Datsun Roadster Forum-311s.org

Hi Guys,
I did a search for 'stroker' and read the posts. I also read the Wiki but it wan't clear after reading all this info:

Can I simply take an H20 crank/rod/piston assembly and install it in my R16 5 bearing and a'la peanut butter sandwiches= Stroker? If I use the R16 pistons, will that give me higher compression than the H20 dished pistons? Oh, and are all H20 pistons dished?

I understand that there will be other considerations in the top end, but do I have it right with the bottom end?

Thanks for your help!

Yes, yes, no.
Details
Crank and rods fit,as far as I know.
R16 pistons may need to have the skirts trimmed to cleat the longer stroke crank, details in competition prep manual. Depending on the head chamber volume, you may get very high compression.
H20 pistons are reported to be dished, except the ones in the complete H20 I bought, which are flat tops. I have the engine # if you want to do the research and see if you can find some from a forklift parts vendor or Nissan Industrial.

Hi,

I´m building a concours CSP311 Silvia. A 5 bearing R16 came with the car where it should be a 3 bearing engine. I purchased a H20 engine from a guy in CA who told me that it was an original engine from a 411 SSS ( is that right ? ). All I´m looking for is a little bit more go so that the car will cruise comfortably on the motorway at 70 mph + so I´ll be rebuilding the motor to original except that I´ll be changing the SU´s to 44mm U20 items. I´ll use the original exhaust manifold but I´ll fabricate a 1 3/4 exhaust system based on a RC40 system that is sold for Mini´s. I´ll have to work out how to get a twin tail pipe like the original Silvia. I´m hoping for 115 bhp + and loads of torque.

Symon

No, the H20 was not original to an RL411 - that would have had an R16. If you want to cruise at higher speeds, check out Daryl's work adapting a diesel truck 5 speed into his Roadster. I think that is the cat's meow for a 1600...

Hi SPL310,

I thought a H20 wasn´t original for a 411 SSS but the seller insisted that it was correct. He is a dealer in Roadsters and early Datsuns just north of SF.

I´ve already fitted a 3.7 : 1 diff ratio and I was going to fit the original 4 speed gearbox to try and keep the car almost original. This will give a similiar top gear ratio as my 260Z in 4th so that would be ok.

Symon

spanish csp311 wrote:I thought a H20 wasn't original for a 411 SSS, but the seller insisted that it was correct. He is a dealer in Roadsters and early Datsuns just north of SF.

Sounds like Mike Young. I hear Mike knows his stuff, but, the 411 SSS came with the same R16 as the roadster. If it's a H20 motor, it was swapped in.

Hi,

I scrapped some of the grime of the H20 engine earlier today. The number is H20 958395. Is there any way that I can find the origianl application for this engine number ?

Symon

This is mine, definitely from a forklift. Also had flattop pistons in it!

Daryl Smith wrote:This is an 1800cc stroker!!

2. Pistons, rods, block, and crankshaft :
Custom flat top pistons, 88 mm. R16 rods. G15 crankshaft. R16 block

Seems that most folks use the H20 or U20 crank. Why did you go this route and ONLY 1800cc's?

Symon,
115 hp should be fairly easy to achieve with a 2L stroker. I would however recommend a little cleanup of the ports and intake with a grinder (80 grit), port matching both intake and exhaust, and an electronic dizzy if workable in your show class.

Pete,
When I decided to do the 1800cc stroker I was working on somewhat eroneous information. That being that the 1600 head would not flow enough to support reasonable horsepower, and would quickly choke out the power for a 2L stroker. I have since learned, from having my head worked, that the R16 head should be able to be made to flow enough to support 150+ hp. Dave B. has said his connection has said he thinks he may be able to get 175 hp. One site I visited had some calculations for hp vs valve size, the calculation for stock intake valve @ 42mm worked out to ~166 hp iirc. Walter Peterson has a fully built stroker which he can run to 9000 rpm........mikew in Oz has a stroker which he has dynoed at 115 hp at the rear wheels (140-145 crank hp). So, from all this you can see that you can get good power out of a stroker. It takes a little money, but can be done. The weak link is the exhaust valve and port, so a good cleanup on this port and an oversize exhaust valve could go a long way to improving power. I did not know all this when I started my project and it was a factor in my decision.
With the alleged limitations in mind, I still wanted to build a stroker, just to see what could be coaxed out of it. I had a 3 main engine and found that the 1500 crank (74mm stroke) would fit and give me 1800 cc's. I felt this would give a good increase in power and possibly a better volumetric efficiency (erroneous thinking me thinks now). I wasn't after all out power but general efficiency. I'd decided to go EFI and thought I'd also get better milage with the 1800. There is a crank with the 83 mm stroke (2L stroker) to fit the 3 main engine, but it is fairly rare.
Geometry wise, I also wanted to keep the rod ratio over 2:1, the 1600 engine is 2.3:1 rod ratio. The 1800cc engine 's ratio is just over at 2.06:1 (R16 rod @ 152,45mm divided by the stroke of 74mm). This supposedly helps with both longevity and high rpm operation (which I'm not so concerned with any longer). This did require custom pistons.

Now, with all the above being said, I am very happy with the performance of the 1800, BUT, If I were to do another stroker, I would just do a 2L with the easily available parts. Lots of headwork (porting, oversize exhaust valves, combustion chamber mods), 280*-285* cam, upgraded valve springs, 10 - 10.5:1 compression, a good 4-2-1 header and 2" exhaust.

More Stroker information in this thread:
http://www.311s.org/phpBB3/viewtopic.ph ... it=stroker" onclick="window.open(this.href);return false;

Some of the info is garbled tho. If you want a copy of my original musings pm me an email address.

Best part of what Daryl has done is he can just move it all over to a R20 stroker later.
BTW, I read that the SD22 Diesel is a 3 main motor, around since the 60's...Maybe a crankshaft source? There's an SD22 with a 5 speed for sale a couple of hours from me in NY for $300.00. I can't play with it, want to remain married , but if anyone wants the info, just ask.

Dave,
That SD22 would be interesting to compare to the R series.
The 5 spd will bolt right up to both the roadster engines. Easy enough to change the gear ratios to be roadster freindly if you play with transmissions. Good thing it's so far away, I'd be tempted to grab it. I've got no place for it and too many projects as it is.........

Daryl Smith wrote:The 5 spd will bolt right up to both the roadster engines.

Now you've done it. Tempting Dave will divert his already short attention span. I hear a Diesel Roadster forming...

spl310 wrote:

Daryl Smith wrote:The 5 spd will bolt right up to both the roadster engines.

Now you've done it. Tempting Dave will divert his already short attention span. I hear a Diesel Roadster forming...

Don't tell me it's a direct bolt in....Now I might have to go get it. And I just bolted the engine to the transmission Sunday, but I didn't tighten the bolts yet......
What are the ratios???