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As I was working on my new to me Z over the weekend, I ended up taking the intake manifold off in order to drill/mill the bolt that is broken in it that attaches the carbs. I decided while I’m at it, it’s an easy and cheap task to replace the intake/exhaust gasket and get new studs/bolts that go into the head. Unfortunately the head itself has what looks like 2 (now 3) broken studs inside of it, and the exhaust manifold is stuck on.

 

To help get the exhaust manifold off and make sure all of the thread in the head itself are clear, I have been considering pulling the engine out. Then one thing leads to another and I start thinking maybe I should just replace all the gaskets, down the rabbit hole we go, i thought maybe I better just do the rings and bearings too. But, I thought I’d check the forums for opinions. I hate to spend the extra money and time to do a full tear down if it was just done 5k miles ago. I was told when i bought the car the the engine was the best part of the car. Should I just treat it as if it has 200k+ miles and do a full rebuild? 

 

I work with the guy i bought it from, so i'm going to ask him today if he has any idea the last time a rebuild was done. But, it's likely he doesn't know. The car itself hasn't been on the road without the help of a trailer since 05'.

 

What do you guys think? Rebuild, or nah?

 

Don't say swap, I'll be doing one eventually. But, i'll only swap for something more modern than an L series and i don't currently have the funds for it.

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40 minutes ago, rturbo 930 said:

I'd leave it alone. L series are tough engines, and unless you have evidence otherwise, I wouldn't assume that it needs rings or bearings. Do the gaskets and call it a day.

 

What about the timing chain? Good idea to replace that as well?

 

I talked with the guy from my work. He wasn't sure when it was last built. But it sounded like one of the previous owners races, or used to race, Z cars and the motor might have been rebuilt by him. It was like 2rd or 3th hand knowledge coming from him. He suggested pulling the head off of the block with it still in the car and checking for wear. 

 

Any other thoughts?

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46 minutes ago, JLuff240 said:

 

What about the timing chain? Good idea to replace that as well?

 

I talked with the guy from my work. He wasn't sure when it was last built. But it sounded like one of the previous owners races, or used to race, Z cars and the motor might have been rebuilt by him. It was like 2rd or 3th hand knowledge coming from him. He suggested pulling the head off of the block with it still in the car and checking for wear. 

 

Any other thoughts?

 

The Factory Service Manual has a whole chapter about disassembling the engine and checking the parts for wear.  Nissan actually molded and machined indicators in to the timing components for that purpose.  

 

Most people do things like check cylinder pressure, record oil usage, examine spark plugs, etc to determine if their engine is worn.  It's sounding like you might not have even had the engine running yet.  Why would you spend time and money on something so unknown?  You might be replacing high quality parts on an engine that's barely broken in, with sub-standard parts assembled by someone who has little experience.

 

Put a list together of what you'll spend to "rebuild" the engine and you'll see that the sentence below doesn't really make sense.  Spending your "swap" money on rebuilding an engine that's not worth keeping?  Good luck.

 

"But, i'll only swap for something more modern than an L series and i don't currently have the funds for it"

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56 minutes ago, NewZed said:

 

The Factory Service Manual has a whole chapter about disassembling the engine and checking the parts for wear.  Nissan actually molded and machined indicators in to the timing components for that purpose.  

 

Most people do things like check cylinder pressure, record oil usage, examine spark plugs, etc to determine if their engine is worn.  It's sounding like you might not have even had the engine running yet.  Why would you spend time and money on something so unknown?  You might be replacing high quality parts on an engine that's barely broken in, with sub-standard parts assembled by someone who has little experience.

 

Put a list together of what you'll spend to "rebuild" the engine and you'll see that the sentence below doesn't really make sense.  Spending your "swap" money on rebuilding an engine that's not worth keeping?  Good luck.

 

"But, i'll only swap for something more modern than an L series and i don't currently have the funds for it"

 

Thanks for your feedback. 

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I'd check compression, pull the valve cover and the little window cover on the front and look at the chain wear.  If you can look in and spot the chain tensioner, and it's not worn, then likely you don't have to touch the engine.  These things last forever, usually it's the EFI cold start/thermotime failure that makes people think it's busted.   Mega-squirt can solve all that. 

 

Sucks about the snapped bolts. That's a pain, but once you remove the intake, the exhaust is much easier, as is replacing those studs. I'd definitely recommend some PB blaster or liquid wrench before getting back in there. an Impact wrench will make short work of most of that,  I love my dewalt electric 20v impact.

 

Good luck,

 

Phar

 

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EEYYYYY. I got the exhaust manifold off last night. I feel like i went through half a can of PB Blaster to ensure we didnt get more broken bolts. Unfortunately, there are two in the head itself. Hopefully i can get those out with another half can of PB and some left handed drills. 

 

So my plan as of now is to do as suggested. Check compression and chair wear. if all seems good i'll replace the needed gaskets on that side of the engine and put it back together. I'd be surprised if i had it running by the Canby meet. I dont have much time to work on it unfortunately.

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I've never done it myself, but word on the street is you can dissolve steel bolts out of aluminum heads with an alum/water solution. It'll take a day or so to work, but should leave you with perfect factory threads and none of the headache of drilling.

 

 

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