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L6 heads; pics and descriptions


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I haven’t heard of the N-47 being manufactured with-out the liners, though that is not to say it didn’t happen. HS30-H or 1 fast Z are pretty savvy regarding what was and was-not offered from Da

  Thank you for the clarification. I really could have screwd my self over not knowing that.

So, since I didn't see this answered earlier, but are the intake ports into the head the same across all of the Z car heads? (I'm wondering because of intake manifold possibilities).

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Looks like your regular old plain jane Z N47 which is different than the MN47. The Z car N47 is an open chamber design with round exhaust ports and exhaust liners. The MN47 is closer to a P79, just with smaller combustion chamber (39 or so cc), hence the quench pads. The P-79 has quench pads and exhaust liners too, but larger chambers (53cc).

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Looks like your regular old plain jane Z N47 which is different than the MN47. The Z car N47 is an open chamber design with round exhaust ports and exhaust liners. The MN47 is closer to a P79, just with smaller combustion chamber (39 or so cc), hence the quench pads. The P-79 has quench pads and exhaust liners too, but larger chambers (53cc).

 

Thank you for the clarification. I really could have screwd my self over not knowing that.

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Guest Widebodys30

I have one of these as well.

N42, no injector bosses, not welded, carb intake.

 

I just bought an N42 block and head the other day. The head looks like an N42 until I had a closer look and noticed that the intakes weren't notched and the head not drilled and tapped for EFI. :shock:

 

Has anyone seen this and can anyone suggest why this N42 isn't like all the others I've seen?

 

Cheers people.

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AFAIK, all the U.S. L6 cylinder heads have 35mm approx. intake ID's. The only L6 heads with smaller ports came on L20's in overseas applications. 05L is 28mm, E30 is 30mm and the Y70 is also 30mm.

I suppose you could count the P79 as having slightly smaller intake runners because of the D shape they were cast in, but it helped promote swirl and velocity, so it probably doesn't count.

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AFAIK, all the U.S. L6 cylinder heads have 35mm approx. intake ID's. The only L6 heads with smaller ports came on L20's in overseas applications. 05L is 28mm, E30 is 30mm and the Y70 is also 30mm.

I suppose you could count the P79 as having slightly smaller intake runners because of the D shape they were cast in, but it helped promote swirl and velocity, so it probably doesn't count.

Ok, thanks. So I guess I won't worry so much about intakes that are advertised as for 240 or 260 heads then.

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After searching on cylinder head posts, I couldn't find info on this question. What are the differences between a P90 and P90a "solid lifter" head? If the P90a had a hydraulic and solid lifter version, would the solid lifter version be any different than a regular P90 or can you rebuild them in the same fashion? Thanks.

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I’m not real familiar with L-series cylinder heads for other markets/countries other than domestic USA market. Though I am pretty certain that this head is NOT a domestic USA head AND it has been modified.

 

1) Injector slots and injector manifold mounting holes along with carb mounting holes indicates post 1975 production.

 

2) The EFI Intake mounting holes “appear†to be 8 x 1.25mm, (Same as the carb and exhaust mounting holes), instead of the typical USDM 10 x 1.25mm, though the pictures could be deceiving and those holes could be the 10 x 1.1.25mm holes. (See picture below showing the mounting hole size difference on an US market N-42 head.)

 

3) In looking at the manifold face, note the 2 bolt hoes above the #6 exhaust port?…. NOT on any USDM L-6 cylinder heads.

 

4) Note the vertical casting lines above and between the ports in the unmachined portions of the head near the valve cover...

 

5) The measurement of the intake port opening means absolutely nothing in identifying that head as it had been “port matched†(opening of the port had been enlarged by hand), evidenced by sanding wrap marks left in the port entrance and the injector slots indicate most of the material removed in the intake port was removed from the roof of the port.

 

6) The casting number had been removed. The picture is difficult to tell but it looks like a sanding wrap finish.

 

7) Pics of the combustion chamber and clear well lit pics of the area surrounding the intake valve guide boss would help greatly in identifying this head, so long as the intake port work did not consist of altering the guide boss.

 

 

N-42 head. EFI mounting holes 10 x 1.25mm, carb mounting holes, 8 x 1.25mm

Mis-match2Medium.jpg

is not the first head with out code that I have seen. when here in Puerto Rico a group of my friend a lot time ago ran circuit races with a '79 280ZX the cut the head so much that the code desapears and then just like this head they port and polished the ports. So im thinking that it is a N47 Head very cut and port polished.

 

My two cents jajajjaa

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Some info on the "rally head"? Found in the Classic Z car photos... Its like single cam crossflow? All the books I've read have the OS as the only crossflow.

 

 

Yes, that's the Nissan 'LY' head for the L6. First seen in late 1971, and fitted to the L24 block to make an 'LY24' - later fitted to the N42 Nissan Sport option blocks to make an 'LY28', eventually ending up at just under 3 litre capacity.

 

It was a 2-valve hemi chambered crossflow design, with 42mm inlet ports and 40mm exhaust ports on the standard unmodified casting. It was single cam with two rocker shafts, and splayed 'finger' rockers operating the valves.

 

We have discussed it many times on this forum in the past ( also on classiczcars.com ) so if you search 'LY' you should be able to find plenty on it.

 

Some pics:

FIA-3032-LY-p1_thumb.jpg

LY-24-on-ECGI-pre-73-RAC-12_thumb.jpg

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Note on the second photo in-car, that it's ECGI...

 

"ITB-Style" Electronic Fuel Injection in 1973 RAC Rally.

 

Can you say 'Alpha-N'?

 

Now I have to go review my FIA papers, to make sure I have the right supplement, I don't recall that optional page. What I have may be incomplete. Thanks Alan!

 

Regards from Johor Baru, gate way of the Imperial Japanese Army's landing force against Singapore...LOL

Heading to Ho Chi Minh City on Monday...I'm on a Month-Long 'Past Wars Blunder-Tour' at work I guess.

 

That red car with the LY looks like photos I took at Las Vegas in Y2K. I may have taken a ride in that car...it was stimulating at the Las Vegas Speedway, though my hat got tipped to Toshi Iwaya and his "Midnight Racing" Red S130 (Overboost.Com had an article on it some time back) Nice Manifold on Toshi's Car...

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Yes, that's the Nissan 'LY' head for the L6. First seen in late 1971, and fitted to the L24 block to make an 'LY24' - later fitted to the N42 Nissan Sport option blocks to make an 'LY28', eventually ending up at just under 3 litre capacity.

Sorry to go off topic, but Alan, are there any significant differences between the Sport Option N42 block and the regular production edition?

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