AbeFM

iTrader: (3)

I have (crap) oversized valves in a head, hence I need to replace them with... oversized valves. I could swear the last set I got were SI, but they lasted a few hundred miles before sinking, and they are missing MILLIMETERS of material on the intake.

So I call mazda to get some from them, they don't have oversized. On a whim, I ask what the MSM uses. Here's what I got:

Stock '00 Valves:
VALVE,EXHAUST Part No : BP4W-12-121
VALVE,INLET Part No : BP4W-12-111 (for NB353*122764–)
VALVE,INLET Part No : BP2Y-12-111 (for NB353*–122764)

'05 MSM valves:
VALVE,EXHAUST Part No : BP6F-12-121
VALVE,INLET Part No : BP6D-12-111

The springs are different, too, 'because of VVT', but I have my doubts, and not just since there's no VVT on that head.

Anyway, does someone know what the differences are, and could I use them?
-Abe.

AbeFM

iTrader: (3)

Just while I'm taking notes here...

Ferrea Racing, competition plus line:
MAZDA MIATA 1.8L - DOHC 16 VALVE (BP056) - 1994-2002 (Hydraulic & Solid Buckets)
Stock Size:
F1829P E 28 mm 6 mm 102.25 mm 3.5 mm 25º Flo. Stock size. Super Alloy
F1827P I 33 mm 6 mm 102.10 mm 3.5 mm 25º Super Flo. Stock size
+1mm size:
F1830P E 29 mm 6 mm 102.25 mm 3.5 mm 25º Flo. 1 mm oversize. Super Alloy
F1828P I 34 mm 6 mm 102.10 mm 3.5 mm 25º Super Flo. 1 mm oversize

http://www.importperformanceparts.ne...lus-mazda.html ~$22

http://www.monge.org/CylinderHeadSpecialists/valves.asp ~$26

http://www.horsepowerfreaks.com/part...s_Intake/11860 ~$22.50 (188.32, 180.32) $300 for dual spring set 272 for retainers
Toda makes springs for only $850/set :-)

FM gets $23/valve for theirs, and $379 for the full valve spring kit. That last bit sounds like where it's at. :-) I've been commanded by my machinist to go with Ferrea valves unless I can find stock +1mm, and it seems reasonable advice.

patsmx5

iTrader: (16)

Maybe I missed something...

Are you building your old fucked-over-line-bored-crocked-lifter-valey-egg-shaped-cam lobes-worn-and-scored used head that recently failed? If you have a new head go with stock size valves that are undercut and polished. Less reciprocating mass and more flow. SS on the exhaust and tell em .060 on the intake seats, .080 on the exhaust seats. I know we've talked valves like 5 times by now.

AbeFM

iTrader: (3)

That was more or less the idea, yeah. :-)

They are going to clean up the tappet bores and tell me how much gap there is.

patsmx5

iTrader: (16)

Clean them up? They'd have to reream them to fix it and then you would have to run larger, heavier buckets and shims. Not ideal from a reciprocating mass standpoint. That head is not fixable Abe. I'm sorry. Too much **** was done wrong before and it self-destroyed itself. If you try to fix it, it will just fail later again. I'm serious. It's done. Over. Use it as an ornament or something.

AbeFM

iTrader: (3)

Where I am with the shop is this:

They are offering to do any machine work for free - cleaning up the tappets, valve job, and honing the tappet bores.

I told them to clean up those bores, and find the gap. If it's in spec, and they are straight, etc... then I don't see the harm?

Of course, it means investing in new valves for a head that's likely junk anyway. Springs might go in at the same time...

As far as smaller valves, well, at this point I don't feel qualified to make that call, but I do know that all the serious cars are doing it. Sure, they could all be doing it because it's a buzz-word, but I doubt it. And if it IS bad, where 0.5mm larger hole is hurting the performance, heck, I guess I should fill them in and run smaller valves than stock. :-)

So I'm wondering if anyone knows anything about the OEM valves!

I'm trying to price out my options here so I can make a smart decision here.

patsmx5

iTrader: (16)

That head is shot. The lifter bores are oval shaped. When the tell you they're fine, go down there with a snap guage and a good micrometer and measure them yourself. Measure the top and bottom of a bore and keep turning your gauge to check for wear. From your previous pics, there's no way in hell they are in spec. You'll still need new cams too, and have it line bored AGAIN. This time correctly. By now you are loosing material from you caps and head, not good decreasing the strength of those. Basically it would cost much more to have the head patched up than to buy a new one and start over.

If you doubt the valve size situation then just 'conform'. It's not my car.

Care to share what the shop said was done wrong before, why it failed the way it did, and what's being done to correct and prevent it from happening again?

patsmx5

iTrader: (16)

You don't listen well. Size and weight are two different things.

AbeFM

iTrader: (3)

Well, this is what has me worried... They are saying it's because some of the tappets have burrs on them - and a couple of them do. Well, several have enough of a burr to catch a knife on, measured ~0.3-0.6 thousandths, with a couple as big as 0.8. Several are fine.

His claim (bogus) is that the screwdriver used to remove the shims dented the tappets. This is obviously wrong if you asked me, but I didn't want to argue that, since I have a good counter argument.

The fact is they are misshapen, I have some guesses as to how. Some of the bores are worse than others, what I don't get is if the wear on the rest of the bores is "ok", or "normal".

My guess is they will bore them out, and they will be over the factory spec. I wish there was a spec for 'roundness', on those or the cam journals.

So my questions are on the assumption that they clean up the bores, and they measure in spec. I know they will offer to sleeve them if they are messed up.

The entire holes aren't oval, or I'd see wear.

rleete

iTrader: (21)

I gotta agree with Patsmx5 on this one. That head is toast. You sink anything into it, you might as well expect to do it all over again, because those bores are shot.

patsmx5

iTrader: (16)

Abe that head is done. They setup the valvetrain too tight last time it was built and it caused excessive heat and wear on every part associated with the cylinder head. Short of sleeving, boring, and reaming new lifter guides, they will not be right. The cam bearing caps get weaker every time you shave them and line bore them. I wouldn't do it once on a high performance car, much less twice. If it was a beater hyundai I planned to sell soon, didn't drive it hard, and just needed some wheels, yeah. But this is different. In short, the valvesprings are about the only salvageable part from the head that wasn't ruined already. Cutting seats twice is a no no too. I bet the valve guides took a beating too. Plan on changing all of them? You looking at so much money to patch this head up it would be foolish to do, even if the machinist covers labor. Plus knowing their previous work failed I'd abort.

Stein

iTrader: (46)

Are you in need of this car right away? Is this is your only car? If you have a couple of weeks, I will have a 99 head available. That is assuming the thrown rod didn't damage it. I'll know when I pull the motor/head. The motor has 88K on it. It will be reasonably priced.

AbeFM

iTrader: (3)

I would *like* it right away, but need would be a strong word. I've got a line on two different 2k1 heads, which are looking more and more the way to go.

Get the head, get some headwork done on it (port/polish/backcut, etc etc).. I don't know if I'd want to throw valve springs at it (FM says their springs are good for 9k... If it was really $400 shipped to use those instead, well... That's 4.5 rpm/dollar. :-)

Would you guys call the wear on the exhaust side tappet guides "normal"? I know one or two are excessive, but I personally think they are all out of the ordinary.

Ok, time to call the shop that did the work the first time on the head - the porting, etc, and see what they want to repeat it.
-Abe.

Thucydides

Why would you want to repeat it? Especially with the same shop that screwed up your head in the first place.

Reminds me of a joke:

There was a hunter who told his buddies that come hunting season he was going to bag himself a bear. So hunting season comes around and off he goes into the woods. He spies a really big bear peacefully picking berries, aims his rifle at him, pulls the trigger, and misses. The bear, understandably annoyed that some jerk would shoot at him, grabs the hunter, ***** him in the ***, warns the hunter never to return, and releases the unfortunate fellow to crawl home in shame.

After several weeks of recovery in the local hospital, the hunter, again while drinking with his buddies, tells them he's going to get that dang bear and make him pay for his outrages.

So the next hunting season rolls around, the hunter finds that same bear picking berries, aims his rifle at him, pulls the trigger, and misses again. The bear, now really pissed off, grabs the hunter, again ***** him in the *** along with all of his other bear buddies, warns the hunter never ever to return, and releases the unfortunate fellow a second time.

Again, and after several weeks recovery in the hospital, the hunter swears a solemn oath to his drinking buddies that he’s going to get that god damn ******* bear if it's the last thing he does.

So the third season rolls around, and the hunter again finds that same bear picking berries, but this time he’s got the drop on the big brute and has him right in his sights at point blank range. The bear knows he’s a goner, and that his berry eating days are over. The hunter aims his rifle, pulls the trigger, and for the third time misses again. The stunned bear, after recovering from his surprise, grabs the hunter by the collar, looks him in the eye, and says, “I'm beginning to think you’re not really here for the hunting, are you?”

AbeFM

iTrader: (3)

Hahaha, well WELL put.

But, poor explanation. A proper race shop did the head the first time, there was nothing wrong with it, just an upgrade. Full work over, on stock sized valves. Everything was back cut, unshrouded, polished, etc etc, got a 20-30% (depending on lift) gain in flow. All around made the car a strong performer, I think. Certainly it always ran better than it should given it's set up at any given time.



When I'd overheated it, this other shop did the work, and they are the ones I'm dealing with. The one I said I wanted to call was the race shop, to see what they'd get to work over the new head.

AbeFM

iTrader: (3)

So, does anyone know what the difference in the valves between the two heads is? :-)

patsmx5

iTrader: (16)

I don't know Abe. I've never heard there was a difference. So be a pioneer and go buy some and report back.

AbeFM

iTrader: (3)

Worst news ever: He says the bores all checked out fine, the clearances are within spec (he's supposed to fax me his measurements of this), and is waiting for me to bring the valves.

WHY couldn't it just be junk? Well, I'll get there with a snap gauge and see if things are round, but.... just... so... unsure....

VVT would be a fun toy, too.