walnut shell blasting of exhaust valves

[mytrplseven]

Just got off the net with Bill Burris, the 944 tech expert with Panorama magazine and as we were discussing halting acceleration issues, he mentioned that Porsche has a procedure using crushed walnut shells to blast carbon build-up off of the exhaust valves.

I called my local dealership about it and since the girl at the desk was new and not totally adept on stuff like this, she's going to look into it and call me back.

Anyone out there familiar with this process and to what extent the engine is disassembled to do it. It's supposed to be done with the head still attached but not sure if the entire intake has to come off or just the throttle body.

[944 Ecology]

This was more of a BMW process for fixing drivability problems caused by deposits. Most independent euro shops should be able to do so for you.

The BMW process removed the intake manifold, cranked each cylinder until the intake valves were closed, then blasted the closed valve with walnut shells, vacuumed out the debris, and reinstalled the manifold. If you have the walnut shells and a media blaster, you could do the job yourself.

And, oh, yes, I am also am on the PCA National Tech Committee, for the early 944 and 924 cars.

[Gawernator]

Who decided on walnut shells? crazy

[mytrplseven]

Originally Posted by Gawernator

Who decided on walnut shells? crazy

It sounds crazy, but several manufacturers use this procedure. Sounds expensive, too. I've decided to use some fuel cleaner that a Porsche expert has suggested I try. It's called BG 44K and I did a bunch of research on this stuff and is very successful at removing carbon build-up on intake valves. It was more effective than Techron, Seafoam and Redline. Hopefully it'll fix the acceleration issues I can't seem to get a handle on. Cheaper than pulling the intake off and blasting the valves.

[Double 97]

Ford dealers were doing this in 1992.

[Toruhiwi]

Motorvac CarbonClean is the way to go.
I have been performing this process for about 13 years on hundreds of cars and it works!

[mytrplseven]

A little far from Florida. Going to put BG44k in the tank tomorrow. My Dodge truck sure seemed to like it.

[TibetanT]

Walnut shells are the preferred method for cleaning up carbon on valves and I use it exclusively for 911 Cylinder heads (combustion side)!

The walnut shells do not damage or pit the aluminum. Of course, once done I run them through the parts washer for that "new" look. Really cool process. Bill and George know what they are talking about!!

[mytrplseven]

My dealership said they're not equipped for this process and therefore can't do it. That's ok, the comprssion checks are good and I'll run the BG 44K through it so remove anything else that might still be on the valves. Seriously getting amped up about the MAF mod from Rogue Ant. Got a good replacement rear hatch last week locally for $250 installed. Another great find.