| Author | Message | ||
| Buddy Tennison (Buddyten)
Registered Member Username: Buddyten Post Number: 65 Registered: 7-2005 Posted From: 207.68.239.252 Rating: N/A |
Hey Guys: We are so confused. I have posted on here before about our concern on oil consumption. Just to update you. Eagle with 8V71, 5 speed tranny. Engine overhauled (rings, bearings, etc) last February. Did not replace new pistons and sleeves as mechanic indicated not necessary. Heads with valve jobs and guides, etc. We don't drive that much. We are a gospel quartet and probably travel 2-3 weekends a month. Most trips about 300-600 miles round trip. We have a problem with oil consumption. When it was overhauled, we started using Rotella 40W. It seemed to drink it. When we changed oil last week, we switched (on recommendation of some) to Exxon XD3 40W. We went on a 400 mile trip this weekend, and it is showing a gallon low. When we changed oil, we put in 6 gallons (including the oil filter full) and it was on the full mark. We have found that when it gets about a gallon low, our oil pressure guage in the cockpit will "tick". Checked it when we got back in and it was about a gallon low. It has little or no smoke except at initial startup and under heavy loads. There is no excessive oil on the back of the bus. Our piano player followed in his car and said little or no smoke and we looked at the front of his vehcile and he had no oil on it. The slobber tubes don't appear to be excessively draining. Oil pressure remains good (45-55 psi constant) except when it gets gallon low. Bus has plenty of power and mechanic said everything sounded and looked good when he changed the oil last week. Said there was no indication we were loosing a cylinder, etc. No excessive leaks, etc. Where is this oil going?? I have tried driving it easier, and with foot in it, and it doesn't seem to make a difference. The Exxon oil we switched to is of course a receommended oil by DD for 2 cycles. Do we need to consider some additives? Should we go to 50W oil, and if so, what kind? We are perplexed. Any suggestion you could give would be greatly appreciated. | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 408 Registered: 8-2006 Posted From: 74.33.56.175 Rating: N/A |
Buddy, how many miles do you have on the engine after the overhaul it will take 20 to 25 thousand miles before the rings seat | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1205 Registered: 5-2001 Posted From: 65.74.72.93 Rating: N/A |
Buddy, and it will take fewer miles to seat the rings if driven HARD. Mountain clembing works pretty well. When the engine is fully broken in, your fuel mileage will rise, as well. Iron will be high in oil analyses until broken in. The reason that you can't find any oil is likely because it is being used for fuel. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1167 Registered: 10-2003 Posted From: 71.58.48.228  Rating: N/A |
If he reused the pistons and sleeves, that's probably why it is drinking oil. It'll take a looonger time to seat IF you are lucky. Should have AT LEAST replaced liners with the rings. Proper job would have been to replace liner, ring, and piston kits while he was at it.And, of course, carefully fitting the liners to individual cylinder bores to get proper heat transfer. Unless you are running big injectors, It should run clean at high rpms with load on a rebuild. Personally, I wouldn't take a chance like that on a rebuild on one of these engines. What ever you saved is going to be eaten up by all that oil over time. Other possible causes could be blower seals leaking, or wrist pin discs leaking or loose valve guides. | ||
| Buddy Tennison (Buddyten)
Registered Member Username: Buddyten Post Number: 66 Registered: 7-2005 Posted From: 207.68.239.252 Rating: N/A |
Thanks Guys. I know that you all know 100 times more about this than us. Unless the situation that Tom gives (being used for fuel) is happening, WHERE IS THE BY PRODUCT OF THE OIL? Shouldn't there be some tell-tale evidence of the oil either being blown onto back of bus or following vehicle; or heavy smoke, etc? As stated, there is neither. Our mechanic has told us exactly what you have said about break-in and seating times for the rings (about 20-25K miles). Granted, we have not put that many miles on her since overhaul. I think only about 15K miles. When will we know the engine is "broken in"? Will it just all of a sudden quit using this oil? We are aware that to do a complete overhual using new sleeves, pistons, etc. The mechanic checked all the wear and tolerances, and the end result was that our liners, etc were within accepted guidelines. This is a mechanic with 28+ yrs of experience and regarded as one of the best in our area. Also, don't think he would have shortcut us as it would have cost him money to do so? If the blower seals are leaking, should we not notice oil residue at least in the engine compartment? Not trying to second guess you all, just asking questions? | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 409 Registered: 8-2006 Posted From: 74.33.56.175 Rating: N/A |
Buddy, you can not tell if the blower seals are leaking from the engine compartment this is done only by removing the air intake on top of the blower and looking to the inside of the blower on each end with a light to check for oil leaking from the ends of the blower, they leak to the inside and the oil is burned as fuel.the engine will not stop burning oil all at one time it will be a slow gradual process And for rebuilding with using rings on old liners and pistions DD does this all the time with out problems and they tell you it will take 20to25 k miles for a break end peroid good luck guy (Message edited by luvrbus on May 31, 2008) | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1302 Registered: 12-2000 Posted From: 76.68.134.96  Rating: N/A |
One good thing, the rate of oil consumption appears to be consistent. Opening up the motor again will be a waste of time and money, with out further indications as to what might be wrong. Was any work done to the blower, or was it just slapped back on there? I might think it worthwhile to have a look down the intake for evidence of blower seal problems. Fairly quick and inexpensive to have a look. Not so much because of the oil consumption, but because of the potential for blower seal failure. You don't mention if an oil analysis was done on the oil. With your problem, this is a must for the next oil change. You'll have to wait for the next change interval, you get flawed results with out enough miles on the oil. You said 6 gallons for the oil change, and the oil gauge ticks at a gallon low. Is this the right amount of oil? 8V71 do come with different sized pans, and dipsticks are notorious for being the wrong ones in this business. Mine takes 7 gallons. Otherwise, just keep topping it up and drive it. At least you are getting some forward push out of the BTU in it! happy coaching! buswarrior | ||
| John Riddle (Jriddle)
Registered Member Username: Jriddle Post Number: 11 Registered: 3-2008 Posted From: 207.171.202.173  Rating: N/A |
Buddy Keep driving it. If blower is not leaking and you have good power and not making a mess on the back of your bus or ground keep adding oil it will be way cheaper, than spending hard $ on trips to the mechanic and additives. With luck you will get those rings to seat. I have to say that I am new to the bus world but have been around all sorts of engines. In our Cessna 182 it take 12 quarts of oil. I only add 11 the last quart will not stay in the engine. I have seen post here that a gallon low may be where your bus likes it to be. Do you have less oil consumption after first gallon is gone? | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 761 Registered: 12-2000 Posted From: 76.3.173.51  Rating: N/A |
Recently on RFD, a veiwer asked a John Deere engineer about oil consumption. The engineer replied that each engine has its own oil level "sweet spot". He said fill your new tractor to the full mark and drive all day. Next morning check the oil, but DO NOT ADD IF IT IS ABOVE THE ADD MARK. Check the oil the next morning and chances are pretty good, it will be at about the same place it was the morning before. This is that engines oil level "sweet spot". We have found the oil level "sweet spot on our 8V71 is 1/2 way between the full and add mark. It will stay at that level for about 1200-1500 miles. If I fill it to the full mark, it will be back to the 1/2 within 500-600 miles. Jack | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 297 Registered: 7-2006 Posted From: 4.240.214.101 Rating: N/A |
Interesting, Jack!. I had sort of figured the same with our engine over the years (as you have done with yours), but was not "aware" of the information you stated. It's almost the same for us as your description. (Cummins 220 Turbo/10 gallons) We have +- 75,000 on the engine. (the Hubometer and the odometer both were on the fritz for a while...) 'preciate the info.  RCB | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1172 Registered: 10-2003 Posted From: 71.58.48.228 Rating: N/A |
I don't know why they didn't make a windage tray for our engines. would have saved a lot of wasted oil. | ||
| JC Alacoque (Jc_alacoque)
Registered Member Username: Jc_alacoque Post Number: 66 Registered: 7-2006 Posted From: 72.45.68.242 Rating: N/A |
John, what's a windage tray? | ||
| larry currier (Larryc)
Registered Member Username: Larryc Post Number: 175 Registered: 2-2007 Posted From: 207.200.116.13 Rating: N/A |
New rings seldom seat well to used liners. I think it will stay togather for ever if you keep it full of oil, but its going to take a fair supply of oil. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1173 Registered: 10-2003 Posted From: 71.58.48.228 Rating: N/A |
A windage tray is a piece of metal that mounts between crankshaft and top of oil pan. It has slots to allow normal return of oil It is designed to prevent spinning crankshaft from whipping and spraying oil returning to pan and cut down the amount that is sprayed onto cylinder walls that makes the oil rings less effective than designed Normal diesel shouldn't need one, but apparently the oil level in these two cycle pans, and especially the tilt GMC models is closer than normal in a truck engine, probably because of the low ground clearance on all the coaches.This is why some owners report lower oil consumption with a 1/2 to 1 gallon less oil in pan. Plus the good chance that oil level indicators could be off over the years because of parts and engine exchanges. Lower oil level doesn't necessarily work for everyone however. | ||
| george bruton (Tazman632000)
Registered Member Username: Tazman632000 Post Number: 69 Registered: 2-2007 Posted From: 65.184.236.52 Rating: N/A |
if i fill mine up to the full mark it will throw a gallom out in less than 300 miles after that i have to add about a quart every 500 miles | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 675 Registered: 11-2005 Posted From: 208.54.200.19 Rating: N/A |
John, Your Cessna 182 holds 12 qts because the FAA says an engine must hold enough oil at its max usage rate to get it to its max range. I had a Navion Rangemaster which also had the same engine and oil capacity. I never ran it over 9 qts and it had much longer range than a 182. I threw out three quarts in 20 min the first time I flew it after it had just come out of an annual! | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 676 Registered: 11-2005 Posted From: 208.54.200.19 Rating: N/A |
John Roan, Is a windage tray the same as an oil slinger? | ||
| Bill Young (Billyoung4106)
Registered Member Username: Billyoung4106 Post Number: 6 Registered: 5-2008 Posted From: 68.209.175.133  Rating: N/A |
My 8v71/4106 likes to stay about a gallon low.Fill it up and it'll drop down a gallon on the next trip. It will stay there on the stick for a long time after. Is the stick wrong. I don't know but I know thats where mine likes to stay. | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1381 Registered: 12-2000 Posted From: 67.181.166.160  Rating: N/A |
Buddy, Bill and others - This has been posted before, but just to refresh everyone's memory: -- The correct "FULL" mark on the dipstick should be 1" below the block/oil pan interface. -- The best time to check the oil level is in the morning, before you start the engine for the first time. IBME while working in the bus industry that halfway between "add" and "full" seemed to give the least oil consumption, like Jack's discovered with his engine. FWIW & HTH. . . | ||
| John Riddle (Jriddle)
Registered Member Username: Jriddle Post Number: 12 Registered: 3-2008 Posted From: 204.8.224.122 Rating: N/A |
Gus. I will not let the shop change my oil. I do not like cleaning the oil off the bottom of the plane. Our little airport has three Navions. One family seems to like them. Parts are hard to get these days for them. John | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 763 Registered: 12-2000 Posted From: 76.3.173.51 Rating: N/A |
Our dipstick has 2 lines on it. The bottom line says ADD, the top line says FULL. Between the 2 lines it says SAFE. I am assuming (yeah I know about ass-u-me)that as long as the oil level is between the 2 lines in the SAFE area, I should not need to add oil. Jack | ||
| niles steckbauer (Niles500)
Registered Member Username: Niles500 Post Number: 842 Registered: 11-2004 Posted From: 204.10.126.202 Rating: N/A |
I have almost 3k miles so far on this trip and almost half is mountainous driving - changed the oil before leaving and left it almost 2 qts. low - have not added any and can see no appreciable usage (of course its hard to find a flat spot here) - FWIW | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 412 Registered: 8-2006 Posted From: 74.33.56.175 Rating: N/A |
Niles, that is the best I ever heard for oil usage on a 8v71 if that is what you have.I am not one for running a engine low on oil if it holds 7 gals that is what goes in it.If my oil gauge ever ticked liked Buddy's did I would have the big one, that would be a sign of the pump sucking air.Allison transmissions will run hot when they get about a gal low so I believe the oil temp on an engine will go up too, but maybe not just my thinking on running the engine a gal low | ||
| Buddy Tennison (Buddyten)
Registered Member Username: Buddyten Post Number: 68 Registered: 7-2005 Posted From: 207.68.239.252 Rating: N/A |
Thanks guys for all the info. I have a couple other questions: 1. When I checked my dipstick, I put a mark 1" below the intersection of pan and block. I then took the dipstick and ran it outside the tube, bending it as necessary down the side of the block and marked it at the mark on the pan. I got to thinking: The dipstick goes in at an angle. Did I do this correctly or is there a more accurate way? 2. When my guage "Ticks", it is just slightly. For example, it will be going along showing 52-55 psi. It will kinda "tick" down to around 45. It never goes down below 40. \ 3. I know that my guage sending unit is old, probably being original to the bus. (Or at least it looks like it). It has three "lugs" on it where the wires attach and screws into a block which has a line running to the engine. (Mechanical guage also screws into this block). Is this sending unit an available product from Parts stores, or a special order thing. If it is available, does anyone know part #'s, etc. 4. I know that all of you have indicated that checking the dipstick is the most accurate way. However, if like you all have indicated it takes an hour or so for the oil to drain down, how would checking the stick on a trip be accurate? I don't have time to sit and wait for an hour for it to drain down. Thanks for all the good help and suggestions. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1174 Registered: 10-2003 Posted From: 71.58.48.228 Rating: N/A |
Not exactly. They use oil slingers to keep excess oil off seals. The windage tray is a barrier to the windage kicked up by the rotating crankshaft. See windage tray that is used on racing engines to get an idea how they look. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 363 Registered: 10-2006 Posted From: 208.100.193.196 Rating: N/A |
I know that all of you have indicated that checking the dipstick is the most accurate way. However, if like you all have indicated it takes an hour or so for the oil to drain down, how would checking the stick on a trip be accurate? In my drivers manual it sez to check the oil after 3 min of being shut down. This gives the best RUNNING oil level, and when you fill with this procedure you wont be getting the oil starvation Ticks on the gage. When it ticks , its time to stop and feed the beast. Yes, in the AM after a drain down it will probably seem "overfull" on the stick but thats normal. FF |