A15 Piston Question

[Kirden]

Are all stock replacement A15 pistons the same profile? I know that there were high mileage heads, different combustion chambers, and those crazy CA only setups, but excluding CA pistons, would the replacement pistons for an A15 equipped 210 be the same as the pistons an A15 Vanette uses? 

 

My A15 has an H89 head. As far as I know this head came stock with my engine and the PO swears it came from a vanette (the only vehicle to receive the A15 H89 combo from factory). I want to make sure I purchase the correct pistons so that I do not change my quench or CR from the factory rating and also do not increase the chance for detonation with my rebuild. From what I have seen, heads and pistons on the A-series engines were matched so "peanut" heads (like mine) had a specific piston design for proper quench and CR. 

 

These were the pistons I wanted to purchase:

 

http://www.rockauto.com/catalog/moreinfo.php?pk=4807821&cc=1208832

 

I haven't taken my engine apart yet because I would rather be prepared to rebuild it quickly once it is apart. These are the other ones:

 

http://www.rockauto.com/catalog/moreinfo.php?pk=4812072&cc=1208832

 

So which is correct? 

[Kirden]

"My A15 project engine i'm working on came with an H89 head and the pistons had offset dishing.. the H89 head has a closed chamber which gives squish effect when used with the correct pistons, in my understanding this enables you to have extra compression and more advanced timing compared with non squish..."

 

 

Found this on an MG site. So according to him the A15 with H89 should have the offset dish like this first pistons I posted. Can anyone confirm? Bueller? ggzilla?

[graveltrapp]

Have you had a chance to check out the 1200 forum? The tech wiki is gods savior to the A series and 1200's in general, or zilla.

[Kirden]

I have scoured over it for the past week trying to find a definitive answer for this and I can't find it. There are parts numbers for vanette rods, bearing, gaskets, ect, but not the pistons. With the H89/A15 combo only being in vanettes it makes it difficult to find an accurate answer. I posted this question in a little less detail on my thred over there but nothing yet. I also tried to message ggzilla directly, but he has a full inbox.

 

This is the last piece of the puzzle before I start buying everything for the rebuild.

[datzenmike]

Vanette???? The only vanette I know of that Nissan made for N Am is a Z24i powered vehicle. They were all recalled and destroyed. Voluntarily.

 

In other parts of the world the A series was used in it. The Z24 was too big for the engine compartment and tended to overheat.

[Kirden]

According to the PO, this engine was an import. Just like people get the SR20 and CA. Thing is, I do have an A15 and an H89 head, so I need to make sure I'm getting the correct pistons. The C120 vanette was the only vehicle to ever come from the factory with the option of an A15/h89 combo. If the PO is correct, this is one of the 80hp (highest rated hp stock for A15) combinations for the A-series that came from the factory. Esentially I should have the same HP as an L20B if I can source the correct parts for the rebuild. Add the M90 supercharger and R1 carbs and I should have a really fun street car  :thumbup:

[datzenmike]

L20B would be just over 90 hp... on a good day.

[Kirden]

Ah, checked again and you are correct. Still thoiugh, 80hp at .5l less seems like a good enough trade to me. I know the torque is a totally different story, but the A-series is so sexy! :P

[datzenmike]

Depends on what gives it the 80 hp. If there is a lot of compression then there may be detonation issues with forced injection. Maybe some of it it in the cam???

[Kirden]

According to everyone over at the 1200 site the stock A15 can handle the boost I will be using. The stock hp rating is 80hp. I am planning for 110-120 hp but in all honesty the power doesn't matter. The goal is to have a fun classic datsun that sounds, looks, and feels good to drive for my 4 days off each week. 

 

I plan to push the boost to 5-8 psi. Nothing major and this vehicle will not be on the track or revved through the roof. Just a fun classic street car.

 

Edit: As for the cam, it will receive a mild regrind to decrease valve overlap. Depending on how the discussion goes with the machinist, we may choose to increase the valve lift as well, but I do not wish to increase the RPM range too much. If I can have a strong power curve from 3-6000 RPMs that will be ideal for what I want.

[Kirden]

A big thank you to datsunfreak. He has confirmed that all of the A15s he has torn down with closed chamber heads have a deep, offset dish. It looks like the first pistons I linked are correct. 

 

Case solved, but hopefully this information helps others as well.

[rbastedo]

It helps me, I was looking at the same pistons and wondering which to buy.

[Kirden]

Awesome! Glad to finally provide help at 1600 posts :P

 

Just make sure you have a closed chamber head. The open chamber heads use a shallow centered dish piston (the second piston I posted). Technically you may be able to used the shallow dish pistons with a closed head to increase compression, but you would have to run less timing to prevent detonation. You lose most of the benefits of the closed chambered head.

[rbastedo]

I have the H89 and a set of British SU HS4's.

Really nice in my Spridget when it's running right.

 

I've got the econo head in my 1980 Datsun 210, which is ok for it (for now).