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Old 12-12-2007, 12:02 PM   #1
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Default Head Gasket and what...?

I'm gonna pull the head this weekend. I want this job to be as simple as possible but I've got some questions. It really looks like a pretty easy deal.

When I pull the head-gasket off, can I expect it to come off cleanly, or will there be parts stuck to the block/head?
Do I have to have the head "decked" or should I expect it to still be flat?
If I have to have it decked, do I need to remove that valvetrain (REALLY WANT TO AVOID THIS)?
The water pump and timing belt were done 30k miles ago, so I won't need a new water pump... but DO I need a new timing belt or can I re-use the current one?
I've heard the stock OEM head gasket is suffiecient for my mild 12-14psi goals... anybody have other ideas?

Thanks all!
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Old 12-12-2007, 12:13 PM   #2
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the OEM gasket is fine from what i hear, only time they fail is when not tq.'d properly
i dont think you have to have your head decked unless you were really overheating it
good luck man
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Old 12-12-2007, 12:18 PM   #3
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I'm told by someone with much more experience than I have that your should get the head machined everytime you remove it from the block. Take that for what it's worth.
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Old 12-12-2007, 12:19 PM   #4
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I would check out the head with a machinist straight edge. I'm sure you can find something like that on the base where you work.
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Old 12-12-2007, 12:19 PM   #5
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I have not pulled a miata head myself, but it should go just like every other head. Disconnect the exhasut mani, wiring harnesses, fuel lines, coolant lines, timing belt, etc, unbolt and lift. It might take a great amount of effort to break the head free, or it may lift off easy. Helps to have 2 people, but you could do it yourself if you had to.

If you overheated, it's likely that the head has warped. Take it to a machine shop and have them plane it. Not deck it. Odds are the head would warp and not the block. Still you want to check the block for trueness with a straightedge and a feeler gauge. Spec calls for .1mm of gap or less.

Replace both the tb and wp while you're halfway there. You also might want to pick up some ARP headstuds. If you haven't touched them, here s your chance to replace the tb tensioner and guide. Also the cam seals and front crank seal. I'd rock with an oem headgasket, but if you want piece of mind, FM has a metal gasket for the low, low price of $100.

You'll need a 12 point 12mm socket if you don't have one, and you'll need a torque wrench for re-installation.
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Old 12-12-2007, 12:38 PM   #6
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I cooked mine bad a few months back and the block was flat, so you shouldn't have to worry about that. Check the head with feeler gages and a straight edge. I think the max allowable is .008". If you are in spec, don't worry about having it resurfaced. If you do have to have it resurfaced, you do not have to remove the valves, but the machine shop may want you to remove the intake. If that is the case, you will need an intake manifold gasket as well.

You will need to take a razor blade and scrape all the rubbery gasket material from the block and head. Fill all the cavities in the block with rags so you are not directing that crap down in the oil and water passages. Make sure you get both surfaces clean and wipe them with mineral spirits before installing the new gasket.

It may also be a good idea to check the rubber cap on the back of the head and replace it as well while the head is off. Those are notorious for leaking and next to impossible to replace with the head on the car.
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Old 12-12-2007, 01:48 PM   #7
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Thanks guys.

I've got an awesome local machine shop that I trust to tell me if it's flat or not. There's no chance of an overheat, so I'm hoping it's good and I don't have to have it worked on.

Rubber water cap was replaced w/clutch 8k miles ago.

Stock OEM headgasket is what I'm gonn ago with.

I need a final consensus on the TB. It's only about 20k miles old... and I'm pretty sure this engine isn't going to last another 50k no matter how well I take care of it. I'm looking to cheap out here. I've decide the WP is gonna stay... but do I have to buy a new timing belt or not?

From Finishline:
Headgasket: $39
TB: $45
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Old 12-12-2007, 02:08 PM   #8
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From Partsdinosaur:

TB = $26 http://www.store.partsdinosaur.com/product997.html

"Head Gasket Set" = $59, includes "
all gaskets and seals from the head gasket up" (head gasket, cover gasket, intake and exhaust gaskets, cam seals, valve stem seals, etc) http://www.store.partsdinosaur.com/product1013.html
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Old 12-12-2007, 02:09 PM   #9
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Since you are opening the block, not a bad idea to have some scotchbrite pads + cleaner as well to scrub off some of that carbon on the head/pistons.
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Old 12-12-2007, 03:47 PM   #10
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pulling the head is extremely easy. did you download the shop manual I linked you to?

pull the manifold off or the remove your downpipe. pop the intake pipes off, pop your TB of, pull all the harness, fuel lines and heater lines, pop the radiator hose off....boom, pop the cover off, pull the head bolts, boom lift.....
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Old 12-12-2007, 04:00 PM   #11
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bam bam bam!!!
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Old 12-12-2007, 04:17 PM   #12
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Brainey, looking like I may be doing this myself at some point in the near future, and I do not have a boom lift.

Assuming the intake manifold, exhaust manifold and turbo are still attached, is it plausible for two men to remove the head by hand? I don't have a good feeling for whether the gasket is going to tend to cause the two to be stuck together.

Worst-case I suppose I can rig a compound block-and-tackle from the ceiling- that should be relatively inexpensive.
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Old 12-12-2007, 04:21 PM   #13
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2 men could remove the whole motor by hand.
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Old 12-12-2007, 04:28 PM   #14
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Here is what you do joe. After you remove the head bolts and before you take off the head. Use the IM as a lever and just yank up on the bitch, the head WILL come free. Then just lif it off, it will weight like 40lb ish. Cake for most grown males (at least if you were born on the east coast, and possibly not asian :P)
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Old 12-12-2007, 04:50 PM   #15
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I removed my head with both manifolds and the turbo attached by myself, but it is easier with 2 people.
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Old 12-12-2007, 05:09 PM   #16
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Yeah, it's not the weight of it that concerned me, it was the possibility that after 16 years of being mated together, the gasket might be causing the head to stick to the block, verily, that neither by the hand of man the two shall be cleft in twain.
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Old 12-12-2007, 05:12 PM   #17
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rock the boat, it will release.

and when i said boom lift, i meant "boom" lift. enter sound effect.

with the IM, EM & turbo still attached it's heavy but a real man like Sam could lift it. I sure as hell couldn't IM and head only shouldn't be a problem.
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Old 12-12-2007, 05:24 PM   #18
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Well, I figured that for a two-man lift, having the EM still attached would be advantageous as it'd give you something to grab onto.
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Old 12-12-2007, 05:24 PM   #19
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I just did a head gasket replacement on a 97 recently. It came off without a problem, wasn't stuck or difficult to come off. Just be sure to undo the bolts for the intake manifold brace.
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Old 12-12-2007, 06:11 PM   #20
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And don't forget the ground wire on the exhaust manifold side rear. Ask me how I know. I was lifting by myself when I get it loose and lift only to have it almost snatched back out of my hands by the tugging of that damned ground wire.
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