When to adjust valve lash on Series 60

[James]

I had thought that Detroit recommended the valves be adjusted on the Series 60 after 60,000.

We're currently looking as several 1999 XLV's and 2002 to 2003 XLII's. The miles on the coaches vary from 60,000 to over 100,000 miles. None of them have ever had the valves adjusted and none of the owners were aware of any valve adjustment needed either now or in the future.

When is the proper time to adjust the valve lash?

James & Kris
Prospective Prevost Owners

[Will Garner]

James,

Good question. I have an ailing 8v92 so can't offer advice. I am in OKC right now and only awake because of the dog. There are a lot of Series 60 owners here that are busy walking their dogs, recovering from a day of blinging out their coaches, or just well - sleepy! I am sure someone can give you that answer to that question before lunch time is here. You might be able to go to Detroit Diesel's web site and check their information database.

Welcome to POG. By the way, how come you are not out here in OKC to ask your question in person. No need to answer that question. We will however expect you to be at the next POG gathering with your new to you coach.

We will be having lots of fun this coming week and really wish you could be here. Coach ownership is not mandatory to partake of everything POG has to offer.

[James]

We look forward to attending one of the "bus meetings". We just need to settle on a coach.

James & Kris

[jack14r]

Even though DD recommends valve adjustment at 60,000 miles I know that most mechanics say that if the engine is running OK then most would not do it,if it is an XLII the closet floor must come out to get the valve cover off,I think that the H3 has enough room to pull the valve cover and not disturb the closet.

[BrianE]

Added to Jack's comments. XL Coaches also require dismantling of the bedroom or closet area. Here is a link to the Series 60 Operators Manual: http://www.ddcsn.com/cps/rde/xbcr/ddcsn/DDC-SVC-MAN-0006.pdf. Table 17 in the manual recommends the 60K mile initial valve lash adjustment.

It can probably be assumed that most converted coaches have not had an initial valve/injector/Jake adjustment at 60K miles.

[JIM KELLER]

James, Welcome to the Forum. If you only knew what you will learn after you buy a Bus before you Buy your Bus you would understand the importance of attending " A Bus Meeting " Come on in !

[James]

Brian,

Thanks for the link. I'll keep a copy of the manual.

The thought process, as far as the valves, seems to be if it isn't causing a problem don't mess with it, however I wonder just how far past 60,000 you can go with a Series 60 before problems show up. I would think at some point you would see a reduction in fuel mileage and possibility an increase in oil consumption.

My preference would be to go ahead and do the valve adjustment and get it out of the way before these symptoms show up. I'm just surprised that none of the coach owners that I have talked too were aware of the need to adjust the valves at all. Makes me wonder what other maintenance items had not taken care of.

James

[dale farley]

James,

A couple years ago, I took my previous bus to Detroit Diesel to get the valves adjusted. They said they could adjust the valves and the fuel injection rack, and maybe improve performance a little, but many times the service resulted in worse overall performance. It had almost 150K miles on it at that time. They performed the engine diagnostics and told me to leave it alone unless I really developed a problem with the engine.

[James]

Dale,

That seems to be the consensus on the valves, if there's no problems don't adjust.

Did your previous bus have a series 60 or an older engine?

James

[dale farley]

James,

My previous bus was a 93 Marathon with an 8V92, but the same logic is applied to the series 60 engine.

[James]

An update.

I went ahead and had Pacific Power in Corborg adjust the valves. The coach has less than 65K miles but we decided it would be better to have Marathon take up the closet floor now, before we put everything in it, rather than have to unload everything later.

The tech doing the adjustment stated that half the valves were too tight and that seemed to be the trend from the factory. He recommends doing them every 50 to 60 thousand miles but of course he wants the work.

He found a loose connection on the Jake brake wire inside the valve cover which he repaired and the fan bearing about to go as well so Marathon is changing that.

Looking forward to taking possession next week.