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.
Hi
ReplyDeleteMy Name is Adrian and I live in Mexico, I hope write my quiestion correct.
I want to be a mechanic, Im still learning, but we (my boss and I)are having problems repairing an engine Cat 3116 because we don´t have the Caterpillar tune-up tools specially the Dial Indicator because is very expensive here in Mexico.
My quiestion is, there is another way to adjust the injectors with a Feeler Guage.
Thanks for yor page is very helpful for people like me.
Hi Adrian,
ReplyDeleteNo you can't get a proper adjustment from a feeler guage because the dial indicator is needed to read the height of the injector from the top of the spring to the bottom on the machined body surface when it's not on injection stroke. This has to be measured in millimeters with a .20mm + or - margin. This is an important adjustment since it effects timing and engine performance.
Greetings from New Mexico, USA. Have a quick question. A neighbor of mine has a Thomas school bus with a 3116 Cat and the rear end shelled. He removed and replaced the diffrential with a 373 when the orinal gear ratio was 529(?) and now he is saying he loses power on small grades. He is wanting me to turn up the power via the injector pump. I declined doing this job for reasons of possibly destroying the injector pump internally when one takes into account wear. Even though I declined doing this job is it possible to turn up the fuel flow to the injectors via the injector pump? I noticed a plug on the side of the pump with a triangle indent with a center post to prevent tampering like the anti-tamper torx screws-is this where fuel flow is regulated? Thanks and pretty intresting site-glad to see a mechanic who started a blog that could be useful. I have close to twenty years in the proffesion and am always learning something new.
ReplyDeleteJT
JT
ReplyDeleteThe only adjustment is the "full fuel" adjustment which is the amount of rack travel. This is usually wired and locked from the factory. It wouldn't be advisable to tamper with this adjustment without the proper tools.
The gear ratio is a drastic change from factory which will lug the engine when climbing grades. This will effect the engine performance as well.
Greetings John- Do you think it would be possible to do an overhead and regain some lost percentage of power? I advised him from the begining to replace rearend with factory correct but he decided on the different axle ratio.
ReplyDeleteAny other ideas on regaining power besides another diff swap?
JT
hi john my name is mike and i have a couple of questions regarding synchronizing the injectors on a 3116 cat motor is there a phone number where i can call you?
ReplyDeletethanks
I have a 3116 cat that i believe ran out of fuel. I re filled, changed the filter and it still runs rough then stalls. any ideas?
ReplyDeleteHow often do you have to adjust the valves on the 3116? I have searched online and can not find a consistent answer. We called a local truck repair center and they asked why you would even check the valves. The truck runs fine and just passed the 100k mark and we keep up with all maintenance to make sure they have a long, healthy life.
ReplyDeleteThanks, Jason
I recommend checking the valve adjustment at least once a year. If they run loose or tight that will severely effect performance. The top end is a weak part of the 3116 and valve adjustment must be manitained.
ReplyDeletehey jhon this info help me a lot i was able to do my boss 3116 just with the info you have here i found a used tune up kit for 250 bucks was incomplete but i was able to buy the rest of the tools i didn't know anything about caterpillar i usually fixe jhon deeres but this help was greatfull
ReplyDeleteI'm glad this information helped you out..
ReplyDeleteIf you want more information do a search on my blog in the search box top left hand corner for Cat 3116.
Lou d
Sounds like you may have developed an air problem in the fuel system.
Hi John,
ReplyDeleteI have a 3116 in my shop that has compression leaking into the fuel tank so based on your info I'm heading towards the injector cup replacements/ machining. As of now I don't have a repair manual on this engine so I was hoping you could give me an idea of how much of a job it's going to be. Do I need to pull the head and which is easier, having the old cups machined or installing new ones. Also which tools am I going to need to do the job. Thanks for your help and I really appreciate all the advice you've given through your blog.
If you can find a shop that does this work it would save you a lot of cash and downtime. The cups can be replaced in-frame but you need the right tools.
ReplyDeleteThe cups can be machined without replacing if they are reusable. Then you need a injector seating tool kit to reseat the injectors.
Do a search on my blog for Cat 3116 injector seating tool. I have a post about it.
I would phone around first and check with your Cat Dealer if any.
hi, i have a 96 GMC topkick. with 108,000 miles on it. the truck runs good, does not smoke. idles good. the problem i have is... when ever i go to start it, warm or cold. i have to hold the gas pedal down just a hair, like an 1/8" of an inch. and it fires right up. i can just turn the key without holding the gas, but it cranks for a very long time and it does finally start. any ideas? thanks john.
ReplyDeleteHi JohnnyK,
ReplyDeleteI've seen this same problem a few times and what happens is the governor rack is supposed to move slightly while cranking allowing enough fuel to start. Oil pressure (line running to the governor) moves the fuel rack. I would check out the line and make sure you're getting oil pressure. If that checks out the problem is internal which requires a reman governor $$$.If you're really brave you can try and disassemble the governor. I've done it before and it's kind of like taking apart a washing machine timer *%#$@^%$!!!
We have resigned to living with the problem since our 3116 engines are in spare buses.
Hi working on cat 3116, We dismantled clinder head replaced injectors copper sleves, We want to adjust valve and injector plus fuel rack, We need to buy tools can you please tell me were to buy anywere in europe,
ReplyDeleteThank you
lillian
Hi again its lillian
ReplyDeleteDo you ajust any other cat eng with the tools that i am looking for??
Timing Guage Block
Magnetic base
contact point
drop wrench
3116
Hi Lillian,
ReplyDeletethese tools are only built for the 3116 mechanical injection engines. I'm not sure about Europe for where to locate tools. If you can find a Caterpillar dealer in your vicinity they would be able to help you.
John whelan parabens pelo seu blog estou aprendendo muito aqui obrigado
ReplyDeleteeu quero fazer uma pergunta. Sobre fuel timing cada motor tem uma medida diferente?. E se não tiver timing na tampa de valvulas ? e se já perdeu? como se faz para regular os bicos injetores? muito obrigado
John whelan parabens pelo seu blog estou aprendendo muito aqui obrigado
ReplyDeleteeu quero fazer uma pergunta. Sobre fuel timing cada motor tem uma medida diferente?. E se não tiver timing na tampa de valvulas ? e se já perdeu? como se faz para regular os bicos injetores? muito obrigado
do you have the valve lash specs. for a 3046t caterpillar
ReplyDeleteIs it possible for the injectors to be grossly out of time. I set my dial indicator to 62.00mm, the rocker cover indicates the injector timing is 64.91mm. When I place the dial indicator on the injector, it reads 58.36mm. The engine has approx 200,000 mile on it, and to the best of my knowledge, no adjustments have EVER been made on it. Thanks in advance.
ReplyDeleteBarry
If you have the engine positioned properly you should be OK if all the injectors are reading the same. That's a lot mileage on them so over time the adjustment will go off base. If one was way out I would be suspicious of another cause.
ReplyDeleteHi, i have a 3116 engine in a 320L excavator, i replaced the injectors using a cat mechanic and it letting out too much smoke when ever it goes under pressure. The turbo was replaced, the fuel pressure is 60-80 psi. The engine do not boiled down whenever under pressure, but it smokes excessively. I even install new air and fuel filters. Any ideas of what we can do to correct this problem.
ReplyDeleteThank you
I don't know what the Cat Mechanic did but the injector seats should have been checked out and machined if required and the new injectors would have to be seated properly with a CAT seating tool.
ReplyDeleteI have a 3116 cat engine in my truck it was not firing and we were advice to change the injectors our mechanic discovered that only two injectors are bad( injector 1 & 6) he change it but injector 1 is not firing. After troubleshooting we discovered that it is the position 1 that is d problem not the new injector. So John what should we do???? please send me an e-mail (ibiobele@yahoo.com) with the solution. Thanks
ReplyDeleteanonymous-Concerning the 3116 engine I would look at the injector while the engine is running. Is it getting full travel out of the rocker arm? Is there a compression problem as in a bad valve? Is it a dead miss..absolutely nothing happening? Did you you check out the injector seat, the new injectors have to be seated properly with a CAT seating tool. You do not use the o-rings on the injector tips.
ReplyDeleteI have a 3116 in a snowcat and we thought it maybe missing. We took a Thermal camera an shot pics of the exhaust manifold. The front maifold temp was generally 125 deg celc and the rear half of the manifold was at around 245 deg C. Just got this machine and I am not familiar with it. What may be causing this?
ReplyDeleteIf the temp is lower than the rest their could possibly be a faulty injector or it needs a reset. Underfueling will cause a cooler temperature reading.
ReplyDeleteJohn I hve not got these tools in a "set" from caterpillar however I have the ability to make every part of this kit... Is it possible for you to provide some information on their use.
ReplyDeletei.e.
1 - does it measure from the machined surface of the head where the injector seats? or does it measure from the "lip" at the base of the exposed portion of the injector to the top of the spring?
2 - is the measurement on the valve cover the distance between those two points or is it what the dial indicator should read when in position pre calibrated by the stand
3 - does the stand measure out to be exactly the preset distance?
Please advise
You may contact me via email if you like Carl@subtechindustries.com
I'm getting to set valve lash and set the injectors in a 3116 engine. My cam and idler gear marks are alined and the left side timing plug has been removed. I see a hole in the flywheel, can I assume #1 tdc? The manuel calls for a bolt to be inserted, is this a special tool?
ReplyDeleteIt sure be nice to ask you some questions about the valve and injector timing. I ordered the tools and followed your directions. I didn't have the timing bolt or get directions from Cat. The manuels I have show a totally different way of setting the injectors. My truck starts and runs good, but it smokes and doesn't sound the the other 3116 cats we have.
ReplyDeleteIs this worth it?
ReplyDeleteWhen setting fuel timing at the injectors, does the dial indicator need to be in the reverse mode after presetting the guage with the guage block? When I don't put it into reverse mode, my readings are way off. I see in one of your photos the indicator is in "rev" mode.
ReplyDeleteWhen setting fuel timing at the injectors, does the dial indicator need to be in the reverse mode after presetting the guage with the guage block? When I don't put it into reverse mode, my readings are way off. I see in one of your photos the indicator is in "rev" mode.
ReplyDeleteSoldier 7
ReplyDeleteYes the TDC hole in the flywheel is an 8mm bolt. I would follow the manual where you're using the valve position to set the engine at the right spot. i.e. For #1 compression #6 has to be on the exhaust stroke. the ex valve will be just closed when the intake starts to crack open. STOP at that point and you are on #1 compression. Do the same following the firing order 153624. The manual should show you what valves and injectors can be set on #1 compression then on #6 compression.
Torino69Petty
ReplyDeleteYes the dial indicator is in rev mode.
hey john. I am attempting to set the fuel timing on a 3116 cat engine. I preset the indicator on the preset block to 62.00mm. my timing spec on the valve cover is saying 65.59. I install the indicator on the injector. when I go to adjust the injector I am turning the screw down pushing the spring down to get to 65.59. am I reading this backwards. I see above mentioned reverse mode for the indicator. should I be pushing the spring down on the injector to get that setting? I tried setting a couple but when I go to turn the engine over I am locking it when I get to the injector that I have adjusted.
ReplyDeleteIf you have preset the dial with block properly and set the engine position once you place the dial indicator on the injector it should be fairly close with minimum adjustment required. I would recheck your calibration and dial indicator.
ReplyDeleteHey John good morning we spoke several years back when i was attempting to adjust injectors on a 3116 anyhow the company that i worked for then ended up retiring the Bus, so my mission was half completed, it seems some what confusing or i might be overthinking the situation any ideas on the steps i need to take to adjust the Injectors. 3116 CAT
ReplyDelete