BAC Forum
General Boards => Technical Support => Topic started by: Mike Nunn on August 10, 2015, 07:38:05 PM
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would one or more of you please give me a little insight as when to have the valve adjustment done on the c9 400 hp or perhaps the answer is not to do it. As far as the engine Manuel recommends we are probably some past the mileage. We have about 40,0000 miles. No engines issues that I am aware of and fuel is same as it has been.
I am just really reluctant to let anyone fix anything that's not broken. Thanks mike
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Mike, let me give info. stright out of Cat Service manual ( valve Settings ) Recommend valve
check after first oil change. Valve Lash Check, an adjustment is Not Nessary if the measurement
of the valve lash is in the acceptable range. Acceptable Range For Valve Lash.
Intake ( ,015 + -, .003 )
Exhaust ( .025 + - .003 )
If measurement is not within this range adjustment is nessary. food for thought Look real close
at task at hand. (under bed is there enough room to get at all valves ) Second there is a Cat
way to set valves and valve bridge. before start correct setting of valve on engine via of Pin
lock to flywheel on engine at number 1 cylinder. many people set valves but I would have a
Cat Dealer check valve adjustment than adjust if nessary. there is lot of miss understanding
about valve clearance and adjustment. Dave Atherton Retired Cat Mechanic
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One of the "aftermarket" service schedules I was given at BCS when we bought our coach says valve lash adj. every 10,000 miles. But I've since taken that to mean "upon the first 10.000 miles". That schedule was not specific to our coach or a C9, but meant for general purpose diesel motorhome reference. My CAT manual recommends after that initial 10k check, do it every 100,000 miles, 15,000 gallons of fuel, 2000 service hours, or 2 years. If you know whether or not the initial one was done, great. Otherwise it's something to consider as a protective move in case it was never done; that initial one is to be sure valve seating is appropriate following some break-in. If you aren't the original owner and don't have a service history, perhaps you can ferret it out by way of CAT and your engine serial number.
Then consider the fuel and service hours parameters. 2 years seems a bit short of a period for coaches that aren't on the road all the time, so I'd be more inclined to go with one or more of the other parameters.
Joel
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Mike, this may be different than for your C-9 but this is what my Cat Operation and Maintenance Manual says for my C-12."Between 15,000 and 60,000 or Between first and fourth oil change" inspect/adjust engine valve lash. Because my coach doesn't get used a lot (5000 miles a year) I chose to go by the mileage. At 42,500 I had the valves checked and adjusted. They were within spec's but a couple did need to be adjusted. I was very fortunate, I found a Cat employee that went into business for himself to do mine. Saved money and still got a warranty. If I were you, I would have it done. You are at or near the mileage point. Peace of mind. Marty
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Mike
we had the valve lash adjustment done by Cat at 36000 miles. Like Marty"s ours was within specs but did require some adjustment according to the tech.
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I am just really reluctant to let anyone fix anything that's not broken. Thanks mike
Mike,
You exactly state my fear. As does yours, mine runs great. Mine gets 8-9mpg even though the average speeds have been around 40mph. The Jake brakes work fine (which for mine that adjustment is also performed C-12). I purchased mine at 65000 miles, have been back and forth across country since, and this was supposed to have been done in the 20,000-40,000 mile mark, and the first owner who paid an awful lot of money for it would probably have had it done, but obviously there's no sure way to know. I gave my engine serial number to CAT but that shop found no record of it having been done.
I just hate to think of having that engine opened up and a stranger work on this and then my fuel economy or what I consider a normal engine idle changes. Though I do consider my idle rough compared to a car. There is vibration to the point that the bedroom pocket door can make some noise rattling. Not sure what other Marquis owners in the 99 to 01 year range experience after start up and during warm up. I don't think that has been discussed on the forum.
But having said that, can others here who've had it done to theirs, give both you and I some confidence that to a CAT mechanic this is like changing a light bulb or something else so that we two Mike's can feel better about it given the likelihood that its already been done by the original owner.
Mike
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Thanks for the responses, the coach had 11000 miles on it when we purchased it so I doubt any valve adjustment had been preformed.
While I suppose cost has something do with everything it really would not be the deciding factor in Having this preformed.
I suppose I was just looking for someone to say yes it should be done or no there is a chance someone would create more problems than they will fix.
I do not think I would let anyone but a cat dealer do this but I have had great service at cat and I have had one create way more problems than I had when I got there. Thanks again mike
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At 11000 miles I would have had mine done, so any objections you might have inferred from my post have now been taken off the table. :) Let me know if you experience an improvement. One thing I would hope for is less vibration when at idle.
Mike
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Any idea how much this would cost? Just rough ball park. Thanks
Jerry
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The cost depends a lot on the access to the engine and how much prep work the mechanic has to do. For example, cover carpeting, move or remove bedding and mattress, remove access panels to engine compartment and so on. On my 98 Monterey I prepped everything and the cost was $140. total and on my 2002 Thunder I prepped everything again, including the mode to the closet, and the cost was $250. There is a member here on the forum that paid around $800. to have his 02 Thunder done and the dealership did everything. Marty
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Jerry, I think Marty's right about cost... "it depends". A lot of it is labor since the only part needed is a gasket for the cover. For example, if you have a bed that's configured in line with the coach, rather than streetside to curbside, the mechanic may have better access and take less time. Many diesel owners do this themselves, but not without some experience. A large wrench can facilitate turning the shaft to get top dead center (TDC), but again it's all about access - whether or not a tech has to run in and out of the coach and you pay "travel time" or they use two techs, one in and one out, etc. If you do it yourself, the gasket is maybe $60?, but if the original is in great shape, some just reuse it - I'd guess most CAT shops would replace with new regardless.
Numbers I've seen on other forums lead me to think $350-$500 would be today's range. But if you do like Marty and spend some prep time doing stuff a tech would have to do otherwise, you can cut the cost a good deal. A CAT shop should be forthright with a quote though.
-Joel
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Thanks, I'm a bit gun shy. I tend to think changing a light bulb is going to cost 2k because it's an RV. Sadly so far I haven't been worrying unnecessarily!
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The quotes for me last fall were $425 from Peterson CAT in Portland, Oregon and $450 from Pape Kenworth in Donald, Oregon. These include the exhaust brake adjustments. I think I have the right bed configuration for the $140 job! Wishing!
Mike
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Don't most places do it by the "book" price? I was quoted $2500 to $4500 to replace my exhaust manifold in Arizona. When I got home, I took it to Cummins Northwest and they did it for $1200 because that was what the price in the "book" was.
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I have to agree with Jerry thoughts, the sky is not falling. every seems to forget your engines were
built tested of which at operation temps. and load to set rings etc. We talk about setting valves soon
after one or two oil changes than we can forget drill again to 150, to 300,000 miles than we run the
drill again. If everyone read my thread look at valve lash adjustment, if feeler gauge falls in this window
don't touch the valves there is a .006 thousands window. In different terms, a piece of typing paper
is .004 thickness per sheet so 1/2 sheet would be .002 thickness. It is very rare providing no major
repairs been made to head of engine after 150,000 miles feelers gauge will still fall in the .006 window
of correct .015 intake and .025 exhaust valve adjustment. I have been around the do it yourself
valve adjustment where not following Cat SOP caused more problem than if not looked at. this was
counting all the dirt that was knocked inside open engine.Again the engine everyone is running are
long life engine. Engines in motorhomes there is no set rule how to approuch getting into the valves without
use of a chain saw. Dave Atherton Retired Cat Mechanic
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Jerry
I paid $355 at a Cat shop in Indiana last June.I did no prep work.
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Thanks Dan, I appreciate your info.
Jerry
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I really appreciate all the input on this forum concerning the valve lash adjustment/inspection. It has been very informative.
I took my 2003 Marquis-Ruby into a Cat dealer to get the valve lash checked on the C12, 505 HP engine since I just rolled over 60,000 miles. The bed is a streetside to curbside. When I called the Cat dealer to get an estimate and schedule the work, he quoted 4 hours to do the work. Now, the dealer is saying a support is in the way to remove the valve cover and if I remove everything out of the closet it still may take 8 to 16 hours to do this work. Has anyone run into this issue? I dropped off the coach at the nearest Cat dealer which is still over 100 miles from where I am staying. I thought I would do some research before I make the trip back to the Cat dealer. Does anyone with this model of coach run into this issue? Thanks the advice.
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I don't see how this could take 8-16 hours to do a valve lash inspection and adjustment.
Mine was about $300 at CAT in Brooksville, Fl a couple of years ago.
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I just looked at my 03 ruby and with the c12 having 3 valve covers, The front is accessed from the bedroom hatch Very easy! the rear from the rear engine access very doable ... however the middle has 1" (OR LESS) clearance to a aprox 3" wide steel support (under the closet wall) that runs the width of the coach. I see no way the covers coming off unless when unbolted you could just slide the cover off almost sideways. I assume the valve assy sticks up some. 115 grand on mine and with that i assume no adj has been done. I dont see how it could be done short of dropping the engine. or cutting that support and the wood 2x above it!!! So, Dave , whats the Risk in not doing it?
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Setting the valve lash on a C-12 in a Marquis or a Thunder is no easy task. The center valve cover has a brace right over the center head. There is a recommended procedure for a mode that I did on mine and saved a lot of money in labor costs. I have tried to post it on the forum but it won't take. If someone can post it send me an e-mail and I will e-mail it back. You could also do a C-12 valve adjustment search. I think someone else posted it for me about 2 years ago. Marty
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If you are getting the valves adjusted on your C12, there are also some Jake brake durability improvements that Cat has modifications for, that can be incorporated during the valve adjustments. Some of the later C12s have these built in, they will know by SN if you have these. I understand that these part changes are not expensive.
Later Ed
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William Jordan, Valve lash is not necessary if the measurement of the valve lash is in acceptable
range. Check the valve lash while engine is stopped. Note: the Correct valve lash setting for
C-12 engine. ( Intake Valves 0.015 +, - 0.003 ), ( Exhaust Valves 0.025 =,- 0.003 ) what
this is telling you ( there is 0.006 gap if feeler gauge will slide for adjustment, no adjustment is
necessary ). There has been many thoughts on correct setting of valve lash that been passed
around that is incorrect. Correct for lock nut torque if valve lash adjuster is moved is 22 +, -
foot lbs. Looking at your milage and removing valve cover checking adjustments more than
likely adjustment will not be necessary as per above info. with valve adjustments taking into
Cat specs the plus and minus measurement of intake and exhaust valves. Again there has been
many different thoughts on correct valve adjustment and again cat specs has not change from
above, Dave Atherton Retired Cat Mechanic
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Thanks Dave . At the company I work for, the tractor mechanics also felt I needed to do nothing . Since the initial check is to make sure its retained its proper setting, and with 115,000+ on the odo and no problems I'll assume it was right at assembly. .. I'll worry about it when it hits 300,000 ;-)
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Roy,
There is a modification that is posted on the forum that some coaches need for access to the center valve cover.
Gerald