hey again....

a quick question, does an a12 dizzy fit and work in the a14 engine by any chance? i think it might but it'd be quicker if
someone already know...

the other option is an electric dizzy, but i have little experience with electric dizzy's in datsuns... what have ppl used in
the past?

cheers
Ben

Ben,
I am sort of used to the difference in slang from American English and other types of English but what is a 'dizzy'? I am not familiar with that word as an automobile part. It seems it has to
be something that spins around so I will assume it is a crankshaft, Correct?
Personally, I am partial to short stroke/big bore motors. I had a head from an early 1200 that had a very small combustion chamber. It came on a wrecked 1971 1200 and when I put it on my A12,
it had 260 pounds of compression. That relates to 14:1 compression ratio. I built an A14 engine with an A12 crankshaft in it. I had to shave .100 inch off the top deck of the block and still,
the piston didnot reach the top of the cylinder. I calculated that the .100 less cylinder wall height would have 8:1 compression with that head. It came out correct with 140 pounds (8:1)
compression. This engine had every racing part that I could come up with inside it but stock bearing and cylinder wall clearances. At first, I used a stock intake and Carb and a tuned exhaust
headerwith 3" pipes. When i first drove it, it was pretty mild but this was only to break in the motor at fairly slow RPM's. When I put the turbo on it, it came off the line very slowly but
then it came on very strong when it got up in its torque range and the little sedan would kick ass on most vehicles that ever come up along side it. It would get 9,000 RPM's through 1st, 2nd
and 3rd but it would only pull 8100 RPM's in 4th gear, but the sedan was pushing a lot of wind resistance. I only got to drive this motor for less than 1000 miles as my exwife screwed me out
of it and it ended up going to the crusher.
Long stroke motors do not get the RPM's as fast or as many as a short stroke motor. NISMO told me they didd not sell forged racing pistons for the A15 motor and that I should build an A14
engine. They had had too many problems with the stress of high RPM A15 pistons and 6500 RPM's was as much as could ever reliably be gotten from the A15.
You are correct in assuming the A15 head would have less compression on the A14 block. For turbocharging, it would be ok but it would have less power in drivability mode than thr A14 head.
A15's were not made for power but for more torque. Hope this helps you some.
Mareo

Mareo,
Just a short note, A Dizzy is a distributor.
Steve

Use this guide to compute compression ratios with a compression guage.

8:1 = 140 # = 308 kg
9:1 = 160 # = 352 kg
10:1 = 180 # = 396 kg
11:1 = 200 # = 440 kg
12:1 = 220 # = 484 kg
13:1 = 240 # = 528 kg
14:1 = 260 # = 572 kg

With the A12 and A14 heads, you can mill off up to .250 inch safely but then you are in trouble with push rod lengths. Shorter push rods or spacers the same thickness of the mill off of the
head to put under the rocker towers are necessary. I have milled .250 inch off an A12 head and put it on an A14 motor. That came out to 215 # or 11.75:1 compression ratio. A high
compression motor makes for a lot of more cheap fun but you have to compensate with higher octane fuel. Water injection helps as does adding one pint of diesel to ten gallons of gasoline
helps. Read back into these messages and you will find a lot of information from a lot of other people that may help you. Hope this helps you and your mate with your experiments. Have a lot
of fun for me too.
Mareo

In AU they call the distributor "dizzy". Yes you can use the A12 distributor in the A14 or A15 engine. You might have to file a little bit on the base plate (mounting plate) to get it to
mount right. The electronic distributor should work, all you have to do is hook one wire up to the positive of the coil, and the other to the negative.

I've checked my compression in my engine, and according to that chart you put up, I would have about 8.5:1 compression in my A15. I think that's a little too low since I'm trying to get
more performance out of my engine, but it works until I have to pull my head.

I've pulled my spark plugs since my 1200 has been acting up, and I also have found some oil on them. The plugs themselves are a nice brown color, so it's got a good burn though. Does
this mean my head gasket may also be the problem?

-Andy

Hi ANdy
Brown on spark plugs are a sign of too high of octane. When octane is correct and everything else is correct, plugs should have a light powdery gray color. Too much octane means that you are
still burning gas when the valves open up and you are not getting the correct effeciency from the fuel. There is a happy medium of when you have the correct octane for the compression you
have. It takes a while to get everything adjusted properly. You are probably a little too young and having too much fun to know all there is to know about how to obtain the correct
effeciency. Spend some time in the library and read about fuel effeciency. When I raced high-speed go karts, I bought an air density meter so I would know how to properly set my jets for the
race. It too some experimenting to figgure out how to use eerything properly but after a few times, I learned to look at the meter and know which jet to use. Full effeciency takes
preparation. A 9:1 motor should use 87 to 89 octane most effeciently. I am also a believer in water injection. Read up on that also. After using water injection, your pistons and valves and
all inside the combustion chamber will look like it was just steam cleaned when you take it apart. It also helps stop detonation. I got an adjustable needle valve and put inline to a vacuum
port on the carb. JC Whitney has a very good system that is controllable and is pretty much inexpensive and has good instructions on what it is all about. You can call them in Chicago and
they will send you a catalog. They have clutches, brake rotors and a lot of good parts that are cheaper than most places.
Mareo

This will change with different cams due to overlap differences, won't it? I know running a cam with more overlap will allow you to run a higher C.R. for
a given octane rating.

Dave Lum
'72 coupe getting SR20DET
'71 510(1600) 2dr w/ VG30DE
www.datsuns.com

Hey Mareo I have had both A14 and A15 engines worked over both engine will rev reliably to 7500 if built properly the A14 would rev to 8000rpm with no real problems. The A15 I had
only had cast pistons 40 thou oversized the A14 had forged pistons 120tho oversized. Even with radical cams had heaps of tourque.The A14 I feel was a better engine as with the
oversixed pistons it had square bore stroke ratio with 12:1 comp it had just over 150hp