Jump to content
HybridZ

New owner, 74 260z -head gasket woes


Recommended Posts

I'm a very fortunate person as I have been looking for over 4 years for a mechanics special. I came across (and purchased a 1 owner 260z with 70k miles. Story I got, he blew the head gasket. Took it apart and never out it together. It's been garages stored for 15yrs since that happened. Car is 100% time capsule and documentation goes back to 77 best I can tell. This weekend wife and I started go through the parts and verifying what it will take to get her on the road again. First part, we can rotate the engine. Sleeves and deck had some rust but scotchbrite green cleaned almost all of it up. Engine has soaked for several days now. But I'm wondering if there is more story here. The oil pan is off. Is there a reason someone would remove a oil pan for a head job? Best I can tell deck and head are flat. Going to give it another go tomorrow and if doesn't budge next weekend I'll pull the motor.

20220715_193850.jpg

Link to comment
Share on other sites

hmm... When you say "sleeves", do you mean the cylinder walls? If so, you definitely do not want to use scotchbrite (maybe the non-scratch kind?) as you don't want to mess-up the prevision hone job that exists. If the cylinder walls had surface rust on them. If you really want to have-a-go at what you have there, you could throw it all back together, pre-lube, and crank it over to check cylinder pressure.

 

My instincts tell me you will not be happy with the state of the motor. It is likely to burn oil (either at the valve seals, piston rings, or both). I would just pull the motor and send it off to a machine-shop for a rebuild. Your seals and gaskets are likely toast as well, which will cause irritating oil leaks. 

Link to comment
Share on other sites

Yeah non-scratch kind. I've built engines before and no concerns about rebuilding it as is. Going to lay underneath it today to see why the pan is off and maybe pop the pistons with a rubber mallet too.

Edited by inis
Link to comment
Share on other sites

If you're going to run it I'd at least put a wrench on everything while the pan is off. Depending on how far you want to go, you could put in new rear cap seals and the the front and rear mains as well before you reseal the oil pan. Sounds like you've already checked everything for flatness. If there's no scoring in the bores you could just run it and see. 

Link to comment
Share on other sites

15 hours ago, inis said:

Story I got, he blew the head gasket.

Took it apart and never out it together.

First part, we can rotate the engine.

Sleeves and deck had some rust but scotchbrite green cleaned almost all of it up.

The oil pan is off.

Best I can tell deck and head are flat.

Going to give it another go tomorrow and if doesn't budge next weekend I'll pull the motor.

 

 

Your description doesn't make sense.  You said it's apart.  Then you said that you can rotate the engine (probably meant can't).  Then you said that you did something that could only be done with the head off.  If the head is off you can't rotate the engine unless the front cover and timing chain are also off.  If you're trying to spin the engine in the car with the head off but front cover on then you might have jammed the timing chain in to the gears.

 

How about a picture of the engine in the car?  That will tell something.

Link to comment
Share on other sites

Yeah can't spin. Bought it with tubs of parts, block is still mounted in car with no head or oil pan. Has sat this way from my understanding 10years. I was told the orginal owners son drove it. Blew the head gasket. The dad aka orginal owner took it apart and never put it back together. The head looks professional machined with valve terrain still in-tact. If I can't get it to spin, I'll take it to a machine shop and see what can be done using as much as possible orginal parts. Might just need disassembled and a light hone job, new bearings, new rings, main cap bolts, rod bolts and then reassembled. I'll expect the worse and hope for the best. Current as it sits, I haven't been able to turn it at all, not even a mm. Best I can tell the timing chain isn't bunched up.

Edited by inis
Link to comment
Share on other sites

22 minutes ago, inis said:

If I can't get it to spin,

 

Looks like you're not reading what people are writing.  No offense.  These aren't 60's era small block chevy engines.  Overhead cam.  You can't spin the engine with the head off, normally.

 

22 minutes ago, inis said:

block is still mounted in car with no head

 

57 minutes ago, NewZed said:

If the head is off you can't rotate the engine unless the front cover and timing chain are also off. 

 

58 minutes ago, NewZed said:

you might have jammed the timing chain in to the gears

 

Link to comment
Share on other sites

@inis, unless you’re planning on making this a build thread, you want want to post your question(s) in the Nissan L6 sub-forum.  Might get more responses and find more topic-specific info related to you specific issue.  

 

Just a suggestion...your call.

Link to comment
Share on other sites

11 hours ago, inis said:

 block is still mounted in car with no head or oil pan

 

2 hours ago, inis said:

Hey update, engine released tonight and spins freely. 

 

 

Good luck with wherever this is going.  It's possible that the engine did spin, but if it did the chain tensioner has certainly popped out of its bore.  You'll never get the head installed with the chain properly on the cam sprocket without pulling the front cover.  Good luck.

 

https://www.amazon.com/Rebuild-Your-Nissan-Datsun-Engine-ebook/dp/B006VUICHG

 

 

Link to comment
Share on other sites

6 hours ago, NewZed said:

 

 

 

Good luck with wherever this is going.  It's possible that the engine did spin, but if it did the chain tensioner has certainly popped out of its bore.  You'll never get the head installed with the chain properly on the cam sprocket without pulling the front cover.  Good luck.

 

https://www.amazon.com/Rebuild-Your-Nissan-Datsun-Engine-ebook/dp/B006VUICHG

 

 

Yeah I'm sure it's not right. I have a new timing set amongst things coming my way. Thanks for the link I'll grab that too.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...