| Author | Message | ||
| mcbud (206.172.157.18)
Rating: |
Out of frame new pistons, rings, bearings, main and rod, all new gear train, new bearings for accessory drives new valves guides and springs and keepers blower rebuilt engine was advanced timed with N65 brown tag injectors, governed too 2350rpm, I ran Shell Rotella T 15-40 oil in it, it was never lugged I always kept the rpm up. The rings ceased on the pistons and of coarse it burnt oil like it was going out of style. this engine I got from a machine shop with not a very good reputation for quality work, we pulled it down and found 7 turbo style pistions and one after market standard piston but it had new liners, rings, and bearings so we ordered 8 new Clevite pistons, I like to drive quickly but what could this cause this type of failure, I would appreciate any ideas you might have as to what caused this failure | ||
| Jim Thompson (209.190.8.89) Rating: N/A |
The manual with my 8V71 say's to use 40 wt oil. Not 10w40,that could be a factor also. | ||
| Merlin -PV (67.250.134.64) Rating: N/A |
No mater what anybody tells you a 15-40 motor oil only has the sheer of a 15 wt oil!! works for your family car, does NOT work well in detroits. FWIW. stay with a 40 wt and save your money | ||
| mrbus (205.188.209.11)
Rating: N/A |
I think you probably answered your own question, when you said the machine shop had a reputation for shoddy work. The mix of pistons pretty much bears that out. As for the multigrade oil, we have run 15 - 40 in our fleet of MCIs with 8V71 engines ever since 1989 when we first bought new buses with Cummins engines, we decided to have one oil in each shop. We have averaged between 375 and 400 thousand on each 8V71 rebuild using this oil. I know everyone is going to say that the book says only 40 wt. and that is fine, but ask some of the fleet users who are in in for the money what they are using. My guess is that you got a sloppy rebuild from a sloppy shop. Gus Haag | ||
| John Feld (Deacon) (150.199.209.48)
Rating: N/A |
If it failed in 10,000 miles something was done wrong in the overhaul. What did the rebuilder say? Did you contact them? I would not deal with a shop that did not warrenty their work for a complete out of frame. While 15-40 would not be my choice of breakin oil, it should not be the cause of the failure. Governer speed is well within limits. Sounds like maybe the rings were damaged when installed, or not fitted proper. If the rebuilder is an authorized Detroit shop, contact Detroit for help resolving issues of workmanship. I did this and got a whole new engine in a Kenworth tractor. John 4104 | ||
| RayC (142.165.222.119)
Rating: N/A |
If the oil rings seized in the piston with that kind of mileage my guess would be that they used a passenger style 3 piece oil ring (2 rails and an expander). While that type of ring is about the best thing that ever happened to oil control in a car it does not work for long in a gas or diesel engine that has to work hard. Normal blowby with this type engine causes a varnish on the rails and the rings stick in the groove. The nature of the 3 piece ring construction is it pushes the rails outwards against the cylinder wall and sideways against the ring lands so any varnish buildup will unitize them with the piston. Your engine should use a cast iron oil ring with an expander behind. | ||
| Paul Tillmann (24.105.194.162)
Rating: N/A |
This is the first thread I have read where someone said using 15-40 oil in a DD two-stroke was OK. All the reading I have done and research on the internet has said that use of the 15-40 oil in a DD two-stroke leads to premature engine failure. Not that this was the cause of mcbud's engine failure but I can't believe it helped it any. Maybe mrbus' DD fleet would have averaged many more miles on those 8-71's if the proper oil was used. I have talked with many a truck driver from years ago that got 750k+ from an 8-71. Just my two cents worth.... | ||
| Bill Gerrie (216.185.72.14)
Rating: N/A |
I talked to the people at Harper Detroit Diesel and they said never use a 15-40 oil in a two stroke diesel. When they have one come in for warranty work they can tell right away if a 15-40 oil was used. It leaves scuff marks on the cylinder walls or something. FYI Bill | ||
| Johnny (67.241.166.113)
Rating: N/A |
What about cold weather--straight SAE40 is like molasses in 20-degree weather, and I'd hate to try pouring it at zero degrees! It seems to me the engine wouldn't have ANY oil floe for quite a while in cold weather with SAE40. | ||
| bobm (152.163.188.227) Rating: N/A |
Detroit diesel designs and builds these engines and publishes a booklet that lists lubricating oil, fuel oil and filter recommendations. For max engine life use API class CD-II viscosity grade 40 oil in series 53, 71, 92, and 149 two cycle engines. Use any other oils and you will shorten the service life of your engine. Then again some dummies spend millions on oil additives and believe anything. | ||
| Lee Brady (Leeb11) (168.192.25.87)
Rating: N/A |
Delo 100 SAE40W is formulated for two stroke diesel motors and recommened by DD. Rotta has to much ash content in it,Call the 800 number on the oil jug to find out if its compatable when in dout. I have no problem starting mine in cold weather with the 40W in it. My DD book recommends only 40W oil. Lee LeeB11 66 01 | ||
| Jose (216.229.92.149) Rating: N/A |
Johnny: Like most engines, their are different oil specs. for different temperatures ! The Detroit Specs: Per; 6SE177 (22) Rev.12-64 Sec. 13.3 Cold Weather Operation Ambient Temperature Vicosity Grade +30 to 0 F. SAE 20 - 20W 0 to -20 F. SAE 10W These are old specs. but I'm sure they are still valid. Jose, just a Old, Dumb Mechanic | ||
| RJ Long (Rjlong) (24.127.74.29)
Rating: N/A |
Johnny (and others) - Here's a link well worth printing out and reading thoroughly: http://www.detroitdiesel.com/public/svc/lof/7se270-9912.pdf HTH, RJ PD4106-2784 Fresno CA | ||
| Mike Stabler (Docdezl) (64.255.109.182)
Rating: N/A |
I would be looking at the invoice you have. If indeed it has a mix of pistons,did they clear the Detroit shelf? Should show 8 kits for a 71 series. If they couldn't do that then fitting and hone and deck highth can't be good? And gear train and blower? I would stop,and re-think the whole thing. Pulling it and stating over....garbage in garbage out? Oil failure,only from a total lack of,IE drain plug or blown oil filter and stupid driver. More than once have followed a big trail of oil for miles until it ended at our truck at a truck stop?Engines with water or fuel delusion never seemed to have any effect on longevity? Often thought I could help my bottom line by mixing oil and water, works on salads? smoke,rattle&,stink......docdezl | ||
| Geoff (Geoff) (66.238.120.92)
Rating: N/A |
Personally, I am having trouble understanding the story from mcbud. | ||
| Paul Tillmann (24.105.194.162)
Rating: N/A |
I have two buses, one with the 8V-71 and one with the 6V-71. Both engines start (with ether) right up down to about 0 degrees (F) with the SAE 40 (CF-2) oil. They may start even colder, I just haven't needed to start them when it's that cold out. I just let them warm up for a little while and then drive easy until normal operating temperature is reached. During the winter I store the new oil in the house to keep it warm in case I need to add some. 40 weight oil pours a lot better @ 70 degrees than at 0 or 10 degrees. I also find that if I use either bus days in a row, they start much better in the morning than if they sit for days or weeks. Just another 2 cents worth.... | ||
| Paul Tillmann (24.105.194.162)
Rating: N/A |
RJ, Thanks for the link, I already printed a few copies out and distributed them to friends. | ||
| FAST FRED (209.26.115.97) Rating: N/A |
These engines were designed to operate most efficently between 1200 and about 1800 Rpm. Boosting it a few hundred rpm doesn't hurt too much , if the engine does not spend its life on the Gov. 2350 is for Fire Trucks , where saving life is worth an engine. Looks like a poor oil choice , and extrime RPM operation did what they normally do. FAST FRED | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
2350 rpm was good and 2500 rpm was better when going to a fire. Otherwise just cruising around at 1500 rpm. Of course the shops changed mills at around 10,000 miles or about 500 hrs. (if lucky)  | ||
| Johnny (67.241.232.173)
Rating: N/A |
Then I guess the 10-wheel Jimmy I drove that had the inline 6-71 governed at 2800 was a bad plan? Still running 2800, still going strong after 32 years. But you're right, probably stil a bad plan. Then again, it sorta fell on its face at ~2300 (2-galve, no turbo, N60 injectors), so about all the extra RPM's do is let you run 80+MPH empty. | ||
| John Feld (Deacon) (150.199.209.5)
Rating: N/A |
My favorite truck was a 1970 Kenworth with a 8V71 and Spicer 4X4 air shift transmission. First overhaul (inframe) was at 275,000 mi. second at 150,000 latter, third was out of frame after another 180,000, fourth (inframe) at 157,000. OK whats the point. I ran peak power at 1850 to 2400 RPM, top governed at 2650 RPM, I ran Rotella T 15-40, changed filters at around 8 - 10,000 miles, and complete oil change every other time. Detroits are made to scream, by nature they are a high torque motor, the harder you run um the better they like it. I always maintained you kick the tire on the way in, slam the door on your finger, and plant your foot on the floor. Now a Cummins is just the other way around, peak power ran 1250 to 1800 RPM, they are a low torque motor. Treat them like a lady. My 1957 6-71 4-speed? Nothing but Delo 100 40wt for this old girl, hold the RPM down to 1950 to 2000 RPM and she gets 10+ MPG. Pukes a little oil from the airbox and burns a little, but I have no idea how many miles on the engine. I don't fulltime, ain't in no hurry to get anywhere, and just like to see the countryside. Maybe, if I get round to it I will put some new jugs in her, redo the bottom-end and run the rack, until then I bought her to have fun, go fishin', visit the grandkids once in awhile. John 4104 | ||
| Don KS/TX (205.187.92.112)
Rating: N/A |
John, your post was sort of misleading I think. If you check the specs on an 8v71 as it came in a bus (at least in a 4106), you will find MAXIMUM torque is developed at 1200 rpm, and falls off rapidly as the RPM's climb above that. Also, I don't think one could call an 8/71 a high torque engine, I think my Ford powerstroke outdoes it. When equipped with the Allison VS2-8 transmission, the book was very specific that it should not shift down until around 1100 rpm, and should never stay in any gear above around 1700. I am not sure what your point was about running oil that was not recommended by DD, why would anyone want to do that? | ||
| John Feld (Deacon) (150.199.209.15)
Rating: N/A |
Don, The point was, it has been suggested that the engine failure in 10,000 miles may be due to the wrong oil being used. An 8V71 is an 8V71 no matter what it is used in. I was illistrating that other oils will work, I did it, I made my living doing it, I also did all my own overhaul work, and saw the results first-hand over 40+ years of experiminting. BTW: I operated 16 trucks in my fleet and did long-haul trucking. Did you notice my comment about my 6-71? No way would I use an oil other than Delo (Chevron) 100 40wt in that engine. BTW: your Ford is considered a low torque motor compared to a Chevy. I am speaking older engines here, not the new generation mid-80's and up. | ||
| Paul Tillmann (24.105.194.162)
Rating: N/A |
John, I'm a bit confused too. The way I read is that the use of 15-40 oil does lead to premature engine failure with only 275,000 out of a virgin (before any rebuilds) 8V-71. Then very low mileages on the rebuilds. Maybe the use of proper oil and more frequent oil change intervals would have let them last much longer. Also, do you mean horsepower when you say "peak power"? Because I believe the peak horsepower on an 8V-71 in around the 1850 to 2200 RPM range. | ||
| John Feld (Deacon) (150.199.209.30)
Rating: N/A |
Paul, Sorry for the confusion, guess I am not a good writer when it comes to making clear statements. Put into contex, an average overhaul in that time period was as I stated. Todays updated materials and modifications have greatly extended the period between overhauls. If overhauling today the total miles expected would basicly double. Also, I am talking engines that ran almost 24/7 pulling 73,280 to todays 80,000 gross weight. You are correct in interpeting the "peak power" to mean "peak horsepower", and that took place between 1850 and 2200 RPM. The added RPM was mainly for hill climbing and passing so that you do not lose momentum in shifting, its a matter of driver skill and each engine had its own "soul", I never drove an engine that fit the "average" scale that the book qouted. Here again, the issue I was addressing was the very unlikely probability that the oil used would cause ring failure in 10,000 miles verses faulty parts or mechanic error. My opinion, he could have used penzoil or quaker state and not had that degree of damage in 10,000 miles. |
