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240z head gasket


gmkeegan

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about to do a head gasket on my 240z. does anyone want to tell me something to look out for before starting ? i hear getting the timing chain back on is a bitch but besides that anything ?  also does anyone have a forum about this already ? thanks in advance 

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Get good gasket sets from a Nissan dealer.  I bought Felpro for the head on my 510 but I heard that brand is so so.  Not sure the condition of your head but get it check out by a machine shop and make sure it's not warped, while you are doing the head, check your cylinder walls and make sure they are good and also make sure the block has no crack.  What was the compression before the head went out? If so so, you may want to consider a total rebuild. You can also do a search on RATSUN for headgaskets replacement and probably very similar to a Z since our engine is similar. Have you been to the NICO web site?  they also have a forum on Zs.  Good luck. 

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DO NOT remove the cam sprocket until you find out how to prevent your timing chain tensioner from falling out. If you do this getting it back together is a snap. Who ever told you that does not know what they are talking about. Failure to secure the tensioner will cost you 4-6 extra hours fixing something that never needed to happen.

 

In the upper right hand corner is the search function. Rather than spoon feed you, spend a hour researching and reading about any head gasket change on any 4 or 6 cylinder L series engine. Type " how to block timing chain tensioner " and start reading. Read several threads and if you gave a question then and only then come back and ask. This is a well documented procedure.

 

Then search " L series head gasket replacement " far a few tips to not only make it easier but get good results.

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Get good gasket sets from a Nissan dealer.  I bought Felpro for the head on my 510 but I heard that brand is so so.  Not sure the condition of your head but get it check out by a machine shop and make sure it's not warped, while you are doing the head, check your cylinder walls and make sure they are good and also make sure the block has no crack.  What was the compression before the head went out? If so so, you may want to consider a total rebuild. You can also do a search on RATSUN for headgaskets replacement and probably very similar to a Z since our engine is similar. Have you been to the NICO web site?  they also have a forum on Zs.  Good luck. 

my compression was 120 dry

 

DO NOT remove the cam sprocket until you find out how to prevent your timing chain tensioner from falling out. If you do this getting it back together is a snap. Who ever told you that does not know what they are talking about. Failure to secure the tensioner will cost you 4-6 extra hours fixing something that never needed to happen.

 

In the upper right hand corner is the search function. Rather than spoon feed you, spend a hour researching and reading about any head gasket change on any 4 or 6 cylinder L series engine. Type " how to block timing chain tensioner " and start reading. Read several threads and if you gave a question then and only then come back and ask. This is a well documented procedure.

 

Then search " L series head gasket replacement " far a few tips to not only make it easier but get good results.

so after watching videos and reading a lot.  i think i might just pull the front cover to see what the tensioners look like so dropping it won't be a problem. now my only question is when the engine is in the car and the oil pan is on it...  if i drop it will i have enough room?  

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Don't fix what ain't broken. If the engine was out, maybe but in the car? no. You would be unsealing the oil pan and then bolting it back up with the same old gasket, same with the head gasket above the timing cover. Good chance of tearing it or causing a leak. Removing the timing cover is a last resort when the tensioner falls our and to be avoided if possible.

 

That search posts would have had pictures of the tensioner, the L24s are identical.

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What type of compression checker did you use, plug in type or screw in type?  Plug in type is not that accurate.  How many times did you crank the engine should do it like 5x or so?  If youa re not sure that you did the compression check properly read the directions on your tester or go on line.  Almost forgot if you do change the head gasket, you may want to consider changing your timing chain and tensioner. I think the one I got for my 510 was Tsubaki or something like that. 

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Don't fix what ain't broken. If the engine was out, maybe but in the car? no. You would be unsealing the oil pan and then bolting it back up with the same old gasket, same with the head gasket above the timing cover. Good chance of tearing it or causing a leak. Removing the timing cover is a last resort when the tensioner falls our and to be avoided if possible.

 

That search posts would have had pictures of the tensioner, the L24s are identical.

the thing is this my car is not road worthy and it's not my dayly so i'm in no rush. i'm about to check if at top dead center does the V and hole line up.. if it does then i will leave it how it is and only do the top end like you say. if it's not most likely my guards are worn and ill be pulling everything off the front.

 

120? have you ck th lash on the valves?

 

is it overheating sucking up water if not Then maybe nothing is wrong

i have yet to check lash on the valves i want to say your you video on head gaskets is amazing!! i learned so much!!! i was going to do a video until i found yours lol.. is there a video online on how to do valves but another video from you would be great!!!!! lol oh BTW i know it's a blow head gasket cause coolant was flying out of clyn 4 and my coolant level went way down. also it will dry lock when the spark plugs are in clyn 4. unless you know another reason why coolant would be inside the cylinder :crying:  

 

What type of compression checker did you use, plug in type or screw in type?  Plug in type is not that accurate.  How many times did you crank the engine should do it like 5x or so?  If youa re not sure that you did the compression check properly read the directions on your tester or go on line.  Almost forgot if you do change the head gasket, you may want to consider changing your timing chain and tensioner. I think the one I got for my 510 was Tsubaki or something like that. 

it was a screw on!! it was also a harbor freight one but it has worked fine on everything else i have ever tried it on.  yeah i turned it over 6-8 times and its stops at 120 cold. 

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120 is kindy low.  Had one of those Harbor Freight tester and they are a cheapo delux.  Used it a couple of times and started reading false readings.  You may want to consider using another tester just to verify the readings.  When you did the compression check did you have the throttle wide open?

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120 is kindy low.  Had one of those Harbor Freight tester and they are a cheapo delux.  Used it a couple of times and started reading false readings.  You may want to consider using another tester just to verify the readings.  When you did the compression check did you have the throttle wide open?

no i didn't open the throttle but regardless the head gasket is blown 100% there is coolant pouring out of cylinder four. 

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Then buy the best parts for the headgasket  and see if the block needs rebuilding.  Will this become your project or a shop?  Either way make sure that the head is nice and flat and the block is also good to go.  Good luck !

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this is a project!!! my hobby its turning into and thanks would you suggest a certain head gasket over another? and would you replace the head bolts as well? in not trying to do ARP but if I have nothing else to buy then looks like I'm going down that road.

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I've used OEM, Felpro, DNJ, and victor reinz head gaskets. They all worked just fine. The rest of the DNJ gaskets were kind of total shit.. 

 

 

Regarding bolts, if they appear stretched, replace them. Otherwise, just re-use them. They aren't torque to yield.. so they are likely just fine.

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the thing is this my car is not road worthy and it's not my dayly so i'm in no rush. i'm about to check if at top dead center does the V and hole line up.. if it does then i will leave it how it is and only do the top end like you say. if it's not most likely my guards are worn and ill be pulling everything off the front.

 

i have yet to check lash on the valves i want to say your you video on head gaskets is amazing!! i learned so much!!! i was going to do a video until i found yours lol.. is there a video online on how to do valves but another video from you would be great!!!!! lol oh BTW i know it's a blow head gasket cause coolant was flying out of clyn 4 and my coolant level went way down. also it will dry lock when the spark plugs are in clyn 4. unless you know another reason why coolant would be inside the cylinder :crying:  

 

it was a screw on!! it was also a harbor freight one but it has worked fine on everything else i have ever tried it on.  yeah i turned it over 6-8 times and its stops at 120 cold. 

 

The V is not going to line up on the #1 hole. The #2 hole is where the factory sets it when assembling it and even then when stretched or worn you can still go to to the #3 to get the V and the line correct. That's the purpose if having them.

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The V is not going to line up on the #1 hole. The #2 hole is where the factory sets it when assembling it and even then when stretched or worn you can still go to to the #3 to get the V and the line correct. That's the purpose if having them.

ok mike i need your help so i went to TDC and the top V and notch lineup for the most part. the cams are at 10 and 2 so that's right i think... but the distributer is at 12:28 i'm pretty sure this is not right but wanted to check? also the last picture can i connect the one hard line that runs to the back of the car right to the engine without that side piece because i'm pretty sure the other one goes to emissions and im not running them anymore!

 

d1_zpsficgx2dd.jpeg

 

d4_zpsjcbnzu9e.jpeg

 

d3_zpsgtr9jgqj.jpeg

 

d2_zps7hkll3yy.jpeg

 

d5_zps87ppl9r6.jpeg

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IF this engine is at TDC then...

 

d1_zpsficgx2dd.jpeg

 

The sprocket needs to be set on the next highest number. This will move the V over to the right where it belongs.

 

 

d4_zpsjcbnzu9e.jpeg

 

This should be at 11:28. It's close. It may even be within timing adjustment range.

 

 

d5_zps87ppl9r6.jpeg

 

The missing hose simply goes to the air cleaner. The hose allows filtered air into the gas tank as the gas is used. It will work as it is, just using outside air. This is the flow guide valve and it's hooked up and working so just leave it.  

 

How it works. The gas tank has a sealed cap so as the tank empties air (filtered) is drawn back into the tank to replace it. When engine is off any evaporated gas in the tank flows forward and out that hose that goes to the engine vent pipe and is stored there in the crankcase. The next time the engine is started the PCV valve draws the stored fumes into the intake and they are burned. Simple, effective and has ZERO affect on running.

.

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IF this engine is at TDC then...

 

d1_zpsficgx2dd.jpeg

 

The sprocket needs to be set on the next highest number. This will move the V over to the right where it belongs.

 

 

d4_zpsjcbnzu9e.jpeg

 

This should be at 11:28. It's close. It may even be within timing adjustment range.

 

 

d5_zps87ppl9r6.jpeg

 

The missing hose simply goes to the air cleaner. The hose allows filtered air into the gas tank as the gas is used. It will work as it is, just using outside air. This is the flow guide valve and it's hooked up and working so just leave it.  

 

How it works. The gas tank has a sealed cap so as the tank empties air (filtered) is drawn back into the tank to replace it. When engine is off any evaporated gas in the tank flows forward and out that hose that goes to the engine vent pipe and is stored there in the crankcase. The next time the engine is started the PCV valve draws the stored fumes into the intake and they are burned. Simple, effective and has ZERO affect on running.

thank you so much i have ordered a full head gasket kit as well as the tool to hold the chain and the tensioner.. should have the tools in the next day or two the gaskets get here the 16 can't wait. in the mean time there is plenty of other things to do need to cut the old exhaust to fit my 6 into 1. as well as figure out how to weld my shifter so it doesn't hit 

 

so with my 240z the previous owner put in a 5 speed but broke the center console since now it sits higher up. so i got a new console but now need to figure out how to weld something into place so i can cut the old shifter to move it back.. any ideas ? i have seen one from looking online.. but do you know of a thread already started about this ?? thanks again   

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to me the dist is correct.with in timming adjustment

on the cam sprocket just make sure you turned the crank clock wise up to the Zero point then check the cam timming. Dont counterclockwise as youll induce slack on the tight side chain.

 

 

break all the bolts loose first then set back up to TDC and remove head ect......

 

 

I saw autohausAZ had tsubaki timming chains. at least for a L16 and that should be the same

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If the shifter is to far forward and hitting on 1, 3 and 5 then the hole needs to be cut not the shifter. Depending.... you may be able to bend the shifter.

it's not hitting the metal it clears that it hits the fiberglass  center console. 

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to me the dist is correct.with in timming adjustment

on the cam sprocket just make sure you turned the crank clock wise up to the Zero point then check the cam timming. Dont counterclockwise as youll induce slack on the tight side chain.

 

 

break all the bolts loose first then set back up to TDC and remove head ect......

 

 

I saw autohausAZ had tsubaki timming chains. at least for a L16 and that should be the same

thanks for the advice.

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