skyfox

2007 IS250, 105,000 miles. No record of a top engine clean or a piston upgrade being done at the dealer.

So I finally tore apart the intake manifold to carbon clean the valves. Valves are in pretty bad shape. I started with just cold soaking the cylinder 1 valves with CRC's GDI Intake and Turbo cleaner. I know it is supposed to be be a heat soak treatment, but have seen a U-tube video of someone cleaning their BMW with just cold soaking the valves without walnut blasting and the valves turned up spotless. He did have a pretty good size carbon build up on the valves when he started. Unfortunately, my results are nowhere near close. Day two and still on Cylinder number 1.

1. cold soaked cylinder one valves for 30 min. Scrubbed (with about 20 long stiff plastic tie wraps bundled together improvising a brush) for about two to three minutes. Sucked out the carbon soup. -Both intake walls were clean but only 10% of the carbon build up was gone. Still chunks of carbon left on valves.

2. Another 30 min soak and a scrub. This time about another 5% of carbon was removed.

3. 1 hour soak and a scrub. about a 25% improvement. So after three soaks, about 40% of the build up was gone and still lots of chunks of carbon on valves. Almost a whole can for the three soaks.

While waiting for the 1 hour soak above, I started cleaning the lower intake manifold using CRC's throttle body cleaner. Much to my surprise, all the gunk that was built-up in their for the last 13 years, just rinsed off completely as if it was being cleaned with a pressure washer (it sort of was. A hand held pressure washer in a can if you will), without any scrubbing required.. One can of it, completely cleaned the lower intake manifold. This gave me an Idea. So I soaked the intake valves with CRC's Throttle body cleaner. After an hour long soak and a scrub, it removed about 80 of what was left after the first three cleanings on the valves. There is still a layer of carbon on the valve but no chunks. So I am on my 2nd soak with the throttle body cleaner now to see how it turns out. Still have 5 cylinders (10 Valves) left to go and want to minimize wasted time. Hence, my valve question.

How many intake valves are fully closed at any given time?
Assuming Cylinder 1 is closed for an example and 2 is open. Are intake valves for cylinders 3, 4, 5, & 6 fully closed?

Reason for the question is that I would like to soak multiple intakes at the same time if that is possible.

In order to help speed up the cleaning process, I was thinking of heating up the valves using a heat gun before soaking them. Buy just heating up one chamber, could I cause the head to warp considering the entire block is not being heated evenly or is that a non issue with a small hand held 30watt heat gun meant for heat shrink for wiring?

Appreciate any feedback.

Cheers.

EDIT: ******** FALSE ALARM WITH TB CLEANER RESULTS********

After 2nd one hour soak with Throttle body cleaner, took a closer look. There is still carbon on the base of the valve about 1 to 1.5 mm thick. So the TB cleaner didn't do all that better as I initially thought. But it did help a bit. It just smoothed the surface so the build up now actually looks like part of the valve base. I had to completely dry the valves out to see the carbon. All of the chunks are gone and the stem is completely smooth without any carbon. I would say after all this, it is 80% better than when I started. But two days for 1 cylinder is a bit much and I still have to finish cleaning it. Doing a 24 hour soak with Intake valve cleaner to see if that extra time helps with this last bit. May have to go the walnut blasting route which I was hoping to avoid.

2013FSport

iTrader: (2)

I can't answer your question directly and have never seen it posted. Your best bet might be to pressure or vacuum check the port using a makeshift adapter like a piece of plexiglass and foam or butyl or something like that. A shop vac would pull down and change pitch pretty quickly if the port is closed.

If we had the tech paper on the crank we could determine it as the firing order is 1 2 3 4 5 6 and the cams 2:1 ratio. 2 crank revs to 1 cam rev.
Not that this will help, but here is crank.

Good luck and honestly I wouldn't hesitate to do some mechanical cleaning before spraying product in there. The only real concern is not maring the valve stem but it is closed so even that is not a concern.

As for applying heat, you won't harm harm it. It will be displaced so you would need a torch to really impart heat. Even then it won't impact the valve which is where you need it unless you keep the valve open so its not touching the head and some air could flow. Otherwise the head acts as heat sink. I don't see it worth the time unless while sitting over night you placed heat lamps (4x) on both heads. These must be off for spraying or you'll make the news in a bad way.

MikeFig82

iTrader: (13)

You can try some B12.

https://www.clublexus.com/forums/is-...lve-clean.html

skyfox

2013FSport & MikeFig82, Thank you both for your help.

MikeFig82,

The cleaned valve with B12 shown on the link you posted, is not really clean. Notice it is very glossy meaning the valve still has the cleaning liquid on it and is not completely dry. So it makes it appear as if it was fully cleaned. I was fooled by it as well until I completely dried my intake valves after soaking. Then you can see there is still carbon on it. Grant it, it is a marked improvement compared to the before picture. My before picture was similar to if not worse than the before picture on that post. After soaking with CRC's GDI intake & Turbo cleaner, my chamber is a lot cleaner than the after pic on that post and the stem looks factory new. Base of the valve looked like it was carbon free while glossy, but after completely drying, it still has about 1 ~ 1.5mm thick layer of hardened carbon on it. Overall I would say 80 to 90% improvement compared to when I started cleaning it. I am after ZERO carbon on valves before I button it back up. I am getting ready to walnut blast today to see if it gets rid of the rest. Also, that same intake port has now been soaking with CRC's intake cleaner for the last 4 days. Going to do a quick scrub to see how much more it had cleaned after the first 4 soaks. I will post a write-up after it is all done.

thanks again.