A real head ache

[smokin joe]

Ive got 3 l20b engines, all assembled and running right now, So I cant see everything on the head, nor can I see the chambers, Ive been trying to ID the heads  on all three. Two of them are the smog W58 which is easy to see on the passenger side. The third one ,I cant see anything . The difference that I noticed though is that the one with no marking on the side, has NISSAN JAPAN cast into the front, and the other two that say W58 on the side, are blank in the front. Any thoughts?

[datzenmike]

Only the '84 610 L20B came with the A87*. '75-'77 used U67 heads on 610/710/620 and S10. The W58 was used on the '78-'80 620/A10/S10 and 720.

 

* the A87 was used on all L18s.

 

210 was used on all L16 engines

 

 

Look carefully between the #1 and #2 spark plug. Check the front on the left side, may have 219. 

 

I have never heard of NISSAN JAPAN on the front. Some SSS heads had A87 on the side and 219 on the front. A LOT of L series engines were imported from Japan in the '70s-'80s. The imported heads were much cheaper than doing a valve job. Trouble is that in Japan they had heads that we did not get so some add balls are out there. With more and more stricter emissions There's no way they would send cars or trucks with closed chamber 8.9 compression heads here. These A87 and W58 'peanut' heads were almost certainly from an import block. 219 heads are from L165SSS and L18SSS engines* and very collectible.

 

*I have a pair of L18SSS SUs on an intake. They were never offered on our vehicles and so came off an imported engine.

 

Can you post pictures of this head?

 

[smokin joe]

The l20b engine with the mystery head is currently in a 79 620 pickup. I dont know the history of the truck or the engine. I took some pictures with a flashlight so not so hot, but the first one is the base of the head between 1 and 2 cylinder. Its a blank there where the other ones say w58 in that spot. Pic 2 is the end of the head right above the chain inspection cover. Thats the cast of NISSAN JAPAN. Had to move to fuel lines to get a better shot.           WELL ive been trying to figure out this URL insert deal with the pictures and ts a no go right now. My son will be coming over in a few days, but till then I only know how to do it with an email.

[datzenmike]

Picture has to be 4k MB or less. You can downsize it or start a free picture hosting site account. Keep you picture there and retrieve the info bring it here and insert into your account.

[smokin joe]

I tried uploading the pictures to the following imgur link. Let me know if you can access them.

 

https://imgur.com/a/RNl9Iq5

[datzenmike]

 

No way to know anything about this head. Interesting.

 

Usually there is a raised boss for the letters and numbers...

 

[datzenmike]

L head use and history as I see it...

 

The 210 head was used exclusively on the L16. It's rumored to have been designed for the smaller L14 or L13 and it's tiny valves, combustion chambers and intake/exhaust ports are about at the limits of use on the larger L16.

 

The A87 head with larger valves and ports than the 210 head was used exclusively on all the larger L18 engines in the 610 ('73) the '74 710 and 620 with the exception of the '74 610 when it changed to the L20B engine that year. The L18 was only used during two years, '73 and '74 and only for one year each on the 610 ('73), 710 ('74), 620 ('74) in North America. Some A87 heads had even larger valves and ports*

 

The '74 610 was the first year the L20B was used and perhaps there was no actual L20B head available yet so the L18's A87 (perhaps modified with larger valves?)* was used that one year.  From '75-'77 all L20B engines used the U67 head which had larger valves than the usual A87 and from '78-'80 the W58 head was used on the L20B. Perhaps this is a head in transition from an A87 to a U67???

 

All 210, A87, U67 and W58 heads are open combustion chamber. All but the U67 do come with closed chamber design but this is explained by having been swapped from import engines in the '70s and '80s. It was cheaper to get an import engine head that to rebuild them. The early '70s was a big change in North American engines with a move to lower more moderate compression ratios and low octane (lead free gas) for emissions purposes so Nissan would not have randomly put higher compression heads on their engines, it makes no sense.

 

 

 

There may be a way to sort of narrow down what you have without taking it off and looking. ALL L heads but the U67 use coolant flow through the intake to warm/cool it. Have a look on your L20B's intake just in front of the carburetor for a hose connection and metal pipe that connects to the thermostat by pass.

 

 

In the picture above look at the secondary opening (top) and to the upper left. There is a small pipe protruding from the intake with a hose and hose clamp on the end. Do you have this on the intake with the mystery head?

 

 

 

 

[Crashtd420]

 I love a good mystery....

Can you take a couple wider shots from the left and right.... might help....

Also to me it looks like the head was milled sown in thickness, possibly removing the identification....

Mike would know what it should measure...

The Nissan Japan on the front is interesting....

 

[Stoffregen Motorsports]

I think I see blue paint on the head in your pic. For whatever reason, some JDM takeout engines used to come with blue painted cylinder heads. If it is a true imported "SSS" engine, it may have a 219 head on it. Most 219 heads had the casting number cast into the front of the head, below where the Nissan Japan casting is.

[Stoffregen Motorsports]

When I say below, I mean at the bottom of the head, where it meets the front cover.

[smokin joe]

You can see the top of the front cover, under where it says JAPAN NISSAN. interesting that those are cast, not stamped, but cant see anything below in the way of a number. I don't see any blue paint on the head, just on the block. The intake manifold does appear to have that water pipe below the carb.

[datzenmike]

Only the '75-'77 U67 heads did NOT have that water pipe. The U67 intake and exhaust manifolds were bolted together and used exhaust heat to warm the intake. All others 210/A87/W58 used coolant flow through the runners.

 

So this is not an unmarked U67 so could be an unmarked A87 or even an unmarked 219 SSS head. BTW Stoffregen some of the 912s that were marked so on the front actually had A87 on the sides. The 219s had monster 1.5" intake ports, the only L head to do so as it matched the Dual SU intake runners. The A87 has 1.25" intake ports.

 

There was a later issued 912 SSS head that could be ordered with the 1.25" intake ports... 11041-U8880. The 912 SSS head with the 1.5" intake ports was 11041-0600A

[Stoffregen Motorsports]

18 hours ago, datzenmike said:

Only the '75-'77 U67 heads did NOT have that water pipe. The U67 intake and exhaust manifolds were bolted together and used exhaust heat to warm the intake. All others 210/A87/W58 used coolant flow through the runners.

 

So this is not an unmarked U67 so could be an unmarked A87 or even an unmarked 219 SSS head. BTW Stoffregen some of the 912s that were marked so on the front actually had A87 on the sides. The 219s had monster 1.5" intake ports, the only L head to do so as it matched the Dual SU intake runners. The A87 has 1.25" intake ports.

 

There was a later issued 912 SSS head that could be ordered with the 1.25" intake ports... 11041-U8880. The 912 SSS head with the 1.5" intake ports was 11041-0600A

Yeah, I've seen that too.

 

The later repop heads were cast with a V before the 912.

[Stoffregen Motorsports]

19 hours ago, smokin joe said:

You can see the top of the front cover, under where it says JAPAN NISSAN. interesting that those are cast, not stamped, but cant see anything below in the way of a number. I don't see any blue paint on the head, just on the block. The intake manifold does appear to have that water pipe below the carb.

Right next to the #1 spark plug. Isn't that dark blue paint? Or is that grime?

[smokin joe]

Looks to be grime. I will say ,The l20b engines I've driven before are torque oriented, but this one likes higher RPMs and has quicker acceleration than the others.

[smokin joe]

Looks to be grime. I will say ,The l20b engines I've driven before are torque oriented, but this one likes higher RPMs and has quicker acceleration than the others. Would  there be any clues under the valve cover?

[datzenmike]

Possibly it has a re-ground cam. That might be seen by looking at the cam or a couple of simple measurements of a cam lobe.

[Stoffregen Motorsports]

15 hours ago, datzenmike said:

Possibly it has a re-ground cam. That might be seen by looking at the cam or a couple of simple measurements of a cam lobe.

Could be a worn out timing chain, essentially retarding the cam timing

[Stoffregen Motorsports]

16 hours ago, smokin joe said:

Looks to be grime. I will say ,The l20b engines I've driven before are torque oriented, but this one likes higher RPMs and has quicker acceleration than the others. Would  there be any clues under the valve cover?

There has to be a casting number on the exterior of the head somewhere. I have never seen one without a number on it.

[Crashtd420]

2 hours ago, Stoffregen Motorsports said:

There has to be a casting number on the exterior of the head somewhere. I have never seen one without a number on it.

I still think this head has been milled down....possibly enough to remove the numbers...

[Crashtd420]

Smokin Joe check the thickness of your heads...

Are they the same or is the 1 mystery one shorter in height....

Seems a stock head should measure around 4.250.... if im right that head will probably measure around 4 inches tall.... 

[datzenmike]

L heads from the valve cover surface to the head gasket surface should be 4.248". It's impossible to trim enough that the ID is removed.

 

By that I mean the valves would certainly not clear the piston at TDC and the timing chain would have at least 1/2"of extra slack. The combustion chamber is 45.3cc. Removing 0.25" of head surface would remove 36cc of volume. Leaving barely 10cc. Just for the hell of it that's a 16.88 compression. lol

 

[Stoffregen Motorsports]

It is not possible to mill a head that much and still be able to use it.

[smokin joe]

I checked the head and I dont think its been milled. It shows around 4.3. There are bosses on the drivers side that are stamped. Front one says A D and the back one is an F. Dont know what that indicates if anything

[Crashtd420]

1 hour ago, smokin joe said:

I checked the head and I dont think its been milled. It shows around 4.3. There are bosses on the drivers side that are stamped. Front one says A D and the back one is an F. Dont know what that indicates if anything

Well atleast that rules that out..... 

I'd still like to seem some wider shots....it might also help Mike out spotting something that could possibly identify it....