Datsun Roadster Forum-311s.org

Hey Everyone,

This is my 1st post. I have been reading everything i can find for the last 2 weeks. I have decided and recently found a H20 engine. I know there is a lot of chat about the H20 and i am sorry if i am going over old ground but i am 19 with my first Datsun Roadster and i need some clear idea as to what can be done to modify this engine to get max hp but maintain "driveability". The engine is a project with my brother and we have time and money so dont be shy to suggest anything. What sort of internal engine mods must we do to valves, cam, pistons, any reinforcement? I am new to cars and this is all a massive learning curve for me at the moment so sorry if any of this seems stupid.
Thanks in advance for any feedback in this area

Scott

Others may chime in, but if you search the forums and read everything regarding the H20, you'll find this has been discussed quite thoroughly. The H20 makes a great stroker motor, and there are two basic ways to accomplish it. Again, all discussed in great detail already.

If you want max HP, swap in a KA or SR.

Welcome to the Looney Bin. Get some pics and info to Steve for the Roadster Registry.

Well, first off, welcome. As to your question on the H20 and hopping it up. Your H20 most likely came out of a car and not a forklift as they do here in the states. So you could reverse engineer a bit and make a nice stroker. You would either need to buy the competition crank for the 1600 from NISMO or find a 2 liter crank and have the front end modified. There is a fellow that is doing a stroker without modifying the 2 liter crank but I have no details as to how he is doing it. Grab some 2 liter rods and pistons if you can. You definitely need the 2 liter rods. Get a stroker cam from American Racing Cams. You can then either put a set of 1600 SUs with the correct needles, go with the 2 liter carbs on a hogged out 1600 intake or I believe the 40mm mikunis would work as well. You do not neccesarily have to do anything to the head except maybe have it gone through. I put bigger valves in mine and had the head ported and polished.

Or you could as Pete mentioned either go wath the KA or an SR swap for a more modern equipped engine. I have to say-I like my stroker and am still working on my SR swap. My three cents worth anyways.

Steve

S Allen wrote:You would either need to buy the competition crank for the 1600 from NISMO...

Is this still possible? I thought someone said recently that they're NLA, but I can't find the post.

S Allen wrote: or find a 2 liter crank and have the front end modified. There is a fellow that is doing a stroker without modifying the 2 liter crank but I have no details as to how he is doing it.

Yes, that would be nice to know.

Dunno for sure. The last catalog I have from NISMO still has them listed but I never tried to order one. What I would really like to see is how the person that is using the non-modified 2 liter crank is making it work.

Steve

Get an R16 head, hot R16 cam, and U20 pistons. That would be the extent of the internal modifications I would make on the H20 motor. Other hop-ups would be similar for any motor. Carbs, lightweight flywheel, electroinc dizzy, nitrous, etc...

Wait a minute here. Before you start chucking parts to buy replacements, take a look at what you have. Unless I am mistaken, the 1600 stroker crank from Nissan is nothing more than an H20 crank. The rods should be fine. If the engine came from an Urvan or other vehicle other than a forklift or industrial engine, then it may have flat tops already. If it does, they are fine. If the head is a stock H20 automotive head, it is quite comparable to the R16 head from all that I have seen.

To hop it up, go through it (bearings, rings, etc), get a performance grind cam, and if you want carburetion to match the potential, you can either do the U20 carbs on a R16 manifold (see the tech info on 311s for Steve's writeup) or you can buy a manifold from either Pierce Manifolds or JAM Engineering. (Pierce and JAM sell the same manifold, but JAM is cheaper!) Bolt on some Webers (DCOE or DCOM) or some Dellorto DHLAs and you will be in business!

Thanks for the feedback. The H20 we have is out of a urvan not a forklift so when we start pulling it apart ill check all those things out.

Cheers
Scott

Yeah, what the heck was I thinking? 1600 of course. Sid is right as you already have the stroker crank in the H20. So a hotter cam, 1600 SUs or the 2 liter carbs, EI ignition and of course a 5 speed gear box for that extra gear. What type of carbs or carb does the Urvan have on it? A single dual or twin something else? Curious as to that one.

Steve

ive heard that the H20 usually runs a single carb but that is only from what i read. We are looking to put twin mikuni solexs on it but that all depends on if we can get them? or is there a better carb set up?

Scott

Mikuni Solex carbs are fine, but they are out of production. Since you are building a hybrid, I would buy some currently available carbs - better parts support. The OER carbs are interesting, and there are Weber parts everywhere. The DCOM is supposedly the final word in Weber side drafts.

I've got a pair of cannon intake adaptors that fit an SU manifold. They allow for a pair of weber 32/36 dowdraft carbs to be mounted. I also have a pair of Rochester 2 jet carbs. They are not progressive. I was going to rig all that up on the roadster before I swapped out to the KA. I would sell the whole contraption for $50 plus shipping. The carbs need a rebuild and there will need to be a custom linkage made. It would definately be different and cool.

What is the difference between DCOE and DCOM?

Weber kept fiddling with the progression drillings and supposedly the DCOM has the best of the bunch, but the real difference is in the accelerator pump. Rather than the plunger style of the DCOE, the DCOM has a diaphram like the Dellorto or Mikunis.