So I’ve located this replacement head for my old L-head Flathead engine which will give me a nice bump in compression over the original one. However, I am really struggling to find something to polish these combustion chambers with! I’ve picked up the port & polish sanding roles and have marginal success before either I brake the thin tip of the rod holding the sandpaper role or the paper just can’t get to the angles I need to reach the areas to polish. I’ve also tried using carbide tools to gently smooth the surfaces but they tend to bounce off the surface & I end up with really no improvement. I’ve tried flap sandpaper roles but with little success here as they are too large. After searching on line, I’m really stumped on what to use? I really hope someone knows what I need! Sent from my iPhone using H.A.M.B.
Why..? They are just going to get a layer of carbon anyway. Just make sure there are no sharp edges anywhere and bolt them on. Any sort of polishing will remove metal, removing metal will reduce the compression ratio. That IS what you are after, right ? Mike
Just take 5 minutes to knock down any pimples by hand and don't sweat the pits and pocks. Lay the gasket on 'em to visually check how stuff lines up. Done. If you have to get obsessive, do it on the outside/top.
You can have combustion chambers powder coated. https://techlinecoatings.com/tech-line-coatings/hi-performance-coatings/internal-engine-coatings/
hmmmm, maybe I wasn’t clear on what I was asking in my original post.... What I was asking for is someone who has an answer to the question on “What products/processes to use to polish up these combustion chambers”. Obviously, removing material in the combustion chamber will have the effect of decreasing compression. This was previously taken into consideration with all things considered on this engine setup & modification. Obviously, there will be carbon build up to one degree or another over time. Polishing will help reduce this somewhat in the combustion chamber. However, these “obvious” statements weren’t the nature of the question I was asking & answers I was in search of. Hopefully, this clears things up for those I may have confused in my original post. Sent from my iPhone using H.A.M.B.
If you want consistent volume in all cylinders wouldn’t you need to cut them all with tooling to the same depth? Just hand sanding could give a variety of depths.
Small stones spinning really fast, followed with sanding rolls, not to course. Getting at them at a good angle is really hard, a very long arbor with the sanding roll will help.
Asa has been stated there is nothing or very little to be gained by polishing the chambers. Never the less in answer to your question you use a fine burr to start with ( they come in various shapes n sizes) then you use a rubber tip and polishing compound. What you do not use unless you are very patient is the little Dremmel that most of us own. You want to lay your hands on the larger industrial strength Dremmel that profession head men use. They are a noisy bastard and best used in the basement when no one else is home.
You use 80 grit Spiracones which fit on an arbor that looks like the tip of a wood screw. There is not an area that can't be reached with this. These will give a finish suitable for running 100% nitro. eBay item number: 262670873655
I'll go with Rich, Roloc discs. Cut the disc backer down to allow the discs to 'curl' into the corners. Buy a box of 50, you'll go through a bunch of 'em…. The 2" size work best for tight quarters. http://www.keenabrasives.com/Mini Fiber Discs - Aluminum Oxide - Type R.htm They have a minimum order if buying direct but sell smaller quantities on eBay...
Great information guys, I truly appreciate it! BTW; the head is cast iron. I did pick up the Harbor Freight version of Roloc discs & they worked pretty well & I agree, cutting the rubber backer down will help. They worked especially well on the exterior surface of the head. I may have to find some better stones & carbide bits to grind with, as I took a good look at the ones I have and they are not of good quality. When they rotate, one can see they have a wobble to them, which ends up causing them to bounce on the surface when grinding. Sent from my iPhone using H.A.M.B.
Quality tools will go a long ways. Another thing...looks like a lot of pitting in the surface, are you trying to get rid of all of that?
Squirrel, definitely not trying to get rid of all of the pitting as that would likely remove too much material. Current state: Sent from my iPhone using H.A.M.B.