Splayed Valve Heads Porting

[FieroWanaBe1]

Further updated.
Data in this is for 706 LS heads, sorry I dont have all the data for a full LX9 input.
But only input cells can be edited.
Graphs references fixed
cell formatting updates for blank flow inputs.
formulas triple checked for validity.

[FieroWanaBe1]

Suzuki 2 Valve Drag Bike port.

kanal.jpg (28.96 KiB) Viewed 19316 times

[ericjon262]

I'd like to make some port molds, do either of you have a specific material you use for the molds?

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so, on the NASCAR heads, what things are similar enough to look at? well, the valves are valves, they can me measured and examined, other than that combustion chambers share a similar shape, so we can make comparisons there. I cleaned the carbon off the deck of the R07 head so that only the chamber had carbon, to illustrate the shape.





First thing of note, is that on the V6, the valves are all more or less inline cylinder to cylinder. on the R07, they're diagonal across each chamber.





The R07 layout helps make the intake and exhaust ports shorter/smaller, in the head. it also moves the exhaust port further from the center of the engine, which I imagine helps with cooling.

the spark plug in each head seems to be closer to the exhaust valve than the intake valve, although both are centrally located.





The valve seats on the R07 are some copper alloy, I believe Beryllium copper? the that actual seating area on the valves is pretty small, although I haven't measured them yet. the valve seats on the LX9 are steel alloy. The R07 valves also seem to have a DLC or other hard coating on them, they do not scratch easily, they're also Ti, so the R07 valves, while being significantly larger, weigh about the same.





This area of the R07 head is deeper, and the valve appears to be closer to the cylinder wall, compared to the LX9



and I think it's readily apparent that the R07's combustion chamber, while being a similar shape, is way smoother than the LX9 chamber. I'm thinking I'll probably smooth the LX9 chamber to make it similar to the R07 in this respect.

Valves... Stock valves are 1.76" and 1.425", later versions of this engine family were equipped with 1.87" and 1.52" valves, I have a set of those heads, so I popped the valves out for a test fit.

on the left, later valves, on the right, stock. to the naked eye looking at a picture, this looks promising, however, because the valves point towards each other, at very low lifts they collide, low enough that I'm concerned extremely small amounts of overlap would result in them hitting. I'll try and take measurements



in this picture I swapped the exhaust valves, the port on the left has a larger intake, and stock exhaust, the port on the right, has a stock intake, and larger exhaust. the net result is that both situations require about .300" of valve lift before contact. I'll draw some lift curves for my cam and see where I can go. I'm probably going to do something in the middle of both of these, install a 1.8" intake, and the 1.52" exhaust, this will require the installation of new seats at least on the exhaust side, might be smart for the intakes as well at this point. The intake ports size in this case, is being limited by the LIM gasket opening, so going to the biggest intake valve probably isn't worth as much because the whole port can't be enlarged proportionally.



I also have another ace up my sleeve that I might throw at this, but I'm not ready to divulge that idea yet.

[FieroWanaBe1]

R07 valves are probably moved around to push the intake further away from the cylinder wall. Similar to the twisted wedge heads for Ford motors.

You can also increase only the intake valve size, and leave the exhaust alone while still having an adequate exhaust to intake flow ratio.
Push the hole cylinder head further over by a 10-20 thousands and get the intake valve further off the cylinder wall?

I have this kit but have yet to use it on my SD4 head.
https://deltronproducts.com/products/po ... -maker-kit

[ericjon262]

R07 valves are probably moved around to push the intake further away from the cylinder wall. Similar to the twisted wedge heads for Ford motors.

You can also increase only the intake valve size, and leave the exhaust alone while still having an adequate exhaust to intake flow ratio.
Push the hole cylinder head further over by a 10-20 thousands and get the intake valve further off the cylinder wall?

I haven't measured, but both heads open the valve away from the cylinder wall, and appear to be similarly located relative to the cylinder wall.

My R07-- 2.2/1.615=1.36
LX9 --1.76/1.425=1.23
LZX --1.87/1.52=1.23

Possible combinations using known available valves

1.87/1.425=1.31
1.84/1.425=1.29
1.80/1.425=1.26
1.76/1.52=1.16
1.80/1.52=1.18
1.84/1.52=1.21

Some things that I think are worth considering,

------obviously the intake port can only get so big, what's the limiting factor? I think it's really the intake gasket, it's already close to the size of the port, without a significant amount of room, to get bigger



I can make the valve bigger and bigger, but I can't make the port match.

------The engine in my car is unlike the R07 in a major way, (lol, more than one) but in this case, my engine is turbocharged, it's not naturally aspirated, I can't do much for the intake, but the exhaust has way more room to get bigger, which could help considering the turbo is pushing air into the engine. because of this, I think increasing the exhaust size and flow could be worthwhile in my application. At present, my plan is to upsize the intake valve to 1.84, and the exhaust to 1.52, unfortunately, this will require new valve seats for both the intake and exhaust, I've been told that it's possible to get away with 1.8" intake valves on stock seats, but measuring the stock seats, I'd rather larger seats be installed.

I have this kit but have yet to use it on my SD4 head.
https://deltronproducts.com/products/po ... -maker-kit

Thanks!

[FieroWanaBe1]

I haven't measured, but both heads open the valve away from the cylinder wall, and appear to be similarly located relative to the cylinder wall.

My R07-- 2.2/1.615=1.36
LX9 --1.76/1.425=1.23
LZX --1.87/1.52=1.23

Possible combinations using known available valves

1.87/1.425=1.31
1.84/1.425=1.29
1.80/1.425=1.26
1.76/1.52=1.16
1.80/1.52=1.18
1.84/1.52=1.21

Some things that I think are worth considering,

------The engine in my car is unlike the R07 in a major way, (lol, more than one) but in this case, my engine is turbocharged, it's not naturally aspirated, I can't do much for the intake, but the exhaust has way more room to get bigger, which could help considering the turbo is pushing air into the engine. because of this, I think increasing the exhaust size and flow could be worthwhile in my application. At present, my plan is to upsize the intake valve to 1.84, and the exhaust to 1.52, unfortunately, this will require new valve seats for both the intake and exhaust, I've been told that it's possible to get away with 1.8" intake valves on stock seats, but measuring the stock seats, I'd rather larger seats be installed.

Larger seats is quite a cost adder for machining, if you can have a full margin on stock seats My recommendation would be use the stock seats and guides as long as you can. GM gets better alloys at much lower costs than any of the aftermarket suppliers, and you will find plenty of racers/streetstrip types complaining about premature cylinder head wear due to the bronze and iron parts used where the OEM has PM parts with better thermal and wear properties, Unless, of course, you plan to use Ti valves.

Valve to valve clearance and Piston to valve clearance aside, the running theory today from what I gather is, now that dual pattern cams are common place, the exhaust flow is secondary to intake flow and layout, there is plenty of time to add more duration, and plenty of blow down pressure to evacuate a cylinder, without affecting the shape of the curve as much as intake timing does. Some camshafts sold off the shelf have 20 degrees more exhaust duration over the intake.

[Shaun41178(2)]

Some camshafts sold off the shelf have 20 degrees more exhaust duration over the intake.

On ls setups the additional duration on exhaust always Dyno higher than less duration on say a reverse pattern cam.. Our motors are similar to LS engines. The person who tries to hock his upside down cams uses less duration on exhaust than intake which gives up power. Bad implementation by that retailer. Stay away

[ericjon262]

Larger seats is quite a cost adder for machining, if you can have a full margin on stock seats My recommendation would be use the stock seats and guides as long as you can. GM gets better alloys at much lower costs than any of the aftermarket suppliers, and you will find plenty of racers/streetstrip types complaining about premature cylinder head wear due to the bronze and iron parts used where the OEM has PM parts with better thermal and wear properties, Unless, of course, you plan to use Ti valves.

I planned to talk to my machinist about the seats and see just how much of a cost difference it would be. the material quality is a very good point though. I would love to install Ti valves, unfortunately, they're prohibitively expensive, and have their own wear concerns. My concern with the stock seats, is that the seat cut would be on the edge of the valve seat, which could produce a stress riser and premature failure of the seat, or the aluminum around the seat if the seat has too much flex from being thinned out.

Valve to valve clearance and Piston to valve clearance aside, the running theory today from what I gather is, now that dual pattern cams are common place, the exhaust flow is secondary to intake flow and layout, there is plenty of time to add more duration, and plenty of blow down pressure to evacuate a cylinder, without affecting the shape of the curve as much as intake timing does. Some camshafts sold off the shelf have 20 degrees more exhaust duration over the intake.

My custom ground has more exhaust than intake duration as well.

Duration at .006"--------------266/282
Duration at .050"--------------216/230
Duration at .200"--------------141/152
Lobe lift ----------------------.354"/.355"
valve lift with 1.6 rocker --.566"/.568"

At this point, I'm looking at where I can make changes, that can have an impact. I can make the intake valve larger, but I really don't have much room to change the rest of the port to accommodate the larger valve, the intake gasket/port mouth being the limiting factor. I'm planning on making a few port molds and looking at CSA throughout the port to see how the area changes as it approaches the seat, and how much those areas can/should be changed as valve size goes up.

the intake manifold itself also presents itself as a factor, but I'm slowly working towards a custom manifold that will hopefully provide significant gains over the stock intake.

[ericjon262]

I got new valves in, and have been researching backcuts, and other possible modifications to the valves.

From the small amount of research I have currently performed, it's suggested that a ~30 degree back cut on the intake makes a massive difference, on the exhaust, it's suggested not to back cut at all, because it could potentially result in an increase in reversion. if anyone has any papers or articles on cutting valves and seats, I would be interested to see what they say.

I'm especially interested in the idea of David Vizard's "conformation groove" he claims a large reduction in reversion from it, but from what I have seen, it seems as though it was only one run of testing, on one engine with 30 degree valve seats, and heads that tended to deform the seats.

[ericjon262]

heads and valves are at the machine shop, said it would probably be a week or two, we'll start tearing into them when they get back.