Valve Cleaning, How To Do It and Why?

How much blast media by weight do you folks find you use for a set of valves? Finding 4lbs to 50lbs boxes of the stuff

 

i bought a 25lb box from harbor freight. used a few lbs of it. wrapped it up and will keep it for next time. was way too much but it's cheap enough that you don't want to run out in the middle of the operation.

 

Will be tackling this job in the coming month or so. Gonna do B12 / picks then blast (both is better than just one method, right?)

Question on the walnut blasting - what PSI / media blaster did you guys use? I'm waffling because I want to buy one that's decent enough to work correctly but also not overspend on something that I'll likely only use once a year moving forward.

Edit: Haven't been able to find a good reason NOT to, but was wondering - is it a bad idea to use a cordless drill + wire brush to try and...clean / semi-polish the runners? I know I've read people being mildly concerned about bristles coming off but I feel like you can just vacuum them out / use a flashlight to make sure none are in there but I am the cautious type. Would love to save my elbow from using a toothbrush for 4 hours.

 

Don't need to do picks and blast unless it's really bad b12 and blast or B12 in picks should be plenty

Corksport makes a nice adaptor for valve cleaning, you don't need anything too fancy when it comes to media blasting gun something like this works


If you want to go down the wire brush thread Checkout this thread
https://mazdaspeeds.org/index.php?threads/how-to-clean-your-valves.9851/

 

this is the one i used:

https://www.harborfreight.com/21-oz...mUO97EUQBppiojNed6jTno7_GmSnmTz4aAutiEALw_wcB

i did have to drill out the bottom hole if i recall as it was a little off center and needed some widening so the media would flow nicely. i also created my own adapter using some hose and an extra shopvac wand. it was cheaper than the corksport adapter (albeit not as nice...still worked just fine).

i personally used the pics, the b12, a tooth brush and the walnuts to ensure all was clean and ready to go. depends on how much build up you have and how long it's been. i didn't want to spend all that time tearing into it and then not get it as clean as i could. also, once it was all ready to be cleaned, i sprayed that b12 in there and let it sit overnight. maybe that was overkill, but it let it soak and get as much loosened as possible. i also used a rag to block the walnuts from spraying back out and so they would all be vac'd out.

overall i was happy with my process and with the results. but depending on how much time and effort you want to put in to it, you could probably get away with modifying the process to fit said time/effort. good luck to you!

 

So I purchased the car at ~80k miles and it's at about 99k now, and I'm willing to bet a pretty penny the valves have never been done so I'm expecting it to be pretty caked on there...hence the possibly wrong assumption that I'd need to do both the B12/ picks AND the blast. I'll take some pics to show yall what it looks like if anyone's curious what nearly 100k looks like.

I'll be doing HPFP internals, Accessport, Intake, TIP, injector seals / o-rings, fuel pump e85 safe o-rings, OCC upgrade, and EGR delete as well as turbo-back exhaust at the same time, so I wanted to make absolutely certain those valves are as clean as can be so I can only have to do it 1x a year moving forward, esp with plans to go to a CST4/5 and FMIC some time this summer.

Thank you for the advice, I'm sure I'll be asking other questions as the weeks roll by since I'm finally getting into the meat and potatoes of upgrading, but seeing as this is my first direct injection vehicle, I want to make sure I do this right and the best way possible.

 

damn. you got a lot goin on. FWIW, i plan on doing this every 15k miles or so.

 

more like 30-40k

 

Yeah, my last 'fun' car was a 300zx TT pushing 450 rwhp so it's time to get this Mazda a bit more pep since I'm missing that 'go' feeling . I think that'll be about my interval as well, and I average around 15k a year (when I didn't work full-time remote) so yearly is feasible / not too painful to imagine...we'll see if my opinion changes once I go to get the IM off!

 

i should caveat that i only put about 3500 miles on my car in the summer nowadays. so it'll be a few years before i do it again. 30k would be a decade between services. maybe that's fine...

not sure if you've done a tear down like that before...but i was most nervous that i'd forget to plug something in or be left with an extra bolt, etc. so i bagged/tagged everything i could; put tape on hoses with notes/directions and even took pics as i thought it would be needed. i was also changing my downpipe and a few other things so i had to keep all that in mind. luckily i didn't FUBAR anything.

thank god @JohnnyTightlips was a patient guy with all my messages to him. he was a calming voice.

 

I have indeed. My experience with cars started early, as my dad was a 'I won't pay someone to do anything unless I physically can't get the tools / parts myself' so I learned on several vehicles growing up. That gave me the (perhaps wrongly placed) confidence when I was 18 to take on a 13b Rotary rebuild for my S5 RX-7 which was...let me tell ya - really, really dumb choice for a 'first' engine rebuild but I learned a lot over that 10 months xD.

I'm just like you though - not only do I bag / tag, I, too, take pictures of each step from the same angle with my finger / tape touching the part I'm removing...maybe overkill, but I have that same perpetual concern - 'oh shit, what if I forget something and blow this up...'

That said, I'm honestly looking forward to working on this engine / car in general...if you're unfamiliar with 300zx TT's, (or even the NA's), their engine bay makes the Mazdaspeed 3 look like you could step into it and you basically had to either pull the entire motor to do any significant work (re: turbo upgrades etc) or literally develop your own tools. There are a few franken-wrenches that are common in the 300zx world and I have yet to encounter any processes / directions for this car that look nearly as painful...maybe the downpipe but otherwise, I think I'll enjoy the work (aside from valve cleaning).

Thanks for the excellent advice!

 

Personally, I'm not going to spend much time on the runners. I'll use a toothbrush and carb cleaner to try and degrease as much as possible and remove any leftover bits of media and then give it all one last blast of brake cleaner and air and call it done.

Everything, and I mean everything will start to get dirty again almost immediately.

This job is a prime candidate for the 80/20 rule...good enough is likely to be good enough, and something is better than nothing.

 

I’ve got 107k on the clock and have never done mine. Been dealing with the after effects from my motorcycle accident for almost two years now. Mazda only sees summer use and at this point it will never be done or I’ll find someone to pay to do it.

 

I did mine at around 47k and it was absolutely filthy. I hadn’t done an EGR delete at that point either. Did it all at once. It’s worth doing if you can find a way.


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I definitely need to get it done. I should be off crutches in a couple weeks. Summer wheels are being dropped off for powder coat tomorrow. It’s probably going to have to wait until I put it up for the winter again I think. Today was the first time I’ve driven it since September. At least I still have brand new winter tires.