looking for a h20 crank?? cheap

steve68 · Post by **steve68** » Tue Jan 11, 2005 11:19 am

the forkilift place by me can get the crank rods and bearings for $450 with a $50 core so $500. which isn't that bad, or is it?

if i used the h20 rods can i use my r16 pistons?

thanks
steve

ambradley · Post by **ambradley** » Wed Jan 12, 2005 8:04 pm

If I read the previous posts correctly, the R16 piston skirts need to be modified to clear the H20 or U20 crankshaft. Also, R16 pistons are domed while U20 pistons are flat, so compression will be very high.

70MTroadster · Post by **70MTroadster** » Thu Jan 13, 2005 2:49 am

Adam is correct. Go to the Datsuns.org web page and download the Sharp 1600 and Datsun 2000 info on how they modified those engines back in the day. That will help explain a lot as to what you can and cannot do. There is also a template that you can download that you can then wrap around your 1600 pistons that will show you where to remove metal from the skirts so they will clear the crank. BUT, as Adam points out, compression will be on the order of 12 to 1 or so.

Scott

70MTroadster · Post by **70MTroadster** » Thu Jan 13, 2005 3:06 am

The easiest way to get the info is to click on Interesting Links on this site, then click on Greg Vallaza's site, then on news and information and you will find the PDF file I mentioned on the 1600 and 2000's.

scott

steve68 · Post by **steve68** » Thu Jan 13, 2005 12:29 pm

thanks for the tips guys.
Whats the highest ratio i can run on premuim?

thanks
steve

70MTroadster · Post by **70MTroadster** » Thu Jan 13, 2005 3:24 pm

Probably 10 to 1 is you don't advance your timing too much. I would shoot for 9.6 to 1 to duplicate the 2 liter personally. My stroker came out at 9.2 to 1 approx.

If you download those files I mentioned, you'll see where they were machining the tops of the 1600 pistons quite severely to acheive 14 to 1 compression in that engine after milling the head and the block quite a lot. WOW! I almost went this route with the idea of using my 1600 pistons but they were too worn plus new ones cost as much as the flat top U20 pistons so I decided to just go with the H20 pistons, mill the block and head "some" and get 9.2 to 1. If I ever wanted to swap in the flat top U20's, I calculate 10 to 1 with those.

scott

SLOroadster · Post by **SLOroadster** » Thu Jan 13, 2005 11:41 pm

I'm at 10.65(ish):1 and it doesn't ping with 20 degrees advance. I have a big cam and the combustion chambers are polished. There are no high spots to become hotspots in any of them. 11:1 might be possible with chambers pollished to a mirror shine and the tops of the pistons absolutly perfect, however I wouldn't risk it. The higher your compression is the more critical your fuel mixture becomes, if you go lean expect bad things to happen. I can pull 5th gear up a climb with the pedal flat on the floor on a cool day, on a warm day I wouldn't even think about it.

If you want to get really exotic, there is a type of coolent that is non water based. I'm not sure what it is called, but the boiling point is far hotter than regular coolent, and it disipates heat much better. It will reduce any hotspots you might have. Also get a big comp oilpan to help cool the engine (larger oil supply is cooler as well.)

I got lucky as my car runs on the cool side all the time, I think this could be one of the reasons that I don't ping at all. I also think the BRE spook airdam helps in this, that is why Pete Brock designed it.

just my $.02

Will

steve68 · Post by **steve68** » Fri Jan 14, 2005 9:03 am

thanks guys. i have a friend that has a lathe. so maybe i can just cut some off the top of the pistons.

ill polish up the chambers plus coat everything. That should help alot.how much hp are you guessing with your car SLO?

SLOroadster · Post by **SLOroadster** » Fri Jan 14, 2005 8:54 pm

I built the engine on a computer program called Dyno 2000. I had to guess on the head flow numbers but it was claiming 191hp and 178ft lbs torque at the flywheel. I'm guessing that its pretty close as I built a stock engine and came up with 151 hp and 138 ft lbs torque. I used the same head flow #s for both engines. According to the program my power and torque curves are very broad, full power between 6500 and 7000 rpm. From the driver's seat I beleve it, the power band is huge, peak torque is 5000 rpm. With the 4.11 rear end, thats freeway speed.

As soon as I can get it back on the road, I will take it down and get it dynoed.

If you are going for high compression, make sure that your chambers are cc'd and polished really well. Also you might look into a set of Total Seal rings and forged pistons. Last year the guy who won best of show at Solvang had a stroker 1600 and he dynoed his car. I think he was only making about 120 but was very peaky. You will need to go with a set of solexs as well. The 40s will work, but you might want a set of 44s with small chokes.

Good luck,

Will

steve68 · Post by **steve68** » Sat Jan 15, 2005 9:45 am

sounds good. Is there a compnay that makes forged pistons?
Ross will make a custom piston for $500 for a v8 so just a little less for a 4. ill call them up.
with the stroker do i want any dome? just flat? so then u20 pistons?

thanks
steve

SLOroadster · Post by **SLOroadster** » Sat Jan 15, 2005 5:47 pm

I'd go with the flat pistons, the domes will push the compression ratio way up. The U20 with R16 pistons pushes 13.5:1 (I think, look at the Bob Sharp racing prep manual.) If you run the H25 crank, you will have the compression way way up, so domes are a bad idea. I'm not sure where to get a set of forged pistons, $500 sounds like a smoking deal for a set however.

Will

steve68 · Post by **steve68** » Sat Jan 15, 2005 8:20 pm

well then since there going to be custom ill get a price with the h25 crank and rod.

how many cc's will that be with the stock bore?

thanks
steve