Tool to thin valve guide boss?
Melting Slicks
Joined: Mar 2008
Posts: 2,666
Likes: 289
From: Spring Park MN
Adam, use paraffin wax on the carbide burrs for lube to prevent clogging. I even used bar soap in a pinch. Just spin the burr in the wax to fill the teeth before you start cutting. It will stop the burr clogging with aluminum and give you a much nicer finish. You'll be able to feel when it needs more wax.
On the valve shape, it really depends on the seat shape, the area of the port before the seat and the shape of the chamber from the seat out as to what valve shape works best. I worked on developing these shapes over decades of doing headwork. I had seat cutters I designed for my head machine and had Sunnen make them for me as well as cutters for the chamber. I used to have all my valves custom made to my specs so everything worked together in concert.
Don't worry about the guides. There is very little to be gained there unless the area just before and at the guide is too narrow. The guide takes up part of the cross sectional area there. You want to maintain the cross sectional area as you approach the bowl. I used to start widening the sides of the port just before and at the guide to maintain the cross section. This gave me much better results than removing the guide from the area.
Mike
On the valve shape, it really depends on the seat shape, the area of the port before the seat and the shape of the chamber from the seat out as to what valve shape works best. I worked on developing these shapes over decades of doing headwork. I had seat cutters I designed for my head machine and had Sunnen make them for me as well as cutters for the chamber. I used to have all my valves custom made to my specs so everything worked together in concert.
Don't worry about the guides. There is very little to be gained there unless the area just before and at the guide is too narrow. The guide takes up part of the cross sectional area there. You want to maintain the cross sectional area as you approach the bowl. I used to start widening the sides of the port just before and at the guide to maintain the cross section. This gave me much better results than removing the guide from the area.
Mike
Last edited by v2racing; Jul 25, 2018 at 03:42 PM.
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
Adam, use paraffin wax on the carbide burrs for lube to prevent clogging. I even used bar soap in a pinch. Just spin the burr in the wax to fill the teeth before you start cutting. It will stop the burr clogging with aluminum and give you a much nicer finish. You'll be able to feel when it needs more wax.
On the valve shape, it really depends on the seat shape, the area of the port before the seat and the shape of the chamber from the seat out as to what valve shape works best. I worked on developing these shapes over decades of doing headwork. I had seat cutters I designed for my head machine and had Sunnen make them for me as well as cutters for the chamber. I used to have all my valves custom made to my specs so everything worked together in concert.
Don't worry about the guides. There is very little to be gained there unless the area just before and at the guide is too narrow. The guide takes up part of the cross sectional area there. You want to maintain the cross sectional area as you approach the bowl. I used to start widening the sides of the port just before and at the guide to maintain the cross section. This gave me much better results than removing the guide from the area.
Mike
On the valve shape, it really depends on the seat shape, the area of the port before the seat and the shape of the chamber from the seat out as to what valve shape works best. I worked on developing these shapes over decades of doing headwork. I had seat cutters I designed for my head machine and had Sunnen make them for me as well as cutters for the chamber. I used to have all my valves custom made to my specs so everything worked together in concert.
Don't worry about the guides. There is very little to be gained there unless the area just before and at the guide is too narrow. The guide takes up part of the cross sectional area there. You want to maintain the cross sectional area as you approach the bowl. I used to start widening the sides of the port just before and at the guide to maintain the cross section. This gave me much better results than removing the guide from the area.
Mike
Most of what you're saying about 10 degree vs 12 degree valves, I realize I have no way to understand to make a determination for my situation, but Ferrea told me to ask Profiler very pointedly if they thought that the 195cc head would benefit from the 12 degree angle on the back of the valves or not; if they answer, I'll be good-to-go. If not then I'll avoid screwing anything up and I won't make any changes there.
I'm kind of shocked by what you said about the guides; I'm going to try to interpret what I THINK you said to see if I get it right: "The CSA at each point of the exhaust port is important and the head designer probably took into account the fact that a valve guide would be where it is and adjusted the width of the port around the valve guide to account for it. Removing the guide just screws up the port by giving it more area than the head's designer intended(adds more area / slows down the flow in the part of the port that now has increased CSA)."
Adam
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
I understand what you're thinking about extra valve support, but I believe the brass insert is soft enough that it won't be doing any useful supporting when sticking into the port like that.
The recommendations for cutting the guide down in the port will be for cutting the boss around the insert and also making the insert flush to the end of it.
I recently saw a cast head that had guide inserts put in it and there was a valve where a gap was left between the insert and the head. It was shoddy workmanship trying to fix a head with a lot of guide wear. The valve rather quickly pushed the insert out into that gap leaving the insert oval. Point is that the brass insert wasn't strong enough to hold shape without the head material supporting it.
The recommendations for cutting the guide down in the port will be for cutting the boss around the insert and also making the insert flush to the end of it.
I recently saw a cast head that had guide inserts put in it and there was a valve where a gap was left between the insert and the head. It was shoddy workmanship trying to fix a head with a lot of guide wear. The valve rather quickly pushed the insert out into that gap leaving the insert oval. Point is that the brass insert wasn't strong enough to hold shape without the head material supporting it.
Melting Slicks
Joined: Mar 2008
Posts: 2,666
Likes: 289
From: Spring Park MN
Mike, good tip about the paraffin wax; is there anything I can do if I've already clogged up the carbide bit? (assuming not)
Most of what you're saying about 10 degree vs 12 degree valves, I realize I have no way to understand to make a determination for my situation, but Ferrea told me to ask Profiler very pointedly if they thought that the 195cc head would benefit from the 12 degree angle on the back of the valves or not; if they answer, I'll be good-to-go. If not then I'll avoid screwing anything up and I won't make any changes there.
I'm kind of shocked by what you said about the guides; I'm going to try to interpret what I THINK you said to see if I get it right: "The CSA at each point of the exhaust port is important and the head designer probably took into account the fact that a valve guide would be where it is and adjusted the width of the port around the valve guide to account for it. Removing the guide just screws up the port by giving it more area than the head's designer intended(adds more area / slows down the flow in the part of the port that now has increased CSA)."
Adam
Most of what you're saying about 10 degree vs 12 degree valves, I realize I have no way to understand to make a determination for my situation, but Ferrea told me to ask Profiler very pointedly if they thought that the 195cc head would benefit from the 12 degree angle on the back of the valves or not; if they answer, I'll be good-to-go. If not then I'll avoid screwing anything up and I won't make any changes there.
I'm kind of shocked by what you said about the guides; I'm going to try to interpret what I THINK you said to see if I get it right: "The CSA at each point of the exhaust port is important and the head designer probably took into account the fact that a valve guide would be where it is and adjusted the width of the port around the valve guide to account for it. Removing the guide just screws up the port by giving it more area than the head's designer intended(adds more area / slows down the flow in the part of the port that now has increased CSA)."
Adam
I wouldn't say removing the guide would cause problems, but I doubt there will be much gain. You could use your burr to taper the end of the guide to make it a little more streamlined.
Mike
Melting Slicks
Joined: Mar 2008
Posts: 2,666
Likes: 289
From: Spring Park MN
I understand what you're thinking about extra valve support, but I believe the brass insert is soft enough that it won't be doing any useful supporting when sticking into the port like that.
The recommendations for cutting the guide down in the port will be for cutting the boss around the insert and also making the insert flush to the end of it.
I recently saw a cast head that had guide inserts put in it and there was a valve where a gap was left between the insert and the head. It was shoddy workmanship trying to fix a head with a lot of guide wear. The valve rather quickly pushed the insert out into that gap leaving the insert oval. Point is that the brass insert wasn't strong enough to hold shape without the head material supporting it.
The recommendations for cutting the guide down in the port will be for cutting the boss around the insert and also making the insert flush to the end of it.
I recently saw a cast head that had guide inserts put in it and there was a valve where a gap was left between the insert and the head. It was shoddy workmanship trying to fix a head with a lot of guide wear. The valve rather quickly pushed the insert out into that gap leaving the insert oval. Point is that the brass insert wasn't strong enough to hold shape without the head material supporting it.
A bronze guide is a lot stiffer than you think, bronze is a fairly tuff material. Harleys, especially the old ones, have about a third of the guide hanging in the port. If you shorten them up, the guides life gets very short. I've seen valves bent pretty good and a bronze guide still be OK. The cast iron ones break if you hit anything.
Mike
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
v2 is giving good advice..ignore that vid of the guy cutting that guide down..
Ill look through my carbides, if I have what you need Ill mail it to you.
Tap Magic...try it sometime. It does help cut & keep your tool clear.
Ill look through my carbides, if I have what you need Ill mail it to you.
Tap Magic...try it sometime. It does help cut & keep your tool clear.
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Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
Adam
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
I came across a formula for estimating the min require valve guide length on SpeedTalk:
Valve Length * 1.15 * Valve stem diameter = min required
4.190 stock SBC * 1.15 * (11/32)=
4.190 * 1.15 * .34375 = 1.66"
It makes sense that the LONGER the valve, the more valve guide length you'd want, but I would've thought that the bigger the valve stem diameter, the more stable the valve would be and that you'd need LESS guide length as the valve stem diameter gets bigger.
The formula ignores valve lift completely which I'm pretty sure is supposed to be a major factor...
Adam
Valve Length * 1.15 * Valve stem diameter = min required
4.190 stock SBC * 1.15 * (11/32)=
4.190 * 1.15 * .34375 = 1.66"
It makes sense that the LONGER the valve, the more valve guide length you'd want, but I would've thought that the bigger the valve stem diameter, the more stable the valve would be and that you'd need LESS guide length as the valve stem diameter gets bigger.
The formula ignores valve lift completely which I'm pretty sure is supposed to be a major factor...
Adam
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
Well, I found out that the Beam cutter won't work. It only cuts up to 0.500" wide; my valve stems are 0.530" wide. The beam cutter also makes a very sharp edge, which is a bad thing on the inside of the valve guide especially on the port side, apparently. Beam's next size up cutter is 1" which is just WAY too big.
A proper valve guide cutter like the CompCams 4726 is designed to cut the TOP of the guide to accommodate smaller ID valve seals (for things like triple springs); that tool is $80+ with the required arbor, it properly chamfers the inside of the valve guide but it won't SHORTEN the valve guide if I were to just use the tool on the bottom side of the guide. I guess I could go super BUBBA and use a big *** drill bit to cut the guide down but I don't trust that remotely.
I think this is just too much of a PITA and too expensive for what is probably a 1-2 CFM gain and I'm just going to use my carbide to roughly "tear drop" the guide... Not whatt I wanted, but way more doable/ way less of a pain and way less $$$.
Adam
A proper valve guide cutter like the CompCams 4726 is designed to cut the TOP of the guide to accommodate smaller ID valve seals (for things like triple springs); that tool is $80+ with the required arbor, it properly chamfers the inside of the valve guide but it won't SHORTEN the valve guide if I were to just use the tool on the bottom side of the guide. I guess I could go super BUBBA and use a big *** drill bit to cut the guide down but I don't trust that remotely.
I think this is just too much of a PITA and too expensive for what is probably a 1-2 CFM gain and I'm just going to use my carbide to roughly "tear drop" the guide... Not whatt I wanted, but way more doable/ way less of a pain and way less $$$.
Adam
Last edited by NewbVetteGuy; Jul 27, 2018 at 01:26 PM.
Melting Slicks
Joined: Mar 2008
Posts: 2,666
Likes: 289
From: Spring Park MN
Well, I found out that the Beam cutter won't work. It only cuts up to 0.500" wide; my valve stems are 0.530" wide. The beam cutter also makes a very sharp edge, which is a bad thing on the inside of the valve guide especially on the port side, apparently. Beam's next size up cutter is 1" which is just WAY too big.
A proper valve guide cutter like the CompCams 4726 is designed to cut the TOP of the guide to accommodate smaller ID valve seals (for things like triple springs); that tool is $80+ with the required arbor, it properly chamfers the inside of the valve guide but it won't SHORTEN the valve guide if I were to just use the tool on the bottom side of the guide. I guess I could go super BUBBA and use a big *** drill bit to cut the guide down but I don't trust that remotely.
I think this is just too much of a PITA and too expensive for what is probably a 1-2 CFM gain and I'm just going to use my carbide to roughly "tear drop" the guide... Not whatt I wanted, but way more doable/ way less of a pain and way less $$$.
Adam
A proper valve guide cutter like the CompCams 4726 is designed to cut the TOP of the guide to accommodate smaller ID valve seals (for things like triple springs); that tool is $80+ with the required arbor, it properly chamfers the inside of the valve guide but it won't SHORTEN the valve guide if I were to just use the tool on the bottom side of the guide. I guess I could go super BUBBA and use a big *** drill bit to cut the guide down but I don't trust that remotely.
I think this is just too much of a PITA and too expensive for what is probably a 1-2 CFM gain and I'm just going to use my carbide to roughly "tear drop" the guide... Not whatt I wanted, but way more doable/ way less of a pain and way less $$$.
Adam
Mike
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
One of my favorite parts of having a hobby is that I'm allowed to over think things there way too much; my boss would never stand for it, I have to be productive / underthink things and just deal with the consequences at work.
-I had to go to professional brewing school in the UK and take a professional brewing industry certification exam @ Guinness in Dublin with their professional brewers to feel like I knew enough to make my own home brew beer in my garage... The Guinness guys were taking the exam to get a promotion, I was doing it for fun; they said "And what department do you work in, Yankee? We've never seen you before."
It wouldn't be as fun if I couldn't over think it; it would be work, then.
Adam
Last edited by NewbVetteGuy; Jul 27, 2018 at 03:07 PM.
Race Director
Joined: Jul 2015
Posts: 13,082
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From: SW Florida.
with some homework it looks like these guides are .500 OD. valves around .343 so there is .160 or so of guide there. .080 guide thickness. mebbe 82 or 83. and there is no boss blocking airflow like those procomp heads. I don't think it is worth it to mess with the guides if you start, you might as well trim some of the guide right off, leaving some but not as much protruding. a larger than .5 drill bit done freehand will also do the trick. but a flat cutter would be better.
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
Maybe +10 or +12 CFM / 20-24 HP. Any of the gains that improve airflow without changing the valve curtain area or min CSA, improve velociity. An average cfm gain of 10 cfm with these heads is a 3.6% increase in average port speeds (port speed and torque correlate very closely).
Lets say all the cleanup with hand tools is 7 CFM, that’s 14 HP for your time/effort.
Maybe with a combo on the edge of detonation, like mine, polishing chambers or exhaust helps you run 1 or 2 degrees more timing - another couple HP.
They're tiny gains percentage wise but they can add up and they’re the fun gains, imho because you get them with your own hands.
Adam