Lots of questions.

> So if i install a 7000rpm racing camshaft would it achieve a higher top seed?

Probably not. The camshaft only works effectively in combination with other parts. With an Engine buildup it will work.


> Also, what is the 3.700 final gear that you mentioned?

The differential ring & pinion (crown wheel & pinion) gear.


> I will probably put on wider tyres on it, and maybe slightly shorter tyres. Will this have a great effect on top speed?

The width of tyre has no effect on top speed. However changing the diameter of tire is the same as changing the gear ratio. Bottom line is that a stock A15 only makes enough HP to power the car to go approximately 100mph/160kph. So gearing or tyre speed cannot raise the top speed. You need more HP to go faster.

I'm sorry, i know i'm asking a lot of questions its just that i'm new to this :/ earlier on this thread you suggested to use a racing 7000 rpm camshaft and head porting. So what would i gain with such a camshaft if topspeed isnt effected? Ok so if what happens if i change the differation? So reducing the tyre diameter will not have a noticible decrease in top speed right?
Again i'm really sorry for asking so many questions, i know its annoying :/

Fitting a racing camshaft won't do much. But fitting a racing camshaft along with all the other high-speed modifications (including valve springs, head porting, larger carburetor, etc) will raise the top speed. For details, see Engine buildup.


> what happens if i change the differation?

The Final Drive gears are part of the differential assembly. B310 came with a variety of final drive gears:
* 3.545 high gearing/low ratio
* 3.700 medium gearing/medium ratio
* 3.889 low gearing/high ratio

Ok thx a lot :) and do you know where i would find the gx parts for the a15?

> So reducing the tyre diameter will not have a noticible decrease in top speed right?

Top speed in the B310 is limited by HP. The stock 80HP A14/A15 have enough power to push the car through the air to about 100mph. The A12, 65HP A14 and 67HP A15 only have enough power to go about 90-94 mph. Changing tyre diameter won't change how much power you have.

The other -- theoretical -- factor is the gearing. You should not rev higher than the engine red line (6000 RPM for a stock engine). With 3.7 gear and stock-diameter tyres, 6000 RPM is ~110 mph. With 3.889 gear it is ~105 mph. But the reality is there is not enough HP to go that fast.

The stock B310 tire diameter is nominally 22.8 inches for stock tire size 155/80R13. The optional tire 175/70R13 is 22.7 inches, practically the same diameter.

To reduce the tyre diameter you could fit 185/60R13 (which are perhaps the shortest 13" tires are currently available). They are 21.6 inches tall. These have a theoretical top speed of 99mph with 3.9 gears -- which sounds ideal for making the power peak at the top speed peak. It will take perhaps 4 miles of track to accelerate up to that speed.

This is all theoretical since no one has actually tested a stock B310 for top speed.

More practical reasons for changing the Final Drive Ratio for a street car (non-racing) have to do with acceleration (lower gears = quicker accleration) or fuel economy (higher gears = increased fuel economy). For a street car, who cares about top speed? Even in most forms of racing the highest possible top speed is irrelevant because there is not miles of road between corners to enable ever reaching such a speed.

> do you know where i would find the gx parts for the a15?

The GX engine parts are for the A12 GX engine. They can be used on an A15 engine.

A12 GX cylinder head is about equal to a ported A14/A15 oval-port cylinder head fitted with dual valve springs.

Benny that engine is pure SEX!!!!!!

A couple of things, the A-series be it A12 pr A15 will run 6000 RPMs for hours one end. Back when our coupe was a road car we did a road trip where the car was floored for 2 hours, then some stop and go for 45 minutes then floored for 2 hours, stopped for gas, then floored for another hour....................this continued for pretty much three days. Amazining we didn't get a ticket since we seldom went below 80 MPH. The engine had no issue whatsoever, your hearing may suffer but not the motor.

While smaller circumference tires will up the RPM's it may end up increasing the speed ever so slightly (think 2 mph) as these cars do hit the aero wall starting about 75 mph and the stock gearboxes have pretty big RPM gaps in them.

Get a moderate cam, port the head, install a Weber 32/36 carb, decent shocks some sway bars and 185/60 tires and have fun with it.


Tom

thx alot everyone! :) i hope i'll start this project soon, almost finished from exams :D 2 jobs during summer and hopefully an a15 B310 soon! :)

hi its me again with another difficulty... so here it is,i don;t really like the datsun B310 grille. i have seen another type of grille on the B310 but i can't figure out what they are called. they have the 's' emblem instead of the 'd'. and the fog lamps holes are situated in the middle of the grille rather than at the bottom. can anyone enlighten me please? if you know of any other good grille conversions that i can install on the B310 it would be really helpful. just to remind you, my B310 is with the round headlights.