Cylinder wall scoring

[Charles Bronson]

I'd file this under "Don't worry now, but let's keep an eye on this for a bit".

You can do a Google search and see that this isn't wildly uncommon and in many cases, isn't an issue.

Let's look at the facts with your motor and these motors in general:

1) You 4Runner isn't, and apparently hasn't, exhibited any driveability issues, misfires, oil consumption, smoking, spark plugs look fine, etc.

2) The 1GR-FE dual VVT-i engine is quite reliable. The most common major issue is a failed head gasket, but that isn't very common to the dual VVT-i motor that's found in the 5th gen 4Runner.


A year after I purchased my 2016 BMW M235, it started making a faint noise that sounded just like low rpm rod knock. The short block in the M235 is ~$12K alone. After some research and inspection, it turns out that a combination of the dual mass flywheel and self-adjusting clutch can be quite noisy as they get a little age. I figured out that I could make the sound go away by simply pushing in the clutch pedal. The car has made that sound for the last 5.5 years and 50K miles. Used oil analysis has been perfect. Point being, don't worry until there is really something to worry about.

 

[BlackWorksInc]

Thank you, i appreciate the effort. I hope others can share photos for comparison. I’m starting to really lean towards the valve seats leaking. Either way after 90k plus miles I don’t believe there shouldn’t be vertical score lines like this in an engine that doesn’t have future problems on its way.

So I'm tearing down a '19 4runner with about 31k on it to swap out the short block due to an oil galley leak. I got it all torn down ready to swap out and snapped a few pictures for you.

This engine has the same marks and "shadows" along the cylinder walls. You can't feel them with a fingernail or fine tipped pick they look more like burnish marks you'd see when someone superficially scuffs a polished stainless steel plate. My best guess is that they're burnish marks from when the engine originally "seated in/wore in" from minor variances in the roundness of the pistons, rings, and cylinder that are totally within acceptable factory tolerances.

 

[BigBlueSince82]

So I'm tearing down a '19 4runner with about 31k on it to swap out the short block due to an oil galley leak. I got it all torn down ready to swap out and snapped a few pictures for you.

This engine has the same marks and "shadows" along the cylinder walls. You can't feel them with a fingernail or fine tipped pick they look more like burnish marks you'd see when someone superficially scuffs a polished stainless steel plate. My best guess is that they're burnish marks from when the engine originally "seated in/wore in" from minor variances in the roundness of the pistons, rings, and cylinder that are totally within acceptable factory tolerances.

You are the best!!!! Thank you very much! I’m sure this topic has peaked some interest on here. I just hope you are 100% right. Keep the pictures coming, I’m interested to see how common this is.

 

[catrains]

you did the oil changes great and then you looked in to the cylinder well,,,,, I was repairing engines and the bores use a tool to buff it ..your picture works great ...
so you did not loose engine oil ...your engine is very good around 100K miles ..

 

[lewdog998]

You are the best!!!! Thank you very much! I’m sure this topic has peaked some interest on here. I just hope you are 100% right. Keep the pictures coming, I’m interested to see how common this is.

I checked my 20 with 48k miles....what I found was quite shocking....I did some research and figure as long as I don't feed it after midnight or install a water injection system on the truck, I should be ok.

 

[BigBlueSince82]

I checked my 20 with 48k miles....what I found was quite shocking....I did some research and figure as long as I don't feed it after midnight or install a water injection system on the truck, I should be ok.

Hahaha, mine was definitely fed after 12! Did you notice any oil in your intake manifold? I have way more then I would like. Definitely need a catch can installed soon.

 

[BlackWorksInc]

Hahaha, mine was definitely fed after 12! Did you notice any oil in your intake manifold? I have way more then I would like. Definitely need a catch can installed soon.

How much are you filling the engine and how are you checking the oil level afterwards? A little too much can result in some excess getting sucked into the intake via the PCV system.

 

[BigBlueSince82]

How much are you filling the engine and how are you checking the oil level afterwards? A little too much can result in some excess getting sucked into the intake via the PCV system.

Fill with 6.5 quarts. Check on level ground. I know the book says 6.6 but I figure there has to be some oil remaining, if not .1 quarts would not make a difference.

 

[Hammer0313]

Subscribed!

 

[baldrik78]

Clearly the answer to is to pull the motor, pull the heads, drop the bottom end and give it a good ol' dingleberry honing.

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[BigBlueSince82]

I was finally able to perform a compression test today and I believe the results couldn’t have been better. Hope I’m not corrected (fingers crossed). I used a digital tester and the results are as follows:
Left Bank:
186.5
188.5
186.5

Right bank:
192
196
186.5

Has anyone else performed a compression test recently? I’m not to sure what the compression pressure should be for the newer version of the 1gr VVT-i but I found that the older version standard and minimum pressure was 193psi and 148psi.

 

[2021nightshade4x4]

I was finally able to perform a compression test today and I believe the results couldn’t have been better. Hope I’m not corrected (fingers crossed). I used a digital tester and the results are as follows:
Left Bank:
186.5
188.5
186.5

Right bank:
192
196
186.5

Has anyone else performed a compression test recently? I’m not to sure what the compression pressure should be for the newer version of the 1gr VVT-i but I found that the older version standard and minimum pressure was 193psi and 148psi.

That’s a really narrow range. Makes my OCD happy.


Sent from my iPhone using Tapatalk

 

[BlackWorksInc]

From the FSM:

3. INSPECT COMPRESSION

(a) Warm up and stop the engine.

(b) Remove the intake air surge tank

(c) Remove the 6 spark plugs

(d) Disconnect the 6 fuel injector connectors.

(e) Inspect the cylinder compression pressure.

(1) Insert a compression gauge into the spark plug hole. (Procedure A)

(2) While cranking the engine, measure the compression pressure. (Procedure B)​

Standard pressure:

1400 kPa (14.3 kgf/cm2, 203 psi) or higher

Minimum pressure:

1100 kPa (11.2 kgf/cm2, 160 psi)

Difference between each cylinder:

100 kPa (1.0 kgf/cm2, 15 psi) or less

HINT:

Use a fully-charged battery so that the engine speed can be increased to 250 rpm or more.
Measure the compression in as short a time as possible.

(3) Repeat procedures A and B for each cylinder.

(4) If the cylinder compression is low, pour a small amount of engine oil into the cylinder through the spark plug hole and repeat procedures A and B for cylinders with low compression.

If adding oil increases the compression, the piston rings and/or cylinder bore may be worn or damaged.
If pressure stays low, a valve may be stuck or seated improperly, or there may be leakage from the gasket.
(f) Connect the 6 injector connectors.

(g) Install the 6 spark plugs

(h) Install the intake air surge tank

Note- I would make sure you're going wide-open throttle when you are doing your compression test, a lot of people forget that and it skews the readings.

Based on your results I'd say that's a healthy engine, I know a lot of people will point out that it's not near the "standard pressure" but it is worn in and I'm going to guess that the engine wasn't warmed up when you did the test. At the end of the day, what matters more is that the compression is decently above the minimum specification and more importantly that the variance between the cylinders is within specification.

 

[BigBlueSince82]

From the FSM:



Note- I would make sure you're going wide-open throttle when you are doing your compression test, a lot of people forget that and it skews the readings.

Based on your results I'd say that's a healthy engine, I know a lot of people will point out that it's not near the "standard pressure" but it is worn in and I'm going to guess that the engine wasn't warmed up when you did the test. At the end of the day, what matters more is that the compression is decently above the minimum specification and more importantly that the variance between the cylinders is within specification.

I think so too. But now that you posted that I have one concern. I removed the air intake tube but I did not have the throttle body positioned open. The engine was warmed up and brought up to temp before the test. I removed the fuses for ignition and fuel, obviously all the spark plugs. Are you implying that the throttle body should be propped open? Getting the feeling I need to do this again.

 

[RAVL 2016]

Those numbers look excellent but you should also do (or have done) a leak down test while you are at it. If that comes back good then you have nothing to worry about.

And as far as test procedure, if you want to get the concern behind you, maybe have all this stuff done by a Toyota shop. Then you know for certain. Peace of mind is worth something.

Again good luck!

 

[BigBlueSince82]

Alright so I performed another compression test and the results were higher then the first test. I believe the main factor for this was that I cranked the key 7-8 times per cylinder instead of the 5 I did previously. I also made sure to have the throttle body open as I performed the test. The extra 2-3 cranks definitely pushed the psi further before it topped out as I was getting similar readings as the first test with only 5 cranks. Definitely a dumb mistake. Not sure why I had 5 cranks stuck in my head. Might have been something i watched.

Left bank:
203
203
200

Right bank:
207
205
200

 

[Bmnorm2]

Great results. You definitely don't have a compression issue. I'm more interested in leak down.

 

[catrains]

Alright so I performed another compression test and the results were higher then the first test. I believe the main factor for this was that I cranked the key 7-8 times per cylinder instead of the 5 I did previously. I also made sure to have the throttle body open as I performed the test. The extra 2-3 cranks definitely pushed the psi further before it topped out as I was getting similar readings as the first test with only 5 cranks. Definitely a dumb mistake. Not sure why I had 5 cranks stuck in my head. Might have been something i watched.

Left bank:
203
203
200

Right bank:
207
205
200

again your engine is working great /............

 

[BlackWorksInc]

Alright so I performed another compression test and the results were higher then the first test. I believe the main factor for this was that I cranked the key 7-8 times per cylinder instead of the 5 I did previously. I also made sure to have the throttle body open as I performed the test. The extra 2-3 cranks definitely pushed the psi further before it topped out as I was getting similar readings as the first test with only 5 cranks. Definitely a dumb mistake. Not sure why I had 5 cranks stuck in my head. Might have been something i watched.

Left bank:
203
203
200

Right bank:
207
205
200

Gorgeous numbers! pumping air like a champ!

Yeah you always want to hold the throttle open (just mash the pedal down when you're doing the test) so that the engine can breathe at full capacity, if you have it closed you're essentially at idle (think difference between trying to breathe through a straw and just taking a breathe normally.)

 

[BigBlueSince82]

Gorgeous numbers! pumping air like a champ!

Yeah you always want to hold the throttle open (just mash the pedal down when you're doing the test) so that the engine can breathe at full capacity, if you have it closed you're essentially at idle (think difference between trying to breathe through a straw and just taking a breathe normally.)

Thank you for all the help and insight. I decided to change the oil early at 3k miles like my last oil change due to winter and higher idle times. Sending a sample to blackstone for some peace of mind. I also installed an oil catch can to see if that helps with the oil in the intake. Early signs show it will.

I have a theory to the scoring on the piston walls. I have a 2nd car that I have been using for work rather then my 4Runner, even though I would still end of taking it to work 50 percent of the time until the gas prices went Sky high. Then I was parking the 4Runner from Monday - Friday and only using on the weekends the last few months. Giving more time to allow the oil in the intake to drip all the way down and soak what ever carbon there was in the combustion chamber. This might have allowed the carbon to loosen up and tumble down onto the cylinder walls. It’s my best guess to all this.

But just to really raise some eyebrows. I have decided to increase the oil weight to 5w-30 by Quaker state. I know this has been discussed on forum before but I decided to give it a try thanks to the 540rat. I will send a sample of this to blackstone as well for comparison. Changing the oil to 5w-30 has decreased the typical 1gr chatter/clatter that they all have. Looking forward to the next oil analysis.