Race Engine Forum UK

I tried one those cheap diamond dusted semi flexible cut off disks to grind a chamber floor flat in a cast iron A series head. This is a task I normaly do by using a miniature sanding disk. quite tedious and you use a whole load of those tiny disks wich are far too expensive to begin with.

My belief was that the diamond dust would come right off .. Lo and behold.. it did not. In fact, it works quite well and i have since "invested" (20 euro) in a set of 50 "burrs" in various shapes and sizes. I even spotted a substitute for sanding rolls. but i gather those are of limited use as i need the flexibility of the normal rolls

they work a bit like a soft stone but do not change form while grinding which is good for tight corners in chambers where stones do no last at all. as a bonus they dust a lot less. Of course if is no subsititute for a proper burr but my first impressions are ok and I think that these things are a welcome arsenal to the porting toolkit.

Do you have a photo or link for those tools SirYun?

Also head photo - before and after? I know you do good photos!

GC

Hi I saw very good burs carabide on site http://www.seiye.cn or com
but look for seat cuting machine on http://www.koroghly.com from Iran price whot they give me for first wos 12500$ . I will like coments from members?
Regards Sime

Sime, I don't know that firm, but I know people who like Serdi, which is similar in operation, personally I think it's great for seat inserts, especially with air bed, but I couldn't afford one, and even if I could I would not buy one. And, yes it's fast for doing seat angle cuts but I don't like the solid piloting system and it's not always possible to get the seat angles you need. Yes, in just 'reconditioning' speed is vital, but with motorsport applications speed of operation is secondary to accuracy. In my view.

For my own part - if I were you - I'd use a small milling machine for boring for seat inserts, centre up using first a solid pilot and then a dial gauge (slow but accurate, which is what you need with seat inserts), and do the race seat angle (as I do) with the Peg 10 grinder. Yes you need the beautiful Peg pilots (6, 7, 8mm etc) and lots of grind stones, but the finish form orbital grinding is the best I have ever seen.

One thing is sure, if you are doing seat boring just on alloy heads, even a very low cost mill-drill from Sealey fitted with boring head can cope with that.

GC

hi. a little update.

I have spend a day porting cast iron and i must say the diamond burrs do serve a purpose. They are nice for tight corners in chambers and flattening floors of chambers, but for other purposes a 25mm stone gives far better results and removes more material much quicker. I was hoping to get a full alternative to the short lived shape changing stones but alas.