Does anyone have any suggestions on safely cleaning carbon from valves without removing the cylinder heads? I'e always been of the opinion that it is best to just tear the heads off and do a valve job, but...

I am doing a major service on an older V8 Ferrari, and the valves have some significant build up on them. Due to the cost of a cylinder head R&R, the customer is reluctant to have me tear the heads down to clean them up. I'm going to do a leakdown tonight and see if we have any sealing issues.

Here's a picture, its really difficult to see the depth, but some valves have 1/16 - 1/8" of crud on them...

seafoam it or gum & sludge remover down the intake .

I know of a couple of ways, but I don't think you're going to like them for use on a Ferrari!


If you start the motor and rev it to 2000-2500 rpm (enough to where it isn't going to stall), slowly pour water into the intake system. It will steam clean the valves. It can get carbon build up off of pistons too.


You could try a tiny vacuum and some oven cleaner. Spray it in there, let it foam up, and vacuum it out before running it.


Toluene or Xylene in your gas helps too. It burns hotter and helps to destroy some of the carbon deposits (I got this tip from an old off-shore guy). Run it at 20% mixture for a tank.

I will certainly run some seafoam when I get it back together.

I have heard of the steam cleam method, but to be honest it scares the crap out of me for some reason! I'm leaning towards making sure the valves are closed, and spraying some oven cleaner or solvent in there, then sucking it out. You think oven cleaner is the best bet? Safe on the aluminum? What about filling the port with some carb cleaner or other solvent?

Some of the valve clearances were a bit more out of whack than usual, I'm hoping that the leakdown results are good.

I can tell you for sure that carb cleaner, vinegar, soaking in pure toluene, etc. won't do a damn thing. It's just not strong enough to break down the carbon.


I'm 90% certain that oven cleaner is safe for aluminum, but that has more to do with me using it on the grill/aluminum pans and whatnot. I've never tried to use it in the method you're using it in.



I HAVE used the steam method and it did work for me. I used it on a fuel injected Dodge Dakota, and I've used it on a couple of old school carb motors. I don't know how well it worked because I never took the motor apart, but it did stop the motor from dieseling (continuing to run when you shut it off), and it stopped some valve noise.

The only issue was neither of those motors are tuned to the same degree that a Ferrari motor undergoes. I really don't know if it would throw anything off, but I don't see why it would?

I remember the water down the carb trick to clean valves and pistons. I also remember sucking in cans of "top engine cleaner" thru the pcv or another vaccum source, until the engine took the whole can, shut it down, let it sit for 15 minutes, then go beat the snot out of it. Smoked like pigs, but seemed to work!

I'm thinking that soaking them might not do too much. I might try it and see if it knocks the heavy gum off of them. Guess I'll try some water spray and sea-foam when i button it all back up. The exhaust comes off next, I afraid to see what they look like

No over cleaner on aluminum intake. Does weird things to the metal. If you pit up the runners you will be worse off then when you started.

What Mild Thunder said works good I used BG 44K when I worked for ford/mazda, We used to stop traffic with the smoke but never had to tear one down after doing that drop a can in the tank also will clean the rest of the system

I can sell you some BG Products 44K. You add it to the fuel tank and run thru several tanks of fuel and all the carbon will be gone off of the valves and tops of the pistons.

PM me if interested.

Smitty