New valve seat cutters how to use them ?

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WHEELSONLY
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New valve seat cutters how to use them ?

Post by WHEELSONLY »

So I have been playing with some ls6 heads lately and decided to buy some mondello signature series cutter that I used on a friends rottler machine.. Today I tried pre boring to 88 percent of the valve diameter then follow up with a 75 in the bowl and my cutter for the seat is a 60 45 39 I will port to blend everything together.. I have almost zero traning on how the cut valve seats. I know how to set the head up in the machine and how to set the 45 to the correct width.. but that about it.. Today I bored with a 90 then i lightly kissed it with a 75 then followed up with the top cutter does this sound rite to you ?


here is the intake port 39 top 45 face 60 under the face 75 under that and 90 in the port
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Re: New valve seat cutters how to use them ?

Post by WHEELSONLY »

Here is the exhaust port again pre bore with 90 tried to get a little 75 but it is very small the the three angle cutter 60 45 30

Should I make the 75 bigger ?
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Re: New valve seat cutters how to use them ?

Post by needforspeed66gt »

You need to be cutting the exhaust seat with a radius cutter.

There's some chatter visible on that intake seat near the spark plug, either slow down your spindle or increase your feed/load.

You also should leave more of the 60* cut in place, do your seat cut first, then come down with the 75* until it leaves you with .090"-.100" of the bottom 60*

That's just a couple of observations, there's plenty of more seat cutting threads on this board if you do a search.
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Re: New valve seat cutters how to use them ?

Post by WHEELSONLY »

How would I get more 60 ? I was thinking the same thing but even the factory 60 is very small... Should I be doing the top cuts first of the bottom cuts first ?
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Re: New valve seat cutters how to use them ?

Post by WHEELSONLY »

anymore info? also what is a good exhaust cutter for 1.57
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Re: New valve seat cutters how to use them ?

Post by WHEELSONLY »

bummer was hoping to get some kind of answer should be SPEEDLOOK.COM cause there is not much talking lol.
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Re: New valve seat cutters how to use them ?

Post by dstaff »

You do not do the bottom cuts first. Set up the 3-angle cutter to where the seating surface is out the very edge of the valve, and cut your seats. Then you can go in and narrow up with the 75 until you have about .080-.100" wide 60 degree bottom cut. On some heads, there won't be enough meat there to do this, so you just have to accept what you have or install bigger valves.
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Re: New valve seat cutters how to use them ?

Post by nickmckinney »

I do the throat cut first myself as I am usually porting and it gives a relation to the core shift and sets the bowl diameter for a visual guide, I agree with the radius on the exhaust only for this application, any other angle other than the bowl cut should be part of the same blade unless you like doing extra work, and my best advice is look up the various seat cutting threads here and practice practice practice practice and practice some more on your particular machine and tooling.
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Re: New valve seat cutters how to use them ?

Post by ProPower engines »

Untill you develope the skills needed to do this the stock type mondello cutters will serve you well.
Check the radius cutter selection in the goodson book under the mondello cutter section. from memory there is a 12deg radius cutter listed for exhaust only that works well.
There is some cutters that Dart RHS etc use for a radiused exhaust seat that are similar that may also work.
You can call them and ask for a cutter number and most times they will give it to you.

AFR sucks that way as they think they are too good to give out that detail for any or their heads when shops want to touch them up after a few years of use.
But as mentioned a larger valve diameter will be needed for a radiused exhaust seat
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Re: New valve seat cutters how to use them ?

Post by needforspeed66gt »

The LS heads allow you to get a full radius cut in there even with the stock valve sizing because they run the seat width so close to the stem and they have a very small venturi to start out with. I cut all the factory 5.3L + heads with a radius on the exhaust and it always fully cleans up.
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Re: New valve seat cutters how to use them ?

Post by WHEELSONLY »

Thank you for all the info These are for a few personal projects I have... I work for a race team and when I am not traveling doing pitstops I Work full time at jerry woods ent.. But in my spare time I like playing with cylinder heads...

How does this cutter look ?
http://www.goodson.com/IFT-4524-HD/
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Re: New valve seat cutters how to use them ?

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needforspeed66gt wrote:The LS heads allow you to get a full radius cut in there even with the stock valve sizing because they run the seat width so close to the stem and they have a very small venturi to start out with. I cut all the factory 5.3L + heads with a radius on the exhaust and it always fully cleans up.

Thanks for the tip Nate
LS stuff here most of the time just gets junked as the repair cost seems to be too high for any head repairs to be done. Not sure what the big deal is but it could be the re-man head availability may be better and as a result get ordered if head issues are suspected to save shop bays being tied up waiting for head repairs to be done.

Used engines are also hard to locate here as well but when they come in they seem to go out just as fast and the cores never get returned as the US core buyers buy them up from anyone as they make regular trips up here in search for goodies they run short of down south
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Re: New valve seat cutters how to use them ?

Post by needforspeed66gt »

ProPower engines wrote:
needforspeed66gt wrote:The LS heads allow you to get a full radius cut in there even with the stock valve sizing because they run the seat width so close to the stem and they have a very small venturi to start out with. I cut all the factory 5.3L + heads with a radius on the exhaust and it always fully cleans up.

Thanks for the tip Nate
LS stuff here most of the time just gets junked as the repair cost seems to be too high for any head repairs to be done. Not sure what the big deal is but it could be the re-man head availability may be better and as a result get ordered if head issues are suspected to save shop bays being tied up waiting for head repairs to be done.

Used engines are also hard to locate here as well but when they come in they seem to go out just as fast and the cores never get returned as the US core buyers buy them up from anyone as they make regular trips up here in search for goodies they run short of down south
That's definitely odd, down here the chevy dealerships send us a set of LS heads weekly for a rebuild, occasionally one will be cracked and they opt to replace the casting rather than repair it.
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Re: New valve seat cutters how to use them ?

Post by ProPower engines »

not so much here and while it seems like different parts of the countries have similar repair policies in place we just never see any to be repaired. Its either they are just lasting longer because where I am there is no free way to speak of where accelerated wear conditions from hot or over heating running at higher speeds etc.

Most shops here have adopted the policy of just replace it or scrap it. While that does nothing for the shops that do the machine work to repair the stuff it seems to keep all there bays either open or full of work.

The bank lending rates have a lot to do with it as well where a 5 yr old vehicle is scrapped because of the high cost of repair work compared to just replacing the car/truck instead.
I know that in the US they have some scrap programs in place for buying cars/trucks of a certain number years old to present and the rebates they get for the old vehicle is very attractive but the sad thing is the cars/trucks that enter the scrap programs do not ever get parted out just shredded as is and all the good cores are lost with them.

Its sad as the LS engines are getting to be real popular for street rods etc. Hopefully as more time goes by it will improve.....
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Re: New valve seat cutters how to use them ?

Post by WHEELSONLY »

Hey nate where do you see the cracking at ? it would be nice to know where to look..
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