S14 Heater Core/Valve Swap

[twistedsymphony]

ok... So I'm swapping an LS1 into my 95 240sx. one thing that has bothered me with my LS1 swap is that my S14 has an external valve going to the heater core. It's got this ugly-ass cable coming out of the fire wall and going to a little valve on one of the heater hoses in the enigne bay... not only is it unsightly but it makes this more difficult when dealing with clearances and what not.

here's an old pic... the valve is on the left the cables comes out of the firewall on the right
http://www.web-nine.com/albums/carpics/s14heatervalve.jpg

Come to find out it's ONLY the 1995s that are like this... AFAIK none of the S13s or 96-98s have this external valve.

Thanks Nissan!

My first question is... do the other S14 model years even have this valve at all? I've looked at some ebay listings for heater cores and didn't see anything on them that looked like a valve, though it could just be out of site

If they do have one I'm wondering if I can swap out the valve from a 96-98 and make it internal to give me some more room and clean up the bay a little. or maybe swap out the whole heater core...

Also how hard is it get at the heater core? I already have the blower and AC evaporator removed... will I have to remove the whole friggin dash to get at the heater core? I would hoping I could avoid taking out my dash if I could... :-/

any pictures/advice/etc would be appreciated.

[tunersedge]

bump.. because im wondering the same thing.

I have a '96 and like you said the valve is located internally, and then on my '95 its located externally. So anyone who has a definitive answer please let US know.

[projectRDM]

Ask and you receive. All S14 have the little plastic housing that the valve sits in, but it's hollow on '96-'98 models. Only the '95s as you mention have a cable coming off the mode door motor on the heater case. In order to pull the heater core the entire dash must come out, as well as the dash crossbar. You can then take the case out, flip it, remove the screw securing the hold down, and slide the core out. It's not fun.

As far as upgrading, I'm sure you could use a '96-'98 motor and core. On both my '96 and '97 I ran new hoses and deleted the plastic housing because as you say, it's ugly. My only issue was finding the right prebent hose (the outlets are smaller on the block hardlines) but I came up with a reducer for one hose and fitted a new outlet on the block for the other. I should have taken pictures then but for a KA it's nice, you can pull the entire intake manifold without even touching those hoses now.

[twistedsymphony]

thanks for the info...

... so then does the 96-98 have the valve at all? did Nissan just get rid of it, or is it actually integrated into the core?

[twistedsymphony]

Someone from my home forum answered this here:
S14 Heater Core Valve Swap - 240sxONE Forums (http://forums.240sxone.com/showthread.php?t=4264)

http://farm4.static.flickr.com/3527/3470315724_21e5640514_o.jpg

that's a picture from his S13 heater core...

I get it now... I can probably just swap out the neck ... since the blower and evaporator are removed too maybe I can even do it without removing the whole core... it's just a matter of running the cable on the inside.

[projectRDM]

I don't think you can get the neck off without pulling the core out. It's really tight, but I'd like to see someone try and verify if it is possible.

[twistedsymphony]

I'll take a look at it tonight. I should know right away if it's possible or not.

is there a bracket or something else on the body of the heater core that holds the cable? all I see on the neck is the arm and obviously something will need to hold the cable body to make it work right.

EDIT:
Interesting courtesy parts doesn't show any difference between the 95 and the 96+
http://www.courtesyparts.com/240sx-parts-s14-1995-1998/genuine-nissan-parts/body-electrical/270-heater-blower-unit/-c-3690_3691_3727_3744.html

what IS interesting though is that for the external valve they DO show that the 96 plus just uses a straight through connector instead of the valve...

[tunersedge]

twisted, i think this is the problem we MAY run into, hopefully you already have the answer to this but wouldn't there be a difference with the heater core wiring in the obd2 s14 compared to the obd1 s14?

[Om1kron]

those necks(white/yellowed plastic male hard tubes going in the cabin you put your heater hoses on) are screwed onto the back of the boxes... you have to pull the boxes out and unscrew them.

[twistedsymphony]

twisted, i think this is the problem we MAY run into, hopefully you already have the answer to this but wouldn't there be a difference with the heater core wiring in the obd2 s14 compared to the obd1 s14?
from what I can tell there is no difference, I don't know why there would be either....

those necks(white/yellowed plastic male hard tubes going in the cabin you put your heater hoses on) are screwed onto the back of the boxes... you have to pull the boxes out and unscrew them.

Actually they're mounted on the passengers side of the box. despite what everyone else told me I simply poked my head under my dash and could see all 4 bolts clear as day, of course my AC evaporator has already been removed but this contradicts what everyone was saying about having to remove the whole core to swap out the neck.

Think about it for a moment... the neck makes a 90* bend... in what possible configuration would it be mounted on the back of the core and still poke straight out firewall?

[projectRDM]

Actually they're mounted on the passengers side of the box. despite what everyone else told me I simply poked my head under my dash and could see all 4 bolts clear as day, of course my AC evaporator has already been removed but this contradicts what everyone was saying about having to remove the whole core to swap out the neck.

Think about it for a moment... the neck makes a 90* bend... in what possible configuration would it be mounted on the back of the core and still poke straight out firewall?

You make a good point, I never have looked at from that angle.

[oewoko]

just saw this thread, and am subscribing.

i actually just played with that valve this past weekend.

drove down to maryland, and even with the unit on full cold, it was still blowing slightly warm air. i thought the valve didn't close all the way, but it was.

but i wouldn't mind eliminating it out of the engine bay either.

any updates twisted?

[twistedsymphony]

no updates on this... on Monday we dropped the LS1 in my car and I will DEFINITELY have to do something because there's no room for the original valve to go back on... I should start looking for someone with a junk s13 heater core that I can steal a valve neck off of.

[m3_il]

bump any updates on this?

[twistedsymphony]

yes and no..

I had a close look at 96 heater setup and noticed that the valve is completely absent from the system, the location where the valve sits int he engine bay just has a plastic straight through coupler.

I was just going to remove the valve and call it a day and then I realized that on an LS1 if I run the heater hoses under the passenger's side header the valve will bolt up to the side of the block using one of the unused engine mount holes... the cable reaches and everything.

So I'm keeping the valve, just relocating it, but failing that I don't see any issue with removing it altogether.

[m3_il]

hmmm, seems like i will have to fumble around with this. hopefully there are no wiring differences btwn a 95 and 96. Still wondering how Im going to make this work.