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Old 05-06-2012, 12:31 PM   #1
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Default Bought a 99 head with bent valves. Input needed.

First a little background:
I finally have all my ducks in a row and I am about to start the build on my 97. The idea is to have a affordable and reliable Track/auto-x car, with low maintenance cost (The 949 rental formula).

So I buy this head, I take it home and measure the valve lash and its out of spec. That sucks, because the seller said it had been "adjusted" recently- whatever its a used part. I take the head to the machine shop and drop it off to be checked and shaved. In the meantime I go home and do the math for the shims I need, and discover they don't make a shim thick enough to get the lash within limits on a few of the valve's. Then on cue the machinist calls and confirms what I suspected, I had some bent valves.

So right now my problem is this- Do I go all in and just go ahead and build the head with the better valvetrain components or should I just cut my losses and focus on the areas of the car that I want (suspension/safety)

Your input will be appreciated.
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Old 05-06-2012, 12:44 PM   #2
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I thinksomeone was selling some Valves on the forum. Tough call, but I think I woulg go with new +1 valves, springs, backcut, 3, angle job, to raise redline and flow. I think but heads retain there value pretty well, which is good if you ever decide to part with it. Just make sure you keep all receipts for parts and work done.

Other option. abandon this head a spend money on a good vvt head. Assuming you have a way to control vvt, then gains might offset a built 99 head. Im no knowledgeable enough about vvt to make tis call.
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Old 05-06-2012, 12:56 PM   #3
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The goal is cheap and reliable. Put new/used oem parts back in it (preferably used ones) and just go beat the **** out of it. That's the 949 formula, right?
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Old 05-06-2012, 01:00 PM   #4
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If you are going to track the car, do SS or SS/Inco valves. If not, stock valvetrain will work.
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Old 05-06-2012, 01:54 PM   #5
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Quote:
Originally Posted by djp0623 View Post
I thinksomeone was selling some Valves on the forum.
LOL yes,I had seen that thread, they were sold by the time I got word from the machine shop, it was the first option I thought of.

I also checked with the local mazda dealer here and the OEM valves are significantly more expensive than supertech's. So If I have to spend the money might as well get something better.

Has anyone ever used the supertech valves with stock retainers? I dont really like the idea but I didnt want to put much into the internals of the engine yet, at least until I get the suspension/rolllbar/ wheels and tires and brakes sorted out.

Im not worried about price, but within my budget it may mean the differance between XIDA CS and Koni Race/GC coilovers.
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Old 05-06-2012, 03:31 PM   #6
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I discovered a bent exhaust valve when I did my rebuild the first time around. A new stock sized one was like $8 if I remember correctly? You can just replace the bad ones if you're on a budget, but I would let the shop make that call.
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Old 05-06-2012, 03:54 PM   #7
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I am pretty sure I have a bunch of stock valve train components-you need how many stock valves? If I have them I'll send them to you for the cost of shipping
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Old 05-06-2012, 08:06 PM   #8
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Flounder did you buy yours from mazda? Because the parts guy here quoted me $50.54 per valve for the exhaust and 31.34 for the intake. That seemed REALLY REALLY high to me, like Vegas call girl type price.

Thanks Kaisersoze, I will know more on Monday when I talk to the machinist, from looking at the head myself there on Friday I would say that most if not all the intake valves are bent. I will definitively let you know, at least let me paypal you some beer money for the trouble lol.
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Old 05-06-2012, 08:20 PM   #9
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And it's not like the offending valve's are bent a lot, just enough that I couldn't see any light in the runner when I checked when I picked it up, before it was cleaned. The deposits on the valves were just enough to fill the gap. I dont think it was a broken T-belt or over rev that caused it then, because they would be really bent from that. I think who ever installed it last bolted the head down with the cams out of time.
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Old 05-06-2012, 08:50 PM   #10
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I bought mine from a local engine parts shop. I do get parts at a discount, but I can't imagine it being more than 15 bucks a piece for EX valves, maybe slightly more for an IN. Did you try rockauto.com?

The miata's engine is non-interference, so if the machine shop says it's bent it's probably due to over rev or mishandling of the head when it was off the vehicle.
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Old 05-06-2012, 08:59 PM   #11
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I haven't tried rockauto.com yet, I'll look them up now
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Old 05-06-2012, 09:55 PM   #12
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Rockauto has them for 9-10 bucks each.
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Old 05-06-2012, 10:20 PM   #13
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I really don't mind. I have a bunch of extra stuff from various heads I have. I bought JayL's old VVT head and it has a built valvetrain as well so I really have no need of all of these stock valves-most of them are cleaned up. You need some valve springs too? check your old ones to make sure they in spec if you don't replace them with supertechs(which I would recommend). I just don't want to eat the shipping costs(which will be nominal)
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Old 05-06-2012, 10:26 PM   #14
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Yep, Ill probably go this route. I don't mind putting the money in for better stuff, but there are more important things to be addressed right now (w/ the car as a whole) And i'm not looking for anymore than 160 hp or to spin it any higher in the long run anyway.
Thanks for the help
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Old 05-07-2012, 11:33 AM   #15
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I wouls shy away from the "cheap" replacement valves and get good used OE ones.

SOME of the OE replacement valves are a 2 peice design, that means the stem is heat welded to the valve head, and that is a weak spot.

If you were doing a box stock NA build they would be fine. But if you are going to up the numbers down the road, get a good aftermarket SS or OE valve.
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Old 05-07-2012, 11:56 AM   #16
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youre fortunate that this is your issue. could've been way worse....just swap the valves for stock and be done with it
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Old 05-07-2012, 11:18 PM   #17
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Yep that's whats been done, only four of them ended up being bent.
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Old 05-14-2012, 10:27 PM   #18
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you already have the entire head apart. Do a valve job. You will take materiel from the valve seat out raising the valve. No need for shims, now take the measurements and start fresh, you should have more then enough room to work with. Id take .0020 off the head since your in there. Get a little compression bump.
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Old 05-16-2012, 10:57 PM   #19
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Yep, I got the head back last week- valve job, 4 new valves, seals and shaved the head .015
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Old 05-17-2012, 01:08 PM   #20
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.015 is a wack to take off.

Your head was warped that bad? Or was there other surface imperfections that needed milled out?

Post a pic of your surface finish.
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