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kurtliveson
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Joined: May 01, 2014
Posts: 12
Location: Marysville, Wa
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 Posted: Wed Jul 16, 2014 4:51 pm Post subject: Possible dead cylinder? |
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I have a '77 fuel injected 2.0 bus. Just got it running after it sat for 9 years and I'm pretty sure cylinder #3 is dead. It gets spark and fuel but doesnt fire. When I pull the spark plug, it's covered in oil so I'm thinking bad rings. I have not done a valve adjustment to it or even looked at the valves. Plan on trying to do a compression test tomorrow if I can get a hold of a gauge. The engine runs but just on 3 cylinders. Any thoughts of what I should do next?
Parts I've replaced:
Spark plugs, wires, distributor cap, rotor, coil
Fuel lines, fuel pump, fuel filter
Oil and filter, air filter
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1977 VW Bus
2003 VW TDI Jetta wagon
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Heathintexas
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Joined: September 24, 2011
Posts: 135
Location: Berlin Germany
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| Posted: Wed Jul 16, 2014 5:25 pm Post subject: Re: Possible dead cylinder? |
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| kurtliveson wrote: |
Any thoughts of what I should do next?
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Post some pictures! 
I'm assuming that you've run it.. so did you pay attention to what color smoke it was shooting out?
Black/brown - rich
Blue/white - burning oil
white - water has somehow entered your aircooled motor 
Your compression test will definitely tell you the answer.
Do you know why the bus was put up for so long? The math is telling me someone burned the engine up. Number 3 cylinder is almost always the first one to go on the type 1 engines, but we definitely need to know a lot more about your bus (pictures!) to be able to help.
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aeromech
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Joined: January 24, 2006
Posts: 16954
Location: San Diego, California
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| Posted: Wed Jul 16, 2014 5:46 pm Post subject: |
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Coupla thoughts.
Does it have hydraulic of solid lifters? If hydraulic maybe the lifters are flat. Also, maybe the rings are gummed up. You can try adding some Marvel Mystery oil or ATF to the engine oil and running it to try and loosen things up or pump up the lifters. Then drain and service with a good synthetic oil like Mobile 1 or Castrol Edge.
You can do a compression check.
You can pull off the valve covers and see if all your valves are even with the rockers removed. This will show a dropped seat.
Lastly, I think I'd run the engine and see if it fixes itself.
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Wildthings
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Joined: March 13, 2005
Posts: 50332
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| Posted: Wed Jul 16, 2014 6:27 pm Post subject: |
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| You can also dump a quart of MMO, 2 cycle oil, or synthetic motor oil into the gas tank. This will lube the combustion side of the pistons well and can free up stuck compression rings. |
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busdaddy
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Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Wed Jul 16, 2014 7:04 pm Post subject: |
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The first thing I'd do is remove the rocker assemblies and put a straightedge across the valve tips, are any higher or lower than the rest?
Careful when putting the rockers back on, make sure all the pushrods are in the cups on the rocker ends and don't torque the hold down nuts more than 9 foot pounds.
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kurtliveson
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Joined: May 01, 2014
Posts: 12
Location: Marysville, Wa
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| Posted: Wed Jul 16, 2014 7:35 pm Post subject: Re: Possible dead cylinder? |
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| Heathintexas wrote: |
I'm assuming that you've run it.. so did you pay attention to what color smoke it was shooting out?
Black/brown - rich
Blue/white - burning oil
white - water has somehow entered your aircooled motor
Your compression test will definitely tell you the answer.
Do you know why the bus was put up for so long? The math is telling me someone burned the engine up. Number 3 cylinder is almost always the first one to go on the type 1 engines, but we definitely need to know a lot more about your bus (pictures!) to be able to help. |
Thats one thing I'm kind of confused about. It barely smokes, if at all. What little smoke there is, I'd say its white. The very first thing I did when I got it was flush the tank so unless the fresh gas I put in it had water in it, I doubt there was any water in the motor.
The bus belonged to my wife's grandma. The story she told me was that she couldnt get it to pass emissions down in California so she had to park it. BUT she is in the beginning stages of Alzheimers so I dont know if I should belive that completely. It was her daily driver for about 15 years.
I have ran it some. I've ran it in the driveway while working on it and I've put about 40 miles on it driving around town. I'm just afraid to do more damage to the motor running it while its only running on 3 cylinders.
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my59
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Joined: August 13, 2003
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Location: connecting the dots
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| Posted: Wed Jul 16, 2014 8:01 pm Post subject: |
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| busdaddy wrote: |
The first thing I'd do is remove the rocker assemblies and put a straightedge across the valve tips, are any higher or lower than the rest?
Careful when putting the rockers back on, make sure all the pushrods are in the cups on the rocker ends and don't torque the hold down nuts more than 9 foot pounds. |
Then, after setting the valves (if hydro lifters are they pumped up?) I'd swap the 3 and 4 injector location and see if the issue follows the injector.
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my59: Well son, my grandfather died before I got to drive it, so does that answer your question?
our79: sunroof bus w/camper interior and 2.0 FI
Other:'12 Jetta, '77 Benz 300D, and a 74 MG Midget. |
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aeromech
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Joined: January 24, 2006
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Location: San Diego, California
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| Posted: Wed Jul 16, 2014 8:32 pm Post subject: |
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I kind of doubt that you could do a lot of damage by just running it around town for a bit. Long term, running with a dead cylinder will possibly wash the lubricating oil off the cylinder wall and ruin the rings.
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Wildthings
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| Posted: Wed Jul 16, 2014 8:43 pm Post subject: |
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| If you are going to drive it with a dead cylinder pull the plug off the injector for that cylinder and that will keep it from burning itself up and/or washing the lube off the cylinder walls. |
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aeromech
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Joined: January 24, 2006
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Location: San Diego, California
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| Posted: Wed Jul 16, 2014 8:46 pm Post subject: |
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| Wildthings wrote: |
| If you are going to drive it with a dead cylinder pull the plug off the injector for that cylinder and that will keep it from burning itself up and/or washing the lube off the cylinder walls. |
Tru dat
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SGKent 
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Location: Citrus Heights CA (Near Sacramento)
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| Posted: Wed Jul 16, 2014 9:05 pm Post subject: |
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Swap the plug wire so that #4 wire is swapped with the #3 on both the cap and plug. See if the issue changes from 3 to 4.
Pull all four plugs and check compression. If all 4 are within 10% -20% swap the #3 ad #4 plug and see if the issue changes cylinders. If 3 is low check the valves as BusDaddy suggested.
Using new injector O-rings cause they are cheap, gently swap #3 and #4 injector and see if the issue changes cylinders. |
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kurtliveson
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Joined: May 01, 2014
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Location: Marysville, Wa
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| Posted: Thu Jul 17, 2014 3:29 pm Post subject: |
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So I did a compression check on #3 and got nothing, no pressure. Checked #4 and got about 110psi. Didnt check 1 or 2 because I didnt have time. Changed the oil and put in about 3/4 quart of MMO in the oil, the other 1/4 quart in the gas. Plan on driving it the next couple days so I'll see how that goes.
How easy is it to check the valves? I'm new to the air-cooled world...
Pictures coming shortly.
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kurtliveson
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Joined: May 01, 2014
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Location: Marysville, Wa
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| Posted: Thu Jul 17, 2014 3:49 pm Post subject: |
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aeromech
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| Posted: Thu Jul 17, 2014 5:23 pm Post subject: |
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I really like that bus.
Well, you're just going to have to take the time to figure this out. I'd disconnect the injector to #3 and drive it some to get the MMO spread around. Then I'd do a complete compression check and record what you find. Then let's say #3 is still dead. I'd pull the rockers and see if the valves all line up. If they do I'd do a differential compression check which should tell you if you have a bad valve or bad rings. After that you'll need to decide which way to go but you'll probably be looking at an expensive rebuild. That bus would be worth it though.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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SGKent
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Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
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| Posted: Thu Jul 17, 2014 6:05 pm Post subject: |
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don't drive it. Right now you have a rebuildable core. Drive it and you may end up with a paperweight. REALLY.
You need to next do the BusDaddy check on that side of the valve stems. See if one is sticking out or in a lot further. If yes the engine has to come out and at least get heads rebuilt or new ones. If no then check the valve clearances cold. Don't waste your time on the valve clearances until after you check the valves to see if that cylinder has dropped a seat. |
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kurtliveson
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Joined: May 01, 2014
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Location: Marysville, Wa
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| Posted: Mon Jul 21, 2014 3:58 pm Post subject: |
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I havent pulled the rockers but I did check the valve clearances on that cylinder. The valve to the rear of the bus (not sure if its intake or exhaust) I had problems with. I can take the adjustment screw all the way out and the rocker arm still is in contact with the valve stem. Is this normal? I was able to get the other valve adjusted correctly.
If there was a dropped seat, wouldn't it be making a lot of noise? The motor is actually pretty quiet it seems like.
I will be pulling the rockers once I get more time.
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busdaddy
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| Posted: Mon Jul 21, 2014 4:17 pm Post subject: |
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| kurtliveson wrote: |
I havent pulled the rockers but I did check the valve clearances on that cylinder. The valve to the rear of the bus (not sure if its intake or exhaust) I had problems with. I can take the adjustment screw all the way out and the rocker arm still is in contact with the valve stem. Is this normal? I was able to get the other valve adjusted correctly.
If there was a dropped seat, wouldn't it be making a lot of noise? The motor is actually pretty quiet it seems like.
I will be pulling the rockers once I get more time. |
You should, and don't be driving it in the meantime.
A seat can come loose and wear (sink) into the head, or the valve can stretch almost to the point of breaking. Right now it sounds like all you need is head work, drive it some more and you'll have much much more to repair/replace.
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