Adjusting valves

[IslandTractor]

Diesel engines do not suffer the valve face and seat erosion gasoline engines do, which is the main reason gas engines' valve clearances close up. Back-in-tha-day, when gasoline contained tetraethyl lead, the issue was not as severe, but with the advent of lead free gas, bingo. When manufacturers began using hardened valve seats and the metallurgy of the valves themselves improved, the issue lessened. I suspect the lubricating action of the diesel fuel reduces, if not eliminates the erosion

I'm not so sure that the metallurgy hasn't already caught up. Last time I had a valve job done was in 1977. I've owned at least ten gas powered vehicles since then and kept most until at least 150K miles.

 

[Patches]

I'm not so sure that the metallurgy hasn't already caught up. Last time I had a valve job done was in 1977. I've owned at least ten gas powered vehicles since then and kept most until at least 150K miles.

Exactly what I was trying to get across; lead free gas was federally mandated in '75, I believe, and it was then the issue began. The metallurgy didn't catch up for several years. I remember doing engine rebuilds on engines with either hydraulic or mechanical lifters where the seats and valve faces had eroded to the point of needing replacement, not refurbishing, as was not the case with pre-nonleaded fuel. Perhaps we might get some input from diesel mechanics as to the frequency of valve clearance maintenance on tractors, which is after all, what we're discussing

 

[winston1]

After pondering everyone's responses I decided to adjust my valves. Was raining this morning so I went at it. Took a few pictures for what it's worth. I removed the hood and later the muffler as I found the cover would not come out without the muffler being removed. A bit difficult reaching some of the bolts and nuts but that all went ok. I found #1 intake @ .008, exhaust @ .012, #2 intake .012, exhaust .015, I did not check #3 but know it was also excessive. Manual calls for .0039, I set all where a .004 would slide under but a .005 would not. Manual states to remove the timing window and set flywheel at TDC. The loader frame covers that window and I wasn't about to take the loader frame off for this operation. Watching the valves I know I was close to TDC when I checked and made my settings.

I don't know how many of you have the repair manual but I can tell you figure 70-80-10 is not correct. It shows exhaust valves closest to the front or gear case. They are just opposite. I am no Bobcat mechanic but have worked on enough engines to know the difference. I even tested it making sure senility had not over taken me. I had the glow plugs out which allows easy turn over using the fan belt. I first opened the front valve, blew air through the glow plug hole and sure nuff, it came out the air filter, I then opened the second valve, did the same and sure nuff, air came out the muffler. I wish I had made a video before and after as I think it ran a little quieter.

Finally, I am glad I did this, they did have much more clearance than I approve of. I did not remove the rocker arm cover gasket. It stuck to the head so I just put the cover right back on top of it and buttoned her up. It is a preformed gasket that probably sticks up 3/8" or so. Rambled long enough.

 

[IslandTractor]

Thanks for the write up and photos. Does the motor run any differently after adjustment? Had you noticed any difficulty starting etc before doing the adjustment?

 

[winston1]

Had not had any difficulties, it has been running fine. I only moved it from my garage into the tractor shed after making the adjustments. I don't expect any difference but as stating earlier I did think it might be a little quieter. If I notice anything different after running with a load for awhile I will report in. I guess the biggest reason I decided to adjust is because of the manual schedule saying 800 hours and I had 1700. Over twice the recommended. I'm glad I did it, now I have peace of mind.

 

[IslandTractor]

Peace of mind is always a good reason.

 

[dfkrug]

I found #1 intake @ .008, exhaust @ .012, #2 intake .012,
exhaust .015, I did not check #3 but know it was also excessive. Manual calls for .0039, I
set all where a .004 would slide under but a .005 would not.

That's interesting. My CK30 manual specs .25 and .30mm for the clearances. Equal to
.0098 and .0118 inches. Your specs are half that, and your tractor seems to be initially
adjusted at the same specs as in my manual.

I am used to seeing about .008" for both on other 3-cyl tractors.

 

[dfkrug]

Just found another spec. My engine is the 3A150 and has above specs. There is also an engine
called the TD1300 which has the .1mm clearances (.0039").

 

[winston1]

Hmmm! Reckon my manual could be wrong? I would sure hate to burn valves. I have run it hard since making the adjustments and it runs great. Looked back in manual and find the 225 and 235 both show .0039 and the 230 shows .0098 and .0118. I find this interesting. Wondering what would cause the difference in the similar engines.

Back again. Old age seems to cause my brain not to function well. Can you believe I had the rocker arm cover out and in my hand and didn't even notice. I was depending on the manual to be correct. There is a tag on the rocker arm cover with valve lash posted at .25mm intake and .3mm exhaust. Just what dfkrug shows as 0098 and 0118. Would there be consensus to believe the tag and junk the manual specs? Bad when you can't believe what you read. The tag on the engine states 3A165LWH which is what the manual shows. I may call Bobcat in the morning and try to get an explanation.

 

[dfkrug]

I would trust the valve cover #s over what's in the manual. Your 3a165 engine is
prob exactly like my 3a150, except for 1.6 liters instead of 1.5.