test there.Will be checking the convertor ,got the belly pan off just need to drain the convertor and check if to much oil.
The machine has other issue(rebuilding the right final drive,park brake and the plantery gears and cage for the left side of the dif steer).Thats another story,but not related to this.
So the machine can't not be run or moved ,so we can't do test yet.My usual mechanic will have that put back togather here shortly(if weather holds) then!
The dealer is sending down Quote " new set of eyes(mechanic)" to run the checks and test.So will have to see how that goes .
I will be pointing out all the great replys everyone has posted.Sorry if i haven't replied to everyone,but sometimes my reply slows down the posts, keeps posting.Thanks again to everyone for your replys.:notworthy:usa
Construct'O
Senior Member
Just one more post for added info.Talked to my Deere mechanic for some input also.(this is a fluke situration but) he said one time they had the cam gear slip on the keyway,sheared the key.
The fuel pumped showed in time ,but with the gear slipped on the end of the cam it was out of time.Unusal but :beatsme who knows.
Also the dealer said cam was in spec was this a visual as to not looking wore or did they actually mike the lobs with a dial indicator? Just a lot here to ponder on.
Also i asked him about the high aluminum on the three oil change(oil sample) and that is where is started to use a some oil a gallon in between oil changes (200 hr) sorry getting off on another subject but........ his thought was might have score a piston a little.
Went from 2 to 6 they posted a to watch note .Next change it was 5.
Just not something you want to see with only around a thousand hour on you overhaul.Anyway more concerned about the other issues.
My plans was too keep this machine until i quit,since i did by it new and working my way threw a pretty much comlete overhauled machine(except trans(next),right final and hydraulic pump) it could be a certified rebuild:usa
The fuel pumped showed in time ,but with the gear slipped on the end of the cam it was out of time.Unusal but :beatsme who knows.
Also the dealer said cam was in spec was this a visual as to not looking wore or did they actually mike the lobs with a dial indicator? Just a lot here to ponder on.
Also i asked him about the high aluminum on the three oil change(oil sample) and that is where is started to use a some oil a gallon in between oil changes (200 hr) sorry getting off on another subject but........ his thought was might have score a piston a little.
Went from 2 to 6 they posted a to watch note .Next change it was 5.
Just not something you want to see with only around a thousand hour on you overhaul.Anyway more concerned about the other issues.
My plans was too keep this machine until i quit,since i did by it new and working my way threw a pretty much comlete overhauled machine(except trans(next),right final and hydraulic pump) it could be a certified rebuild:usa
Iron Horse
Senior Member
High Aluminium content , low power , black smoke . Is it possible the piston cooling nozzles are not correctly aligned or are not functioning properly ? This could cause the high Aluminium content in the oil from scuffing pistons . It could also cause the other problems as the engine comes on boost , Pyro temp goes up , pistons expand and become tight in the bores . I have seen this before , the Banjo bolts going through the nozzels were over tightened causing the internal spool valves in the Banjo bolts to be jambed shut . The engine grabbed a piston and was rebuilt three times before i was asked to have a look . I replaced all 6 Banjo bolts and it never had another problem .
LonestarCobra
Well-Known Member
That is a good thought, but the cooling jets in a 3300 engine dont have a bolt. They just stick up out of thr block about a eighth of an inch. I have seen silicone protruding from the before, causing a galded piston due to no oil coming out of them. And the camshaft gear bolts on, and has an irregular bolt pattern so it cant go on wrong. Lots of people thinking deep on this one.:Banghead
Iron Horse
Senior Member
Does the gallery that supplies the cooling nozzles have a restrictor valve that only opens when a pre determined oil pressure is achieved ? That's what the valves in the Banjo bolt type do , give full oil pressure to the crank while starting . I too have seen Silicon block oriffices .