garagelu

S13 and S14 head differences: I believe the most significant difference between the two is the design of the intake manifolds. I believe the difference is going to be the most significant change if any in horsepower and torque. The s14 IM has significantly longer runners and a notably larger plenum.







Another difference that correlates to the IM is the fact that the s13 is a high port head and the s14 is a low port head. This difference affects the angle the air and fuel enters the chamber. I also want to point out the fact that the s14 ports have a significantly improved casting compared to the s13 ports. I want to state that I am only basing this observation on what is in front of me. I know castings, depending on how tight quality control is, can vary quite a bit.

PLEASE READ: A while ago when I was thinking about doing this swap, I was scouring the forums for more information on this swap. I kept seeing a lot of misinformed posts. One misconception was something about a VTC hole on the head. The only difference between the surface that mates to the block is one hole and that is a oil hole for the timing chain tensioner. On the s13 there is only one hole for oil pressure. On the s14 it looks like one hole is for pressure and the other is for lubrication. Other than that every hole lines up just as it would on the s13 head.

I also want to note how much more user friendly the s14 head and manifold is. Especially the coolant hose routing under the manifold was so much better in my opinion on the s14. In my situation, I am going to run a ¾ inch coolant hose from the lower coolant neck to the coolant port on the firewall. The other line goes from the firewall to the port on the intake manifold. Two other things that clean up the coolant hose routing is on the s14 there are no coolant lines running through the IACV and on the s14 the turbo coolant line doesn’t go behind the head. It routes from the upper coolant neck to the turbo.




Initially I had thought that the IACV differences were going to pose a problem. On the s13 IACV there is only one plug where the s14 one has two separate plugs. Upon closer inspection they just integrate the two sensors/solenoids into one plug. Luckily my friend that I bought all this stuff from pulled two plugs off some random Nissan harness that worked with the s14 IACV. In this situation, you have two choices. My first and recommended choice is to solder the plugs onto the s13 harness. Your second choice is to swap the sensor/solenoid over to the s14 IACV body. Also there are some differences between the two IACV which is the fact that the s13 IACV has coolant in and out lines but the s14 one doesn’t. The s13 IACV has a port that pulls air from the coldpipe but the s14 pulls air through a hardline on the IM.



Another problem I have run into is differences between the s13 and s14 throttle body. The s13 throttle pulley design does not allow me to use it. This poses a problem in my comparison. The s14 butterfly is 2 inches compared to the 2.5 inch butterfly on the s13. This .5 inch difference will definitely cause a skew in the results. I might have to just run with it unless someone can find me a s14 NA throttle body or donate one to me.





And finally this is what my kitchen looks like right now....


I will be updating with more information on this swap. Right now I am waiting on my valve spring compresssor to change over everything on my s13 head over. After that I can shine a light through my glass table and get good lighting for an in the port picture. And following, my head will be sent to the machine shop for decking and solvent washing.

So now to give some data behind this head swap, I will be taking this up to my original tuner hopefully and get it dynoed tuned. My setup is almost exactly the same from last year when I tuned. The things I changed on the car should not affect my hp or torque number much. Here is just a brief list of things I have changed: upgraded from evc 5 to evc 6, changed my blitz downpipe to a XS engineering downpipe, replaced my cracked exhaust manifold with a dc sports one. Hopefully this will give me some hard evidence on which head is better. I know there are many variables that can affect it but I will take them into consideration.

drifter_for_life06

some good info...keep us updated. Although I dont plan to do this...it has me interested

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Om1kron

very good an informative thread...

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Wayne

Sileighty_85

Its been along time but i believe the T/B off an N/A FWD SR (Ex. G20 infinity)
Will work for the S14.

I think the G20 one might work, i cant remember what SR we pulled ours off of. (Japan threw SR's in alot of differnt cars)

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後輪駆動車１番
1989 Built SR GT2871R -363whp
1998 S14 W/RB25- 250ish (For Now)
1986 SR86 - 200ish
1990 R32 GTR - 320hp
Don't Buy Engines from JDM-Online http://zilvia.net/f/businesses/207457-jdm-online.html
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garagelu

If a sentra se-r or g20 TB is going to work, I am pretty sure it would have to be a 95 and up since that is when they went to the low port design. I was thinking about modifying the pulley by drilling a hole in the pulley. The only reason why the s13 sr TB won't work is because the cable will not reach.

And yes they will work, but does anyone know what size the butterfly is on those fwd sr20de. If they are non-turbo I would like to say they are the 60mm.

Sileighty_85

The N/A should be the same size as the R/T DET

I have one laying around here (I beleive its a DE) it meausres 60mm

can't you swap the pully's?

Its really been along time since I've had to do this lol

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後輪駆動車１番
1989 Built SR GT2871R -363whp
1998 S14 W/RB25- 250ish (For Now)
1986 SR86 - 200ish
1990 R32 GTR - 320hp
Don't Buy Engines from JDM-Online http://zilvia.net/f/businesses/207457-jdm-online.html
Don't Buy XS-Power or SSAC Shit

s15specR

I'm looking to buy an s14 SR20 head if anyone knows of one, bare head is fine.

Thanks.

slider2828

So the two benefits are small change in quality of the IM and better IM coolant hose management? But overall you doubt there will be any HP or TQ changes?

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garagelu

If you read through my post, I have a few things that I think will affect HP and TQ. Number one being intake manifold design and next would be head port design and casting. And another benefit is the fact that the s14 engine looks so much better than the s13 engines.....IMO.

And I am not doing this because I think that I will make 100 more hp with a s14 head. They are both sr heads. Its not like they did a huge redesign. I expect more of a shifting in the powerband. I am mostly doing this because there were so much misinfomation about this swap. Especially about this VTC hole that I still don't know who would even start this rumor.

Just a few examples:

http://zilvia.net/f/tech-talk/214857...top-block.html

http://zilvia.net/f/tech-talk/209544...s13-block.html

http://zilvia.net/f/engine-tech/2017...-involved.html

And I may have forgotten to mention this but I will be using s13 cams and not using VTC. I have a s13 power fc with a couple hundred dollars in dyno time plus I don't feel like redoing my harness just to use VTC. I've seen pictures of s14/s15 engine modded by tuners in japan and I don't even see the VTC solenoid plugged up.

Om1kron

If anything maybe more efficient combustion, and the vvt/vtc whateeeever it's called. wont work.

in a nutshell.

The cams should be pretty similar, I don't know the exact numbers i'm sure the OP can provide all of that. It's just a better head design, down from the casting, the cooling, and the oil baffling through cover design.

edit : the op is using the s13 cams so yeah... same cam design just a chance in efficiency.

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Wayne

hksevo

bummppp-....

slider2828

I DID read it, but was wondering I thought high port is better no? But since your are mating a S14 IM to a S14 head, why not just go all S14 since the Valve cover is going to change to S14 valve cover as well....

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Om1kron

The point of the thread is more the interchangability of the blocks. You could build an s13 block and throw an s14 or s13 head on it.

Most people are afraid of building high hp applications with the s14 because they don't want to deal with the variable cam timing shit, or at least this is what I've found from research.

Where as most high hp cars pushing 530hp and what not are using red top motors because of the older design without the gas efficiency design. that's all VTC is, gets you more gas mileage.

the port design and such I don't recall where I found the information but like I said combustion and moves air more efficiently. Most sr20det's headwork improvements don't come from making the combustion chambers bigger, it comes from polishing, and modifying bowls and other head terms I cant remember.

Should be interesting to see how the s14 head behaves with s13 cams in it.

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Wayne

garagelu

I'm sorry but this doesn't make sense to me. I would change everything over to s14 but I just don't see the point right now. I could have run a s14 block and just change over all the sensors (only sensor I can think of on the block is the oil pressure). So really s13 blocks are not so different from s14 blocks with the exception of the better oil pickup and better pistons.

And I would have bought the s14 block but it had a spun bearing and I don't have a garage to be doing a full build.

I wish I had access to a fwd sr TB to see if it will work. And no, I can't swap pulleys. If you look at my side shot comparison of the two TB, you can see that the shaft size is different.


I just got my valve spring tool today from UPS so I will be updating the thread with some port pictures tonight.

garagelu

Update:

So today I got my valve spring tool and disassembled the whole head to prep for decking, solvent washing, valve seals, and upgrading valve springs. Here are some port shots comparing the two heads. I did some porting on my s13 head so it kinda sucks I couldn't get a picture of an untouched s13 port.

S13 HEAD







S14 HEAD

slider2828

Ok, but one more thing I should say is that most longer duration and bigger cams for S14 eliminates the VTC all together.... Its really up to the buyer to see if he wants to keep it or not. lol....

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Om1kron

The problem is he is running redtop power fc, and would have to change his ecu setup for the thing to be compatible with the vtc.

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Wayne

slider2828

Yah the thing is his redtop powerfc.... I guess he source a head,vc, and IM cheaper than tune with blacktop PFC... but I wanna see how much better it is.... really interested in this project nontheless!!

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slider2828

Wow s14 is alot better noticeably....

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DJ_Sunrise

Nice work, I'm diggin the post. Do you have the S14 VTC stuff by chance? My VTC kind of wore out ;-) lol

-Bart

garagelu

I can't sell the solenoid because then that hole would be just open unless I could find I plug for it. I do have the VTC cam gear for the intake cam. What else do you need? PM me.

heiyuu

woo hoo finally the answer to my question. and lol at my thread getting linked up as a noob thread.

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garagelu

Today I got my head back from decking and solvent washing. It always puts a smile on your face when you have clean parts coming back to you. Next will be installing valve seals, valve springs, etc, etc and then I will be pretty damn close to installing it on the block.










Today I also got my JWT C1 cams and valve springs in. I wasn't planning on changing cams but I have wanting some JWT cams but just couldn't bring myself to pay the 600 dollar price tag. But I finally found an incredible deal on them and therefore I couldn't pass it up. C1 cams have pretty much the same duration and lift as the BC stage 2 cams but as you should be able to tell from the pictures the overall design is COMPLETELY different. The BC cam lobe looks to be wider than the JWT lobe. I initially tried to take the picture with it light on the lobe but I found that taking a picture of the shadow differentiates the two much better.

BC Stage 2


JWT C1



Also here is a comparison of JWT(left), BC(center), stock(right) valve springs. My first observation was the fact that the JWT spring is overall wider than the BC and stock springs. I guess you could say the coil width is wider on the JWT as you can see from the picture taken of the top of the springs. But on the side view picture, you can see that the BC coils are taller. Also, you can see that JWT spring is wound counterclockwise and the BC and stock spring are wound clockwise. And finall you will see that the JWT spring sits a couple mm shorter than the other two springs. I'd like some input on why this is and what difference it will make. OH and also just buy using my hand to compress the spring, the BC spring has quite a bit more tension that the JWT. BC springs have to be one of the stiffest sr springs on the market.

garagelu

I haven't tried to contact Cody about this but I saw on his site that he had posted up some pics of his JWT springs. It looks like all his springs are the same except for one. And the odd one out looks like my whole set.

I wonder if JWT changed their design somewhere down the line. It looks like all his are wound clockwise like the stock springs.

Gallery :: JWT Springs

Anybody else have JWT springs that can give some input?

garagelu

Well I've got a pretty big update here:

This is something I didn't realize till I was starting to install the head. On the s14 head there is a separate oil pressure source coming up from the block and into the timing chain tensioner. It took me a good couple hours of probing holes in the head to figure out how oil is routed in the head. I am still confused about how the VTC solenoid works. It looks like there is a oil passage going from the solenoid up through the cam bridge, through the cam and cam bolt and into the VTC sprocket. But how does the solenoid regulate oil pressure is what I am wondering. Anyone have any input on this? I don't know that it will really matter in my situation. I am thinking that as long as I have oil going to the tensioner then I am ok.

On the s13 it get oil pressure to the tensioner from a hole coming from the front left head stud hole. Here is a picture of the s13 oil pressure hole location.



On the s14 head, it has the same hole in the head stud hole but that supplies oil pressure to the VTC solenoid. This poses a problem because if I don't modify the head then I will have no oil pressure to the tensioner.

So here is some info for anyone in the future who decides to attempt this. I went to several machine shops and some said they could do it. The shop I had my head decked quoted me 150 dollars to drill a hole. Another shop said 100. Both said they couldn't get to it for at least a week. I decided to take it to a place nearby called Midwest Chassis and Performance. The shop is built behind the owner's house. It sounds shady but this guy is recommended by everyone in town. I take it to him and he says he has a bridgeport to do it and it will be 30 dollars. I am in disbelief. Then I tell him that I jb welded the other hole and he said he will use a threaded plug to plug it for 20 dollars. And on top of that it only took him 1 day to do it. I am thoroughly impressed. Here are some pics:





What great about the plug is it is removable. If I ever decide to go to an s14 block I have the option of plugging the hole in the block or removing the plug and running it that way.

So when looking for a shop to do this, make sure they have a bridgeport. Also bring them both heads so they can drill the same location as the s13 head. And don't be like me and find out about this till I am about to install the head.

Today, the head is bolted and torqued down, head assembled, cams installed, timing all set. Tomorrow will be rewiring iacv, installing turbo, running vacuum and fuels lines, and other misc tasks. Should be 2 or 3 more days to get this thing running. Can't wait.....the weather is so nice!!!

bmx269

I know this post is old, but I am trying to get more info on the head modifications for the oil feed. I have blown my S14 SR at Irwindale during the FD Proam Finals, and decided to go the S13 block for added convenience in the future, if any engine problems were to occur at the track. S13 blocks are easy to come by.

All pics of the oil feed setup and or anything you can provide will help. Thanks.

-Trent

S14DOOD

So the hole above the bottom hole is the one you had drilled to get oil to the tensioner? Also there is a oil hole on the front side what is that for?

s14unimog

Interesting write up. I'm sure this will be a great reference for someone in the future. To add, I am using an s13 head on an s14 block and noticed a few differences as well. To get everything assembled I used a variety of parts from both setups. First off, since I had a new s13 oil pump/front cover; I used that. I noticed that all bolt holes line up except one. At the very top left of the cover the last bolt is about a 1/4" off. We used a washer to span the gap and it works great. Next I found that you must use the s13 SR coolant piping and thermostat housing and actually bend some of the connections out of the way of each other. Since the coolant port on the block is s14, there is a point where they come really close to one another. Another obvious change is the need to run an s14 oil filter and an s14 water pump. I'll check with my engine builder but I'm pretty sure there was a port on the block we closed up, but as you said, everything in an s13 head lines up to an s14 block; aside from that of course. As for the intake manifold, I chose to go with a Greddy style and used an s14 throttle cable pulley ,then made a bracket for the cable.

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garagelu

Yea that port that you closed up is definitely the oil pressure source coming up through the block to the head for the tensioner.

And pretty much to sum it all up if you are using a s14 head, you want to use all s14 stuff from the head gasket up. And same for the s13 obviously.

s14unimog

^ yup, pretty much...

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