Another Head Gasket Install - Nismo

Engine, Transmission and related drivetrain.
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loungin112
Posts: 256
Joined: 05 Mar 2014 21:34
Location: Colorado

Another Head Gasket Install - Nismo

Post by loungin112 »

I searched first...promise.

Quick rundown on the setup:
L20b
Euro NA 280zx pistons
cast iron exhaust mani
Dual 38mm SU carbs
ARP studs/nuts
Mallory Dist
A87 Open Chamber - rebuilt and port matched

The primary question I have is regarding the oblong slot at the rear of the gasket. Stock replacement has the oblong slot, Nismo does not. I couldn't find a definitive answer anywhere but could find info indicating this oblong slot in the gasket is a point of failure, so would adding it back in reintroduce a point of failure. Is this wisdom of Nismo deleting this oblong slot? Just want to get this right before I reinstall. I've already been through 2 of these head gaskets and have a third, don't want to have to find a fourth.

Thanks all!
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Tedman
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Joined: 01 May 2008 22:06

Re: Another Head Gasket Install - Nismo

Post by Tedman »

I have never been able to find a straight answer on this, either. Some say to cut the hole in the Comp gasket, others install as-is. Me, I figure Nismo/Comp knew what they were doing, so I have always installed as-is and never had issues. I wouldn't sweat it on a street motor, but reasonable minds may differ.
loungin112
Posts: 256
Joined: 05 Mar 2014 21:34
Location: Colorado

Re: Another Head Gasket Install - Nismo

Post by loungin112 »

Thanks for the insight. And, that is a great perspective to take on the matter. Unless I hear otherwise, I think I will take the same approach.
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Byron510
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Location: Maple Ridge, BC

Re: Another Head Gasket Install - Nismo

Post by Byron510 »

The advise I’ve been given while running the 2.2 blocks with L heads is the drill the 2x 8mm holes per cylinder down the spark plug side of the block to promote water flow up into the head. L16-20’s all have these holes as do all L heads. Scuffing of the pistons had been noted on motors not running this mod.
So it would be reasonable for me to think that the trapezoid shaped water hole at the back of Head/block. And while pinching out the 8x 8mm water holes into my 2.2l felpro head gaskets I use, I also punch the trapezoid hole out of the back...
I’ve never gone without, and I do wonder what would happen if I didn’t punch out that gasket?

Byron
Love people and use things,
because the opposite never works.
loungin112
Posts: 256
Joined: 05 Mar 2014 21:34
Location: Colorado

Re: Another Head Gasket Install - Nismo

Post by loungin112 »

Thanks Byron. Always good to get another perspective. Better coolant flow can't be a bad thing....can it? I see both sides of the observations. I wonder why Nismo, or other manufacturers, didn't match the head gaskets exactly to the block and head?
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