head and block combonation
10-02-2004, 05:25 PM
#1
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head and block combonation
Hey
z-guys!
just got back from a car show at wolf creak park in coldspring texas, and there were a lot of ford 50 modle coops.
but anyway I have been doing some performance work on an engine. I have noticed that my 1980 n/a head is a N47 and the block is a N42. wile my 1976 head is a N42 with a N42 block. my 1979 also has a N47 head on a N42 block.
any way, I was wundering why the different head with the same block? I figure it is comprestion reasons. I think the N42 head with the N42 block gets more horse power or is it the N47 head with the N42 block that gets more hors power.
I am also trying to figure out, how much I can shave my N47 head without making the pistons and valves kissing if I am putting a 1.0 mm. performance head gasket, and a stage 3 performance cam in. I have looked everywere for the clearance but havn't found it yet. I am porting and polishing the head, I have had it cleand, and I am having the block cleaned as well in the tank. I am also puting the 4 barel Holly carb on it. I am taking on a 289 fast back when I have completed my performance engine. do you guys think I can take it? the fast back only has a 3 speed transmiton, and as you know the 289 has those big *** ports.
I am curious to know what the best head and block combonation is for performance out the but I mean ***** to the wall man.
z-guys!
just got back from a car show at wolf creak park in coldspring texas, and there were a lot of ford 50 modle coops.
but anyway I have been doing some performance work on an engine. I have noticed that my 1980 n/a head is a N47 and the block is a N42. wile my 1976 head is a N42 with a N42 block. my 1979 also has a N47 head on a N42 block.
any way, I was wundering why the different head with the same block? I figure it is comprestion reasons. I think the N42 head with the N42 block gets more horse power or is it the N47 head with the N42 block that gets more hors power.
I am also trying to figure out, how much I can shave my N47 head without making the pistons and valves kissing if I am putting a 1.0 mm. performance head gasket, and a stage 3 performance cam in. I have looked everywere for the clearance but havn't found it yet. I am porting and polishing the head, I have had it cleand, and I am having the block cleaned as well in the tank. I am also puting the 4 barel Holly carb on it. I am taking on a 289 fast back when I have completed my performance engine. do you guys think I can take it? the fast back only has a 3 speed transmiton, and as you know the 289 has those big *** ports.
I am curious to know what the best head and block combonation is for performance out the but I mean ***** to the wall man.
Last edited by EatmyDust; 10-02-2004 at 05:27 PM.
10-04-2004, 09:12 AM
#2
The Evil Twin
Join Date: Mar 2001
Location: Seattle, WA
Posts: 9,296
The N42 and N47 have the same size and shape combusion chamber. (same compression) The differnce is that the N42 has softer valve seats and square exhaust ports out the head. The N47 has harder steel valve seats and round exhaust ports with emissions steel liners in the ports.
If you want higher compression, shave your N42 0.4 or so. Use flat top pistons in the block or just swap in a F54 non-turbo block that already has flat tops. You'll be running over 10:1 compression. Then get a long duration cam and all the other goodies.
If you want higher compression, shave your N42 0.4 or so. Use flat top pistons in the block or just swap in a F54 non-turbo block that already has flat tops. You'll be running over 10:1 compression. Then get a long duration cam and all the other goodies.
10-04-2004, 10:03 PM
#3
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So, do you mean use the N42 head, because there isn't any sleves in the exaust ports? If this is why, can't I just port throgh the slevs, or will that not work, and if not how do I get them out or go thrugh them?
I figured I could just bor my N42 block out and keep it flat top, you know just get some pistons out of J.C.W. that should kick me up to 10:1.
The 289 fast back with the 3 speed transmition, kind of sucked ***, but loocked really cool. I am pretty sure I can take it when I have finished this project. My only concerns are having the body done befor I race it, oh yea and having all the parts worked in. I have been working on the body ever sence I became a member of zdriver.com, and I am still working.
I figured I could just bor my N42 block out and keep it flat top, you know just get some pistons out of J.C.W. that should kick me up to 10:1.
The 289 fast back with the 3 speed transmition, kind of sucked ***, but loocked really cool. I am pretty sure I can take it when I have finished this project. My only concerns are having the body done befor I race it, oh yea and having all the parts worked in. I have been working on the body ever sence I became a member of zdriver.com, and I am still working.
10-05-2004, 08:07 AM
#4
The Evil Twin
Join Date: Mar 2001
Location: Seattle, WA
Posts: 9,296
and I meant 0.04 inches, not 0.4 inches on the shave! 
you can't shave the head almost half an inch. hehehe...
The steel liners can be removed, but its some work. Use some needle nose visegrips. Then smooth out the ports.
Ya, put the pistons in and leave your head unshaved. That'll be fine too. Get a bigger cam while you're at it! And a 4.11 rear with the 81-83 280zx 5-speed.
you can't shave the head almost half an inch. hehehe...The steel liners can be removed, but its some work. Use some needle nose visegrips. Then smooth out the ports.
Ya, put the pistons in and leave your head unshaved. That'll be fine too. Get a bigger cam while you're at it! And a 4.11 rear with the 81-83 280zx 5-speed.
10-05-2004, 09:41 AM
#5
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No way.
man I am totaly shaving the head. Didn't you know that the stage 3 performance came was a pretty potent cam? That sucker turns 3 grand easy. It is really great for top end with Ok bottum end, or good enough should I say. It is one of those ruff iddle deals you know. but seeing how we don't have emisions test here, and I can do just about anything I want performance wise and stay legal I thought a port, polish, shave, performance cam, 1.0 mm head gasket, bor, and 4 barel carb shoud be all I need to sucseed against the all mighty 289 fast back. I have a dogde 318 I am thinking of building up the same way. just don't know what I would put the dogde in.
man I am totaly shaving the head. Didn't you know that the stage 3 performance came was a pretty potent cam? That sucker turns 3 grand easy. It is really great for top end with Ok bottum end, or good enough should I say. It is one of those ruff iddle deals you know. but seeing how we don't have emisions test here, and I can do just about anything I want performance wise and stay legal I thought a port, polish, shave, performance cam, 1.0 mm head gasket, bor, and 4 barel carb shoud be all I need to sucseed against the all mighty 289 fast back. I have a dogde 318 I am thinking of building up the same way. just don't know what I would put the dogde in.
10-05-2004, 09:47 PM
#7
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Well
you make an exceptional point.
The SU's will provide the parolell in pull, straight into the head wile the 4 barell has all six cilenders to cover frome one position under it, but I knew all this ahead of time. the reason I am going 4barel, is it is cheaper than the weber system. Besides I can get flood jets for the carb, they are readely available. the carb will cost like $400, the bracket is only a little poket change and the intake for it is about $300. The weber kit is a little bit over $ 1000.00, and you have to fite constantly to keep them insink. I know this to be fact because a buddy of mine did the same thing, and it pissed him off. He ended up getting a 4 barell carb, and he sayed it actually felt, and performed a lot better. Any person who likes to just full with there tools every ones in a will I would tell them to get the dual system. I have no beef with the system, or the makers, I just like knowing that with the four barell intake I can put any four barell carb of my choice on top. Other than the needless crap I just spit out you have been great at giving me and others very helpfull tips, and info. I don't know what we would do without you man
Keep up the good work.
you make an exceptional point.
The SU's will provide the parolell in pull, straight into the head wile the 4 barell has all six cilenders to cover frome one position under it, but I knew all this ahead of time. the reason I am going 4barel, is it is cheaper than the weber system. Besides I can get flood jets for the carb, they are readely available. the carb will cost like $400, the bracket is only a little poket change and the intake for it is about $300. The weber kit is a little bit over $ 1000.00, and you have to fite constantly to keep them insink. I know this to be fact because a buddy of mine did the same thing, and it pissed him off. He ended up getting a 4 barell carb, and he sayed it actually felt, and performed a lot better. Any person who likes to just full with there tools every ones in a will I would tell them to get the dual system. I have no beef with the system, or the makers, I just like knowing that with the four barell intake I can put any four barell carb of my choice on top. Other than the needless crap I just spit out you have been great at giving me and others very helpfull tips, and info. I don't know what we would do without you man
Keep up the good work.
10-06-2004, 08:03 AM
#8
The Evil Twin
Join Date: Mar 2001
Location: Seattle, WA
Posts: 9,296
ok then, as long as you've done your research on the 4-barrel.
I think the 4-barrel feels better than tripples because of the added velocity of running a single carb vs. the wide open intake of sidedraft Webers. The SU's are easier to tune to each other being only two, but honestly I've never tuned SU's or sidedraft Webers! I'm happy with fuel injection.
On my 4-cyl Datsun I went with the common Weber downdraft for its ease of maintenance and slight performance increase for the street. I like it. You can actually get a lot out of it even though its a small carb. You just have to do some work to the intake manifold.
Maybe do more research on the different 4-barrel intake manifolds available. Getting the right manifold might make the difference for how well the engine performs. Oh, and don't over jet the carb. Keep it on the lean side for the best overall power.
I think the 4-barrel feels better than tripples because of the added velocity of running a single carb vs. the wide open intake of sidedraft Webers. The SU's are easier to tune to each other being only two, but honestly I've never tuned SU's or sidedraft Webers! I'm happy with fuel injection.
On my 4-cyl Datsun I went with the common Weber downdraft for its ease of maintenance and slight performance increase for the street. I like it. You can actually get a lot out of it even though its a small carb. You just have to do some work to the intake manifold.
Maybe do more research on the different 4-barrel intake manifolds available. Getting the right manifold might make the difference for how well the engine performs. Oh, and don't over jet the carb. Keep it on the lean side for the best overall power.
10-06-2004, 10:43 AM
#9
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Good advise about the jets man.
I am not sure how big will actually go. I am thinking I am going to keep them the same until I get the parts all worked in, then switch to senthetic oil, and change the jets in the carb.
You are like the freaking z god father man if I can't figure something out I always know you will allways reply to one of my post atleast once. How long did it take you to aquire all your knowledge on these little thumpers?
I am not sure how big will actually go. I am thinking I am going to keep them the same until I get the parts all worked in, then switch to senthetic oil, and change the jets in the carb.
You are like the freaking z god father man if I can't figure something out I always know you will allways reply to one of my post atleast once. How long did it take you to aquire all your knowledge on these little thumpers?
The more problems you see and the time spent to correct them is what teaches you!
10-06-2004, 10:04 PM
#11
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Oh I heard that man.
the only real thing that gives me a problem, with thes things is all the vacum, and electrical. I am old fasion when it comes to engines. I like carberators because they are not hard to work on, and you don't have any electrical crap to worry about unles you run into one of those electric chokes, and I couldn't tell you about that because I have been for the ones without it evean though they make it easy.
the only real thing that gives me a problem, with thes things is all the vacum, and electrical. I am old fasion when it comes to engines. I like carberators because they are not hard to work on, and you don't have any electrical crap to worry about unles you run into one of those electric chokes, and I couldn't tell you about that because I have been for the ones without it evean though they make it easy.
10-07-2004, 08:18 AM
#12
The Evil Twin
Join Date: Mar 2001
Location: Seattle, WA
Posts: 9,296
True, true... I accidently figured out a charging problem with my Z that i had been putting up with for about 1 year. Besides that, I haven't had any electrical issues. I'm keeping my fingers crossed. A friend of mine has had two 280ZX's with major electrical problems that we coudln't fix so we bypassed things. It sucks. My car was totally stock when I got it and I think that helps. Cars that have had people putting various sound systems and alarms in them tend to get hacked and the wiring harness is never the same...
Carbs are nice in their own way. But my fuel injected Z has just been good to me I guess. My electric choke on my Weber is a single wire connection. seems to work fine.
I've fixed all kinds of problems with brakes on my Z. Cooling, some electrical, ignition switch, interrior lights.... and as for engine teardowns I have torn my truck's 4-cyl L-series engine down several times. that's what taught me about the internals of these engines. I've only torn down an L28 once. Alot of other advice I give is just theorys on engine mechanics (performance) so, its just advice and not facts. I read a lot online so I'm just shooting stuff back that I think is true. haha! ya, don't trust me!
Carbs are nice in their own way. But my fuel injected Z has just been good to me I guess. My electric choke on my Weber is a single wire connection. seems to work fine.
I've fixed all kinds of problems with brakes on my Z. Cooling, some electrical, ignition switch, interrior lights.... and as for engine teardowns I have torn my truck's 4-cyl L-series engine down several times. that's what taught me about the internals of these engines. I've only torn down an L28 once. Alot of other advice I give is just theorys on engine mechanics (performance) so, its just advice and not facts. I read a lot online so I'm just shooting stuff back that I think is true. haha! ya, don't trust me!
10-07-2004, 03:23 PM
#13
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I know that fuel injection is far more responsive than a carb, and the fuel injection seystem I have in the car right now is problem free. but I was looking for more fun with out messing with expensive computers. a thing a have noticed with the new engines is all the electrical. they can make engines smaller now and pump out more horse powere, and you just about cant blow them. all the computer stuff preety much gos out befor hand. I like the horespower but I like it to come from the engine and only the engine working with itj's self. No nos, or cheats just good old fasion metal.
Here is a real turn on! My girl friend is going to put my performance engine toghether for me. she has never worked on anything befor so I was going to show her how and supervise her and make sure everything is done right. Man I love that girl. She is almost up there beside my car you know. she is going to have to waite till it is finished.
Here is a real turn on! My girl friend is going to put my performance engine toghether for me. she has never worked on anything befor so I was going to show her how and supervise her and make sure everything is done right. Man I love that girl. She is almost up there beside my car you know. she is going to have to waite till it is finished.
10-07-2004, 04:27 PM
#14
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Location: killeen, tx
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good points, some things are for some and some for others. as far as my build went with the su's, i guess if you build it.... the rpms will come (10,500rpm with su's. i was scared to go further on bad valve seals)
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