Cleaned Intake Valves Again

[Bladecutter]

Install a catch can and a bottle of Techron in the tank every couple of months.

What do you think either of those are going to do to reduce intake valve deposits on a direct injected engine?

The fuel doesn't hit the backside of the valve on the engine's intake stroke simply because it's a direct injected engine.
And second, there is ALWAYS oil sliding down the intake valve's shaft via the valve stem oil seal.
Primarily from the vacuum created by the intake stroke, but also by the splash feed as the valve train is oiled.

Weak valve stem oil seals are probably the biggest cause, but there's nothing that can be done to eliminate oil entry because the valve stem needs to be oiled.

 

[jetman]

What do you think either of those are going to do to reduce intake valve deposits on a direct injected engine?

It "has and does" on my GM port injected gasoline V8 LS engines, both with catch cans. I've had the intake manifolds off of 2 of my LS engines in the last yr after using Techron. I could see the cleaning pathway in the intake port runners, and not a speck of anything on the back of the valve heads.

The fuel doesn't hit the backside of the valve on the engine's intake stroke simply because it's a direct injected engine.

Of course there is. Nothing gets into the combustion chamber without going past the intake valve.

And second, there is ALWAYS oil sliding down the intake valve's shaft via the valve stem oil seal.
Primarily from the vacuum created by the intake stroke, but also by the splash feed as the valve train is oiled.

Weak valve stem oil seals are probably the biggest cause, but there's nothing that can be done to eliminate oil entry because the valve stem needs to be oiled.

With a healthy engine, there shouldn't be enough getting by the intake valve seal to leave deposits on the backside of the valve head.
198k miles on my 07 GM 6.2L, not a speak of anything on the intake stems or valve heads.

 

[Astro14]

It "has and does" on my GM port injected gasoline V8 LS engines, both with catch cans. I've had the intake manifolds off of 2 of my LS engines in the last yr after using Techron. I could see the cleaning pathway in the intake port runners, and not a speck of anything on the back of the valve heads.

Of course there is. Nothing gets into the combustion chamber without going past the intake valve.

With a healthy engine, there shouldn't be enough getting by the intake valve seal to leave deposits on the backside of the valve head.
198k miles on my 07 GM 6.2L, not a speak of anything on the intake stems or valve heads.

There is a big difference between a port injected engine, and a direct injected engine.

It has to do with - where the fuel goes in.

So, I really don’t see how a bottle of Techron is going to go past the intake valve in the OP’s engine.

It doesn’t. That’s what direct injection means.

You can pour anything you want into the fuel tank of the original poster’s direct injection vehicle, and that stuff goes directly into the combustion chamber.

Leaving the valve to potentially get oil on it from the PCV system or leaking intake valve seals.

 

[shortyb]

It "has and does" on my GM port injected gasoline V8 LS engines, both with catch cans. I've had the intake manifolds off of 2 of my LS engines in the last yr after using Techron. I could see the cleaning pathway in the intake port runners, and not a speck of anything on the back of the valve heads.

Of course there is. Nothing gets into the combustion chamber without going past the intake valve.

With a healthy engine, there shouldn't be enough getting by the intake valve seal to leave deposits on the backside of the valve head.
198k miles on my 07 GM 6.2L, not a speak of anything on the intake stems or valve heads.

Direct injected and port injected are 2 different animals. One washes the backside of the intake valves with atomized fuel (PI), the other one (DI) does not. Hence the deposits from oil, either breather vapor or stem seal seep, or both.

 

[jetman]

@shortyb and @Astro14 and @Bladecutter :
I stand corrected I thought reversion might be enough to clean some.

Then try this DI cleaning procedure:

 

[KrisZ]

With DI the only chance a cleaner can have any hope of being effective is if it's sprayed directly over the valves. Spraying through the throttle body has minimal to no effects because by the time the solvents get to the valves, they are mostly in vapor form.

Unfortunately the only way to spray the cleaner directly would be to drill small holes in the intake manifold and then plug them after the treatment. For Subaru, these location would probably work great, but I'm not aware of anyone that actually did something like this.

 

[Astro14]

I don’t own a Subaru - so, forgive my ignorance on the topic, but what would a shop charge to walnut blast this?

Looks like manifold removal, at a minimum, would be required. Which makes it expensive…

 

[shortyb]

@shortyb and @Astro14 and @Bladecutter :
I stand corrected I thought reversion might be enough to clean some.

Then try this DI cleaning procedure:

Yeah, depends on overlap I suppose. But even my VW Budack engine will not create enough to allow for any solvent laden fuel to wash back over the valves.

I bought a walnut blasting kit from ECS Tuning that I have done several other valve cleaning jobs with. Have paid for the kit with customer $$$ and beer. Chemical induction cleaning service has never produced good results for me. Have to do mechanical cleaning, ie; walnut/media blasting has ALWAYS worked the best. The valves and ports always look brand new after the blasting too.

 

[IndianaDIY]

On my '18 Forester XT with 42 K miles. This is the 5th treatment. (CRC) looking at Youtube videos it me be a waste of time. But for a total of 80 bucks. Better than nothing. I may do the walnut shell thing in another 10 k miles

Hi Al
Are you doing this in front (closer to engine) or behind (closer to filter) of the throttle body?
You can buy this cheap or use the other chemicals on the market
https://parts.subaru.com/p/Subaru__/ENGINE-MAINTENANCE-KIT/72845783/SOA868V9341.html

This guys video is pretty good



Me personally, I would, easiest DIY to hardest.
Run the upper cleaner the right way, clean the throttle body and mass air flow sensor, and replace the PCV Valve.
...all this as and I'm already there and keep oil out.
Pull your battery terminals off after and let it sit for an hour, a few hours, whatever.
If you don't, and you clean your throttle body it will idle wrong/bad as it is like "where did all my carbon go"
it needs to relearn.

Put in that subaru fuel cleaner or put some Lucas Deep Fuel System Cleaner in the fuel tank...why...well just because of the maintenance you are already doing.... though as someone else has said it won't help your valves as the fuel injectors is not behind the valves to spray this stuff on them.

Put some Amsoil engine flush...or similar in the oil, run it for a bit and change the oil. It cleans the top end as well. Then Italian Tuneup while you have that juice in your fuel tank.

Check for oil leaks on each of your valve covers and replace those yourself...its not a fun job...or pay someone to do it...and your spark plugs while you are at it...if you do do the cover gaskets that is.