240Z E31 Head Gasket Options

[madkaw]

I have HG's of every variety now for some reason and I will take some pics when I get a chance. The latest Felpro HG has turned into a universal gasket which covers 70-80 models. The Nismo was very specific to the e30 block with the HG being cut out around unused water passages. The Felpro has a decent reputation amongst the Z owners I have read. I have two of the Victor Reinz HG's and I wouldn't put them on-they look cheap to me. Oval bore holes? Hmmm. That's weird. You might think the combustion chamber was oval or something   

[redzedsled]

See reference pics below showing ring dimensions.

 

Aftermarket generic head gasket at top and original head gasket off E31 head at bottom.

 

Nissan superceded to 11044-27L00 and 11044-27L01 most likely because of the size this oval ring.

 

The only issue is the Datsun 810 and early Maximas gaskets dont have the same cooling holes as the original gasket.

 

 

 

 

[madkaw]

Here's my collection.

top to bottom:   Old felpro(I believe)

                          Nismo

                          New Felpro(universal 1970-1980

                          Victor reinz

                          1983 stock HG

 

All Hg have oval FIRE RING except new Felpro and 83 stock Nissan

[redzedsled]

Please see attached images of the head gasket. It is supposed to be a graphite type head gasket and was confirmed it was from a 240Z Regrind Kit.

 

When I looked at it on top of the block at the engine builders, there were a total of four holes obstructed from the passages that extends into the block.

 

It is stamped L24 Nissan and Stone. Dan at the Z Shop, from whom I purchased the gasket has suggested that this is the correct gasket as the later L24 gaskets had limited cooling passages.

 

He had a generic Felpro gasket on the shelf, with the fire ring measuring 89mm round, with all passages present.

 

The 280ZX gasket he had on the shelf actually had the water passages blocked completely, and was also 89mm round.

 

So which begs the question are all of the cooling passages really necessary, and why would they change the design.

 

Can anyone help me to understand why they would block off these passages to the block, yet leave selective passages open.

 

 

[Zed Head]

Because the coolant flows from the block up in to the head, and the head cooling is more important than block cooling, I believe.  Plus the fact that if there's no matching hole in the head, the hole in the HG doesn't matter anyway.  The head gasket is actually designed to control coolant flow, that's why the holes are not as large as the holes they match in the block and head. 

Any chance you could put the gasket on the head and see what holes match?

[redzedsled]

I don't have ability to put the gasket on the head at this time. But I found a pic of a F54 block and this gasket seems to fit the cooling passages of this block.

 

There seems to be more water passages in the E31 and P30 blocks than the block shown below.

 

 

Please see reference pics below with a side by side comparison of head gaskets. original on top, new gasket at bottom.

 

 

   

 

Please see passage holes indicated in red to show which holes are blocked below:

 

[Zed Head]

Here's a good thread from the past that I was able to refind.  Were it mine I might just punch a new hole where the E31 needs it, if the gasket material in the area is sufficient.  Looks like you'll just be missing two center holes.  Size might be different though.

 

Also made a composite picture so you can see the differences.  I'm assuming that the guy who put the drawings together used the proper heads and knew what he was doing.

 

http://forums.hybridz.org/topic/115160-l6-cooling-system-diagrams/

[Zed Head]

The N42 head looks similar though.

[Zed Head]

Comparing the Stone HG to the E31 diagram it looks like there are no issues.  The gasket makers are just putting extra holes in everything.  If there are two passages you get flow if not, you get a little round spot on the head.

 

Edit - actually, what's interesting is that even the HG designed for the head has blocked passages in to the head.  The bottom row has tiny holes in the gasket and some are blocked.  The HG is the flow controller, not the passages.

 

So you really need to compare an old E31 HG to a new HG to see what's what.  I don't think the passages in to the head matter much.

[redzedsled]

Thanks very much for this thread link. I think it proves my theory that the gasket is similar to the F54 block based on the water passages drawing you so kindly mentioned.

 

The F54 block was for the 280ZX and the bore would have been 86mm, perhaps the later L24 blocks were equipped with a reduced number of water passages.

 

I asked the engine builder if he felt he could punch in four more holes in the gasket and use it, but he was very apprehensive.

 

This gasket is not your typical composite head gasket it is very tough and most likely difficult to punch.

 

Still at a loss why the later blocks had reduced cooling passages.

[redzedsled]

Comparing the Stone HG to the E31 diagram it looks like there are no issues.  The gasket makers are just putting extra holes in everything.  If there are two passages you get flow if not, you get a little round spot on the head.

 

Edit - actually, what's interesting is that even the HG designed for the head has blocked passages in to the head.  The bottom row has tiny holes in the gasket and some are blocked.  The HG is the flow controller, not the passages.

 

So you really need to compare an old E31 HG to a new HG to see what's what.  I don't think the passages in to the head matter much.

Hi Zed Head,

 

See earlier posts for comparison of Original and Stone gasket...

[Zed Head]

For clarity...