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Anyone care to teach me how to change a headgasket?


dpascual1986

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And more zip locks. :) Daniel, are you still dead set on (A) changing the head gasket, or are you interested in (B) repairing your motor? If you answered A, ignore this post, if B, I hope you have not removed the head yet. I suggest putting your timing chain right, too, if possible. You really should get compression readings for each cylinder. Can you take out the spark plugs and check for coolant in the cylinders? If so, use a syringe and piece of clear tubing, like for an aquarium pump and see if you can syphon it out and spray something to absorb the coolant and lightly lube the cylinder walls. Of there is no fluid in there, you and I will deserve one of those beers. I also suggest removing the oil pan. Check it carefully for shreds, crumbs and chunks of steel, aluminum, any thing. If nothing, I think we should have another. Could you post pics of any parts you've removed, especially inside, mounting surfaces, water pump for example. Get same for block. Get pics of the block from several views. Get your radiator pressure and flow tested. Do whatever you can to determine the cause of the coolant in the oil. Sorry for long posts. Cheers! Jim

Edited by alternativez
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And more zip locks. :) Daniel, are you still dead set on (A) changing the head gasket, or are you interested in (B) repairing your motor? If you answered A, ignore this post, if B, I hope you have not removed the head yet. I suggest putting your timing chain right, too, if possible. You really should get compression readings for each cylinder. Can you take out the spark plugs and check for coolant in the cylinders? If so, use a syringe and piece of clear tubing, like for an aquarium pump and see if you can syphon it out and spray something to absorb the coolant and lightly lube the cylinder walls. Of there is no fluid in there, you and I will deserve one of those beers. I also suggest removing the oil pan. Check it carefully for shreds, crumbs and chunks of steel, aluminum, any thing. If nothing, I think we should have another. Could you post pics of any parts you've removed, especially inside, mounting surfaces, water pump for example. Get same for block. Get pics of the block from several views. Get your radiator pressure and flow tested. Do whatever you can to determine the cause of the coolant in the oil. Sorry for long posts. Cheers! Jim

I am planning to do both A and B. I have a good amount of tasks to do, I will update you guys by Monday.

1. Get radiator pressure tested

2. Check compression (is this possible with a non starting engine? I mean Ive already removed the water pump, intake and radiator)

3. Pictures

4. Remove timing cover, change all core plugs (except for front and back per reading material, unless absolutely necessary)

5. See if I can get fluid from cylinders (I dont think I should get any, I dont have white smoke)

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6. Keep the fridge stocked. I think you shouldn't worry about replacing the core plugs just now. You can check compression as long as your timing chain is properly aligned to cam and crank and with tension. See your engine book. I'm hoping you find no fluid on the cylinders and no loss of compression at any piston. I'd be getting the pan off, if only to clean that goop out. Examine everything for anything suspicious. You haven't said if the motor uses oil frequently or leaves puddles or has seeps, only the small coolant? leak up front. And no white exhaust, which likely be steam from vaporized coolant, or blue, which would likely be oil. Yet, absence of proof is not proof of absence. Gotta be sure. I'll bet somebody knows what this problem is, and they're waiting for you to figure it out. Good luck!

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6. Keep the fridge stocked. I think you shouldn't worry about replacing the core plugs just now. You can check compression as long as your timing chain is properly aligned to cam and crank and with tension. See your engine book. I'm hoping you find no fluid on the cylinders and no loss of compression at any piston. I'd be getting the pan off, if only to clean that goop out. Examine everything for anything suspicious. You haven't said if the motor uses oil frequently or leaves puddles or has seeps, only the small coolant? leak up front. And no white exhaust, which likely be steam from vaporized coolant, or blue, which would likely be oil. Yet, absence of proof is not proof of absence. Gotta be sure. I'll bet somebody knows what this problem is, and they're waiting for you to figure it out. Good luck!

My dear Z brothers, I have once again made a mistake...

Blunder #2 - I removed the thermostat and replaced the housing thingy. I then proceeded to replace the water pump with the intent of doing a cooling system pressure check - I was able to borrow a set from my friend. As I was tightening the bolts, the top left long bolt broke with barely 1/8 inch left of thread left on the broken off bolt.

Which means...

1. The broken part is deep in there.

2. I cant just use a shorter bolt.

I can't fix this blunder with a water hose, a brush and powdered detergent. Please advice. I have used the harbor freight broken bolt remover thing, it doesnt work for anything. Any recommended brands? Techniques?

Daniel

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4. Remove timing cover, change all core plugs (except for front and back per reading material, unless absolutely necessary)

You need to do step 4 now and take

it to a machine shop and have the bolt extracted. You were planning on

removing the timing cover anyways right?

Im not sure what you're trying to do here. Why don't you just pull the head

and take it to a machine shop and

have it pressure tested?

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You need to do step 4 now and take

it to a machine shop and have the bolt extracted. You were planning on

removing the timing cover anyways right?

Im not sure what you're trying to do here. Why don't you just pull the head

and take it to a machine shop and

have it pressure tested?

aha! you're right, its not in the block, its only in the timing cover -unless that bolt was meant to go through the cover and into the block (it is pretty long).

i meant to check the pressure to find where my leak is, the current theory is that i might have a hole in a core plug positioned inside the timing cover.

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soo... I have successfully removed the timing cover.. and I have found the source of our problem..

no timing cover gasket...

I also found some JB weld right next to the inlet on the block for the coolant. see below...

post-28358-14150826712277_thumb.jpg

So.. the questions are..

1.why would you go through all that trouble removing a timing cover, replacing the timing belt (i assume was new bc there doesnt seem to be any chain stretch) and not put a gasket on it?

2. Why the JB weld? (maybe to seal up the coolant inlet for the block?)

3. Would a machine shop be able to check the cover for warpage, cracks and other mickey mouse crap the PO did to it?

4. Does anyone have a link to where I can buy a new timing cover?

On a different note, I was able to get to the broken bolt. Here it is in all its glory

post-28358-14150826713138_thumb.jpg

You can see the jb weld that went around the inlet. (i dont know the proper term). I can't get over people that screws others over. :tapemouth

I tried to drill it out with a left handed drill bit, no success, I then tried to ez-out it (i got a firm bite but it felt so hard that I didn't want to risk breaking the ez-out in there. I will attempt to weld a new head on it by this week.

My question is..

1. I read that welding on the block is relatively easy because the block is cast iron and the bolt is steel -meaning that if you miss the bolt remnants and hit the block with your mig wire, it wont weld on the block for a few reasons

a. the block takes longer to heat up

b. two different types of metal (steel and iron)

Can someone confirm my information?

This week's goal

1. Remove head and get it machined.

2. Repair timing cover or replaced

3. Weld a new head on broken bolt

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1.why would you go through all that trouble removing a timing cover, replacing the timing belt (i assume was new bc there doesnt seem to be any chain stretch) and not put a gasket on it?

2. Why the JB weld? (maybe to seal up the coolant inlet for the block?)

3. Would a machine shop be able to check the cover for warpage, cracks and other mickey mouse crap the PO did to it?

4. Does anyone have a link to where I can buy a new timing cover?

This week's goal

1. Remove head and get it machined.

2. Repair timing cover or replaced

3. Weld a new head on broken bolt

It's looking more and more like you either bought your car from someone who thought they knew what they were doing and was way over-confident or you got scammed.

Since you've found the source of the water/oil leaks maybe you don't need to remove the head. Can you tell if it's ever been removed before (new gaskets, etc.)? If not, you might be able to get back in to running shape with just the timing chain cover work.

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If not, you might be able to get back in to running shape with just the timing chain cover work.

I would assume that a gasket is the first thing you think of when joining two parts like these.

the gasket seems to be new, I removed the cover without difficulty, the gasket is undamaged, you can see it in the picture with the broken bolt.

I still need to pull the head

1. broke the dowel pin that secures the cam sproket to the cam shaft. its not a pin is it? its an appendage to the cam, and not replaceable by your noob DIYer?

2. PO screwed the wrong bolts to the fuel pump, it broke through the inside.

3. I might as well, there's only about 10 head bolts in my way now.

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You might consider that taking the engine apart is for your learning experience but buying a used, good condition engine (they are out there) to put back in is the economical choice. If the head gasket is new that means the IPO has been in there, which is not a good thing. You've had a poor lubricant running through the engine so there's probably extra wear on various bearing surfaces. You have a variety of broken parts. It's not you vs. the engine anymore, it's you vs. the PO's errors.

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What is IPO?

I believe you are absolutely right about poor lube and wear on bearings.. I will put this thing back together for educational purposes and be on the look out for a newer engine.

From what I read, the later 280z engines were preferrable.

Zedhead - what do you think about that dowel pin that I broke?

Edited by dpascual1986
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What is IPO?

Zedhead - what do you think about that dowel pin that I broke?

IPO is just a typing error. Zed meant PO (previous owner).

The dowel is a slight press fit in the cam and came be removed. Some say its only needed to locate the cam, and once the cam gear is tightened to specifications, the dowel is no longer needed. I would have it replaced. Dont want to hit a couple of pistons with the valves through bad valve timing.

I agree with Zed Head on buying another engine. Reading what the PO has done so far is scary and now knowing he has also had the head off.

This engine could turn into one of those angry dogs, no matter how much time and care you put into it, it just keeps bighting you.

Chas

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