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L6 heads; pics and descriptions


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I used to get confused about which heads had what kind of combustion chambers.

I thought I'd create a thread with pics of different combustion chambers showing differences and describing each different head.

 

E88, 260Z spec

This is an open chamber head meaning that there are no quench pads. It has rectangular exhaust runners. Intake runners are NOT notched for fuel injectors

Notice decent unshrouding by intake valve. I'm pretty sure that this is OE but I'm not sure.

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As pulled from motor:

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Maxima N47 (A.K.A. MN-47)

Comes on the 1981-1984 Maximas that are gas powered.

Outside can be easily identified by the N47 marking AND a threaded hole right behind the #5 spark plug.

The MN-47 will NOT work on a L24 block without eyebrowing the bores. A L26 block can be substituted since it is IDENTICAL to an L24 block but with eyebrowed bores.

The MN-47 has 38-39.5CC combustion chambers. Supposedly there are different size chambers but I think most of them are straight 39CC.

The MN-47 is not generally suitable for a turbo application unless pistons with a very large dish are used to lower compression.

 

Exhaust runners have cast-in round steel liners that should flow decently well.

Intake runners ARE setup for fuel injectors.

 

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Close up on combustion chamber:

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MYSTERY DOHC Z head

Nothing is known about this head from the guys I have talked to.

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Note "Paeco" on casting. "Paeco" in Alabama states that they know nothing about this head.

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I'll update with more pics as I assemble them.

Others feel free to add 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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The mystery head is the 'Paeco-Goerz' head bought in SanDiego at a swap meet complete with tooling for machining and full size hand drawn blueprints. Those photos were taken in the back of the new owner's truck at a Group Z meeting by ME!

 

Intake and Exhaust ports are symmetrical, so the option for either side being either function is open. Note the plug holes are not complete.

Somewhere I have the photos of the combustion chambers which are hemispherical in conformation.

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He was looking to flip it, and nobody seemed to care. I could not bring myself to ask him how much it cost at the Swap Meet.

He was looking to make coin on the deal, and you know the deal on the Z-Car Community. They're not big on buying memoriabelia at four digit prices, regardless of the 'Cool Factor'...

Myself included at that point. Those photos were taken sometime between 1999 and 2003, so who knows what happened to it. He had my home phone number, and all I can remember was he said his name was "Richard" and he spoke with something like a light German Accent.

 

Oh, yeah, I have seen these photos linked all over, and nobody gives credit for the source of the Photos. Call me "Alan" on that one, I figured the least someone could do is say "Tony Took Em"... They were stolen off this site from a post I responded to regarding DOHC Heads. Drax was nice enough to host them for me at the time so I could get 'em out and people could see it. I took em because trying to tell someone about that head and it's mere existence is almost insurmountable when people don't believe you in the first place! I ended up pulling down the photos at several places due to idiots.

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Can I add info also????

 

 

 

E30= This head came on Cars that never came to the states. It was available on the 2.0 L

series engine. This head has 37cc chambers, and SMALL intake ports. The valves are also small in

diameter. Bronze seats as well. This head would be a screaming High Compression head if someone

would take the time and put the bigger valves and do a decent port job on it as well. This head also does

have a high quench design as well.

 

E31= This head is available on all 240z's up to about the month of 10/70. There were about 10,000 of

these heads made. This head has 42cc chambers and is also a high quench design as well, much like the

E30, except this head has the 35mm Intake Ports and the larger valves. E31's had bronze seats as well.

 

E88= There are actually 3 variations of the E88. The first variation is of which it is the EXACT same

head as the E31, except it has the E88 casting code.

 

The second is which it has the large open chamber to where it is a 47 cc chamber now, and not the 42.

 

The third is where it has the open 47cc chambers and also has the large Ex valve inserted, the 260z's got

these, and to where the bore had to be notched to accept the larger valve.

 

N42= This head came on all 75-76 and EARLY 77 cars. It has the 47cc chamber, and this head is a

fully open head. This head was used on a fully dished piston, to where no quench was used. It has the

largest of the valves much like all 280's did. 44mm intake and 38mm ex. This is the last of the L heads

that came with bronze seats. This head has Square ex ports, and has the Injector notches as well.

 

N47= This head came on all mid 77 through the 1980 z cars. It has the same exact characteristics as the

N42 except that it has the cast in ex liners. These liners were cast in place, for the reason that when the

motor is running, these liners get so hot that they glow red hot, and with that you get the advantages of

them burning off the hydrocarbons that are left over in the exhaust charge. This is the first head to have

hardened seats put in all of the valves.

 

P79= This head is a Good head. This head came on all 81-83 NA cars. This head has the Ex liners cast

in as well, but the chamber is a HIGH quench design. The chambers are 53cc's. This head when used

with a Flat top block will yield a HIGH quench design, and will reduce detonation.

 

P90= This head is also a good head, as it has the same exact characteristics as the P79, except that it has

the non-linered square port ex ports. This head is wildly used for NA setups also, to where most shave

.08" off of the deck, and then insert the 75-80 valves to take up the valve lash, and then put cam tower

shims to make up the timing chain slack.

 

P90A= There are actually two variations of the P90A. One is the solid lifter style to where it is exactly

like the P90. The second is also exactly like the P90, except it has Hydraulic lifters.

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To Bryan's list I will add on the N42 that at the same mid77 breakpoint that got the US the N47, most of the rest of the world got the N42 with the hardened seats. I know because I have one, and have seen several more, usually on JDM replacement engines. They ran an N42 all the way up to when the Fairlady 280Z got supplanted by the Z31. Same for Cedrics, Glorias, Leopards, etc. Japan Market Stuff all had N42's way later than we did, and they have the good later style hardened seats. They're out there! And in pretty good numbers as well, especially in the SoCal region where the JDM importers did lots of business.

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Hey Guys,

Here are the pics of the cut-up P-90 showing the inside water passages.

 

The first two pictures show the inlet points in the gasket surface. You will notice that there are holes in the head that are blocked off by the HKS steel gasket. These could flow water if the gasket was opened up. In the second picture you will see holes in the head gasket that do not have holes going into the head. This makes me wonder if this was for a reason, or just a manufacturing convenience, so that 1 head gasket design would fit many application of the different years. I wonder if an improvement could be had by opening the gasket up to the holes in the head, and the head up to the gasket. Hmmm.

 

The other pictures show a large casting flash rib blocking probably 50% of the water passage from the bottom of the head to the top. This web was going from the #6 to the #5 cylinder. It appears that these flash webs are through the whole head. There are also some large casting bumps from the exhaust studs that would appear to restrict flow.

 

The final pics show the nice open cavity that flows above the exhaust ports. We talked about taping into the head above the exhaust ports, this looks like an ideal place.

 

Sorry about the big pics, but wanted to show the details. Click the pics to enlarge them from my gallery

 

Enjoy, Jeff

 

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original thread post by Monzter

 

I have been collecting photos of various heads for some time, trying to keep credit and track of who gave me what. I will post the meager collection I have thus far later this week, I need to upload all the images to a gallery here so they are hosted locally.

 

Detailed photos to go with the descriptions and the detailed explanation of the various differences seem to be the most lacking when it comes to head information here.. lets see if we can make this thread good enough to be worth making it (another) sticky.

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E30 Head,

It's of my 1977 Datsun 240K (or Skyline out side of Oz), running a L24

the head doesn't have the notches for the injectors, it has square exhaust ports.

It was used with dished pistons (standard).

I've included a picture of the cam, I noticed that there were no identification on the end of the cam

 

Nigel

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Hi guys, great thread. Very interesting.

 

I have currently torn down my N42. I am an apprentice Machinist and before I mill this head (will be bolted to a L28 block, dished.) I am concerned about how much I can cut off this head. I have read on this site some have taken 060 thou! What is my safe amount? I am concerned about what I've read here with regards to shimming the cam....I don't want to get into this. I am merely cleaning things up. I am not going to overkill here with respect to the ports. I might "tidy" things up. However what I don't want to do is open up the ports so wide the valves can't possibly move the air anyway. Essentially, the stock cam is going back. I want a ride that is smooth and tight. I am not chasing HP at this point. One day I will build something really special for my 260 but for today....decking and as mentioned above is my goal.

 

So, in short, if I cut 30 to 40 thou am I going to cause more grief then I need.

 

Thank you to all.

 

tim

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Hi guys, great thread. Very interesting.

 

I have currently torn down my N42. I am an apprentice Machinist and before I mill this head (will be bolted to a L28 block, dished.) I am concerned about how much I can cut off this head. I have read on this site some have taken 060 thou! What is my safe amount? I am concerned about what I've read here with regards to shimming the cam....I don't want to get into this. I am merely cleaning things up. I am not going to overkill here with respect to the ports. I might "tidy" things up. However what I don't want to do is open up the ports so wide the valves can't possibly move the air anyway. Essentially, the stock cam is going back. I want a ride that is smooth and tight. I am not chasing HP at this point. One day I will build something really special for my 260 but for today....decking and as mentioned above is my goal.

 

So, in short, if I cut 30 to 40 thou am I going to cause more grief then I need.

 

Thank you to all.

 

tim

 

Update: I just received in the mail my 'how to modify your Datsun L series" - WOW what a book! :mparty:My questions are answered. Thanks anywho...;)

 

T

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I think I have another oddball head. It is brand new and never been run. It was a nissam OEM replacement part, but for what I have no idea. It is a N-33. The combustion chambers are a wedge shape and it has a small exhaust valve with a large intake. The exhaust ports are square and there is no injector cuts in the intake. It is also only drilled for the 6 bolt intake. Any ideas?

 

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Veritech-Z has this N42 closed chamber cylinder head with round exhaust ports.

DSCI0005.jpg

 

DSCI0007-1.jpg

Exhaust ports look like they could have been square at one time with the round liner/disc mounted in over it?

DSCI0011-1.jpg

It looks like the quench pads are flush...not sure though.

Doesn't the regular N42 have a wedge shaped chamber similar to the E88 chamber?

 

*edit*never mind that last comment. Blue72 answered my question below.*edit*

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  • 3 weeks later...

I thought I would include this photo of my head. It seems different then the E-88 in the first post that was found on a 260. Please correct me if I am wrong but the chamber is shaped just slightly different and is not as open,granted this head was shaved .010. My car is a 9/71 production so i guess this would be the middle series e-88. Oh, I forgot, I did put the bigger valves in this head which brought my chamber size down to 39.5 I believe.

project z 001_thumb.jpg

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Olderthanme wrote:

Maxima N47 (A.K.A. MN-47)

Comes on the 1981-1984 Maximas that are gas powered.

Outside can be easily identified by the N47 marking AND a threaded hole right behind the #5 spark plug.

The MN-47 will NOT work on a L24 block without eyebrowing the bores. A L26 block can be substituted since it is IDENTICAL to an L24 block but with eyebrowed bores.

 

 

My 240z, has a P30 block and a MN47, and no need to eyebrowing the bore... I just remove the old Z n47 and put the mn47, use 91 octane gas and the car runs better whit this setup.. I really dont know why it works...

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I agree, the big hulabaloo about eyebrowing the bores is not a 'NOT'. The heads WILL work, but it depends on how the dowels and head are positioned on the block wether or not the valves tag the tops of the bores or not. I have even seen early L24 engines with big-valve N42 heads on them where the valves 'self clearanced' against the block at original crankover, and then ran tens of thousands of miles before anyone found out the valves were (at one time) interfering with the block.

 

It's more of a 'should' eyebrow the block statement, rather than a positive declarative sentence structure.... Always check interferences before assembly and determine what needs clearancing and what does not. Some may need it, some may not. Do it and you know you won't have a problem.

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