| Author | Message | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 25 Registered: 12-2011 Posted From: 99.100.88.196  Rating: N/A |
Long story short When I had my bus serviced they replaced two fuel filters. No problem then I notice a third fuel filter on the back behind the trans mounted on the wall. So I take it apart today and it was filled fuel and a ton of sediment in the bottom and no filter inside. I cleaned it out and put it back together. I only had enough fuel in my can to prime it 1/2 way and I figured that would be good enough to get it going. Guess not... It started ran for 3 min then died. I went and got some diesel in a can to prime the filer. Then I wouldn't start at all. I check the filter and it's primed. So for the hell of it I check the two large filters on the motor and they are now both empty... no diesel fuel in them. So I prime them and the bus starts runs for 2 min then runs rough and dies. I check the filters and they are empty again??? Huh??? I prime and it runs... but has no power on acceleration it shakes at first and the filters keep getting air it seems like the left one on my DD 6v71. I ran it for an hour even drove it for ten miles. It gets up to top speed but it takes forever smokes black and has no get up and go. Is there something about priming that I am doing wrong? It starts and sounds fine. except when you hit the throttle full it shakes bad for a second or two then sounds good... sounding good but has no power. I'm sure if I drop that filter again it will only be half full1/4 or less. Somehow air is in the system. Help?? Ideas?? | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 26 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
Maybe it's a bad gasket on the fuel filter. It looks kinda "roached" so I'm off to get a new gasket and see if that helps. We think maybe it's sucking air from the bad gasket?? anyway that's what I'm trying next. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 2219 Registered: 10-2003 Posted From: 71.58.71.157  Rating: N/A |
if it sucks air, you'll get the symptoms you have. | ||
| Bill Gerrie (Bill_gerrie)
Registered Member Username: Bill_gerrie Post Number: 598 Registered: 3-2006 Posted From: 216.198.139.38  Rating: N/A |
Scott Any time you take a filter off you must replace the gasket. When you put the filters on if it is a canister type make sure the housing doesn't rotate as it will cut the gasket. Hold the canister while you tighten the bolt. If it is a spin on type oil the gasket surface. When you put it on only tighten 3/4 to 1 turn after contact. Bill | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 1421 Registered: 11-2005 Posted From: 173.202.23.98  Rating: N/A |
That third filter is probably the original primary filter and was just left in place without a filter element when the two spin-ons were added. My 4104 has one like that with a stacked disk element. | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 27 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
That fixed it. Sucking air. When I started this mess I should have remembered that "curiosity kills the bus". When I saw the other filter and saw that it has fuel lines in and out I knew they never changed that one. So I took out the drain plug.. All the way out and not one drop of fuel came out. .. I thought that's not good... So I just had to know what was going on Inside of there... Well I found out... No filter and a good inch of 50 yrs of sediment. And since there were two other large filters and this one was 1/2 the size 1/2 way full would be fine to prime since the others were primed. Anyway I don't think prime was the issue but the air sucking was, then since I dropped all three multiple times I replaced all gaskets primed all three, started it and it ran perfect. 6 hrs of work because I just had to know what was going on inside instead of leaving well enough alone, ordering a replacement filter, then finding out when I change it. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 1654 Registered: 7-2006 Posted From: 97.224.33.187  Rating: N/A |
Great news, Scott!!! Hang in there!.  RCB | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 28 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
Taking the "New Look" bus to Chicago today... Do you think I can get valet parking? It's about a 400 mile round trip. We are getting ready for a trip to Florida in 3 weeks and this is just a little open road test in preparation for that trip. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 1655 Registered: 7-2006 Posted From: 97.224.51.2 Rating: N/A |
One day...one mile....at a time...as it were . Got a manual? (Da Book) Muy importante!!! Best wishes. RCB | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 2220 Registered: 10-2003 Posted From: 71.58.71.157 Rating: N/A |
You may get valet parking if you are wearing a Muppet outfit. | ||
| Jack Hart (Jackhartjr)
Registered Member Username: Jackhartjr Post Number: 83 Registered: 8-2007 Posted From: 64.12.116.203 Rating: |
Actually, you probably prevented a future problem. If that gunk in the old filter ever let go, imagine what it could clog.! Jack | ||
| Bill Gerrie (Bill_gerrie)
Registered Member Username: Bill_gerrie Post Number: 600 Registered: 3-2006 Posted From: 216.198.139.38 Rating: N/A |
Scott Jack is right. Why don't you just remove the extra filter housing and join the two lines together with a connector. One less place the fuel system could suck air. Bill | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 29 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
I did eliminate the bulkhead mounted filter... Technically It's been eliminated for a long time since there was no filter inside. There was a back flow preventer on there which I kept on the new filter. We put almost 450 miles on it yesterday and no issues. I recently added a "Slobber Tube Catch Container" and this was the first road trip with that on there. And WOW what a difference on the back of the bus. 95% cleaner after the trip. Plus this was the first trip with the Delo 40Wt instead of the 15w40 so I'm sure that helped with some of the back of the bus mess. I have some really amazing before and after photos... good news is all of that slobber tube oil spit is now going to be recycled instead of ending up on the road and in the environment. I also keep the oil level only a quart above the add line instead of all the way up to the full mark. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 1427 Registered: 11-2005 Posted From: 173.202.4.145 Rating: N/A |
Scott, That back flow preventer is the check valve that keeps fuel from draining back to the tank and causing a loss of engine prime. A very wise decision to keep it!! I keep my oil level about halfway between Add and Full, only a quart above is cutting it a little close plus more oil means better cooling in hot weather. | ||
| Bob Glines (Robertglines1)
Registered Member Username: Robertglines1 Post Number: 66 Registered: 11-2010 Posted From: 75.207.40.248 Rating: N/A |
Scott: for what its worth those ck valves in line with your slobber tubes (air box drain) should close at 900rpm they sometimes become dirty inside and stay open causing this not to happen. With results much as you described oily substance on back of bus. You can take them apart and clean or replace them. You are losing blower pressure if they are not sealing (closing) at 900 rpm. Others will comment. | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 30 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
Please explain more Bob... I've researched the oil on the back of the bus and have never read anything about a check valve or them closing at a certain rpm. | ||
| Bob Glines (Robertglines1)
Registered Member Username: Robertglines1 Post Number: 67 Registered: 11-2010 Posted From: 75.249.60.141 Rating: N/A |
Your air box is located below blower. is pressurerized by blower. There are no intake valves on your engine just ports inside of the linner that let air in when piston is in correct position. This air box is common to all cylinders(imagine a shoe box) some oil and humidity from seals and atmosphere collects in there. when engine is at low idle the check valves are open and lets this mixture pass out the so called slobber tubes. about 900 rpm it closes and this mixture is burned as part of the combustion process. When these check valves stick open this mixture is forced out the tubes and end up on the back of your bus or catch can. As a engine gets wear on it it seems to produce more mixture. That is the simple explanation. If you ever get water running out of them stop you have a major problem. They are a good diagonistic tool. Hope this helps. | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 31 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
Messing in the firewall area has caused my speedometer to stop working. I jiggled the wires around and checked that everything was tight on the speedo output on the trans. It started working but cut out about five min into a test run today. I'm going to take it all apart tomorrow and clean the connections I'm 99% sure it's a bad connection or short in a wire. If cleaning the conections don't work I'm going to replace the about 2ft long sections of wire before the harness on the trans unless any one has any other ideas. Ps I like the bus speedometer better than my gps... The bus speedo is like your favorite bathroom scale that subtracts a few pounds... It says 55 when my gps only says I'm actually going 53. I know it's not right but it just feels faster. | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 117 Registered: 5-2009 Posted From: 65.92.49.204 Rating: N/A |
The airbox drain check valves are about 2" long, 3/4" in diameter and have threaded hose connectors on them, should be one on each side. You can take them apart to service them, and they kind of rattle when you shake them. They are position sensitive, so you do need to install them the right way round. If your bus is like mine was, the check valves are there, but someone took the guts out and as hollow tubes they don't work at all... As said the idea is they close at some rpm over idle (there are a couple of different settings you can get) so that all the pressure is retained inside the airbox, and the mess is reduced. Brian | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 740 Registered: 2-2001 Posted From: 184.0.13.120  Rating: N/A |
Guys, Detroit didn't use check valves on older engines. I'm not sure what year they started but I have 3 engines that never had em. (1950's & 60s) Just a pair of tubes that go from the front & rear corner of the air box down to the bottom of the block. I have them piped to a Walker air box drain cannister. | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 118 Registered: 5-2009 Posted From: 65.92.49.204 Rating: N/A |
Very true, they came into use in the 1970's I think. Nice retrofit, in any case, and probably more important on turbo engines. Brian | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 32 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
My bus is a 61 and I have not seen them before. Maybe a photo would help? If you are saying that I can see them on the outside of the air box they are not there. | ||
| Scott Crosby (Scott_crosby)
Registered Member Username: Scott_crosby Post Number: 33 Registered: 12-2011 Posted From: 99.100.88.196 Rating: N/A |
 Both images have about 500 miles of highway driving on them. The before from when I bought the bus, and the after... after making some improvements like tightening loose connections on oil lines, bolts on gaskets, and other little things like that. Changing the oil from 15w40 to the straight 40wt and running the slobber tubes to a catch container. FYI I just drained about 1/2 a pint out after the 500 miles. Over all the oil lever looks to be about the same as before I left so not a noticeable difference on the dip stick. From the first photo I was about a gallon every 700 miles or something crazy like that... Actually I think I put 4 gallons in along the 2300 mile trip. My guess is that tightening loose connections stopped about 30% of my oil loss, changing the oil to thicker straight 40wt cut down on 30%, not keeping it filled to the full line 20%, the slobber tubes are about 15% so now I'm down to only 5% of the drips I was getting. Like I said 95% improvement. Still working on it... Anyway from a gallon to a 1/2 pint I'm getting there. I know it will always leak but I should also add that my rear end is rust free. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1653 Registered: 10-2006 Posted From: 67.238.59.158  Rating: N/A |
A leak I found really hard to find was the return connection from the fan drive . Since it is only pressurized when fan cooling is needed , driving from highway to residential home was enough to cool to the point of no oil flow. Found it be crawling under after a hill climb to a highway rest area. FF |
