Fly Cutting Tool
Team Owner
Joined: Sep 2001
Posts: 23,283
Likes: 906
From: Lake Elsinore, CA
Drifting
Joined: Oct 2004
Posts: 1,384
Likes: 8
From: Southwest Virginia
Normally you have to use a head that has had the valve seats removed. Don't know why they designed the tool that way. But if you modify the tool slightly as shown in the first photo it will work in a stock factory head. I bought a cheap pair of used factory LS1 heads to use on my LS6 and didn't have to remove the seats. If you have heads using non-standard valve angles you may have to use your new heads.
If you are very careful you should be able to use good new heads. Keep the pilot lubed good so you don't damage the guides, and be sure you don't pull the tool back into the seats while spinning. But I would use good new heads at the absolutely last choice!
To modify the tool I used a small lathe and grinder, those tools are HARD!
Object is to grind a 45 degree angle on the back of the cutter just like a valve face where the cutter is normally square on the back. I used the factory pilot mounted in the chuck, then stuck the cutter on the end of the pilot, then put a hard piece of rubber against the cutter face and pushed the lathe center into the rubber. This holds the cutter head tightly in place while grinding. The main thing you don't want to do is let the cutter get hot. I would recommend not letting it get hotter than you can touch. I used a small plastic bottle filled with water and with the side cut out to cool the cutter every 20-30 seconds of grinding. Probably took 5 minutes to modify each tool.
Also, if you are installing milled heads and using a factory (unmilled) head for flycutting, you will want to use the factory head without any gaskets under the head during flycutting. This will place the valves very close to where they will be in a milled head.
If you are going to do the flycutting yourself shoot me a PM, I got some tips that will really help in the process!
If you are very careful you should be able to use good new heads. Keep the pilot lubed good so you don't damage the guides, and be sure you don't pull the tool back into the seats while spinning. But I would use good new heads at the absolutely last choice!To modify the tool I used a small lathe and grinder, those tools are HARD!
Object is to grind a 45 degree angle on the back of the cutter just like a valve face where the cutter is normally square on the back. I used the factory pilot mounted in the chuck, then stuck the cutter on the end of the pilot, then put a hard piece of rubber against the cutter face and pushed the lathe center into the rubber. This holds the cutter head tightly in place while grinding. The main thing you don't want to do is let the cutter get hot. I would recommend not letting it get hotter than you can touch. I used a small plastic bottle filled with water and with the side cut out to cool the cutter every 20-30 seconds of grinding. Probably took 5 minutes to modify each tool.Also, if you are installing milled heads and using a factory (unmilled) head for flycutting, you will want to use the factory head without any gaskets under the head during flycutting. This will place the valves very close to where they will be in a milled head.
If you are going to do the flycutting yourself shoot me a PM, I got some tips that will really help in the process!
Advanced
Joined: Apr 2007
Posts: 93
Likes: 0
From: Conroe Texas
Isky
Great tool but,
1.) Isky gives you the option to rent this tool then return it. Any modifications to it and it is yours.
2.) When I rented mine, it was only 60 bucks and u returned it whenever you wanted too, up to a certain limit. I think the tool was 150 bucks back in the eighties.
3.) They DO look them over when they are returned. Dial Calipers and Micrometers.
1.) Isky gives you the option to rent this tool then return it. Any modifications to it and it is yours.
2.) When I rented mine, it was only 60 bucks and u returned it whenever you wanted too, up to a certain limit. I think the tool was 150 bucks back in the eighties.
3.) They DO look them over when they are returned. Dial Calipers and Micrometers.
Drifting
Joined: Oct 2004
Posts: 1,384
Likes: 8
From: Southwest Virginia
Thanks
That is an option. When I did my H&C I tried to rent the tool and head from a well known forum supporter, they wanted $150 just to rent the tool and a modified head, but I just ended up getting screwed. And that $150 does not include shipping a cylinder head accross the country twice! Figure at least another $50 just for shipping. Modify a tool and you can use any stock un-modified head, as long as your new heads have the same valve angle/position.
They are about $165 now from Thunder Racing, not a bad price when you figure time and expense of cutting the seats out of a head to properly use the tool. And you get to keep the tool for future use for you and your friends.
I'm guessing if I sent one of these modified tools back to them they would say "Damn, why didn't we thing of that?", I have no idea why they would not cut the backside of the tool. Other than to simply discourage someone to use their band new $3,000 heads to fly cut their pistons!
I'm guessing if I sent one of these modified tools back to them they would say "Damn, why didn't we thing of that?", I have no idea why they would not cut the backside of the tool. Other than to simply discourage someone to use their band new $3,000 heads to fly cut their pistons!
