Valve adjustment info found under hood (Periodic valve adjustement required?)

[Eggman]

Hi Eggman,

I have read the thread, but since there is a service bulletin and it says in the manual specifically referencing the 39A engine, I would bet that this is something that would be worth doing.

Cant remember where but another member linked the attached service bulletin.

I would say I like to see and do something myself after appraising the available literature.

If the valves are not adjustable will report back the findings.

I understand and appreciate your concern about the valvetrain, and your drive to get to the bottom of it.

Looking forward to learning more about your findings. When do you think you'll tackle this?

[sunbeam]

Aiming for spring or summer. Will also give the chance to put more miles on the car haha.

[Fummins]

You can “adjust” the valves. As mentioned in this thread. Remove the camshafts, then replaced the cups that fit between camshaft and valve. I’d sure like to see this service bulletin you mention. Facebook group maybe? Here, you can study this picture and search for the adjusters. Hopefully this helps.
Attachment 26358

Attachment 26359

If anything, you get to see the differences in camshafts over the years. Top pic is what a 2014-2015 camshaft looks like.
The bottom pic is a 2017+ Cvt engine. I believe the 2017+ 5speeds only had rollers on either the intake or exhaust cam for some reason. I don't have a pic of one of those engines.

[Mark]

You can “adjust” the valves. As mentioned in this thread. Remove the camshafts, then replaced the cups that fit between camshaft and valve. I’d sure like to see this service bulletin you mention. Facebook group maybe?

My 2017 Owner's Manual handles the topic this way -

Inspect & adjust valve clearance* for 3A9, 4B1, 4J1, & 6B1 engines**.

* Check valve clearance in case abnormal noise is heard from valves.

** Refer to the "Specifications" section of your owner's manual for your applicable engine model.

The boxes are checked every 30,000 miles on the maintenance schedule.

I believe this is what he is referring to?

Are Mirage owners having their valves checked every 30,000 miles?

I had that done with my 1989 Plymouth Colt Wagon, which was entirely a Mitsubishi.

I have not bothered to have it done for my 2017 Mirage, which is at approximately 84,000 miles.

[skyblueII]

Can someone do a deep dive into 3a92 valve adjusting!

[Fummins]

Sure. Check clearance then replace these as needed. They come in different sizesAttachment 26365 but if it’s not ticking, just leave it alone. The engine I just tore down with 450,000 have no visible cam or cup(lifter looking deal) wear.
Pull the balancer, timing cover, timing chain, valve cover, camshafts, then you can see the cups. It’s easy, I don’t get why everyone doesn’t do this.

[7milesout]

Pull the balancer, timing cover, timing chain, valve cover, camshafts, then you can see the cups. It’s easy, I don’t get why everyone doesn’t do this.

I agree. And while you're in there, you can shoot for the minimum specified clearances. Converting to good old inches, the intake cam to valve bucket clearance is 0.0087 ± 0.0016 inches (minimum clearance = 0.0071 inches). Exhaust is 0.0118 ± 0.0016 inches (minimum clearance is 0.0102 inches). So set them at 0.0071" and 0.0102" respectively.

Once set it at these minimum clearances, you're probably going to pull another 0.16 horsepower. When we have our ALL MIRAGE dragrace, those who do this will be KINGS.

On the other hand, if I were to hear a ticking sound, and decide to adjust the valve clearances, I'm guessing that if I went through this exercise, microscopically all my valve clearances (except the one that was out of spec and adjusted) would slightly increase ... because I'd likely not get it back together as well as it was to start with.

[Fummins]

I agree. And while you're in there, you can shoot for the minimum specified clearances. Converting to good old inches, the intake cam to valve bucket clearance is 0.0087 ± 0.0016 inches (minimum clearance = 0.0071 inches). Exhaust is 0.0118 ± 0.0016 inches (minimum clearance is 0.0102 inches). So set them at 0.0071" and 0.0102" respectively.

Once set it at these minimum clearances, you're probably going to pull another 0.16 horsepower. When we have our ALL MIRAGE dragrace, those who do this will be KINGS.

On the other hand, if I were to hear a ticking sound, and decide to adjust the valve clearances, I'm guessing that if I went through this exercise, microscopically all my valve clearances (except the one that was out of spec and adjusted) would slightly increase ... because I'd likely not get it back together as well as it was to start with.

If it doesn't run after then it's probably because you aren't running premium fuel. After valve adjustment the compression ratio will be increased so the blinker timing might have to be synced as well so as not to throw off the balance of the cam phaser. This can be accessed via etacs. If this step is ignored cvt, or if a 5speed-clutch damage may occur. Trust me.

[sunbeam]

From the section 11B in service manual, confirming what @Fummins said earlier, manual says to adjust valves replace tappets.
Step 12 in bold (emphasis mine).

Thanks Eggman for providing the links to the more detailed service manuals.




Measure the valve clearance as illustrated.
1.Set special tool crankshaft adapter (MB992000) to the crankshaft, and install the crankshaft pulley center bolt and washer.
CAUTION
The crankshaft should always be rotated clockwise.
2.Rotate the crankshaft clockwise until the mark on the camshaft sprocket exhaust is aligned with the mark on the upper surface of cylinder head. (Set the No. 1 cylinder to TDC on the compression stroke.)
3.Make paint marks on 3 places at the camshaft sprocket exhaust by means of the following procedure as shown in Figure.
(1)Make a paint mark on the place of 65 degree angle (6.5th tooth) in the counterclockwise direction of the timing mark.
(2)Moreover, make a paint mark on the place of 120 degree angle (12th tooth).
(3)Also, make a paint mark on the place of 120 degree angle (12th tooth).
NOTE:
The space between the teeth of the camshaft sprocket exhaust is 10 degree angle.
4.Turn the crankshaft clockwise and locate the paint mark of the camshaft sprocket exhaust on the upper surface of the cylinder head as shown in figure.


5.The valve clearances (arrows) shown in figure are measured.
6.Using a thickness gauge, measure the clearance between the cam base circle and the valve tappet.
If the measured value does not conform to the standard value, record the measured value.
Standard value (cold engine):
Intake valve 0.22  0.04 mm (0.009  0.001 inch)
Exhaust valve 0.30  0.04 mm (0.012  0.001 inch)
7.Turn the crankshaft clockwise and locate the paint mark of the camshaft sprocket exhaust on the upper surface of the cylinder head as shown in figure.
8.Measure the valve clearance at the location shown with an arrow.
If the measured value does not conform to the standard value, record the measured value.
9.Turn the crankshaft clockwise and locate the paint mark of the camshaft sprocket exhaust on the upper surface of the cylinder head as shown in figure.


10.Measure the valve clearance at the location shown with an arrow.
11.If the measured value does not conform to the standard value, record the measured value.
12.Replace the valve tappet for the valve whose clearance is out of the standard value.
NOTE:
Valve tappets are available in 31 sizes, at 0.02 mm (0.0008 inch) intervals in the 5.10  5.70 mm (0.2008  0.2244 inch) range.
13.Valve tappets should be selected in the following manner.
(1)Remove the valve tappet and measure its thickness.
(2)Calculate the correct thickness for a new valve tappet as follows that achieves the standard valve clearance.
A: Thickness of new valve tappet
B: Thickness of old valve tappet
C: Measured valve clearance
Equation:
Intake valve: A = B + [C  0.22 mm (0.009 in)]
Exhaust valve: A = B + [C  0.30 mm (0.012 in)]
For removal and installation procedures for the valve tappet, refer to P.11B-40.

[Basic]

I know you aren't a bot, but you act just like a bot... no human would post what you just did and continue to stand on this island of futility you have landed on... truly fascinating.