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Setting the overhead on a Series 60 Detroit
Hey all, I have been meaning to post this up for sometime but have just been too busy.
I have a little more than 4500 miles on the engine since doing this and I think I can give a fair assesment for the before/after performance.
DDC recommends that you initially check the overhead at 60,000 miles, I believe this used to be 120K but they updated the interval and ammended the manual. After the initial check I think you are pretty much good to go until you see either a drop off in MPG or power. Some truckers like to do it every 200 k or so.
My bus had right around 83k on it and I am pretty darn sure the valve cover had never been off.
On an XL2 you will need to remove the rear access hatch to get to everything and perform the adjustments. I have heard some say you do not need to remove it, but I can not see how….even if you can get the valve cover off it would be next to impossible to get in there and adjust everything….and see what the heck you’re doing!
Anyways, luckily on my 40ft Marathon, this was just pulling back some carpet and then removing some plywood covers before getting to the Prevost cover. I had to prey the Prevost cover up from the engine side, it was pretty well stuck on there after so many years. 4 bolts hold it to the body.
You can now get some proper acess the to S60:
So, I perused my factory DD S60 manual, read a lot online and also consulter Erich from Serious 60, a DD tuner and engine builder. He suggested setting both intake and exhaust just on the loose side of the spec.
For injector height I purchased the DD tool that is 82.1mm, this will vary depending on what model you have. I have a later DDECIV and the injector height spec is also located on the valve cover sticker.
So we begin.
Detroit wanted a minimum of $500 to do this job, and I could not observe or be in the coach so that was no go, I knew it would take me longer than the 5-8 hours they said, but I also knew that I could take my time and be very thourough, which is what I did.
It is all very straight forward, and once you do a couple cylinders you start picking up speed as you find the best way to get in all the small areas you have to work.
Ok, we need to get some stuff out of the way first….
Remove intake plumbing:
There is our destination:
Now with the top half of the valve cover removed:
To be continued…
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11 Replies
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Bottom half of the valve cover removed:
You can get a big 3/4 ratchet with extension in the lower pulley to bar the engine over with the bumper on, but it is much easier to remove the bumper:
There are two parts to the Jakes, front and rear, here you see I have the fronts removed:
You will replace a few of the bolts to hold down the valvetrain to perform the check and adjustment once you remove the Jakes.
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Now both Jakes removed, ready to start checking the valve adjustment and injector height:
Using the method as described in the DD manual, you can set valves on one cylinder while setting injector height on another and so forth and so on. The manual describes this, for example, set valves on 1, set injector on 5 (I forget off top of my head so check manaual)
,Bar the engine over and move on to next set, and repeat. Here you can see setting injector height , the injector height tool is seen to the left of the wrench. You need to pay attention to getting the tool in the small alighnment hole to get a proper reading.
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Here you can see adjusting exhaust valves:
Follow the sequence as outlined in the manual and bar the engine over…the engine is not difficult to turn over:
Once you set all valve heights replace the Jakes and make sure to relieve any oil pressure in the solenoids before attempting to set lash. This is outlined in the manual, also there is a Jake supplement you can find on line.
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This is a close up of the exhaust adjustment on Jakes:
Be sure to make sure electrical connections are all routed correctly and firmly connected, this is all very simple.
Re assemble everything while taking great care not to leave any debris or tools around valvetrain etc, use a little extra silicone around the cam area on the valve cover as sealing pressure is a bit less there. Replacing the valve cover gasket is optional, mine was in nice shape so I re-used it…no leaks, but if I had to do it over again I would have replaced it since it will probably be a looong time before this valve cover comes off again.
And that is about it. Hardest part may have been getting acess to bedroom, and learning how to contort yourself to get at everything. Laying down in bedroom made easy adjustments to the rear cyclinders.
The result?
So far biggest thing I noticed on first drive was better throttle response and a huge difference in how the bus idled. It is much smoother at idle now, noticeably so, when you are stopped and back in the bedroom or bath it is a different experience.
Power is slightly better, but very close to how it was before adjustment, the Jakes feel about the same but mine always felt strong.
MPG: I am going to go out on a limb and say I am picking up 3/10ths. I track MPG like a hawk and we are getting into winter fuel, cold temps and LOTS of wind. I went through incredible wind on my last trip which killed MPG, before that I was doing much better, all other conditions were about the same.
So bottom line, was a pretty straight forward project with good results, wish I had done it sooner when I bought the bus with 65K on it.
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Awesome! I always wondered what was involved.
I wonder how one accesses the rear of the valve cover on a 45′ Marathon. Seems like it is right where the rotating closet and drawers are.
Gerald
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Great job G-man, both the actual work and the great job documenting it.
Two comments……you can turn the engine over by hand using the pulley above and to the left of the harmonic balancer. You do not have to pull the bumper. I think it takes a 1 3/8 socket. (I’m guessing).
I saw the small coolant line going to the top of the coolant pipe to the left of the engine. If you haven’t done so check all three of those small lines coming from the reservoir tank. They have aged very quickly and they snap easily due to being brittle. A local hose shop can remake them if they are the type that hardens and breaks.
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Nice job G-man, thanks for all the photo’s. This would be a good valve cover adjustment info Article.
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THANK YOU for the excellent write-up! In what state did you find the valves prior to making the adjustments? How far off were they? Were some still right on?
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Yeah I will try and download that PDF creator and do a lil more detailed write up…I should have taken some more photos but was kinda focused on getting it done.
It is also worth mentioning that ALL of my valves were on the tight side, nothing out of spec but close. ALL my injectors were also off spec and required adjustment.
I think when I started out I was checking the adjustment to see where things were at then when I noticed most were off just went about setting them all fresh. I think maybe a couple were outside of the spec all together.
If anyone wants to borrow the 82.1mm injector height tool just let me know.
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Jon, I think you are correct as I thought I read somewhere you can turn the engine over as you describe. Luckily all my coolant hoses are in good shape, a few small ones I have already replaced.
I had a very small drip from the big hose going into back side of radiator, I was able to get down and tighten that one up via the top acess panel, no other way to get to it that I know of!
I did replace both belt tentioning bags right after I set the valves and I think I got a bit more access by removing the bumper…anyways bumper comes off very easy, just 6 bolts if I recall with the air ratchet.
The more I read and learn about the Series 60 the more I like it, they have an incredible reputation for mpg and reliability. Lotta mechanics on truckers forums say they will also tolerate a lot of abuse.
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Great Job. Thanks for all the pictures with your explanation. The whole thing is way beyond my pay grade.
Davy
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Good job G-man, thanks for all the pictures!
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Great presentation G-man. Taking the time for pictues is very helpful to owners to understand what takes place.
Your a great asset to the PC Forum.
Al
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This is pretty slick. I didn’t realize how easy it would. Just like setting the valve lash on the race car.
I think this sounds like a great thing to do at a rally. Like the coaches up and go from one to the other until they are all tuned up.
I presume you’re setting the valves cold.
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