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-   -   Blown head gasket. Removed head today. (https://www.miataturbo.net/engine-performance-56/blown-head-gasket-removed-head-today-31183/)

patsmx5 02-05-2009 09:56 PM


Originally Posted by what miata? (Post 364129)
lol ok you know what pats......... im sorry you know what your taking about and i dont. maybe you should be a engine builder.. you prob be the best in the world. hey apply for a job in a shop or maybe a high performance shop even. because your the best and right and sorry that i questioned your knowledge.

I'm not an engine builder. I built a few motors when I was in machine shop back in high school, but none since. (don't have 300k worth of tools at my disposal anymore...) Again, I'm no expert by any means. It takes a lot of know how and real world experience to be a competent engine builder. With race engines and other performance-oriented engines, it takes much more. Details are what separate the good from the best. The things above I mentioned aren't even details.


You shouldn't have to retorque a head gasket 3 times before starting a motor. It's common to retorque a composite gasket though after 500 miles on a cold engine. Also a good idea to retorque any head gasket after overheating an engine, especially 2-strokes.

NA6C-Guy 02-05-2009 10:04 PM

I think maybe in my case it was the actual studs turning. I installed just as told by ARP and FM, hand tightened into the block till they bottomed out, then torqued the nuts in 3 or 4 steps to 65lb/ft. THe 2 times I re-torqued them, I got maybe a 1/64 of a turn, if not 1/128 of a turn on each of them, so probably not even 1 or 2lb/ft. Just minor slippage, which could have also been a difference in any number of things, temperature, or my wrench. Only felt it as a pop, I guess either the nut slipping and regripping the head, or the studs popping in their bores. Everything was well lubed, so Im not sure how that happened.

patsmx5 02-05-2009 10:13 PM


Originally Posted by levnubhin (Post 364083)
Thanks Pat, The gasket is deffinately shot. #2 cylinder has a puddle of water sitting in it while the other 3 are dry. Also with the car running and the rad cap off the water jumps like crazy.

Just to say this, don't run the motor. If it gets enough of a puddle in that cylinder and you try to crank it, it will hydrolock and something will give; likely a rod. Check things over very carefully when the head is off to make sure all the pistons are coming up to the same height. If the #2 rod bent any, that pistons won't come up as high as the others. Just put the motor at TDC and check a pair of pistons for height against the deck with a rule (or a dial indicator with a magnetic base, but you probably don't have one), and then TDC for the other pair and compare. They should all be the same of course.

levnubhin 02-06-2009 06:11 PM

Head gasket is trashed. Everything else LOOKS kosher.
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cardriverx 02-06-2009 06:16 PM

damn! I do need to run some water through the engine, it cleans it real good!

Braineack 02-06-2009 06:32 PM

yeah dude, that thing looks just like mine did. I'm blaming uneven and/or not enough torque to the studs.

patsmx5 02-06-2009 06:33 PM

Looks :ne: Is. You better figure out what failed, why it failed, and correct the problem or else you'll be doing this again. That gasket didn't fail for nothing.

levnubhin 02-06-2009 06:49 PM


Originally Posted by patsmx5 (Post 364613)
Looks :ne: Is. You better figure out what failed, why it failed, and correct the problem or else you'll be doing this again. That gasket didn't fail for nothing.



Yeah I know, thats why I put looks in bold. Once I get it back together I'll do a leakdown test.
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patsmx5 02-06-2009 06:59 PM


Originally Posted by levnubhin (Post 364620)
Yeah I know, thats why I put looks in bold. Once I get it back together I'll do a leakdown test.

How did it check out before you pulled the head? Or did you not do a leakdown test? ;) I'm laughing.

hustler 02-06-2009 07:03 PM


Originally Posted by patsmx5 (Post 364033)
He probably fucked something up. My guess. Or you detonated. Pull the head and find out what's wrong. Check the torque on ALL the head bolts before removing it for reference. If it detonated, it will almost always blow between two cylinders. I can not stress this enough, yet you will likely ignore it: DO A LEAKDOWN TEST! There, I said it. Do this and all will be known.

Is there anything that's not caused by detonation in your book?

patsmx5 02-06-2009 07:06 PM


Originally Posted by hustler (Post 364627)
Is there anything that's not caused by detonation in your book?

Yes. I highly doubt this head gasket blew from detonation. It would have blown between two cylinders if it hat detonated. I guess after he gets the head back on and does a leakdown test he'll know where to start to fix it once he pulls the head again.

levnubhin 02-06-2009 07:20 PM


Originally Posted by patsmx5 (Post 364624)
How did it check out before you pulled the head? Or did you not do a leakdown test? ;) I'm laughing.



No I didn't. The cylinder was filled with water. Even you said do not run the car. The gasket was blown. Doing a leak down test would have shown a massive leak in that cylinder, how would I've known if something else was bag with that huge leak there?



I'm glad your enjoying this.
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patsmx5 02-06-2009 07:24 PM

You don't have to run the engine to do a leakdown test. Doing a leakdown test would have told you where all it's leaking. It it had any leakage past the rings, or intake valves, or exhaust valves, or a crack in the combustion chamber, the leakdown test would have identified that down to which cylinder. Anyways, care to share what you think the problem is? IE-why the gasket blew?

levnubhin 02-06-2009 07:32 PM

Well, I rechecked the torque on all the bolts and noticed that several of them weren't at 60ft lbs. Specifically the ones around the #2 cylinder. Now I dont know if it was because I didn't recheck them at 500 miles or if it was put together that way. Im not pointing fingers. I also can't ignore the fact that this was an ebay head gasket and you get what you pay for. I did put 1000 trouble free miles on the car with half of them being at 12.5 psi. I also had temperature issues when I first put the car back together so who knows if that didn't weaken the gasket.
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patsmx5 02-06-2009 07:37 PM


Originally Posted by levnubhin (Post 364642)
Well, I rechecked the torque on all the bolts and noticed that several of them weren't at 60ft lbs. Specifically the ones around the #2 cylinder. Now I dont know if it was because I didn't recheck them at 500 miles or if it was put together that way. Im not pointing fingers. I also can't ignore the fact that this was an ebay head gasket and you get what you pay for. I did put 1000 trouble free miles on the car with half of them being at 12.5 psi. I also had temperature issues when I first put the car back together so who knows if that didn't weaken the gasket.

If it boiled over-overheated, then it could be a HG failure that's coolant temp related. Else, I would say that overheating is not directly related. Several things could cause the bolts to not be tight. Make sure you do everything to ensure you fix the problem there. I HIGHLY suggest you put a MLS head gasket on it. Can not emphasize this enough. It's like 100 bucks from FM. Best $100 you'll ever spend. And get new head bolts for good measure.

levnubhin 02-06-2009 07:43 PM


Originally Posted by patsmx5 (Post 364645)
If it boiled over-overheated, then it could be a HG failure that's coolant temp related. Else, I would say that overheating is not directly related. Several things could cause the bolts to not be tight. Make sure you do everything to ensure you fix the problem there. I HIGHLY suggest you put a MLS head gasket on it. Can not emphasize this enough. It's like 100 bucks from FM. Best $100 you'll ever spend. And get new head bolts for good measure.



;)

Also picked up ARP hardware today.
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NA6C-Guy 02-07-2009 01:11 AM

That should do it. You going to check, or have the head and block surfaces checked? Dont be like me :giggle:

TonyV 02-07-2009 01:19 PM


Originally Posted by levnubhin (Post 364648)
;)

Also picked up ARP hardware today.



Your my boy so I wont throw salt in the wound,


:hustler:

^that sums it up tho.


Get er back on the road asap, def at least make sure the surfaces are straight.

Ps--you're supposed to be blowing diffs not HG's ;)

mrtonyg 02-07-2009 04:14 PM

Getting fancy, expensive parts and components isn't going to get you past the basics.

1: Make sure the head and block are nice and flat. Max distortion should not be greater than .0008". Preferably no more than .0002".

2: Run a tap through the threads on the block. Afterward clean the block threads with compressed air. Lubricate the bolt threads with light oil.

3: Clean the head and block mating surfaces spotless. Remove all traces of the old gasket. Use a fast evaporating cleaner (get the highly flammable type) and a lint free rag on the mating surfaces.

4: Tighten the head working in circles from the inside out a bit at a time. Finally torque to final specs. Make sure while final torquing that none of the bolts/studs go limp on you. If they do, you need to replace the culprits.


Get these right and you will not have any blown head gaskets.



Tony

patsmx5 02-07-2009 04:48 PM


Originally Posted by mrtonyg (Post 364961)
Getting fancy, expensive parts and components isn't going to get you past the basics.

He knows. :cool:


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