Intake/Exhaust Manifolds' Gasket - Difference in L series?

[KamakSun]

Hi Ratters,

 

I'm about to reassmble my exhaust manifold and intake.  I'm not sure what head I have but it is on an L20B block.  Is there a difference in the manifold gaskets used on the heads of an; L20, L16 and L18?

 

Additionally, y'all use anything gooey in addition to the gaskey? If so, what?

 

Thank you,

 

KamakSun

[KamakSun]

And what is the preferred gasket brand?

 

Thanks again!

[Doctor510]

All depends whether you have square exhaust ports or round exhaust ports. Just get the right one.  I have used FelPro forever.  I like the copper spray stuff

[wayno]

On the bottom edge of the head between number 1 and 2 spark plugs there is a number, it will likely say either 210, A87, U67, W53, or W58, it could say 219, or V912 but these are rare race type heads that are not that common, what is your head number?

[Stoffregen Motorsports]

OEM type steel core gasket is the best with stock cast iron exhaust manifold. Copper coat is cheap insurance, but be sure the surface of the head and the manifolds are clean and straight. If you want to be extra sure, take a piece of 1x2 (wood) and wrap it with 200 grit emery cloth (or regular sandpaper) and give all the surfaces a light sanding. Any imperfections will show up this way too.

 

Whatever you do, DO NOT use a roloc disc on a pneumatic die grinder to clean these surfaces. They do more damage than good.

[DanielC]

I just got back from my friendly local Nissan dealer, Dick Hanna Nissan, in Gladstone OR. and got two of these gaskets.

This is the gasket for the square exhaust port head.

[datzenmike]

W58 are round exhaust L20B heads and has coolant holes for the intake. Found on all '78-'80 L20Bs.

 

The '75-'77 L20B used with the U67 head. The gasket will have square exhaust ports and will not have the coolant intake manifold holes in them.

 

All L16/18 will have the coolant holes and square exhaust ports.

 

 

Naturally an earlier L16/18 gasket will work perfectly on a U67 but the coolant holes won't be needed or used. After marker gaskets will all have the coolant holes in them even if not used because why have two different ones that do the same job..

[KamakSun]

The head says U60. A quick search says that the U60 is the same as the U67. My piston have an inward curve, any idea what the compression might be?

[wayno]

The head says U60. A quick search says that the U60 is the same as the U67. My piston have an inward curve, any idea what the compression might be?

Then you have a square port exhaust, so get an intake/exhaust manifold gasket with square exhaust ports, I have always had good luck with the Felpro brand.

And you had to have the casting number that I left out, I have never seen one myself, so I didn't mention that one.

[KamakSun]

Hey all,

 

My apologies, I forget this is ratsun so if there is no pic, it didn't happen. Is this an SSS head? I'm getting mixed info.

 

For your viewing pleasure:

[wayno]

No, it is not an SSS head, the SSS heads have a 219 or V912 casting mark, and there are a few A87 heads with a 219 cast into the front of the head.

You have a U60 casting that is an open chamber type head like the U67, but you do have the large valves like the SSS heads, but the SSS are closed chamber.

Hey all,

My apologies, I forget this is ratsun so if there is no pic, it didn't happen. Is this an SSS head? I'm getting mixed info.

For your viewing pleasure:

[datzenmike]

Open chamber on an L20B.... 8.4 compression.

[wayno]

Open chamber on an L20B.... 8.4 compression.

 

Look how much it has been shaved, it's likely a little higher now.

[KamakSun]

How would I be able to spot that it has been shaved? Would there be anyway to find out the compression without dissembling and measuring?

 

And I guess the next question is how do I identify the cam?

[Doctor510]

Unless it's an after market performance cam, what would you worry about it?

[banzai510(hainz)]

Nissan and the Felpro are 1.5inch port size gasket.  I have burnout the Felpros in the center due to loose intake bolts

Others might be 1.25 inch (Victor renz)

[DanielC]

The head thickness from the block surface to the cam cover surface thickness should be 4.248 according to one source I have seen.   That was not a number from a Nissan service manual.   It might be possible to get a measurement off the edge of the head on the spark plug side, but more difficult on the manifold side.  If the manifolds are off the head, that would be easier.

 

Nissan gaskets come with a sticky sealer on them.   Nissan recommends retorquing the manifold gasket on the engine after it has been ran.  

 

Basic steps to use when installing the manifolds, on engine with separate manifolds.

Clean gasket surface on head, and both intake manifold, and exhaust manifold.

Clean out all the threaded holes used to hold the manifolds on the head.

Put the center exhaust manifold stud on the head, and both exhaust manifold end studs.  

Put the gasket on the studs, and then the exhaust manifold.  Hand tighten the three nuts on the ends, and center of the exhaust manifold.

Just start four lower bolts with the thick washers that clamp both manifolds.   Pull the thick washers out to the head of the bolts.

Slide the intake manifold between the thick washers, and head, keeping it away from the head.  Try to not contact the manifold gasket until the intake manifold is in place.  Do not tighten the lower manifold bolts, yet.

Start one of the top four intake manifold bolts to hold the intake manifold, and then install the other three top bolts.

Now you can tighten all the manifold nuts and bolts, starting from the center.   Work across the port holes, from top to bottom toward the ends of the manifolds.  Use several steps, and a universal joint on the socket helps to get to the lower manifold bolts.

[Stoffregen Motorsports]

Look how much it has been shaved, it's likely a little higher now.

Using the casting numbers as evidence that it has been shaved is less than reliable. More often than not, I have seen the numbers hanging off the edge on a virgin head.

[Stoffregen Motorsports]

The head thickness from the block surface to the cam cover surface thickness should be 4.248 according to one source I have seen.   That was not a number from a Nissan service manual.   It might be possible to get a measurement off the edge of the head on the spark plug side, but more difficult on the manifold side.  If the manifolds are off the head, that would be easier.

 

Nissan gaskets come with a sticky sealer on them.   Nissan recommends retorquing the manifold gasket on the engine after it has been ran.  

 

Basic steps to use when installing the manifolds, on engine with separate manifolds.

Clean gasket surface on head, and both intake manifold, and exhaust manifold.

Clean out all the threaded holes used to hold the manifolds on the head.

Put the center exhaust manifold stud on the head, and both exhaust manifold end studs.  

Put the gasket on the studs, and then the exhaust manifold.  Hand tighten the three nuts on the ends, and center of the exhaust manifold.

Just start four lower bolts with the thick washers that clamp both manifolds.   Pull the thick washers out to the head of the bolts.

Slide the intake manifold between the thick washers, and head, keeping it away from the head.  Try to not contact the manifold gasket until the intake manifold is in place.  Do not tighten the lower manifold bolts, yet.

Start one of the top four intake manifold bolts to hold the intake manifold, and then install the other three top bolts.

Now you can tighten all the manifold nuts and bolts, starting from the center.   Work across the port holes, from top to bottom toward the ends of the manifolds.  Use several steps, and a universal joint on the socket helps to get to the lower manifold bolts.

Great play by play.

 

One minor modification I might add is the swapping of the four inner manifold bolts to studs. I have seen these bolts strip out the threads in the head so many times I can't count. If you convert them to studs, the torque load gets transferred more evenly across the aluminum threads, allowing more torque in the process.

[DanielC]

That is a good idea, you mean the four lower manifold bolts, with the thick washers?

[Stoffregen Motorsports]

Yes, those four.