A15 rebuild Q's

[Dave Lum]

I have an A15 I am going to rebuild. It's for a 410 (to replace a tired A14). I don't want anything exotic, but what are some things to look for while going through this thing? It has the smog H95 head which apparently can't be ported much due to coolant passages. Are there some reasonably inexpensive things that can be done for a little more scoot?

It just needs to be a reliable daily driver, but if we can pick up 5-10hp without much effort, that's worthwhile.  I will be using the 38mm SU's that are currently on the A14.

TIA,
Dave

[datzenmike]

Start with finding 1mm oversize pistons and bore the A14 to match. This adds about 35cc more volume and will very slightly increase the compression and makes the A14 basically brand new.

 

5-10 hp, probably a cam swap. Nothing crazy.

 

Port match to get rid of the ever present miss match of head ports to both manifolds by the use of the manifold gasket to outline around the ports on the head and both manifolds and then grinding away what shows inside the scratch mark extending an inch or two into the head. Now, flow in or out has no obstructions. It can be rough, mirror polish isn't worth anything except inside the actual combustion chamber.

 

Big gains from smoothing the bowl area of valve seat machining and casting flash.

 

If exhaust is looking to be replaced go up in pipe size by 1/4" not more. If you have a 1.5" exhaust going to 1 3/4" is a 36% increase in pipe cross section. If not, replace the muffler with a lower restriction turbo style and NOT a see through fart cannon.

 

 

 

 

 

 

 

[Stoffregen Motorsports]

Out side of the engine, I'd do a two inch exhaust, and a distributor re-curve.

 

Inside, I'd go as big a bore as you can find pistons for (.040") and bump the compression with either a piston with less dish or by cutting the head a bit. Careful on pushrod motors though. Cutting the head too much can mess with the pushrod length. Then add a cam and valve springs.

 

I wish I remembered more about the A motors. Yes, I've built a few, but I don't recall the part numbers, casting numbers, etc.

[Dave Lum]

Any thought on the H95 head? Any reason to swap something else on at this lower power level (I forget what the A14 has, IIRC nothing spectacular)? Schneider makes some mild cams that has .382 lift vs .331 of the stock cam.  Seems like a reasonable upgrade.

[datzenmike]

http://datsun1200.com/modules/mediawiki/index.php?title=Cylinder_Heads_Overview

[Dave Lum]

Thanks!   Yeah I have looked though that site a lot, it's a great resource. I was looking more for "head casting xxx is pretty easily found and better than the H95" or "H95 can be made to work well enough here since the good castings are hard to find".

Being used to L-series stuff 9well, before I went VG in the 510), it's amazing how many variations on A-series there are!

[Stoffregen Motorsports]

If you can't find another casting, then you're kinda stuck with the H95. The swirl ports aren't great though.

[Tom1200]

Use the head off the A14 unless that's an H95. If you can find a H89 head that's a good one. I use a ported GX head on my 1200 race coupe bit those are going to be at least $800-$1000.

 

 

[datzenmike]

Did N Am get this GX head? Does it have a casting number?

[Stoffregen Motorsports]

The B210 GX came factory with an oval port cylinder head, but...there are two oval port heads that people confuse with each other.

 

To answer your question, I don't know if the true GX head was ever available on a vehicle in the USA.

 

[datzenmike]

So what designates a GX B-210. Has to be a 2dr coupe and built after Aug '78?

 

What head code would the GX engine have?

[Stoffregen Motorsports]

There seems to be a discrepancy about the engine designation on the GX. Some say A14S, others say A14T.

 

From that other website -

 

 

From wikipedia -

 

[Stoffregen Motorsports]

Some JDM versions used am A12S or A12T.

[datzenmike]

Only A14 B-210 coupes after August '77 starting with car number 960001- were GX. A parts search also says GX emblems from August '77.

 

 

[Stoffregen Motorsports]

I just looked again at datsun1200.com for casting numbers and the only oval port casting number they list is H95. Though there are two other oval port heads. Their info is good, but incomplete.

[datzenmike]

I have cylinder head 11041-H9500 for the 08 '80- A15 in the 210. 1200.com says it has cast in restriction to promote swirl.

 

the '80 head for A14/15 210 was 11041-H9911 were oval

[Dave Lum]

On 2/1/2023 at 6:41 PM, Tom1200 said:

Use the head off the A14 unless that's an H95. If you can find a H89 head that's a good one. I use a ported GX head on my 1200 race coupe bit those are going to be at least $800-$1000.

 

 

IThe A15 has an H95 but I have an A14 with a 728 head which looks to be at least better than the H95.