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Av8ferg

L28 from 82 ZX teardown

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Thanks ZH. I have the book and will do some of those things but not go crazy. These engines run pretty darn good stock. So far the engine is in good shape, probably would have gone a many more miles than I’d ever drive it. All the carbon will be nice to clean up as I’m told they can become relative hot spots and start degrading performance.
I plan to send the block, crank and head next week.


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Okay, pulling crank now. I decided to label with a paint pen after wiping the areas with denatured alcohol. My kids have a habit on moving crap in my garage. They’d be sure to mix them up while I’m on a work trip.

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Some folks just use a starter punch and put dots on the caps . It doesn’t take much to mark them so you don’t have to wack them hard or anything . They won’t wash away either 

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I just pulled the same engine apart that had been sitting in someone’s garage for over 10 years on a stand . I was pleased to see these cylinder walls

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Almost got all the freeze plugs out, except the front and back ones. They don’t want to move.
There appears to be a bunch of rust in the engine behind all the plugs I pulled. Behind the coolant drain plug is was packed full of debris.
This block needs a nice hot tank to clean all this up.
Probably need the shop to remove front and rear drain plugs. c3c1e7582109ebb2d19659fb10fc3673.jpg
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They do serve as a high pressure "path of less resistance".

I've read on here where someone romped on their Z before the thermostat opened and one blew out. I've seen one that was pushed out of a water filled frozen block on an old pickup of my Dad's.

They're the duct tape of the liquid cooled motor. Started out as one thing but ended up useful as others.

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I ruined an f54 trying to get that rear plug out. Drilled a small hole in it to thread a screw in to pull on with some vise grips. It's so close to #6 I drilled through the soft plug and before I could stop I'd drilled all the way into the bore. Stupid, stupid, stupid or maybe 1beer, 2 beers, 10 beers?

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I ruined an f54 trying to get that rear plug out. Drilled a small hole in it to thread a screw in to pull on with some vise grips. It's so close to #6 I drilled through the soft plug and before I could stop I'd drilled all the way into the bore. Stupid, stupid, stupid or maybe 1beer, 2 beers, 10 beers?

I can see that happening without beers. I drilled a hole to put in a small bolt, screwed the self tapping bolt in with my drill and almost hit the bore. Whew....had to flash a light in there to verify I didn’t hit it.

That plug is in there good. I need to have a professional remove it. I tore it up good trying. 4f3e2664a8d9361a1cd79ffd8951842b.jpg&key=ce1ca746cf830a7f9855945853fd49b58075add65f3098cc0f77532e257b7db9

 

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 Looking at its current state, in my mind, it's begging for a hook of some sort, attached to my slide hammer with a lot of heat around the edges. Beer is optional.

 

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I ran a long wood screw through the middle and let it press off of the inside of the passage. It cocked a bit so I punched one half in and pulled the other half out.  Rotated on the edges.  Then I grabbed it and pulled it out.

If you get the middle torn out the edges will fold in pretty easily with a punch.  The sealing surface is wide and you can use sealant on it.

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7 hours ago, siteunseen said:

I ruined an f54 trying to get that rear plug out.  It's so close to #6  I drilled through the soft plug and before I could stop I'd drilled all the way into the bore.

If it makes you feel any better, that's not the first time I've heard of that.

I haven't done it (yet), but apparently it's easier than expected to do that. I don't think you are the only one.   :facepalm:

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7 hours ago, Av8ferg said:

That plug is in there good. I need to have a professional remove it. I tore it up good trying.

As suggested, a hook on a slide hammer tool (or a crude substitute) would probably pop that out. Or just let the machine shop take care of it. It won't add any significant cost.

Did you get the front one out? If not, be careful drilling that one too. #1 is close behind that front plug.

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As suggested, a hook on a slide hammer tool (or a crude substitute) would probably pop that out. Or just let the machine shop take care of it. It won't add any significant cost.
Did you get the front one out? If not, be careful drilling that one too. #1 is close behind that front plug.

No I left that one in there. After the battle with the rear one I didn’t want to risk it. I’ll ask the shop if they can get it. I’ll remind them how close the bore is to that one.
Everything is loaded up in the SUV to take to the shop tomorrow.
Here’s the task list:
1. Hot Tank block
2. Inspect and clean head
3. Inspect crank and journals
4. Hone cylinders
5. Install new core plugs (like that ZH)
6. Will inquire about shaving head.

Crankshaft journals looks beautiful to me, no signs of anything to be concerned with. Getting all this rust out of the cooling jackets and chambers will be nice and I’m sure it will help it run cooler.
I need to start ordering rebuild parts.

A question for the crowd. When I removed the pistons I had a couple rod bolts fall out on to the garage floor. Which means I lost the original orientation. They can only go in two ways. (180 deg out from each other) Each bolt has two markings on either side of the head a “12” one one side and “H” on the other. I have the correct bolt in the correct side of the rod but it may be spun 180 out. I’m assuming either way is fine but wanted to confirm. I’m only concerned because of this comment on the book.
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I'm guessing the reason it's important to keep the rod bolts in the original location is that they locate the lower bearing cap against the bottom of the rod. Take a look at the rod bolts... there's a thicker section up by the head. That thicker section is a locating shaft for the caps.

Now that you mentioned it, I've got to take care of that too. I dropped two of them and I'm relatively sure I got them back in the original orientation. I know they're on the right rod and the correct side of that rod... Only thing I'm not positive about is the rotational orientation. When mine fell out, I put them back with what looked like (in crappy light) the cleaner side towards the rod, but I need to double check them now.

Have you looked at yours to see if you can use the oil staining as a guide?

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Although, I'm not convinced that "interchanging rod bolts has the same effect as interchanging rods and caps". I think interchanging rods and caps is much more risky than interchanging rod bolts.

As a testament to that... You can buy and install a whole new set of rod bolts. In fact, some people even recommend that.

Of course, it would be a better idea to keep everything together and in the exact same orientation as it was originally, but I certainly don't think it's as high an impact as mixing up all the caps.

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CO, that’s a fantastic idea. The pistons and rods are wrapped in cloth and individually bagged but I’m going to open them back up tomorrow and looks for the staining. The other idea I had was to put them in the direction that requires the least force to seat. That may the original orientation that goes in smoothest. I was hoping that the stamps of the bolt heads would be consistent but I don’t think that’s the case....rats.



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Yeah, I don't see how rod bolts would effect clearances or roundness the way caps would. The only issue I could see would be stretch and that would be resolved if they fully reached finished torque. I also don't see how orientation would be relevant either. As CO pointed out you could replace all of them with ARP hardware and I wouldn't expect to have to big end size as long as the cap was on each mating rod.

CO, you could experiment if you have the proper measuring tools. Take a known rod with the properly located bolts. Torque it down and check the ID both ways to determine roundness. Then relocate the bolts or change the orientation and recheck. I suspect your dimension won't change as long as the torque wrench is accurate.

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Regarding core plug removal: It is much easier to tap the plugs inwards. Just use a flat screwdriver and tap in one side (red line), the plug will tilt and can be pulled out easily afterwards!

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Edited by german240

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Regarding core plug removal: It is much easier to tap the plugs inwards. Just use a flat screwdriver and tap in one side (red line), the plug will tilt and can be pulled out easily afterwards!
Unbenannt.JPG.2ce04ed0b45e93412353c70d6f6aa57e.JPG

I tried that. That was how I did all the other ones but this one was so stubborn the screwdriver kept puncturing the plug.


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Okay, so I did a little investigative work this AM to see if I could find patterns or consistencies in the rod bolt orientation. I found no smoking gun but have some observations. The staining didn’t show anything remarkable. Captain I’d like to see what you find. Since I don’t know which ones are right and which ones the bolt fell out, I can’t determine which is correct. So there is a 12 and and R on the rod bolt. I’m assuming that was stamped there for a reason.

I took one piston and rod assemblyI think is correct and placed the piston notch forward and then assessed how the bolts were oriented from both sides. It appears that on the left side (looking down) the 12 is forward (same direction as piston notch) and the right side the R is forward. CO see if you have a similar observation or anyone who has one they know is assembled right can verify that orientation. See pics below. I love a good mystery.

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I've only got one of my pistons here (the rest are out at GGRs), but the one I have here was assembled like the one you pictured above. And I'm confident that the one I have here was NOT one of the two bolts that came out during disassembly. (Point is, I have high confidence that the one I have here is the way it came from the factory.)

I don't know if my other five pistons are like the one I have here but I'll let you know when I get a chance.

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The statement in the book about the bolts doesn't make sense.  Maybe he had a bad experiencing in the past and assumed it was the bolts.

Like any bolt and nut it just uses leverage to apply force to the cap.  Break it down to simple physics and you can't find a reason that mixing them up would matter.  I'd be more concerned with metal fatigue and stretching, from the first usage.  New bolts and nuts is probably just a good safeguard against failure.

 

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The engine is at the shop.
$50 hot tank and replace core plugs
$65 clean and inspect head and cam
$55 to shave head .040
$50 to hone cylinders and polish crank
10 day turnaround.
$220 out the door plus tax.


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