P79 Head on L24 Block Gaskget Help!

[Evanso]

Hi

I have taken my engine apart for the first time and I need to replace the head gasket. But I am not sure what head gasket to order. The bores have a diameter of 84mm so have been overbored by 1mm so there is clearance for the valves.

Do I need to order a 280zx head gasket or can I get away with using the 1976 280z head gasket that I already have?

Thanks
Ben

 

[Rob Gaskin]

What gasket was on it? Dia of bores?

 

[Evanso]

What gasket was on it? Dia of bores?

I am not sure what gasket it is. Is definitely not a 280z gasket. The bore size on the gasket is 89mm.

 

[Rob Gaskin]

When I overbored my L24 to 86mm I used a 280 (Z or ZX?) gasket but a lot of the waterways on the L24 were not in the gasket so I cut them out! I had an E88 head.

One of the gaskets I've used in the past had elliptical bores which I never understood? Surely any space cause by an ill-fitting gasket would reduce the CR?

 

[jonbills]

you can lay the gasket you have on the block and as long as the fire rings are wider than the bores and there aren't water passages outside the gasket, itll be ok.

 

[Evanso]

you can lay the gasket you have on the block and as long as the fire rings are wider than the bores and there aren't water passages outside the gasket, itll be ok.

Okay I have done that and I believe fire rings are wider than the bores. Here are some images. What do you think?

 

[jonbills]

its pretty close isn't it!
do you have the two hollow dowels? if they hold the gasket so it can't move at all, it should be ok, but if there's any movement you'll have the piston hitting the gasket.
I'd probably get a bigger gasket TBH.
My recollection is that late 280zx gaskets only work on late engines, but the earlier gaskets work all.
so a 79/80 gasket would do it.

 

[Evanso]

you can lay the gasket you have on the block and as long as the fire rings are wider than the bores and there aren't water passages outside the gasket, itll be ok.

Here are some photos with the gaskget I want to use on the head. The gasket I have actually fits the block and the head better than the gasket that was on there befor.

 

[jonbills]

oh, you said its a 280z gasket already. so it should work.

 

[Evanso]

its pretty close isn't it!
do you have the two hollow dowels? if they hold the gasket so it can't move at all, it should be ok, but if there's any movement you'll have the piston hitting the gasket.
I'd probably get a bigger gasket TBH.
My recollection is that late 280zx gaskets only work on late engines, but the earlier gaskets work all.
so a 79/80 gasket would do it.

Yh I won't risk it and I'll order one as I have to order other parts anyway.

 

[Evanso]

Yh I won't risk it and I'll order one as I have to order other parts anyway.

And thank you for your help.