Need some ideas on 12A engine

[poohmanhome]

The cap and rotor is a 2 tiered deal, so the leading and trailing plugs fire about 20 degrees apart.

I'll try the other ideas.

Thanks.

[joeg]

I concur with Daryl's advice--drag the car around the block to bump start it.

I have been involved in "Rotary Rebuild Parties" on numerous occasions and never saw a fresh rebuild start on the starter in the garage.

The wierdest episode was one that refused to start after many miles of dragging it around the block. That one turned out to be a "coked-up" SuperTrapp.

A Rotary rebuild party involved four select people, each with a special task--one to assemble the seals to the rotors, one to build the "sandwiches", one--the most important--the huge guy who jumped on the breaker bar to "torque" the gland nut on the end of the eccentric and one to manage install.

They were always fun, with lots of beer and oil smoke.

Good luck!!

[crushed]

The cap and rotor is a 2 tiered deal, so the leading and trailing plugs fire about 20 degrees apart.
[/b]

Not true, the rotor is also a 2 tiered deal so it is entirely possible for both plugs to fire at the same time. The split is adjusted by moving the adjustable dashpot on the rear of the distributor in or out (all the way in should have both plugs fireing at very close to the same time).

[Tak]

I've built 2 12A's for my own use, and they both started easily in the garage, with the starter motor...so I (respectfully-not trying to raise an argument) would not take it for a drag.

I'll repeat what I said earlier--
-The intake huffing sounds like you have the #1 and # 2 wired backwards (it's easy to do if you are rushing). Double check that L1 distributer terminal is connected to the lower front spark plug, L2 is connected to the lower rear spark plug, T1 to the upper front, and T2 to the lower front.)
-Fresh, new spark plugs. I like the BUR9EQP plugs that mazda comp recommends. fresh new Stock plugs will also work, but I don't like racing on them.
-In light of the carburator problem you described, I highly suspect the carburator is your culprit, not the ignition or your rebuilt motor. See if you can borrow a carb from a running car.
-Freshly charged battery helps too!

Silly errors that happen when rebuilding a carb:
-swapping primary and secondary jets.
-forgot to install or loose jets.
-forget to plug a smog device hole (big vacuum leak)
-loose needle and seat.

Lastly, it sounds counter intuitive, but when I start a stone cold motor, I give it 6 to 8 full pumps on the gas before I try to start it. If it fails to start (3 times in 10 years), I end up with dripping wet plugs just like you have described. (When I get the accelerator pump properly adjusted --so it doesn't hesitate when I agressively open the throttle in 3rd gear-- it does not put in enough fuel to start a cold motor with the choke removed.)

One last parting thought...On a Mazda distributer cap, 1 of the 2 coil terminals is aluminum, (the other is brass). Aluminum oxide is an electrical insulator. If you see any corrosion on that 1 aluminum terminal, replace both the distributer cap and the wire that goes to it.

Good luck!

Tak

ITA #29
SFR SCCA

[Daryl DeArman]

Tak, (not trying to argue--I feel that your rotary knowledge is probably deeper than mine, I am only speaking from past experiences I had with a troubled motor)

While I might agree that the carb might be a contributor, the fact that the compression in the rear chamber is low, I felt that the dragging down the block might be a solution to the initial after rebuild no-start issue.

I've only rebuilt 4 12A's(2 for me and 2 for friends) and 2 13B's for friends---so I am far from experienced. 5 of the 6 motors fired right up. One of the 12A's was giving us similar issues...after exhausting our collective knowledge resources we towed the car over to a local drag racing rotary guru shop for a "listen to this and tell us what you think we did wrong". He said "oh that happens all the time with fresh builds"--and he drug it down the alley behind his shop and it fired right up. It was the only one that did that to us and I don't know what was unique about that build. That same motor was never a hard starter again.

I have also been victim of a huge vacuum leak, it was not a hard start foul the plugs issue. It was a high rev, super lean kind of ooops.

[ddewhurst]

Thanks guys, lots of good info being posted for those of us who have not been through these wars of trial & error learning.

[Tak]

Daryl-
Thanks for sharing the 'drag' experience and putting it into context--that helps!

Poohmanhome-
Are there any more news on this difficult motor???

Tak

[Daryl DeArman]

what is the latest on this motor?