Lessons in Valve Adjustment

[Favunclerich]

I have a 2008 R-25 with the Yanmar 110 HP 4JH4-HTE. It's been running fine, but I'm approaching 1000 hours, so I decided to have my valves adjusted per the owner's manual schedule. The local Yanmar mechanic came to the boat. It took him a little over an hour and about $80 in parts (valve cover gasket and fuel injector to valve cover seals). Of the 16 valves, he found 10 OK as-is, 4 a little loose and 2 a little tight. He made adjustments, buttoned it up and and we tested it at the dock. Everything seemed to be running fine.

The next day, we took some friends out for a cruise. The peak RPM at full throttle had dropped from the normal 3200 RPM to 2900 RPM, and the engine was running warmer than normal. I dove the boat to see if I was dragging something and checked the cooling intake, sea strainer and impeller. Everything was fine.

I called the mechanic back and they came out a couple of days later. This time there were two mechanics, and the guy who had done the work originally was now the assistant. They readjusted three valves, and we took a test run. Performance was back to normal. It's possible that the second guy adjusted the valves back to where they were originally. There was no charge for the return trip.

Here are the lessons;

Peak power performance is very much a function of valve adjustment for this engine. It seems rather sensitive to accurate adjustment.

If the valves had really needed adjusting in the first place, there should be some symptoms like smoke or clattering of decreased performance.

This education cost me about $300, but I'm sharing it here for free.

By the way, the owner's manual also says that I'm supposed to have the fuel injectors removed and have the spray pattern tested on some machine. Yeah right. Like that's going to happen.

 

[trailertrawlerkismet]

Rich:

Sorry to read of your unneeded financial expense but glad to hear they corrected it with no additional charge. As it relates to performance and maintenance I learned from a veteran boater some time ago to run periodic test and log the results. As an example I'll run my engine at idle, 1,200 rpm's, 1400 rpm, full speed, and other rpm's and keep a log of the speed, engine and trans temp., mpg, gpm, etc and compare my base original results with each subsequent test. The benefit of this procedure is that you'll know something may be going wrong when your test numbers change. This procedure obviously doesn't tell you what the problem might be but it can help a technician get to the problem quicker. It may also help a boat owner notice an engine problem when it still might be under warranty.

Jim

 

[NewMoon]

FWIW,

I've adjusted a bunch of valve clearances, on cars, motorcycles, and my 24-valve Cummins truck, and have watched them done a few times on my Volvo KAD44 boat diesel. My experience suggests that for the diesels the first time may be the most important, to get them just right after they've been worn in a bit. I noticed a bit smoother running with a little less clatter after the first one or two adjustments on the diesels, but before they were done there was no obvious problem. I would not assume the Yanmar needed no adjustments. If the injectors had a problem, I would expect to notice it.

Subsequent adjustments often involved more checking than adjustment, but for me they were worth doing on engines I wanted to run their absolute best, to work hard and yet live long lives (5100 hours on the boat so far). I can do my Cummins in 45 minutes, with no parts required. The Volvo takes more like 2 hours, mostly in getting stuff out of the way and back on again.

 

[baz]

Rich:

Sorry to read of your unneeded financial expense but glad to hear they corrected it with no additional charge. As it relates to performance and maintenance I learned from a veteran boater some time ago to run periodic test and log the results. As an example I'll run my engine at idle, 1,200 rpm's, 1400 rpm, full speed, and other rpm's and keep a log of the speed, engine and trans temp., mpg, gpm, etc and compare my base original results with each subsequent test. The benefit of this procedure is that you'll know something may be going wrong when your test numbers change. This procedure obviously doesn't tell you what the problem might be but it can help a technician get to the problem quicker. It may also help a boat owner notice an engine problem when it still might be under warranty.

Jim

Jim: That all sounds very well, but how do you establish a base speed with varying tides & currents over time, along with hull surface condition as well as boat laden weight etc ? I do like your approach and this will be something I plan on doing. Also, over time I suspect an engine's performance to lower simply due to wear and tear.

In addition, I would think a more exact test baseline should be made immediately prior the the boat's engine maintenance and then compare that with the same test immediately after the boat's maintenance.

I've found that it's always wise to check things after maintenance has been performed, be it a boat or some other mechanical/electrical product.

I've collected a number of tools from my car's engine bay over the years... :lol:

 

[trailertrawlerkismet]

Barry:

Sorry I forgot to menton that I also log in if I'm in salt or fresh water, with or against current and what the general weather conditions are. As far as hull condition and weight I just assume I'm always about the same.

Jim F

 

[Levitation]

Rich, an education is only worth what it cost you.
Musta been a good one.
I'm leaning the other way. We have diesels that have not had the valve lash checked in thousands of hours. If it ain't broke, we ain't fixin.
After my last education at the hands of a 'certified' CUmmins mechanic, it will be a long time before they touch it again.
(look how smart they made me with just one lesson :roll: )

 

[knotflying]

Also according to the manual you are supposed to adjust the valves when the engine is cold. I seem to remember when I woked on gas automobile engines we adjusted the valves after the engine warmed up and while it was running. We would just slip the feeler guage in and thighten until you could not remove the gauge. Seems to be a bit different on the Cummins.

 

[baz]

For my MY2010 R-25 with the Yanmar 4BY2-150 engine I see that valve adjustment is unnecessary per their Service Manual. The valves are hydraulically operated and self adjusting.

 

[knotflying]

Yes, that is correct on the Yanmar 4by2's The poor Cummins guys don't have that advantage. The 4by2 is mostly preventive maintenance. All the other stuff requires computers and special equipment.

 

[baz]

Yes, that is correct on the Yanmar 4by2's The poor Cummins guys don't have that advantage. The 4by2 is mostly preventive maintenance. All the other stuff requires computers and special equipment.

Off topic here...

I wonder how the Volvo 200HP D3 engine in the newer R-27s fairs in this regards? I know it does not have anodes.

As an aside, I'm positive that Yanmar mechanics performing the 'preventive' maintenance on our 4BY2-150 engines are likely to cut corners and not check all the items the Yanmar Service manual states should be. I had to insist my mechanic check my raw water impeller for wear and tear and replace if necessary. Had I not, I'm sure he would not have done that.

For example, my manual states for each 250 hours

• Draining Water and Sediment from Fuel Tank
• Replacing the Fuel Fine Filter
• Replacing the Fuel Filter / Water Separator Element
• Changing the Engine Oil and Replacing the Engine Oil Filter Element
• Checking / Replacing the Seawater Pump and Alternator Belts
• Replacing the Anodes
• Checking or Replacing the Seawater Pump Impeller
• Replacing the Turbocharger Heat Shield
• Checking the Exhaust / Water Mixing Elbow
• Replacing the Air Filter Element
• Cleaning the Turbocharger Blower
• Checking / Changing the Alternator Belt
• Checking / Changing the Power Steering Fluid • Checking the Shift Cable Adjustment
• Adjusting the Propeller Shaft Alignment
• Checking the Hydraulic Oil Cooler
• Checking or Replacing Rubber Hoses
• Checking the Flexible Engine Mounts

I had to insist/ask that the red items be done (and loaned my special wrench for the lower mounted anode) and the blue one was done at 50 hours but not done for the 250 hour one.

I have to wonder if the Yanmar 4BY2-150 Engine Service manual needs updating. It's information is fixed in time of publishing and maintenance statements presumably can change with the passage of time. This may be evident when chatting with the service mechanic who says "Oh -- that no longer needs to be done....". 😉

 

[mspaugy]

I was a diesel mechanic for over 27 years in the USN. That does not by any stretch of teh imagination make me an expert in this subject. We used a program called ADETA. It was a diesel engine trend analysis program. It was critical that conditions were as close as possible from each test to the next. We always recorded sea state, wind etc. If the sea state was not conducive to performing our trend analysis we did not do it until conditions were right. Each test was done for an hour after the engine reached operating temperature and all parameters were recorded and then graphed on a sheet of graph paper to show if anything was changing. Each parameter had it's own sheet.

If the tech manual recommends adjusting valve lash then it should probably be done (IMHO) because it may be too late to do it when valves start clattering or the engine starts smoking. Paying someone to tune up your engine will almost always be less expensive than paying someone to overhaul it or in extreme cases replace it.

As far as injector testing, it may surprise you to find out that replacement in many cases may be cheaper than testing. We did not test small boat injectors as far as pulling them out and spray and pressure testing on our injector tester and small was quite a bit bigger then Rangers Yanmars and Cummins. We only tested large propulsion engine injectors and most of the time only when trouble was suspected. On the smaller Detroit engines we were able to cut out an injector while running the engine with the valve cover off to see if the injector was operating. The engine noise would not change if the injector was bad.

Many small diesel engines built today do not have individual cylinder injectors. They have an injection pump and a unit injector that injects atomized fuel into a manifold to each cylinder. Many small engines also have individual cylinder fuel nozzels rather than injectors. The nozzles could very easily be changed by anybody.

 

[knotflying]

mspaugy,
Not sure about the Cummins but the 4BY2 engine is a common rail and has individual injectors that are controlled by the computer. The system is fairly sophisticated and even measures the temperature of the fuel and adjusts timing and injector flow for maximum efficiency. Mack Boring in the NE, I was told, is the only one who has the equipment to test the injectors and recalibrate them. I have never inquired what the cost is for testing V replacement and hopefully never have to.
Another point of interest is that these engines are marinerized BMW engines. The 6BY2 is a BMW X 3.3.OD and the 4BY2 is a BMW X3 2.OD
Mike Rizzo