Detroit 60- time for an Overhead adjustment

I have a 1996 liberty xl. I need to do an overhead adjustment, Valves, Jakes and Injectors. Who here has done it or has photos of the bedroom access door location. I would rather not start a hide and seek game.

John

@ skywagon180 how many miles do you have on the engine? What is prompting the adjustments? Wasn't sure if it was due to service interval or performance related.

Although a one time adjustment is recommended, old time Detroit guys say leave it alone unless you have a performance problem or your Jake's performance gets worse.

FWIW, some have reported they had their valves adjusted without in coach access. If you're near Missouri, America Fleet can roll you engine out in no time.

I have around 280,000 miles. Some of the shops and million mile Detroit owners I have meet recommend 100,000 miles. The doesn't seem to be hitting that hard at all.



John

The earlier 60 series had valve stem clips that were changed due to more clip failures than they were comfortable with. If u have one with the old original clips and u have 250000 miles u should do it, they would get changed to the newer better ones. Otherwise IMHO do good service take oil samples and push that decision off to 500000 miles. That perticular service is only as good as the guy with the feeler gauge and I'm always worried about that. I took a customer's bus to Stewart Stevenson in Houston to have that done and those guys are really really good shop they know what they're doing they put two guys on the bus that work good and the first time it wasn't right they had to take it all apart again and readjust them they had it a bit too tight. It took them two shots at it and these r guys that have done it before. just saying.

The bus I was babysitting was an H and you can get the valve cover off on an H without pulling the hatch XLs are definitely more difficult you either got to take the bedroom apart or you got to pull the engine

My son and I got back from a 450 mile round trip last weekend. I went out to level the bus in the drive and plug it in. (My wife wanted to do some things while it was in the driveway. She was not ready for me to park it back in my shop). So I started it and had it set on high idle. No time at all I heard it kick down then die. I then found a oil pressure low fault code #45 and a #36. Mechanical and electric but read pressure. Felt very fortunate this didn't happen away from the house.

So I went and picked up a sensor. I am not sure who has changed one before. But no way am I a small guy with 6' arms. So long story short I now know where the access hatch is in the back. Yes the carpet had to come up. Not that big of deal. Joe like you said earlier I am impressed with Liberty. The things I have found are done Liberty has made the job easier than it could have been with there engineering. I will get the sensor in this afternoon. I can try to post photos later if y'all want. I know a good mobile 60 guy. The work on some of my other equipment. I will call them while it's apart.

John

I certainly don't have the hands-on experience as Joe. I was around fire rigs for nearly 25 years - most were 8V92TA early on and then later Series 60. About the same length of time in OTR Class 8 trucks. None of these I had any experience/knowledge with ever had overhead run as PM. Whether or not that was a good or bad thing I don't know. What I do know is if it was ever discussed the reason given for NOT doing it was exactly what Joe described. The end result is only as good as the technician doing the work - which might be difficult to duplicate factory assembly precision. Not saying it can't be or isn't done. That being said I have NEVER come across anyone that had overhead run on an otherwise good running engine and said it it improved anything (performance, fuel economy etc), tho I have known of a few that things were worse afterwards. I certainly believe in PM, but also suscribe to "don't fix it if it ain't broke" philosophy. Mine has just over 100K and I wouldn't consider doing overhead UNLESS a technician had to be in there for something else. Just my opinion, not trying to discourage those that believe otherwise.

Joe you have a few good points. This my first 60. I have one little 2 strokes Detroit. The rest are Cat and Deere.

The Jakes don't seem to be hitting well. I have the floor open now. It's not hard to open and see whats going on. I don't even know if this has been done before.

The Jakes are weak with the automatic transmission. The performance is way less than when it's combined with a manual transmission. You should get a second opinion about the valve stem clips that I'm referring to. Get your engine family number and the serial number and get ahold of a DD dealer and ask him about them. If you've got the bedroom disassembled and you've got the hatch open on it you've already done the stuff that's foreign to them that you really can't trust them to do.

I had a customer ask me to seal up an oil pan gasket leak on a 2000 and when I dropped the pan a couple of them Clips were stuck into the perforated holes on the oil pickup and you really couldn't tell that they had fallen out by the way it sounded or by the way it performed.

The jakes aren't great at slowing, but do well at holding. The typical setup is 2 jakes on low and 4 on high. I wonder why they don't use all 6 on high.

To aid in slow down effectiveness the factory setting is to downshift to 4th when the jake activates. I personally don't like the down shifting. It doesn't make using the Jake with cruise control together effective. I, and many others, have the transmission reprogrammed not to downshift. Some prefer the downshift, so check your configuration.

I had the overhead on my previous 02 Marathon H, 110K miles, done at Detroit in Ocala, FL, they’re bus friendly and a lot of folks have gone there. As Joe pointed out, I had 3 clips that came off and were laying on the head. No issues with the engine, I just wanted to do the adjustment and glad I did. It idled smoother and just sounded a little better afterwards. Old clips replaced with new style and since it was an H, easy access to get the valve cover off even being a jake with the higher valve cover. Here’s the old and new style clip.

Attachment 15450
Old Clip
Attachment 15449
New Style

truk would you be willing to share the expense for the overhead with parts.

Sure, 1844.00. That included the cam cover kit, overhead, new adjusters, engine service oil & all filters including the DD Need Release coolant filter. Keep in mind mine was an H and valve cover removal was easy, plenty of space above the cover.