The Head Thread (Rebuilding, Port, Polishing, Lapping, Flow Rates)

[KAT-PWR]

Hey guys been working on rebuilding and port/polishing this spare KA head that I have. Figured I would do a little write up on my experiences and consolidate the information available on this topic. This isn't a complete write up, and is rudimentary, but will update as I go.
For others, feel free to share your experiences, results, methods, and finished works or any data you have acquired

The KA24DE head has been shown to flow
Intake CFM at .XXX" of lift:

.100" = 99.3 CFM
.200" = 171.1 CFM
.300" = 223.4 CFM
.400" = 241.8 CFM
.500" = 243.6 CFM

As you can see it peaks at just over .400" lift

Exhaust CFM at .XXX" of lift:

.100" = 75.8 CFM
.200" = 144.5 CFM
.300" = 173.9 CFM
.400" = 182.9 CFM
.500" = 183.6 CFM

The SR20VE/DET head flows
Flow test was done on a completely stock SR20VE head. Machine used was a Superflow 600 test bench at 28" of H20 and low 80's temp.

SR20VE
Intake
Lift CFM
.050 49
.100 86.2
.150 122.6
.200 158.6
.250 192.5
.300 225
.350 249.2
.400 263.5
.450 272.9

Exhaust

Lift CFM
.050 46.5
.100 86
.150 118.5
.200 147
.250 171
.300 183.5
.350 188.8
.400 193
.450 196

Intake test at 28in H2O, temp 88deg F
SR20DET
Lift CFM
.060 43.4
.080 60.7
.120 92.9
.180 134.5
.260 175.6
.340 192..3
.440 201.8
.460 202.3
.480 203.5
.500 203.6


exhaust test at 28in H2O, temp 95deg F

Lift CFM
.100 41.1
.140 75.0
.200 98.2
.240 106.5
.280 110.2
.360 113.0
.440 114.3
.480 114.7
.500 114.9

* I do not claim this information as my own

[KAT-PWR]

Reserved for results

For the head rebuild you will need a couple tools. I HIGHLY recommend the JWT tool for KA24DE heads, this will make re-assembly very easy
http://www.jimwolftechnology.com/images/vq_tool4bsmall.jpg
(Tool available here http://www.jimwolftechnology.com/customer_part_detail.asp?PartID=485)

For disassembling the KA24de head I found the fastest, and sketchiest way is to use a 16mm or like socket and a hammer. Position the socket on top of the bucket and give it a solid hit with a hammer. If it goes as planned when you lift up the socket you will have removed both C shaped keepers. These keepers can go shooting off, perhaps putting a rag between the socket will help prevent this, I only had one keeper go shooting off and luckily it didn't go far. Then you can remove the bucket, spring, and shim that is under the spring. It is important to bag and label these parts to ensure the head goes back together exactly how it was taken apart.

Cleaning
Clean up your valves using a bench grinder bristle wheel. I was able to get the exhaust valves decently clean using Coke (yes the drink) let them soak over night and scrub with a stiff bristle brush.
http://www.musclecardiy.com/wp-content/uploads/2015/04/83.jpg
I used a card board box and punched some holes in it to keep the valves organized
http://i166.photobucket.com/albums/u116/waxball88/41A3440C-E95A-426B-8FE3-8790E5AD11F6_zpszfr5ywqp.jpg

Valve Lapping
For this method you can use the valve lapping suction cup tool or do what I did.
Buy some valve lapping compound and apply it around the under side edge of the valve where it will contact the seat.
Place the valve into its original seat with some oil on the valve stem, spinning is not a natural motion so I advise oiling or greasing it for this step.
http://i166.photobucket.com/albums/u116/waxball88/2B31D493-C3BC-4D41-9C70-7906D51E0A99_zpsyvs7jmv1.jpg
Then use a straight piece of vacuum hose through the top and push it onto the valve like so...
http://i166.photobucket.com/albums/u116/waxball88/DAF4C5E8-8F26-46D4-B9A7-FA7E8F38E1CD_zpsnzeojo9i.jpg
Then a fix the vacuum hose into a drill. Constant alternate direction and between each direction change push in so the valve lifts off the seat. This will re-distribute the lapping compound, then pull back toward the seat applying power. This should lap the valves fairly quickly. Once they seem lapped and have a uniform smooth pitch while spinning by hand inspect the valve and seat for a uniform seal.
Lapped nicely
http://i166.photobucket.com/albums/u116/waxball88/78873DA0-8BAA-473B-A38D-E79941C9A929_zps7uk9lmzl.jpg

[KAT-PWR]

Porting and Polishing

This is the big one. The last gentle who provided the information for the stock KA head low rates was able to get 15-20 CFM on the intake side and 10cfm on the exhaust side. A bit counter intuitive as the KA exhaust ports are so small in comparison to the intake ports.

TOOLS
Buy this pack of sanding drums from harbor freight, they run about $20 and you will definitely use most of them.
http://i166.photobucket.com/albums/u116/waxball88/1AB4099B-D7C3-4971-AE4E-5C6AB2FC13CE_zpsz98ygd6i.jpg
A dremel with flex shaft, this will be used for cleaning up and blending the valve seats and bowls. And for polishing.
http://i166.photobucket.com/albums/u116/waxball88/23D361EC-996C-4DBB-8346-1DD50CC82049_zpssdrbqqf9.jpg

Using a drill (I used air drill) First work on cleaning up all the poor castings. I apologize for the poor pictures.

Work on smoothing out any bumps and sharpening the divider (knife edge) and level the floor in front of it. This will take a fair bit of time, if you want to go crazy you could use a carbide to really cut out material followed by 80 grit to smooth it out. I'm more interested in a basic port job removing interruptions to flow
http://i166.photobucket.com/albums/u116/waxball88/1BD34EE3-015D-4E7B-B7C8-A4DD7C413398_zpsyelakjo0.jpg
http://i166.photobucket.com/albums/u116/waxball88/62C8F0CC-094A-4A82-8516-84317021813D_zps2lkjov0z.jpg
http://i166.photobucket.com/albums/u116/waxball88/5CDDF141-1112-4ECC-97D0-B1743D92728B_zpswesubaqk.jpg

[KAT-PWR]

Head Gasket finishing (Not finished)
[img]http://i166.photobucket.com/albums/u116/waxball88/5F955069-DB9A-49E9-8AFA-1C41CCAFF59B_zpsri8pr9yq.pngg]

[KAT-PWR]

JWT valve tool is a beast for re-assembly. Took about 45mins. You can see the supertech valves stem seals (Part # N7E) the KA uses the same seal for intake and exhaust.
http://i166.photobucket.com/albums/u116/waxball88/A9C44B12-44A0-4FCA-9542-7B5AED903727_zpsuh9cfxpg.jpg
http://i166.photobucket.com/albums/u116/waxball88/B336E799-0AE2-4C05-9184-6B6C63621672_zpsry5pdxlm.jpg
Water test the valves to ensure lapping was good, no leaks. Will re-test with gas before putting it back on. The intakes leaked when they were just set in so I was a bit worried I didn't lap them enough, but after putting the springs in they didn't leak a drop.
http://i166.photobucket.com/albums/u116/waxball88/437BB299-DAF0-436B-B0AC-E73443A0E078_zpsa14kksyo.jpg
Intakes polished up nice. I chose to just polish the long radius (roofs) and leave the short radius (floor) rough for the tumbling effect for the intake air
http://i166.photobucket.com/albums/u116/waxball88/658D4939-96FA-4F50-8AFE-222B6096F44C_zpstwhqsfqj.jpg
http://i166.photobucket.com/albums/u116/waxball88/98D178BA-CC46-49DD-BF23-CA011006BCA1_zpswbf4ykik.jpg
Valve bowls
http://i166.photobucket.com/albums/u116/waxball88/978088EA-5B52-45D2-81A2-6DB07D954071_zpsvtihreld.jpg

Please post up if you've done any work on your heads!

[Sforteen]

Didnt know the KA heads flowed that well let alone better than an SR20

[Frank_Jaeger]

What tool would you recommend for the SR20?

[hanzbrady]

What tool would you recommend for the SR20?

If you're talking about for the springs and retainers I recommend the Snap-On style that bolts to your head like this, https://store.snapon.com/Valve-Spring-Compressors-Compressor-Valve-Spring-Universal-P754870.aspx

That's what I used on my head and you can get a sping installed in less than a minute once you get the technique down.

As for the port and polish you'd use the same tools.

[RalliartRsX]

I see a fair amount of pitting in the "bowl". Will all that be cleaned up??

[KAT-PWR]

In the combustion chamber? I tried to level it out more but got scared using more aggressive grits so close to valve seats.
These pictures are not in chronological order as I went back to several steps multiple times.

[hanzbrady]

In the combustion chamber? I tried to level it out more but got scared using more aggressive grits so close to valve seats.
These pictures are not in chronological order as I went back to several steps multiple times.

It's pretty much always going to have "pitting" due to our heads being cast pieces. The only way you could 100% get rid of pitting in the chambers is get extremely lucky taking material out or tig all of the pits closed

[KAT-PWR]

Le sigh, that is the truth.

[hanzbrady]

Just to show that you're not alone, mine have some minor pitting that's filled with compound in these photos (just look for the black specs)

http://i1369.photobucket.com/albums/ag214/HanzB_/240%20build%20v2/IMG_0845_zps9f0mlkbh.jpg

http://i1369.photobucket.com/albums/ag214/HanzB_/240%20build%20v2/IMG_0847_zpsbicrwp0r.jpg

Also keep in mind that mine and your are hand done, the CNC service that we offer in store yields a better result

[jr_ss]

I see you borrowed my info for the VE flow numbers... ��

I'll see if I can find some completely worked flow numbers or various stages to have documented in this thread.

[KAT-PWR]

Nice, please do man. The more info the better

[Hoonigan19]

awesome write up and pictures man! keep em coming!