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Discussion Starter #201 (Edited)
Thanks, doing my best.

And finally........I ended up using the Valve lapping compound on a spare intake valve, the other intake valve was kept to check the face contact with the prussian blue. It's funny because Neway says valve lapping isn't required. Well, when using their hand valve grinder.......it's required. The carbide cutter was simply riding the high and low spots like a needle on a record player and just following the existing seat profile. This wouldn't have happened on rigid setup like a CNC. The lapping compound cut thru the high spots in about 10 minutes and left the valve nearly air tight, needs a bit more work and it'll be good to go. Really amazing how fast it worked. No seat cupping or any weird issues that the experts complain about, just a dead flat surface. I'll then have to lapp again to match every specific new valve to it's own seat, but for now I'm doing it to get the big dips and valley's out. It's weird because the carbide cutter makes it look like everything is getting cut perfectly even with the prussian blue dye, so it's very misleading. The valve concentricity gauge would have detected this up and down movement from the wavy valve seat, so I'm starting to think that it's a very wise investment of $150.

Anyhow, life is all about lessons learned.
 

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Yeah I will send my head out to get redone.
 

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Discussion Starter #203
Yeah, definitely do it. I know you were asking me a ton for the intake valve pics. Man, the intake/exhaust valves and ports were so bad honestly I couldn't believe a vehicle could physically run with that much oil and carbon in the valves/runners. On the engine rebuild I was like; "Maybe the head doesn't need a cleanup". I was kinda just looking for excuses to rebuild the engine, but it really did need it. I'd think pulling the head off with the motor in the engine bay isn't a ton more work than a timing chain swap. I know Portflow have a 2-week turnaround time, they are known for being consistent on that. I'm gonna try HeadGames for my EVO X, the mitsubishi guys seem found of them.

A lot of these weird idle, fuel economy, fuel trim, power issues, etc. I'm wondering isn't a problem from the carbon deposits and valve sealing. I'm telling you I could hit 31 mpg when my car was brand new and right before the car went down for the last couple of years I'd be lucky to crack 25 mpg no matter how I drove. The only thing in the entire engine that looked terrible was the cylinder head. An oil catch can & some water/meth injection for cleaning purposes only is probably the only way to minimize it. I did the Seafoam treatments and I feel it didn't achieve much after looking at the head, but it's better than nothing. I'm gonna try BG44k next time.
 

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Well thats not gonna be for a while. Stiffer Springs would be nice to increase the RPM Limit. But that would cost as much as the Turbo Bay Turbo and the power gain would not be as much either.

I am curious how much gunk I have with only 9,100 miles. I will boroscope it one day. Maybe just take off a spark plug and see if I can get it to bend upwards in the cylinder to see the Intake valve. I want to see the cylinder gunk anyway and maybe then take off the TB and run it down the intake plenum.
 

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Discussion Starter #205
Mac,

The sure way of getting the gunk off is to run a rotating wire brush, but the various solvents might help it loosen up a bit.

Update:

I've been learning some hard lessons during this rebuild. So, what I have now deduced is that MOST of the lapping compounds.....are junk for this level of detail work. I've gone into the limitations of the Neway carbide hand valve seat cutters and won't expound much more, but to just say they need a special technique to work consistently. They definitely can give a good result though, if slow going. Now, back to the valve lapping compounds. The stuff you buy from Autozone......never ever use that stuff. This is something close to 40 grit and this cuts massive deep ugly grooves into those pretty valve seats. This will take hours of clean up and require cutting deep thru the valve seat to level out. I then tried 120 grit, then 280 grit, with varying success.

So, starting with a cleaned up used intake valve which is almost ground to a mirror finish from the factory, I started using 800 grit lapping compound purchased from McMaster Carr. This compound leaves a nice frosted surface finish on the valve seat that is dead flat once everything is worked in a bit. This "frosting" is actually the initial method of checking a good honing/lapping, if there is a break or shiny spot in the frosted finish, you need to continue lapping or apply more lapping compound on continue on. This frosting is actually the silicon carbide embedded into the steel, so it's a good idea to wire brush it off afterwards. It takes maybe 2-3 times longer than the course grit compounds, but it's so much easier to achieve a nice clean consistent surface finish. If it's lapped for too long, then the valve seat does get "cupped", not so good. This is where I again pull out the carbide cutter, cleaning the seat first of the abrasive silicon carbide, and re-dress the valve seat by applying "light" cutting pressure to sweep or "straighten" the cut profile to a perfect 45* straight line again. If the surface finish looks good, I then move on, if not I start lapping again. The end goal is to get a perfectly even circuler contact ring that the valve sits on that is maybe .055" wide (intake). Now, some of the valves need only maybe 1-2 minutes of light lapping, and they were good to go. Others required 30 minutes of heavy lapping due to a badly cut seat, thus needing to be corrected.

OK, the reason for this level of intense machining is because the valve needs to seal 180-200 psi of air pressure during the compression stroke. With any kind of valve leakages, I'd be wasting precious compression from my fancy racing pistons, so it pays to sweat the details here. This'll also pay dividends in stable idle control while also helping to prevent misfires. A good seal also provides a nice heat path to cool the intake/exhaust valves. And a polished valve seat surface that is not too thin, will knock the carbon deposits off. Lot's going on here.
 
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