A14 Mild street performance build

[sick620]

1 hour ago, Tom1200 said:

First; I run all stock Nissan components in the bottom end of my A12 & A15. I rev them to 8600 rpm all the time without issue.

 

I'm using a Delta 280 cam and the powerband is 4500 to 8200 RPM. I'd check with Delta bit for the street I'd go with the milder of the two cams.

Tom, can I run the Nismo brand dual springs with factory collets and retainers etc.? I see Nismo had part numbers for them but I cant find any for sale only the springs themselves. I also cant find A series spring anywhere on the isky site, but the Nismo ones are available on eBay. Nismo recommends you use the Nismo collets and retainers with the Nismo springs, but since they are not available anywhere I'm wondering if I can just reuse my factory stuff.   Thank you for all your info. 

Edited November 4, 2022 by sick620

[Stoffregen Motorsports]

Isky springs - https://iskycams.com/shop/index.php?main_page=product_info&products_id=2134

 

This jives with the info on the http://datsun1200.com/modules/mediawiki/index.php?title=Valve_springs site.

[sick620]

8 hours ago, Stoffregen Motorsports said:

Isky springs - https://iskycams.com/shop/index.php?main_page=product_info&products_id=2134

 

This jives with the info on the http://datsun1200.com/modules/mediawiki/index.php?title=Valve_springs site.

the springs you link show they are for an alfa romeo? 

[Stoffregen Motorsports]

I took the part number off of the 1200.com site and entered it in the google search bar. That's what came up. Look at the measurements as compared to the specs on the isky website. They are the same.

[datzenmike]

Duration specs by cam makers are universally measured at 0.050" valve lift. I doubt Nissan did this.

 

L and Z series are 248 degrees but could they really be more like 220???? Has anyone ever degreed an L cam???

[sick620]

7 hours ago, Stoffregen Motorsports said:

I took the part number off of the 1200.com site and entered it in the google search bar. That's what came up. Look at the measurements as compared to the specs on the isky website. They are the same.

Oh ok I see what you are saying, 1200 wiki shows those spring specs being for a holden? and they are listed under the "possible" section.. I wonder if they will work.. Maybe worth the try at half the cost of Nismo and says they can see 10k rpm damn...

 

So I get the biggest cam from delta, arp rod bolts, these springs... rebuild the block with the new .030 over pistons, new bearings... Basic head port and polish. New valve guides... Re use valves (heads in great shape 120k miles)...  nismo gasket to bump compression a bit..

 

should I get a valve job or just lap them? seats look to be nice... 

 

will I need to buy any new valve train parts IE rockers, push rods etc.? I don't know much about these push rod motors anything I need to replace as far as wear items since I'm running a shiny new cam? 

 

any other recommendations? I don't want to rev this thing up to 8500 and blow it up. 

 

any value in gapping rings a bit bigger since I'm sure Ill be introducing a bit more heat revving it up higher than a stock motor don't want them to expand and crack a piston. While on the subject and chances are I won't do this but the idea has been rolling around in my head a while, but can one of these motors handle a 35ish shot of a wet nitrous system? I feel like that would be a pretty fun set up being able to cruise it around at low rpm getting reasonably good mpg, then bring it up to 130ish HP on spray for short bursts when I want to rev the crap out of it.. I'd do it as safe as possible with step colder plugs, timing retard, only spray at WOT. Not a lot of information on spraying the datsun motors, but I've always thought it would be a fun adventure. 

 

 

[datzenmike]

Gaping for hot street/strip should be fine multiply the bore diameter (A14) 2.9944" X 0.0045" = 0.1347" Make it an even 0.014"

 

Moderate turbo/nitrous is 2.99" x 0.0055" = 0.01646" so split the difference and say 0.015"

 

Still have to work out the second ring

[Stoffregen Motorsports]

Mike's right about the gap. I gap them a bit tighter, but it can depend on the type of ring being used. Modern low tension chromoly rings get .003" per inch of bore.

 

I would definitely have a three angle valve job done by someone who knows what it means to have a three angle valve job. The contact area of a three angle valve job should be about .050" for maximum performance.

 

Stock rockers, pushrods, main cap bolts, cam bearings, oil pump, timing gears and chain are all good. Main and rod bearings should be tri-metal, no exceptions. Hit the main bearing saddles with some emery cloth to remove the burrs from the edges of them. This helps not get scratches on the back of the bearing shell during bearing installation. Also, radius/chamfer the oiling holes in the main saddles. Deburr them too.

[Stoffregen Motorsports]

Somewhere I've got pics of a couple killer A motors I built when I was young. Guys raced them in SCCA GT5 and in DSR. The DSR motors were 1000cc, so we used a custom billet crank. They would rev well past 10K. All of these motors had dry sump systems and custom valve covers with no oil fill or breather holes. We got them from TDC, which is probably not in business anymore.

 

The pics are probably in the same box as the pics of your Toyota blue 510.

 

[Tom1200]

I haven't been on the site for a few weeks. The link to Isky appears to be the correct part; from memory 455D is the correct number.

 

As for the collets I've always used the stock ones.

 

 

[sick620]

An older man drove by my house and saw my datsuns so he stopped at my house. He used to work at the datsun dealer in my town installing aftermarket AC systems from 68 ish to 72. He used to build and race 1200's. I ended up buying a nice set of mikuni carbs and intake for my 510 from him, as well as a built head for a 1200 race car. Built in the late 70's so it has been sitting forever but it's all brand new. He says it is a jdm larger valve head, it has a 290 cam I have all the specs for it written down if anyone is interested. Nice polished valve cover. I have not had a chance to look at it much yet just saw it sitting in the corner of his shop need to go back and pick it up. Also got a 1200 block with it but it is missing its crank and rods etc just the block. So I plan on running this rebuilt head on my A14 block with the .030 over pistons I have and nismo head gasket.. I'll post pics of head when I grab it. 

[Stoffregen Motorsports]

A nice older man, who knows Datsuns and lives in ID? Was it Dennis Hale?

[sick620]

haha negative we have a lot of good folks in idaho. 

[sick620]

Does anyone know what head I have here? Seems like a gx head possibly? It is closed chamber and dual valve spring.. the valves are a tiny bit smaller than my a14 head but just barely smaller, but the ports are bigger.

[datzenmike]

 

Has the oil feed hole so pre '74. After '74 the oil feeds up beside the head bolt.

 

Look here... for head ID

 

[sick620]

44 minutes ago, datzenmike said:

 

Has the oil feed hole so pre '74. After '74 the oil feeds up beside the head bolt.

 

Look here... for head ID

 

It has no markings there at all.. just Nissan Japan otherwise no markings ..

[sick620]

Ok so the 1200 wiki shows that this is the head I probably have. A12 gx. Pretty sweet score I’d say. The issue is I have no intake manifold that fits it properly and it is a rare head… it was rebuilt in the 70s for an scca race car and never installed so I’ll probably do a simple port and polish, a quick valve lap to make sure everything is sealing good and replace the valve guides and run this head as is.. do you think there is any benefit upgrading to the nismo or isky valve springs over these stock gx springs to make it a more high reving motor?  Any ideas or leads on intakes ? So far all I can find are intakes from Japan for mikuni carbs or dual Weber and all are between $500-800… I do have mikuni carbs but they have a l series intake already and I was going to save them for the 510…I guess these had hitachi su carbs from the factory but I can’t find one of those intakes for sale, maybe I will need to have some bike carb intakes made and run some r1 carbs or something? That seems like it may be a bit more cost effective.. or maybe I can port the hell out of a small oval port intake from a a14 or a15? I already have an Aseries Weber downdraft adapter and a 32/36 Weber… 


 

all I can find so far
 

 

 

Edited March 20, 2023 by sick620

[KELMO]

There are some of those oval port intakes out there, or there used to be. I think I found one either on a B210 or 210 but can't really recall. The intake I have uses the usual Hitachi down draft (or a Weber could be used). I also don' think there is enough material in a round intake manifold to port that out.

[datzenmike]

 

Some 1400s had them but... the down draft immediately has a 90⁰ bend to horizontal followed by another 90⁰ bend towards the intake port and a slight bed where it diverges to the two ports. Bends are no good for high speed flow. Try for side draft(s) or R1 carburetors.

 

 

Each cylinder has it's own 38mm carburetor and you can tune the intake lengths

[Stoffregen Motorsports]

I'd leave that head alone. In stock form it flows pretty well, so porting may not be needed at all. If anything, remove the valves and clean up the bowls and pockets.

 

I modified a stock A series down draft intake using the bowl and flange portion of a Cannon 240z DGV adapter manifold. Basically, I machined out everything except the material that held the runners together on the A manifold and then machined the DGV adapter manifold down to fit in between, then welded it together and smoothed everything out inside. It had twice the plenum volume of a stock A manifold and also had the DGV pattern on the flange so no adapter was required. I wish I had a pic of it, but I don't.

 

[sick620]

Ok yeah I think the simplest solution is to run some old bike carbs and have someone make me a flange and tube intake.. do you think my old A14 exhaust mani will flow well enough? I’m not a big fan of steel headers 

[datzenmike]

 

Made my own intake. R&D was about $350 to find out all the ways that don't work. The end result above was less than $20 for the steel.

 

[Stoffregen Motorsports]

The only reason I don't love bike carbs is because they are from a bike. A Weber looks right at home on a car/truck motor. That's all. Petty, I know.

 

Couple tricks to building a nice header are

1 - thick flange

2 - thick wall tubing (16ga or thicker)

3 - stainless tubing

4 - quality connection at collector (v-band clamp)

 

If all these boxes are checked, it will fit nicely, not blow out gaskets, and last a long time.

 

Unless the motor is more than a little modified, a stock exhaust manifold will work fine.

[sick620]

On 3/20/2023 at 12:46 PM, datzenmike said:

 

Made my own intake. R&D was about $350 to find out all the ways that don't work. The end result above was less than $20 for the steel.

 

Mike does steel intake not eventually rust when exposed to gasoline because of water content? Seems like people shy away from making steel intakes usually for some reason 

Edited March 22, 2023 by sick620

[datzenmike]

I don't think it's a concern. I can make another for $20. Look at all the car intakes that were cast iron.