tomekz

How Well Do They Actually Work?

IndigoInkTaco

Short answer, is no IMO. I think a lot of people at the local parts store think they can buy one can of this stuff and they'll have shiny new intake valves. Drive the car hard, use good gas and don't sweat it......oh, and hope you have port injection if clean valves is the goal lol.

TMc993

I agree that if one uses 93 octane of a premium brand of gasoline, that there's nothing to be gained by using these products. I do wonder, however, about the "Drive the car hard..." part. I'm not sure that this isn't lore passed on from the days of low quality leaded gas, manually adjusted carburetors and valves and low voltage ignition systems.

It's true that with those old cars, extended high RPM runs up and down through the gears, commonly known in my world as an, "Italian tune-up," would work to "blow the soot" out and clean deposits off of plugs and, to a lesser extent, valves. I used that "tuning technique" on my 356, 912, and even my 993 regularly and with good success.

Yet, I wonder, given today's cleaner fuels, along with computer-controlled fuel-injection, ignition and exhaust systems, if there is any evidence that driving "hard" is any more effective at keeping an engine running well than simply driving distances long enough to really heat up the engine components. I know spurts of WOT are more fun than an hour at 50-70 MPH, but wonder if it really makes a difference.

Just thinking over morning coffee...

KBell

Agree with above.

To summarize video, I could barely tell any difference from before and after treatment.
The carbon buildup on the valves stayed the same.

okie981

Using any of these products and/or using high quality 93 octane gas will not prevent carbon buildup on the upstream side of your intake valves in your 981 Boxster/Cayman. Nor will driving the **** out of your car on a regular basis. I know this from experience with my own 981 that I've owned since new. Used only Top Tier 93 octane fuel since new. Also used only motor oil with low vaporization qualities since new. Also did 34 track days in the car where it spent plenty of time at WOT and high RPM. Also drive to redline on a regular basis during extended street drives. Also inspected my intake valves at a little over 50k miles on the car and found plenty of carbon and gunk buildup on the valves. Tried several of those products in a can when I attempted to manually clean the valves. Some of them do loosen the gunk and dissolve some of the gunk, but zero of them remove the gunk by themselves even after soaking all night. It takes mechanical blasting with walnut shells and scraping with metal tools to remove appreciable amounts of the gunk. I posted a thread about this in this forum in Spring of 2022, with photos. I also installed a catch can as an experiment to see if it helps reduce future buildup.

See here: https://rennlist.com/forums/981-foru...tallation.html

Larson E. Rapp

Not disagreeing with the overall conclusion that mechanical cleaning is better, but that video is a joke. His methodology has nothing in common with the environment inside a running engine, where the cleaners are designed to work.

You might as well evaluate laundry detergent by putting it in a bucket and soaking clothes in it.

MrMoose

So there may be a good out-of-car test for these cleaners, but this test ain't it. Several of those products use PEA (poly ether amine, the same stuff as in Techron) which is an extensively studied and used detergent additive in most (all?) gasolines. I absolutely guarantee that that will remove valve deposits in running engines if it can get to the valves. So it doing nothing at all in these tests is telling me the test has issues.

Here's the thing to remember: PEA is not a just physical cleaner, it is a chemical cleaner. The nitrogen in it chemically reacts with the buildup, and this requires the high temperature environment in the engine. So the main problems I can see with this test:

- It's unclear that he actually got the valves hot enough. I don't know the valve temperatures in an operating engine either, but close doesn't cut it: 300F vs 500F is a HUGE difference in reaction rate, and if he got it wrong the test is invalid
- Even if he did get the valves hot enough, he's dropping them in cold liquid and they cooled down in seconds. So for almost all of the test period the cleaner is doing nothing
- He's using liquid cleaner rather than vaporized cleaner in air. I'm not an expert the exact method by which PEA works, but if it involves combustion of the carbon then it isn't going to work with out oxygen being present. Dunking it in liquid means no oxygen

So I don't know if these cleaners work in DI engines, but this is a crap test and you should not draw any conclusions from it. Again, you can't just soak in this stuff, it doesn't work like that. The only test I would fully trust would be to inspect the valves with a borescope, do the cleaning, and then re-inspect the valves after in-situ.

With all that said, here's my opinion: I have seen professional rail-based and intake-based cleaning effectively clean valve and piston deposits off multiple cars and make a difference in running and idle. Rail-based are the setups where the cleaning solution is hooked up to the fuel rail and sprays through the injectors; intake-based is like the BG Products system that uses a sprayer into the intake. Obviously the rail-based systems won't help with valves on a DI engine, but I see no reason the intake-based cleaning system couldn't also help on a DI engine.

So my hypothesis is that these spray cleaners *could* work effectively on DI engines, but I have no personal data so far. If I were having an issue, they're cheap enough that I'd give one a shot and see if it made a difference given how much easier it is to try than walnut blasting.

okie981

Using them in a running DI engine as an intake based cleaner will remove some deposits. Won't remove all of them. You'd be there for a long time running a lot of cleaner through to get anywhere close to mechanical cleaning. There are plenty of tests around on the interweb video channels where this has been attempted. Doesn't get the baked on crap off the valves. If you want your valves clean, mechanical cleaning is the only way to accomplish that. If you want them cleaner, the solvent cleaners can achieve some degree of cleaner.

MrMoose

True dat, I doubt any in-situ cleaner is going to work as well as mechanical cleaning. That said, with regular use it might be good enough: the valves don't need to be perfectly clean, and a little bit of buildup won't hurt anything. People think if there's any oil or blackness or build-up at all on the valves or surrounding surfaces it's significant, and that just ain't the case.

As an aside, back in the day when I was in the refining biz we had a group that did long term fuel testing. They used BMW engines because (at least at the time) they were pretty notorious for being prone to valve build up from fuel issues. They had a set of calibration valves with varying levels of build up 1-10 mounted to a board that was used as a scale to report test performance. 1 was bare metal, where 10 looked like a big charred marshmallow had been jammed over the valve stem, lol. A lot of photos online where people think they have "bad valve deposits" are really at the low end of the scale and not something that requires immediate action, IMO.

Kancamagus

Gasoline has little to nothing to do with intake valve build up because the air/fuel mixture doesn't "wash" the non combustion side of the valve in direct injection engines. The carbon build up (on the intake side of the intake valve) is from traces of oil that bake on, and the intake valve doesn't get hot enough to burn it off (like the exhaust valve does). Some oil companies (like valvoline) are developing oils that may help, but products of this type are generally not effective. IMHO

okie981

Several motor oils have been on the market for a few years that minimize crankcase oil vaporization and therefore PCV routing of the vapor to the intake plenum where the fumes get cooked onto the backside of the intake valves. This minimization of vapor is accomplished primarily by the base stock used in the oil with mPAO base being one that is beneficial. That being said, the best that can be hoped for is a slight reduction in the vaporized oil.

Some other posts in this thread are clearly armchair theories and variations of I think this and expect that. And lots of people have experience in industry or technical training that gives them some good theories (I had mine as well). But until a car owner has inspected the intake valves in their own engine knowing how they have maintained it and what methods they have used, if any, to reduce intake valve buildup, they are guessing at what the reality is or will be.

Another source of intake valve crud buildup is oil seeping pasting the valve guide seals. I saw evidence on my intake valve stems that indicated that might be a significant contributor in 981 engines but I have no way of confirming that.

MrMoose

Ahem. My hypotheses are formed in a stylish mesh task chair, thankyouverymuch

But seriously, I dunno if the stuff works, but hypothetically it could help and it's cheap to try. That video test is bunk, though.

Larson E. Rapp

Ekornes Stressless or GTFO

davecramer

techron actually works Does Techron work? | Bob Is The Oil Guy

IndigoInkTaco

Probably for fuel lines/pump/injectors? But again, on a Direct Injection motor, I don't see Techron, or any other fuel additive, being an effective cleaning agent for the intake valves which is what was originally in question.

I think this might be good for the thread.