valve adjustment on CAT 3116

[Aernan]

I have no written documentation I'm just going by my cat over the road buddy who gave me the 100k overhead interval, but it isn't hard to stick in a set of feeler gauges to check and verify if an adjustment needs to happen sooner.

On some other posts people talk about replacing the valve cover gasket. Do you think that is necessary every time I get in there?

 

[Awesomeness]

On some other posts people talk about replacing the valve cover gasket. Do you think that is necessary every time I get in there?

I would. They aren't very expensive, and they seem to be a part that frequently springs an annoying leak (not really frequently, but far more valve cover gaskets go than head gaskets, or other things). For $20, it's just good practice to change it.

 

[Aernan]

I would. They aren't very expensive, and they seem to be a part that frequently springs an annoying leak (not really frequently, but far more valve cover gaskets go than head gaskets, or other things). For $20, it's just good practice to change it.

ok after some google searching I found the local cat dealer has it for some $38 and I did find one for under $20 shipped so that's a good deal. Is there any pressing reason the dealer sells parts so much higher than available elsewhere? Should I worry about getting sub standard parts?

 

[tennmogger]

This Cat parts store is local to me and has been very helpful getting parts at good savings.

https://www.offroadeq.com

They buy up excess inventories of Cat stuff for resale. Nice people too.

 

[Aernan]

This Cat parts store is local to me and has been very helpful getting parts at good savings.
https://www.offroadeq.com
They buy up excess inventories of Cat stuff for resale. Nice people too.

Wow I wish I knew earlier. The gasket is half what I paid.

 

[Reworked LMTV]

Here's what an experrienced 3116 mechanic says....

With regard to valve adjustments, please read this info. from a bus mechanic on the 3116: http://schoolbusmechanic.blogspot.com/2009/10/cat-3116-diesel-engine-synchronization.html

 

[Aernan]

With regard to valve adjustments, please read this info. from a bus mechanic on the 3116: http://schoolbusmechanic.blogspot.com/2009/10/cat-3116-diesel-engine-synchronization.html

Yeah I found that great post.

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[Aernan]

I finally found one big reason for my poor performance. The previous owner put in a floor mat that was preventing the peddle from going all the way down.

My max rpm went from 2400 to 2700 in neutral. I still need to find that missing 1000 rpm. It also now shifts great at 2500 under full throttle acceleration.

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[Awesomeness]

My max rpm went from 2400 to 2700 in neutral. I still need to find that missing 1000 rpm.

I'm pretty sure the engine is governed at 2700. So I don't think you're missing any RPM any more.

 

[Aernan]

I read somewhere the governed RPM should b 2800 with the actual red line being 2900 but I'm not sure where I read that. It seems plausible it's supposed to be 2700 given how precisely my engine went to that speed. I guess all this concern about adjustments and impairments was unnecessary.

I'm still going to swap my fuel filters because they look antique and I don't know when the last owner changed them. I also plan on running some fuel injection cleaner because it can't hurt. The tools for a valve adjustment are still on order including a valve cover gasket. When time allows I might still go in there and check things.

I am still unable to find the recommended valve adjustment interval in the TMs or anywhere Cat official. I would like to call the local CAT dealer but I have still not located the engine serial number. It's not on top of the engine so I now need to find the one ground/stamped into the engine. My new hunting spot is under the compressor on the drivers side. I plan on using a mirror. I have a really early truck so it's anyone's guess where the serial is on this motor.

 

[Awesomeness]

I have still not located the engine serial number.

Maybe just use someone else's serial number who has a truck of similar age? My `97 M1078A0 engine was 7AG04876.

 

[Adventure Driven]

Adjusting my valves now, no special tools needed

Seth

 

[Pointman0853]

Interesting... 2 questions:

What/How did you rotate the crank to bring each rocker up to TDC when adjusting.
What are the cold specs for the adjustment?

Pointman

 

[Aernan]

Interesting... 2 questions:

What/How did you rotate the crank to bring each rocker up to TDC when adjusting.
What are the cold specs for the adjustment?

Pointman

You can put a wrench on any belt driven accessory to rotate the engine. The intake/exhaust tolerances should be on a build plate on the engine.

 

[Aernan]

ok found it. It's in TM 9-2320-365-34-2 section 3-103
Intake - 0.015 in. (0.38 mm)
Exhaust - 0.025 in. (0.64 mm)

Ranges:
Intake - 0.012 - 0.018 in. (0.30 - 0.46 mm)
Exhaust - 0.022 - 0.028 in. (0.56 - 0.72 mm)