So I posted on here several months ago about head gasket and oil cooler replacement. When I put it all back together, I obviously had to adjust the valves which was the first time I ever did so. My fuel mileage has seemed to be 3 to 4 miles per gallon less than before the work. Is it possible that I did not adjust them properly? Anybody have any thoughts ?

 

unless you are way out i cannot see how milage could be affected without seeing a huge change in how it runs and sounds.

what did you set the valves at?

 

They are set to whatever the factory manual specs are? Don't remember exact number.

 

I think if one of them ended up a tight it might effect it, but couldn't say for sure. It wouldn't hurt to adjust them again just to eliminate that out of your trouble shooting process.

 

compression loss would make it run rough at idle

 

Did you rotate the engine back to TDC on #1 cylinder and recheck your valves after your first adjustment? Sometimes rotating the engine another 360 degrees allows the valves to seat and could change your adjustment. I believe that the intake gap should be .010" and exhaust should be set to .020".

 

One reason I love my 1st gen...

Fuel mileage..


Your fuel mileage can't be as bad as these guys in the 4th gen group..

https://www.dieseltruckresource.com/...0-t301083.html


7 mpg average ??????


Thanks, but I'll stick with my old truck.....

 

I was between 18 or 19 now more like 15 or 16. It doesn't seem like that much but it bothers me. I think it's time to look into some minor modifications. It still has a muffler so I think I will straight pipe it as I think I am the only guy with a cummins that hasn't done so yet and look at the valves again.