Flycutting....should I be scared of it?
12-09-2007, 05:53 PM
#1
Flycutting....should I be scared of it? I am planning on going with the MS4 this winter and am trying to decide what heads to go with. I've seen alot of guys making pretty big power with the MS4 and TSP PRC 2.5 heads, however, this requires flycutting. The only heads that don't are the PRC 1.5's but these don't seem to make quite the power that the 2.5's do and it's pretty much the same price with only a few hundred dollars difference. So I think that I want to go with the PRC 2.5 stage 2 heads.
My problem is that I've never done any flycutting on pistons and it seems like you can screw quite a bit up if you don't know what you're doing so it makes me nervous. And all of the shops around here said they wont do it unless I pull the motor... So, what do you guys think? Should I just go with the 1.5's and not worry about the flycutting or should I go with the stage 2's and flycut myself? How hard is it?
My problem is that I've never done any flycutting on pistons and it seems like you can screw quite a bit up if you don't know what you're doing so it makes me nervous. And all of the shops around here said they wont do it unless I pull the motor... So, what do you guys think? Should I just go with the 1.5's and not worry about the flycutting or should I go with the stage 2's and flycut myself? How hard is it?
12-09-2007, 07:42 PM
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12-10-2007, 10:21 PM
#13
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It's really not that bad. You just need the right tools. You can get something that mounts on the drill and will turn make a 90 degree turn so you can fit it up in there. Call up LG and rent their flycutting kit (scrap head with no valve seat and cutters) and you'll be good to go with this drill bit right angle thingy (technical term)
How much does LG charge to rent the kit?
12-11-2007, 08:52 PM
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I did it two weeks ago, I bought all the tools from Thunder, It only took about 5 hours going very, very slow, its not hard at all. would do it again in half the time or less, simple.
12-12-2007, 11:10 AM
#16
as stated, nothing hard, just time consuming. about the only way you could F'up your engine doin this, is if you dont take the time to do it cleanly (is that a word?), or if you dont tighten down that coller enough and when your cutting you push down on the cutter/drill and cut too deep. I ended up cutting most pistons 2 or 3 times cause I was a bit paranoid the collar would slip and cut too deep. plus after doin it once, decided I should also cut the exh. notch's too.
but its a good learning experience and is well worth the extra insurance. me personally wouldnt do an MS4 w/o flycutting even in a cam only setup cause its easy enough to bend a valve with the stock cam and missing a gear. let alone after making the clearance tighter then the generally accepted .080I/.100E. Im pretty sure they have seen .040" clearanceon average cam only MS4 installs, and thats not good enough for me. plenty have done it, but again, I like solid #s, and to be safe.
I paid LGM I think it was $160 for the tool, plus shipping cost both ways. they give you 2 weeks which ofcourse is way longer then you need IF you have the eng. ready to go when the tool show's up. in the end I paid $230 after shipping cost's were factored in. but be aware they also make you pay a deposit cost. which is understandable thats refunded when the tool show's up safe and sound at there shop.
chris
12-12-2007, 04:39 PM
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I am working on my own flycutting tool that would not require removeing the seat's.
I plan on useing my own heads to do it.
My plan is to get one new exhauste and intake valve and machine 8 slits in them about 3/16 wide then tig weld a small bead of tool steel weld on the leading edge. grind it flat and then put a deg or 2 of releif on it so it will cut and not chatter.
Also i the weld will be about .015 higher than the rest of the valve to control how fast it cut's.
And then the one size bigger debate. I think as long as the cutter is the same or maybe .030 bigger should work as long as you use a thinner spacer to cut with than what youre head gasket is.
My idea is to use 1 peice of a stock mls gasket(pull it apart). you only need enough to clear the pist .006
and due to the angle the valve travels in. As the head move's out( thicker head gasket)
the contact point of the valve to piston move's down away from the eyebrow you cut.
So that will keep the cc's down and the scr up.
Just a idea. I will try it. but if it works i could make these for $20 more than the cheapest valves i can get. so like maybe $50 bucks for youre own cutter with tool steel cutting edge's.
And for the depth will be controlled by a simple lock collar you can buy from msc or grainger for 5 buck's. Set the depth with a feeler gage and lock it down and cut till the collar is rubbing on the valve guide.
I think it will work .do not know. I just think it would be nice to cut pistons for less .
My cam will be here friday so i should know by monday.
mike
I plan on useing my own heads to do it.
My plan is to get one new exhauste and intake valve and machine 8 slits in them about 3/16 wide then tig weld a small bead of tool steel weld on the leading edge. grind it flat and then put a deg or 2 of releif on it so it will cut and not chatter.
Also i the weld will be about .015 higher than the rest of the valve to control how fast it cut's.
And then the one size bigger debate. I think as long as the cutter is the same or maybe .030 bigger should work as long as you use a thinner spacer to cut with than what youre head gasket is.
My idea is to use 1 peice of a stock mls gasket(pull it apart). you only need enough to clear the pist .006
and due to the angle the valve travels in. As the head move's out( thicker head gasket)
the contact point of the valve to piston move's down away from the eyebrow you cut.
So that will keep the cc's down and the scr up.
Just a idea. I will try it. but if it works i could make these for $20 more than the cheapest valves i can get. so like maybe $50 bucks for youre own cutter with tool steel cutting edge's.
And for the depth will be controlled by a simple lock collar you can buy from msc or grainger for 5 buck's. Set the depth with a feeler gage and lock it down and cut till the collar is rubbing on the valve guide.
I think it will work .do not know. I just think it would be nice to cut pistons for less .
My cam will be here friday so i should know by monday.
mike
12-12-2007, 05:14 PM
#19
how exactly did you do the flycutting? did you use your stock head for it?
