GXman,

If you run a massive cam and dont rework the dissy youll only see about 50% of the true benefit, I went and got a dissy from a scrap yard, removed the vacuum advance and limited the rotation of the counter weights to limit the amount of advance (so i could run much higher timing at idle yet not over shoot the 32-36 range you want to be in up top) I then slowely added weight onto the countweights in the dissy till i had my full advance in where I wanted it... took me a few tries to do, would have taken 10 minutes with the right tools, springs and weights the differene is night and day!

You have to run a 1.6ohm ballast resistor if you want to run a hard core coil like the flamethrower 3 or the blaster SS like I do.

RSA is a stuff up for getting anything done, when I build my SR20's and RB's I actualy sit in the machine shop and watch them do the stuff I cant do at home (cnc line bore ectr) if you want it done right either diy or supervise, I have been to at least 9 machinests already just to find one that does work semi on part with my machinests i used in the USA when I was building cars there.

Was playing with my jetting this evening, 9000rpm clean, can not wait for the next track day!

No you don't 'need' to recalibrate the distributor. It'll run OK as is, just retard it enough to avoid pinging. Recalibration is done to optimise the power.

Several club members have reported rev limits due to the carburetor settings. I'd be looking there.

So you didn't modify the dizzy and it is advancing correctly without any vacuum. Reason why I am asking is I thought that the distributor needs to be re-calibrated to work correctly with sidedrafts w.r.t advancing.

I am also running a entry level Pertronic ignitor and also thought that you can't run a high energy coil through it.
So you are running one without damaging the ignitor module?

Through reading this whole thread I saw you also came to the conclusion that RSA is a f$%^up country when it comes to modifying engine components. I also found out the hard way with some stuff I did in the past. Now I am either doing it myself or standing with and supervising when it is being done by someone else.

dissy is not using vacuum advance, 12degree's at idle, 34degrees all in by 3300rpm

there's a trick of sorts - if you route the vac advance hose to a large 'ball' then to the dizzy, it acts as a bit of a damper and prevents the mechanism fluttering. Alternately you can run a small balance tube from all runners. This won't be enough to alter carb calibration, but can similarly smooth out the vac signal to the dizzy

Yeah not nearly enough load! worked it out to be almost 4mm less inner spring load when using the flat washers,,, could kill the machine shop! trust it to be the only head I ever had them put together for me.

GXman, buy and A15 here in RSA and youll find out very fast we have no pistons that fit, my A15 was rusted BADLY inside, had to take it 1mm bigger bore just to get a good clean surface, I run a .5mm oversize Mazda E5 piston which has the crown machined off, rods resized to suit and the block skimmed to give me just over .4mm quench area at install height (IE the piston sits proud of the block by .4mm and im using a .8mm Nismo head gasket = nice compression for a flat top piston when using the smaller chambered H89 A15 head,

I am going to have another cam cut with a slightly closer LCA, this one is almost fluid smooth, car hardly sounds like it has a cam in it, could do with a little more tq upstairs so ill drop the LCA from 110 to a 108 or maybe 106 if im feeling brave.

Quote:
When I read through the whole post I also thought that this sounded like a valve problem. Glad you came right. I took a drive one night with someone that had a A14 with similar specs to your A15. His did exactly the same. At 7000rpm it made a strange tapping noise. The guy also did'nt know what it was and said he decided not to rev it past 7000rpm due to this strange noise. I also told him it sounded like valves.

Just a bit off topic. Why Mazda pistons? And also what bore are you running to fit them. Did you bore your block to max?
Also what Mazda engine's pistons is it?

so there wasn't enough preload on the valve springs?

Just to let people know for future searching & problem resolution

I redid the seats and retainers with B-projects parts (very fast servise!) and she is now reving CLEAN to 8500rpm! what a difference to now finnaly be able to finnaly use the motor to its full potential.

Next up is a slightly larger exhaust, 52mm must be restricting it a bit.

My other baby

When im not breaking the A15 (which is supposed to be my cheap run around)