Have you guys been using masking tape and the stupid imperial measuring system for marking your pullies?

That's basically how I did my first one, but masking tape can stretch. I discovered this while marking every 120º for testing my 20B ignition on a two rotor engine (can you believe it?). I needed something more accurate in the long run, and it turned out easier as well to just use a metric tape measure. Now it's all I use to mark my pullies. I also use a small triangle file because a hack saw is a bad idea (as some of you have already discovered).

If you wrap a metric tape measure around the pulley, you'll see that it is exceptionally close to 360mm in circumference if not right at 360mm. I think the FC style pullies are about 1mm larger than the older ones. Either way, it's so close you'll still be able to mark it with greater resolution than the stock (wide) marks. I'm so glad Mazda made their pullies this size.

 

Oh, I also had the choice of using either my MSD 6AL or DLIDFIS on my latest 13B project. I have enough components for either setup. I decided to go with DLIDFIS because I didn't have the room for the MSD box, amoung other reasons.

I've just gotta hook up the wiring.

 

The imperial measuring system has the same accuracy as metric, it is the methodology, technique and equipment that determine the precision.

If I pulled out the optical comparator (used to have use of one) vs using a ruler and masking tape it would not make one bit of difference on the dyno or the track.

I try not to over complicate things. The amount of stretch in a 2" section of masking tape is negligible, especially when looking at the big picture.

Running 26* BTC L/16* BTC T is conservative. I've run up to 30* with no problems, but with no huge benefits either. A friend ran 34*+ for an extended period of time with no trouble. So, being within 1 or two degrees is fine. This is also why I don't like the zero split, there is no room for error.

Igniters vs MSD. Everyone is absolutely free to do whatever they want. Igniters are great value for the dollar but that's about where the comparisons end.

Everyone should take the time to learn some very basic electronics and to also understand exactly how the ignition system works. Learn exactly what is going on in a coil, how it is constructed and how to read specifications. Learn exactly how the coil charges and discharges. Then look at the numbers that the stock (igniter fired coil) ignition gives over a multiple strike capacitive discharge system. It is astounding.

I mount the boxes inside the car, there is plenty of room and they are safe from the elements.

 

For cars without the direct fire system would you suggest advancing the timing 26L/16T also?

 

Yes, 26 BTC L/16 BTC T for 13B's, 24 BTC L/16 BTC T for 12A's (Yaw's suggestions).

I did a tuneup on a stock base model 12a. Just cap, rotor, wires, BR9EQ-14's and I set the timing to 24/16. The only other mod the car had was a 'test pipe' in place of the cat, that's it. His first trip to the track got him a 16.50 (with an averge launch, I think it was around a 2.2 60'). I think this is exceptional! At a later date I did the exhaust but he didn't get a chance to take it to the track after that. I'm sure it was in the 15's, very strong.

 

I'm using that FPR, but the 0-120 PSI FPR rising rate on the turbo mtor. Good FPR, works great!

 

Alright, I got my marks made. From the stock Leading mark(TDC). I measured 31 deg. to the right for my new leading mark and 21 deg. again to the right for my new trailing. This should now give me the 26 deg. L and 16 deg. T that I'm after. I'll keep you posted.



Thanks, Ed

 

Just got back from a test drive with the newly marked pulley. Leading is now @ 26 and Trailing is @16. I noticed very little lowend loss but the car just totally screams! I power shifted @ 8200rpm in the 1st 3 gears and it is definately a solid 14 second right now. The funny thing is, I had the silencer on the fart can because I didnt want my neighbors to complain while me and my wife, YES WIFE. set the timing at 8.30 at night on Easter Sunday, so I know for a fact that my exhaust was all choked up. Just imagine! Anyways I'd like to give dvcn props for all his help and patience. DVCN the car is being parked for now awaiting a gsl third member. The track opens up on the 17th and I'll try very hard to make it so I can post some time slips. I'll do my test and tuning there without the worries of being pulled over with the unmuffled fart can. LOL!


Thanks again, Ed

 

Hopefully if I do this stuff I'll get the same results. When I floor my car flat out it bogs down first and then takes off, I suspect the fuel pump to be the problem. I was running at 16.6 at LACR with a racing beat intake, header, weber carb, and full exhaust. We'll see what new plugs, timing, and fuel pump does. Hopefully it gets good results like yours did.

 

Oh and also, my trailing timing starts at 20 advance, do you mean to advance it another 16* total?

 

Ed- I'm glad that things are improving. Good job! If your rear end (housing and axles) toss in a GSL-SE 3rd member, it'll give you a little bit more gear - 4.08 vs 3.90. Keep tuning!

prefix- Please read the Yaw article, he explains total timing in it. Change only the parts that aren't doing their job. Spend time and money on diagnostic tools.
I ran at LACR in 1991? I'm not sure where you live, but you have probably have to have two setups, one for the high altitude of the track and one for your normal stomping grounds.

 

Tuning is key! I still have to watch my fuel pressure while I'm on it @ 7000-8000rpm so I know if its dropping off or not. Also get new BR9EQ-14's for the track. I actually have a chance to get an SE read end but opted for the thirdmember swap for now. Maybe in the near future.


Thanks, Ed

 

i've had the same power loss past 6k... but i'm set to running lean... so i wasn't that surprised.

good to know you're ride's all fixed though

 

With all that stuff in the article isn't it easier to just use an advancing timing light? The pulley is already marked at TDC for leading. So what should be done about trailing?

 

Timing lights with built in advance, sure you can use them to set your timing wherever you want, but why add more variables? The worst part about it is that the operator has to think.

Normal timing lights are cheap, easy to use. You see your custom marks line up on the pointer and that's it.

Yes, there is a lot of 'stuff' in the article. The most important thing is to fully understand what is going on.

 

Oh I get what's going on, I'm just wondering about trailing timing. Due to the fact that my trailing is advanced 20 initially and can't be retarded anymore.

 

dvcn, that was a good article. I read the other articles as well. Some great information on that site. I bookmarked it for a later reading.

 

Your trailing timing is at 20 degrees BTC at idle or total timing? What is your leading at? Is the distributor indexed properly?

 

Initially, so at idle. It's setup stock 0 L and 20 BTC T.

 

Do you mean 20* ATC? If it is 20* BTC that means the trailing is firing before the leading, which would cause some pretty noticeable pinging under any kind of load.

I will assume you are at the correct stock 12A timing settings of 0 Leading and 20* ATC Trailing.

Please re-read the Yaw article!

You want to set your TOTAL timing to 24* BTC Leading and 16* BTC Trailing. This is TOTAL timing! You set the leading first, then the trailing.