Datsun Roadster Forum-311s.org

Anyone know the right valve clearance for an H20? The car I just helped a guy in town buy has that motor. Runs great but I just want to give everything the once over before he takes off with the car. Also are the timing specs the same as an R16? She dieseled once yesterday after a drive.
Mike

I thought someone with a 2L stroker would have answered by now....However, since you are here in North America, where the H20 was only used in forklifts, it is very likely what you have is an H20 with an R16 head and an aftermarket cam.
I believe most strokers are using the R16 timing specs, and valve clearance as spec'd by the grinder. If you don't know anything about the cam I would suggest probably the best place to start would be stock R16 valve lash??
If you have a degree wheel and dial indicator, you may be able to get some reasonable duration and lift measurements and get better ideas from that.......

Iron or aluminum head?

Anyone else have another idea?

Not sure about your valve clearance but on my H20 the timing is the same as on the R16, but I would bet the valve clearance is the same also.

Thanks guys, good to know. I was hoping Nissanman would poke his head in on this thread. I think these motors get used more down under. This motor romps though compared to the R 16 that is in my 1970. Really sits you back in the seat when it starts to get into the cam. She does have a slight vibration in the drive line somewhere that goes away when I push in the clutch and let off the gas. I am thinking bad U-joint. I will get under there tonight after work and take a quick peek.

Thread revival.
A friend has an H20 motor with SU carbs. What is the timing spec and valve lash? Manual seems to indicate .020 cold and 7 BTDC? or is it 16 like the R16 motor? Not sure how many H20 motors are around in the Roadster....
TIA,
Linda

H20 full Factory Service Manual here: -
http://www.mediafire.com/?nwur7tapf9qaq

Thx Nissanman.
Do people usually put a 1600 head on the H20 then add the SUs? Valve adjustment looks the same for cold .020.
Timing per manual is different though,7? But Fairlady 66 said R16 timing, so 16.... maybe. The head on this car looks like a 1600 but has the H20 valve cover.

Linda

Timing is usually cam determined.
I'd think you need to know what cam you have.
Dan

Assuming the stock cam for the H20, don’t otherwise know.
Linda

"Timing is usually cam determined."

I agree with Dan.

Best timing can/will vary with cam specs, compression, squish clearance, combustion chamber shape, carbs, and porting. Change any/all of them and some 'experimentation' or dyno time could help get the most from the engine. You may need more initial and less total timing with longer duration and higher compression. Lots of variables.
Not up for that? If the compression is near stock, stock timing will likely be safe, but, not ideal, with increased duration.
If you've closed up the squish clearance to .050" or less, and/or increased compression more than half a point, a degree or 2 LESS timing could be of benefit.

Many cam grinders will spec a valve clearance with the cam. If not, I would assume they are fine with stock valve clearance settings.
ymmv

I doubt this motor was ever rebuilt.Just a H20 with some SUs into a Roadster that is backfiring off idle.
Not sure if distributor is correct but it looks pretty clean. Carbs have been cleaned, new floats, valves, needles but they could be leaky. Looking for what is usually done for this swap with an emphasis on the bare minimum, since that is what he has and not likely to do any major mods.
I am trying to help but I don’t know the H20 so I passed along the manual info at least off this site and via Nissanman’s link.
Linda

I have an H20 w aluminum heads and a B spec cam from American Cam Grinding and run stock R16 valve clearances. Seems fine to me and I've put about 2000 miles on this summer.