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Discussion Starter #1 (Edited)
Well, as if there aren't already enough threads related to Headgaskets in the 3.8 forum, here is another. This is what my Mom's '93 Thunderbird looked like when I tore it down. I'm in the process of replacing the headgaskets. Enjoy:





Hrrmm........ Engine Coffee :D

Thomas
 

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Yeah I think it's safe to say the bearings aer fooooocked. That stuff in the pistons is pure coolant! That's like....not good man. Nope. New engine time.
-Thomas
 

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that looked bad and hey Engine Coffee sure i will take some lol not and hey man you got green stuff in the pistons lol i think you need to replace more then just the headgaskets have fun
 

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What does the oil in the pan look like? I ask because the sludge in the lifter valley may only be from taking the heads off with a cylinder full of water. If, however, all the oil looks like that, you may have serious bearing problems. Was it knocking when you tore it open? If the rest of the oil is ok and it doesn't knock, I would try replacing the headgaskets only (with an oil change) and see how it runs. That's just what I would do ... but if the engine had high miles, I might try to get a junkyard engine and swap it. My engine blew a HG at 96K ... and the first cylinder was full of coolant, just like yours. My oil still looked good, though. I replaced the HGs and it still ticks nicely along at 142K miles.

Oh ... I noticed that the first cylinder is rusty with no carbon build-up, and the other 2 have lots of carbon. I can't really tell where the gasket leaked, but the carbon suggests to me that the last 2 didn't really see coolant until the head came off. Or, if the gasket leaked there too, it was much later than the leak in the first cylinder.
 

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Wow that looks pretty bad. The 3.8 tbird that myself and my buddy did only had coolant leaking into one cylinder, we must have caught it earlier than this one.

It might be less troublesome for you to find a low mileage wreck 99+ mustang 3.8 and drop that in there if she likes her birdy still.

If you aren't going to swap the motor, at least send the heads out for some milling.

JH
 

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yes thats all in good fun.....if the engine will run later on and keep ticking later keep it....if not.....put a better 3.8 in there adn tell your mom it will give her better gas miledge....cuase it will......would head milling make you lose horsepower b/c it increases piston chamber cc, witch in turn lowers compresion ratio??....im lost on the concept of head milling an n/a car can someone help me? :(
 

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Discussion Starter #7
In thoery, it would actually raise your compression ratio, but very, very little.

The oil still looks good. I'm going to go ahead and clean up the block, and have the heads gone through, and new valve seals put in. I'll stick it all back together, run it for a couple of minutes, and then drop the oil out.

Thomas
 

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Discussion Starter #9
Nope. sure didn't :tongue: Guess I prolly should of

Thomas
 

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Yeah, I was sort of guessing that the coolant had just spilled onto the lifter valley because the gasket didn't look bad enough to have made all the oil that bad.

And what I said about the carbon buildup or lack of it ... it really looks to me like the only cylinder that leaked was the leftmost one in the picture. But, you would know better than I would, because you can see it in person. I was just thinking that maybe the coolant spilled into both the lifter valley and the other cylinders when you took the head off.

Milling the heads is definitely recommended. I don't know if it's absolutely necessary, but if the car overheated, then it probably is. BTW, when a machinist mills heads, he just puts them on this machine that grinds the bottom precisely flat. Typically, they remove 0.002 or 0.003 inch of metal ... which makes the chambers smaller and slightly raises the compression ratio. I think it would take about 0.6 cc off the chamber volume on the average 3.8 ... maybe a 1% change in volume and CR.
 

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im not geting how it raised the compresion ratio.....wouldnt more cylinder volume mean less presure built up in the cylinder(the compression ratio)?
 

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when you mill the head you are taking off some of the combustion chamber, decreasing the displacement of the engine. the piston is compressing the same amount of fuel and air into a smaller combustion chamber, rasing the compression ratio.
-Thomas
 

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oo....ok.....i thought milling involved take off material......
 

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it does doesn't it? milling the heads is planing then flat. Because when the engine overheats it can warp the flat surface of the head.

Isn't the amount of volume in the combustion chamber the displacement? So wouldn't decreasing the size of the combustion chamber decrease the displacement very slightly?

-Thomas
 

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it is about taking off material........................to use your cup filling statement in your sig, think of your combustion chamber in the head as an upside down cup, if you mill the heads, it is the same as shaving off the top rim of the cup. Now the cup and the combustion chamber both hold LESS volume.

Piston moves the same distance = same displacement
Forces this into a smaller combustion chamber = higher compression ratio.

displacement is the volume all the cylinders DISPLACE as they move from bottom dead center to top dead center.

PI * R^2 * Stroke * # of cylinders = total displacement
ratio of the displacement of the cylinder to the size of the combustion chamber = Compression ratio.
 

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ah that makes sense then. thanks for the explaination. But why does boring the block over increase displacement if it doesn't affect the travel of the piston?
-Thomas
 

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it affects the displacement of the cylinder because when you take material off the wall of the cylinder, you are increasing the 'R' in the equation, the Radius of the cylinder, (R = 1/2 diameter).

displacement = Pi * R-squared * stroke * # of cylinders

increase any of them (Pi is a constant, that leaves bore, stroke, number of cylinders) and you increase the displacment.
 

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oh yeah duh, brain fart. I thought of that just as I hit Post Reply lol.
-Thomas
 
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