HOW TO: (w/ pics) STI cams in WRX heads

[Spec V to Wagon]

I searched and didn't find to much so I'm writing something up myself. My motor took a dump so I'm doing a 2.5 hybrid and I'm using STi cams. As you know STI cams can be used but the AVCS plugs need to filled. You can either weld them or plug them. I decided to plug them.

First you'll need some supplies

1. Eight (8) 5mmx5mm .8thread set screws

2. 5mm x.8 pictch tap

3. Red loctite

4. STi cams
5. Some grease
6. File
7. Carb cleaner
8. 2.5mm allen key

Step one.
Put some grease on the tap and run it down into each hole on the front side of the cam (4 on each cam.) Only the intake cams have these holes. Make sure that after each turn or so you back the tap out to clean off the filings.



Step two.
Make sure that all your holes are deep enough. The set screws want to be just below the surface of the cam. If they are deep enough you want to take the file and clean the face of the cam as when you tap it you'll pull material to the surface. Be carefull to not file the face of the cam to much.

Step three
Take the carb cleaner and clean all the holes with carb cleaner really well and make sure they are dry.

Step four.
Apply red loctite to the the threads of the set screws and screw them into the cam. Seat them just below the surface of the cam face.




Step five.
Enjoy.

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[wrxhard]

Ummmm... Carb cleaner usually leaves a light oily residue, i HIGHLY recommend using brake cleaner. The oily residue will affect how and if the loctite sets up.

[S L O W W R X]

Nice writeup thanks

[Spec V to Wagon]

Originally Posted by wrxhard

Ummmm... Carb cleaner usually leaves a light oily residue, i HIGHLY recommend using brake cleaner. The oily residue will affect how and if the loctite sets up.

They set up very quickly. My turner told me to use carb cleaner so I did. But good advice to look out for.

[Bombay994]

I'm a few days away from my motor tear down and will be doing the same 2.5 hybrid with the STI cam swap....greatly appreciate this post...huge help!

[turboL]

glad to see the cams worked out well for you jeff. Order buckets yet?

Nice.

[Paulys05wrx]

Thanks to Spec V for the write up... I followed it pretty much to the T. I had a few problems; The M5 tap I was using was a bit large in diameter and I had a hard time getting it in. My solution was to drill out the holes just a bit until my tap fit. My suggestion to anyone else who is doing this is to use a 8/32 tap which fits perfect but I do not know if you can find 8/32 set screws so I stuck with the above parts. Anyways just throwing my two sense in and here are a few pics of my finished product.

[jaxscuby]

nice job on the write up..

[wrx2k4]

+1 good stuff!

[8Complex]

FWIW, the tap drill diameter for a M5x0.8 thread should be 4.2 (0.165"). If you drill those holes up to that size before tapping, everything should go smoothly.

Rule of thumb for metric threads, tap drill = thread diameter minus pitch (5 - 0.8 = 4.2).

[02wrximpreza]

Would it be worth while doing the cam swap in a WRX? Using WRX block and head?

If so what would the pros and cons be anyone know?

[LiquidForce]

Why isn't this thread a sticky?

[Ralliart4]

Please make this a sticky...

[wrxwagon253]

Im getting ready to throw sti cams in my wrx heads and finish up my hybrid build..My question is are you guys still using stock wrx valvetrain with the sti cams? Im looking to do the same but am on a budget so im trying to see what my options are and whats in my best interest..Thanks

[paintbing]

Originally Posted by wrxwagon253

Im getting ready to throw sti cams in my wrx heads and finish up my hybrid build..My question is are you guys still using stock wrx valvetrain with the sti cams? Im looking to do the same but am on a budget so im trying to see what my options are and whats in my best interest..Thanks

As the only difference in the STI cams and the WRX cams is the lift, you will be able to reuse the WRX valvetrain. I suggest you take the heads to a machine shop to be refurbished and have the lash set though. It's well worth the money.

[Paulys05wrx]

Yes you may use the WRX valvetrain with no problems. Just check and re-check the valve lash and everything should be good! Good luck. Mine are on my motor now and it is getting put back in this weekend.

[AdamBOMB_STi]

Awesome stuff man!

shameless plug, but I have a set of stock USDM 04 STi cams for sale.

[Paulys05wrx]

Okay, I have everything in and ready to be started shortly. I am very very scared and concerned that the plugs I put in might leak. I have no reason to be concerned as i did the mod correctly it's just my human nature to worry I guess. Lets just say somehow a little bit of oil gets through those plugs, whats the worst case scenario? Oil leak from the cam seals area? Any comments are welcome to help calm my nerves.

[Spec V to Wagon]

I forgot about this thread and I was going through my photobucket account and saw the pictures were still hosted.

glad I could be a service!

As answered just doing the STI swap into a stock block and head wrx isn't worth the trouble. Though the stock valve train can be used cause the STI cams only have a higher lift.

[turboL]

doing mine now jeff. but wtf, tapping these holes is a bitch. My hands are raw, the tool is stripped (not the tap but the tap holder)...and I am only done two.

[wrxwagon253]

Is there a easier way of plugging the holes that anyone knows of?

[turboL]

JB weld.

[Spec V to Wagon]

Originally Posted by turboL

doing mine now jeff. but wtf, tapping these holes is a bitch. My hands are raw, the tool is stripped (not the tap but the tap holder)...and I am only done two.

Make sure you use grease and back the tap completly out after like one full turn. The **** that grinds off will bind the hell out of the tap and make it very hard to keep going.

Like posted above, drilling the holes a little bigger will also work, though I don't know what size bit to use.

[turboL]

i drilled it...and then it was easier than pie.