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Author
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Topic: fly cut pistons help
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RONNIE
unregistered
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posted 06-23-2003 05:53 AM
can you cut the top of the piston to make room for 202 valves while there still in the motor thanks ronnie
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KULTULZ
Gearhead Posts: 959
From: Rockville, MD
Registered: Oct 2002
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posted 06-23-2003 06:36 AM
Yes. ISKY is just one that makes a special fly cut valve that fits into the cylinder head in place of the regular valve and you power it with a hand drill.[This message has been edited by KULTULZ (edited 06-23-2003).]
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scottford351
Gearhead Posts: 151
From: reedsville ohio usa
Registered: May 2003
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posted 06-23-2003 02:21 PM
My friend welded a piece of a file onto the head of a old valve to make cutter that enlarged the valve reliefs. It actually did a nice job.------------------
91 LX 398w street/bracket 6.88 1/8 60FT 1.44
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Tbird
Gearhead Posts: 298
From: USA
Registered: May 2003
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posted 06-23-2003 03:11 PM
If you have to cut a pocket in the piston that is over 50% of the valve face (1/2 of the face of the valve), then according to Isky's catalog, their cutter will not work efficently (which I can vouch for this statement). There is a cutter similar to the one mentioned above made by Lindy tools and sells for about the same price as the Isky tool ($125). Always buy the cutter at least 1/8" larger than your valve. 2.000" valve, buy the 2.125" cutter.http://www.lindytools.com/inheadpistoncutters.htm When you go to cut the pocket with the piston in the block, take some masking tape and tape around the edge of the bore and piston. Also, use an old head gasket when cutting the new pockets, this assures you get an accurate depth and don't accidently go too deep by mistake. Also, don't make one cut and think all of the other cuts will be the same setting on the stop collar, measure each one. [This message has been edited by Tbird (edited 06-23-2003).]
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RONNIE
unregistered
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posted 06-23-2003 06:14 PM
quote:
Originally posted by Tbird:
If you have to cut a pocket in the piston that is over 50% of the valve face (1/2 of the face of the valve), then according to Isky's catalog, their cutter will not work efficently (which I can vouch for this statement). There is a cutter similar to the one mentioned above made by Lindy tools and sells for about the same price as the Isky tool ($125). Always buy the cutter at least 1/8" larger than your valve. 2.000" valve, buy the 2.125" cutter.http://www.lindytools.com/inheadpistoncutters.htm When you go to cut the pocket with the piston in the block, take some masking tape and tape around the edge of the bore and piston. Also, use an old head gasket when cutting the new pockets, this assures you get an accurate depth and don't accidently go too deep by mistake. Also, don't make one cut and think all of the other cuts will be the same setting on the stop collar, measure each one. [This message has been edited by Tbird (edited 06-23-2003).]
do you have to take all the valves out or can you just take them out of one cid. thanks ronnie
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KULTULZ
Gearhead Posts: 959
From: Rockville, MD
Registered: Oct 2002
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posted 06-23-2003 06:14 PM
Thanx for the information Tbird.Very helpful... 
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RONNIE
unregistered
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posted 06-23-2003 06:31 PM
do you have to take all the valves out or can you just take them out of one cid. thanks ronnie
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KULTULZ
Gearhead Posts: 959
From: Rockville, MD
Registered: Oct 2002
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posted 06-23-2003 07:16 PM
I would think it would be easier to remove the cylinder head each time to swap cylinders (cutters) rather than swapping piston/rods. Is this what you are asking? Do you need to cut both int. and exh.?Be nice to have a spare bare cyl. head laying around for this...
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Tbird
Gearhead Posts: 298
From: USA
Registered: May 2003
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posted 06-24-2003 08:32 AM
Ronnie,you can remove the valves from just one head and use that head to cut both sides. Make sure you check the piston-to-valve clearnces of the intake from 10* BTDC to 15* ATDC. This is usually when the intake is the closest to the piston. The exhaust valve clearance is usually not a problem in most motors unless you have a really wild cam and popup's. Also, another tip, get a light weight spring like CompCam sells for p-v checking. And check the clearance once you have cut the new pocket. You only need to assemble it for the cylinder you are working on. And last tip, have a decent shop vac around to suck the shavings off the piston when you remove the head each time. Mom/wifey won't appreciate you using her house vac.....  [This message has been edited by Tbird (edited 06-24-2003).]
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RONNIE
unregistered
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posted 06-24-2003 05:31 PM
so i need to take all the valves out of one head,ijust cant take the valves out of,say the 1# cid. and use that as a guide,and do i need to do both int.and ext.on my pistons, my cam is 520 230 solid lift thanks for all the info ronnie
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RADRIDE
Gearhead Posts: 305
From: Va.Beach, Va.
Registered: Aug 2002
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posted 06-24-2003 09:17 PM
I used the Lindy cutters putting my alum. heads on and it does a nice job.I bought 2 shafts and cutters so I could do both cuts at once.It still required putting the head on and off a lot.Thank GOD for alum.You should also use the brand of head your using to cut with.My AFR exhaust valve seemed to be a little off from relief in piston.
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RADRIDE
Gearhead Posts: 305
From: Va.Beach, Va.
Registered: Aug 2002
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posted 06-24-2003 09:22 PM
One more thing use a battery drill as it will not take much to cut piston and mine are forged.When my battery died I couldnt wait and used my electric drill and the cutter caught in the top of the piston. The drill bent my shaft ,luckily it was the last hole.
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RONNIE
unregistered
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posted 06-25-2003 04:52 AM
quote:
Originally posted by Tbird:
Ronnie,you can remove the valves from just one head and use that head to cut both sides. Make sure you check the piston-to-valve clearnces of the intake from 10* BTDC to 15* ATDC. This is usually when the intake is the closest to the piston. The exhaust valve clearance is usually not a problem in most motors unless you have a really wild cam and popup's. Also, another tip, get a light weight spring like CompCam sells for p-v checking. And check the clearance once you have cut the new pocket. You only need to assemble it for the cylinder you are working on. And last tip, have a decent shop vac around to suck the shavings off the piston when you remove the head each time. Mom/wifey won't appreciate you using her house vac..... [This message has been edited by Tbird (edited 06-24-2003).]
so i need to take all the valves out of one head,ijust cant take the valves out of,say the 1# cid. and use that as a guide,and do i need to do both int.and ext.on my pistons, my cam is 520 230 solid lift thanks for all the info ronnie ------------------
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Tbird
Gearhead Posts: 298
From: USA
Registered: May 2003
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posted 06-25-2003 08:00 AM
Yes, just take the valves out of one head. You will use this head to do all the cuts on both banks of cylinders. You will put the cutter(s) in for one of the cylinders and do the cutting before moving to the next cylinder. To do the cylinder on the opposite side, you will need to rotate the crank. I swapped the cutter(s) to the corresponding chamber for the piston that was at TDC on the other side.You will also need to make sure the piston is at top dead center before you start the cutting. It was mentioned to use a battery opperated drill, well that is okay if you have a small relief to cut. I had to remove a lot on the pistons in my motor. The new vavle pocket in the piston was almost 3/4's the size of the valve. (No, not saying you will need this much). I ended up using a good 1/2" drill motor that turned at a slower speed to cut them. The battery drill just didn't have the duration or the torque to do as much cutting as I needed to do. The new pockets enmded up being almost 3/8" deep due to the relocated intake valve in the new Ford Super CJ heads. You can figure about an hour to 2 hours per cylinder to get it done. This time is from being scared to make the first cut on the first cylinder, vacuuming of shavings, then doing a lot of measuing and taking the head on and off. [This message has been edited by Tbird (edited 06-25-2003).]
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RONNIE
unregistered
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posted 06-25-2003 04:30 PM
quote:
Originally posted by Tbird:
Yes, just take the valves out of one head. You will use this head to do all the cuts on both banks of cylinders. You will put the cutter(s) in for one of the cylinders and do the cutting before moving to the next cylinder. To do the cylinder on the opposite side, you will need to rotate the crank. I swapped the cutter(s) to the corresponding chamber for the piston that was at TDC on the other side.You will also need to make sure the piston is at top dead center before you start the cutting. It was mentioned to use a battery opperated drill, well that is okay if you have a small relief to cut. I had to remove a lot on the pistons in my motor. The new vavle pocket in the piston was almost 3/4's the size of the valve. (No, not saying you will need this much). I ended up using a good 1/2" drill motor that turned at a slower speed to cut them. The battery drill just didn't have the duration or the torque to do as much cutting as I needed to do. The new pockets enmded up being almost 3/8" deep due to the relocated intake valve in the new Ford Super CJ heads. You can figure about an hour to 2 hours per cylinder to get it done. This time is from being scared to make the first cut on the first cylinder, vacuuming of shavings, then doing a lot of measuing and taking the head on and off. [This message has been edited by Tbird (edited 06-25-2003).]
thanks for all the info now i understand what i need to do thanks agin ronnie ------------------
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RONNIE
unregistered
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posted 06-27-2003 06:03 AM
quote:
Originally posted by Tbird:
Yes, just take the valves out of one head. You will use this head to do all the cuts on both banks of cylinders. You will put the cutter(s) in for one of the cylinders and do the cutting before moving to the next cylinder. To do the cylinder on the opposite side, you will need to rotate the crank. I swapped the cutter(s) to the corresponding chamber for the piston that was at TDC on the other side.You will also need to make sure the piston is at top dead center before you start the cutting. It was mentioned to use a battery opperated drill, well that is okay if you have a small relief to cut. I had to remove a lot on the pistons in my motor. The new vavle pocket in the piston was almost 3/4's the size of the valve. (No, not saying you will need this much). I ended up using a good 1/2" drill motor that turned at a slower speed to cut them. The battery drill just didn't have the duration or the torque to do as much cutting as I needed to do. The new pockets enmded up being almost 3/8" deep due to the relocated intake valve in the new Ford Super CJ heads. You can figure about an hour to 2 hours per cylinder to get it done. This time is from being scared to make the first cut on the first cylinder, vacuuming of shavings, then doing a lot of measuing and taking the head on and off. [This message has been edited by Tbird (edited 06-25-2003).]
i got the parts# but i told them iam useing .202/160 is the stem size for a a 69 302 head the same, i dont want to take out my valves on my new heads,they said i need a 11/32" pilots thanks ronnie
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Tbird
Gearhead Posts: 298
From: USA
Registered: May 2003
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posted 06-27-2003 09:07 AM
11/32 is the right pilot to buy.
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RONNIE
unregistered
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posted 06-28-2003 05:45 AM
quote:
Originally posted by Tbird:
11/32 is the right pilot to buy.
thanks ronnie
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jeffstar
Gearhead Posts: 161
From: Toronto, Ontario, Canada
Registered: Feb 2003
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posted 07-05-2003 02:08 AM
Assuming your starting with a balanced motor, enlarging the valve releifs changes the weight of the piston, is it safe to run a motor to say 7000 rpm without reballancing the entire assembly after fly cutting???
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RONNIE
unregistered
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posted 07-05-2003 06:23 AM
thanks for the info,but i got a new set dont have to worry about fly cutting. ronnie
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Tbird
Gearhead Posts: 298
From: USA
Registered: May 2003
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posted 07-07-2003 08:19 AM
You only have to worry about re-balancing when the amount removed exceeds approx 10 grams per piston.
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RONNIE
unregistered
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posted 07-09-2003 06:10 AM
quote:
Originally posted by Tbird:
You only have to worry about re-balancing when the amount removed exceeds approx 10 grams per piston.
thanks for the info but i went with a set of K.B.pistons ronnie
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