Hi Guys,

I’m experimenting a bit with tuning my cylinder head. I’m currently working on a valve job and pocket porting; using a coefficient of 0.87 for the 33mm intake valve gives me 28.36mm.
Unfortunately, that doesn't remove the casting flaw or notch located just below the valve seat.
I’m now considering a coefficient of 0.89, which yields 29mm, as that would allow me to remove more of that casting flaw.

What coefficient do you guys use when flowing the Savage head?

I don,t want to be that guy that remove,s to much and kills the flow.

Thanks for your five cents. I’m kind of torn on this one. The valve seat and its angles are the bottleneck—you can't afford to mess that up—but turbulence right in front of it isn't ideal either. I didn't build a flow bench, so I can't just gradually remove material and see what happens.

I don't have a Serdi machine, but I do have Wolf valve seat grinding equipment, so I can cut the angles very precisely and keep them sharp.

https://www.worthpoint.com/worthopedia/wolf-electric-valve-seat-grinder-set-5...  
It’s a slightly more recent version that I’ve refurbished.

Edit:

I’d like to revisit my earlier comment about achieving sharp transitions with grinding stones.
After playing around with the tool for a bit, I’ve realized it’s not ideal; the stones chatter against the seat, and within a blink of the eye, a groove forms in the stone, ruining the flat surfaces.
I got one seat done by turning the stones slowly but it takes forever.

Also, with a 33mm valve, there is practically no room for the 60-degree angle required for a 3-angle valve job. I was only able to create a small chamfer that looks more like deburring than anything else.

A slightly larger valve would solve this.
Some where in a topic I had heard "Dragbike Mike" wanting to usage a valve that was 1mm larger, and now I understand why.

That would allow for a 3-angle valve job and likely let you mill away that casting defect as well.
So, the next step is to look for a larger valve. Does anyone have tips as in were to find them?

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Thanks for thinking along. This device was made specifically for this purpose, so I think something else is going on. This device dates back to the 1950s and professionals used it daily.

I put some of the grinding stones in the ultrasonic cleaner with a de-greaser. The resin inside the stones may have partially dissolved, perhaps that is why they lose their shape at the slightest chatter.  

I would indeed outsource replacing those valve seats, because if even a bit of aluminum curls up during insertion, the job is ruined.

Thanks for that address on eBay , I'm going to contact him for a number of valves (probably 2).

I also found an address that has a Chrome Silicon Steel 34.5mm valve with a chrome-plated valve stem. Only the keylocking part doesn't match. The price including shipping works out very low. I'm going to test if I can make that modification on an old valve; that would save a lot of money.

Now that I look closely at the drawing of the eBay valve, my attention is drawn to the dotted line at the end of the valve; it looks as if the end is hollowed out.

Hi there DragBikeMike,
Nice to hear frome you.

I have several stones with the Wolf kit. None of them want to say what type of seating material they are intended for. And believe me, I have tortured them quite a bit.

I use this type of centering shaft: (see picture)

The pitch is +- 1.2mm and the diameter +- 14.29 mm

I have now managed to achieve a neat finish. Instead of using the supplied 16,000  driver or turning by hand, I am now using a cordless drill.
This allows me to still achieve a reasonable machining speed. The chatter is still difficult to avoid, but the stones remain intact now.

There is no play anywhere, not even in the stonedresser. I just overhauled it. Maybe that is the problem, and it needs to have a little play here and there.

I will keep experimenting.

I have decided not to install larger valves just yet.

I have now made the 45-degree surface the same size as the valve. And I am trying to approximate a 3-angle job as closely as possible.

It is clear that the seat is not centered in the head around the valve stem because the seat is not uniformly thick everywhere.

On the standard head, the valve job consists of 75-45 degrees. A 3-valve job isn't really feasible, but there is still room for improvement by making the seat uniformly thick everywhere and giving it the correct thickness. I think I will go with 0.875 to be able to smooth out any cosmetic flaws I made.

I am going to see if I can build a flow bench and if I still have room for it. We have two vacuums (three, actually), so that should work.
And I will have a look if I can find your topic about your flowbank.

Thank you for sharing your data and insights Mike. I appreciate it. It is most help full.
And you to fhinnhammer. Tanks

“The radius of the valve is much smaller than the original, and it has no undercut. So the flow will probably be lower.”

This is precisely why I suggest that you use some sort of measuring tool.  That new valve might actually flow better.  Only way to know for sure is some sort of repeatable test.  The flow bench permits you to always test at exactly the same test pressure.  So, you might find that the new valve flows better across the board, or the new valve might flow better at low lift, or flow better at high lift.  You might find that flow is improved with a narrower back cut rather than a wider back cut.  Sometimes something that looks intuitively obvious is actually not so good, like grinding away at the short-side radius.  It's actually very challenging and also very gratifying when you realize a significant gain without increasing port volume, and with a flow bench you will actually have conclusive evidence that your modifications work.


“And I will have a look if I can find your topic about your flowbank.”

Look no further, here it is.  The contraption is amazingly simple to construct.  Pretty easy to figure out and use.  Just a bunch of plastic pipe and clear tubing.  The links to DTEC will give you the in-depth info on orifice size, inclined manometer scale, etc.  No need to be very precise since you are simply using the rig to compare your before and after results to see if you are improving your head.  It's not intended to provide precise flow values for comparison to other cylinder heads or advertised flows.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1538442855/0#12


If you are uneasy with the epoxy buildup in the intake port, this old post shows how I tested the product.  I have lots & lots of miles on my current head and the epoxy is still hangin in there.  Haven't found anything suitable for the exhaust port, but the JB Weld High-Heat works great in the intake.  The only area of the intake port where the epoxy doesn't hold up well is the craters just above the valve seats. It seems to disappear from those divots in about 10,000 miles or so, probably because of its proximity to the combustion chamber (heat).  The area I built up along the short-side radius has held up admirably (much cooler there).

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1557210973


If you are curious about what sort of improvement you can expect from a ported head with stock 33mm intake valves, I think this old post provides some good data.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1627891507

zevenenergie wrote on Yesterday at 10:16:47:


I did not coat the intake port or the backside of the intake valves - I though that the cool air coming in would help cool the engine down, and that was more important to me than getting ultimate power.  I did coat the combustion chamber side of the intake valves to help keep the intake valves cooler.

I also did not coat the combustion chamber portion of the head.....maybe that would be a good idea as well.

I have not found anyone that has actually done testing on the Cerakote to prove how well it works.  The only testing I have ever seen is folks with torches showing the difference between coated/uncoated pistons.

My engine ran cooler when I installed the piston and coated head - but DragBikeMike found the flat top piston alone reduced the running temperature below what he experienced with the Pop Top piston.