Wednesday, December 22, 2010

How To Set Valves & Injectors - Cat 3116 Diesel Engine

Diesel Mechanic Tips:

Today I am going to show you how to adjust the valves and injectors on a Caterpillar 3116 Diesel Engine. The injectors are mechanical and are checked and adjusted manually using the appropriate Caterpillar tune-up tools.

Here are the tools needed to perform the valve and injector adjustment:

Caterpillar Part #'s

*Dial Indicator # 1U-8869

*Contact Point # 9U-7274

*Feeler Guage # 123-4941

*16mm/18mm Drop Wrench # 128-8824

* Timing Guage Block # 9U-7269

Magnetic Base # 123-4940

Setting the valves and injectors is a preventive maintenance operation and should be done on a regular basis. Once you get through one setting it's a cakewalk the second time around. Below is the dataplate that tells you the timing specification for setting injectors.


The dial indicator has to be pre-set so it reads 62.00 mm when placed on the timing guage block as shown below. These tools come with the complete Caterpillar tune-up kit with detailed instructions included.



The first thing to do is rotate the engine over until # 6 cylinder valve rockers are rocking. Watch # 6 valve rockers as you are rotating the engine, keep turning the engine until the exhaust valve closes and the intake valve JUST starts to open. Stop there, # 1 cylinder is now on the Compression Stroke and ready for valve adjustment as well as the other designated injectors and valves.

*Adjust 3-5-6 injectors to timing spec. / in this case 65.74 mm / + or - .020 mm

*Adjust 1-2-4 intake valves .015 in.

*Adjust 1-3-5 exhaust valves .025 in.

Rotate engine over 360 degrees and adjust the other remaining valves and injectors. # 6 cylinder is now on compression stroke since #1 and # 6 pistons are always at TDC [top dead center]together.

*Adjust 1-2-4 injectors

*Adjust 3-5-6 intake valves

*Adjust 2-4-6 exhaust valves

As you can see from the above picture the magnetic dial indicator holder sits on top of the injector. The dial indicator measures the distance from the top of the injector to the machined body surface at the bottom which must be set correctly. This dimension effects injection timing and can be adjusted at the injector rocker arm set screw.

I hope this post helps out all you Cat 3116 owners. The valve and injector adjustment is probably the most crucial as adjustment can change with normal wear and tear as your diesel engine racks up the mileage.

That's all for now, thanks for visiting and be sure to check back for more Diesel Mechanic Tips.


10 comments:

Anonymous said...

Have you had any experience with a Cat 3126 engine? Have flash codes on dash check engine lite. codes 15&39. What should I be looking for? Realize I am poking in the dark w/out electronic tools. Could the IAP valve be causing the problem as the engine has 94000 miles on it? Have changed the IAP sensor which didn't help. The IAP valve solenoid has the correct resistance.

J. E. Whelan said...

Yes I have had problems with the HEUI system. It was a no start problem and we replaced the Heui pump.

I can't tell you what those codes are, what are the symptoms and is there a shop you could go to for a quick scan of the codes?

This in the electronic age with diesel engines, laptops and OEM software is upon us. This would get you started in the right direction...

Paul said...

Hi can you let me know where I can get hold of the calibration kit to do the job.
Thanks Paul

irfan said...

Dear Jhon,
I have 3116T engine in my Wheel Loader 950F II series.
I am facing strange problem. If its cold it will start fine and quick and run smooth.
But if i shutdown the engine then it will never start but only after it become cold.
Can you tell me whats the problem. i have changed all the filters, checked for air but return feul is without air bubbles
pls suggest.

Irfan.

Ed said...

If the head is replaced, how much should be added to the fuel timing???

Ed said...

How much should I add to the fuel timing spec if the head was replaced???

Anonymous said...

I live in Jamaica and would to contact other mechanics who repair Cat 3116 engines like myself. Johnny
johnny_shim@yahoo.com

John Whelan said...

Paul, The calibration kit was found for us through a Cat dealer.

ED, If the head was replaced there won't be any timing changes required. I've never changed timing and had no problems after replacing the head.

Johnny, just keep posting comments here on my blog and I will get back to you.

Tony said...

Tony said, Can someone tell me the valve settings for a 3126 b engine.Would it be the same as the 3116? Thanks

John Whelan said...

The intake valves set to 0.015 thousandths of an inch. The exhaust sets to 0.025 of an inch.

There is a bolt hole in the flywheel housing on the turbo side of the engine. This is used to put cylinders one and six on TDC.

Rotate the engine clockwise from the front while holding a small bolt or screw driver in the bolt hole. When it goes in to the flywheel bolt hole, the engine is on tdc.

If the intake and exhaust valves on number one are both loose, you set the lash on the intake valves on cylinders 1,2, and 4. Then set the exhaust valves on cylinders 1, 3, and 5.

Then rotate the engine 360 degrees.


Then the valves on six should be loose. Then you adjust the intake valves on cylinders 3,5, and 6. Then also adjust the exhaust valves on cylinders 2,4, and 6.