Cleaning Intake Valves - PeachParts Mercedes-Benz Forum

tvpierce · #1 08-01-2006, 12:03 PM

My car is a ’92 201 w/2.3 ltr. with 185K miles.

I was experiencing an extremely high idle, so I have the whole intake off searching for vacuum leaks, and for a good cleaning. I actually found my air duct housing (the rubber bottom of the air flow sensor) had a major tear in it – I’m waiting for the part to arrive tomorrow.

In any event, I’ve completely cleaned the air flow sensor, the throttle body, and the intake manifold. It was a disgraceful mess of carbon/fuel/crud. Everything is spotless now, but I can see that the intake valves are all “crudded” up. Does anybody have a slick way to clean them without removing the head?

Thanks in advance for your insight.

Jeff Pierce

andmoon · #2 08-01-2006, 12:17 PM

Seafoam.
During the 80's there was another product that you sprayed into the intake until the motor died, let sit for 30 mins. then blow all the crud out by reving...the epa banned the darn thing as it rivaled a volcanic eruption as far as smoke was concerned.

ILUVMILS · #3 08-01-2006, 01:31 PM

GM Top Engine Cleaner works great.

bowin · #4 08-01-2006, 02:02 PM

Bg-44k

tvpierce · #5 08-01-2006, 02:35 PM

I'm aware of each of the products mentioned (Seafoam, GM TEC, BG-44 -- and that the GM TEC comes highly recommended by professional techs, like ILUVMILS), and I'm aware of the proceedure in which you carefully allow said substance to be sucked into the intake manifold through a vacuum line. (or is there a better way?) I have my doubts that this is going to do a thorough job of cleaning -- I mean, I had to scrub this intake clean with carb cleaner and a brass brush! Is it possible for a simple chemical treatment to get similar results?

It would seem that since I have direct (albeit limited) access to the valves now, that maybe there's an opportunity to really clean them up. Would it be crazy to apply one of the above mentioned chemicals directly to the valves and scrub them with a toothbrush? (or am I just pissing into the wind on this one?)

Thanks in advance for your further input.

Jeff Pierce

manny · #6 08-01-2006, 05:40 PM

I don't think just chemicals will desolve much caked-on crud.
In the early 1980's, BMW's used to have a lot of problems with intake valves " caking " up.
Most dealers used a cure of blasting ( this is true ) crushed walnut shells at the intakes, followed by a good vacuuming.

tvpierce · #7 08-02-2006, 09:45 AM

Manny,

Actually, I have heard of that -- although not specifically with BMWs. The rationalle for using walnut shells is that if grains of it are lodged in the cylinder, they'll burn and the ashes will be pushed out the exhaust port (unlike sand that would stick around and cause scoring).

It's an interesting idea. I have a sandblaster, I just need to find walnut shells for a blasting medium. (maybe I should just plan to bake a few dozen loaves of banana nut bread:-)

Does anyone know if a welding supply place would carry blasting media?

Jeff Pierce

andmoon · #8 08-02-2006, 10:26 AM

My bmw motorcycle had so much carbon buildup it was pinging. The dealer did the wallnut blasting (w/ heads removed) and it left the parts looking new. I hear there are plastic beads in use as well.

As for the Intake...I cleaned my vw intakes and noticed no change in performance....And it is easy to feel a diff. in a 36hp engine.

david s poole · #9 08-02-2006, 10:30 AM

if you have access to compressed air how about using a high speed grinder tool[the long skinny one]and using a wire brush end.i'm sure that if you use care each of the valves can be turned to clean the backside.david poole european performance dallas tx.

tvpierce · #10 08-02-2006, 12:20 PM

David,

Interesting idea. I do have compressed air, but another tool that may be even better for this is my dremel with the flexible extension. It gives you something similar to a dentist's tool. I'd be a little concerned, however, about using a wire wheel on the valves and particularly where the valves seat in the aluminum head. Do you think my concern is warranted? I suppose a brass wire wheel might be fine.

Anyone have further thoughts?

Thanks.

jp

al parker · #11 08-02-2006, 01:05 PM

The glass bead media is available at an auto paint supply parts store. My NAPA carries it here. The glass beads will work better on the valves.
The corn husk and walnut blasting media is not readily available in large quantities but you can get 5 top 10 pounds at a store selling guns, ammo, and bullet reloading supplies. It is used in tumblers to clean up bullet hulls before reloading.
G'luck
Al

jonschwenke · #12 08-02-2006, 01:11 PM

Harbor Freight has walnut shells....

http://da.harborfreight.com/cpisearch/web/search.do?keyword=walnut

I have no idea about cleaning valves - way out of my league.

tvpierce · #13 08-02-2006, 03:21 PM

Dang, Harbor Freight has just what I need, unfortunately I can't wait for their delivery. I think I will get a bag of the walnut shell when I order from them next.

I searched all around locally (auto parts, paint supply, even machine shops) and no one knew where I could find walnut shell.

I think what I will do is put some Techron fluid in a spray bottle, and apply numerous doses directly to the valves over the next 24 hours. That ought to help some. Then I'll take a whack at it with the dremel and see how it goes.

If anyone has further suggestions, I'm interested.

jp

mctwin2kman · #14 08-02-2006, 04:58 PM

You could take out the injectors and just spray carb cleaner into the closed valves and let it sit there. It may get quite a bit off if you use it liberally. I would pull the plugs when doing this so you do not fill the chamber with carb cleaner and also change the oil when done since the carb cleaner will get past the rings somewhat.

Tomguy · #15 08-02-2006, 07:42 PM

Jamie: I don't think that's a good idea. I am pretty sure that carb cleaner would slowly leak past the valves, even if they are closed, and into the cylinder wall. It's very "thin" (low cohesive and adhesive properties) and also quite volatile. It'd probably evaporate too fast in an open environment to do any good. And if it didn't, I can imagine it going into the cylinder with dissolved crap, getting on the walls of the cylinder, thinning the oil, getting past the rings and into the crankcase and polluting/thinning that oil...

I think sandblasting with particles too large to go through a closed (nonburnt) valve, and which will burn quickly if not all removed, is the best option.