quadman_20

After sifting through a few thousand threads, messages, how-tos and other stuff at different sites, I'm still in the dark on a few things.

I have an '84 12A that sat for over a year before I bought it. The guy who owned it told me that he came out one day and it just wouldn't start. Well I've turned wrenches for quite a few years both as a hobby and professionally(never on a Wankle), so for the price, I thought what the heck.

After a few hours of pouring gas down her throat and beating on the throttle, I figured out the fuel pump wasn't pumping. This was before I knew about the fuel cut relay so I bypassed it all and ran relayed direct power to the pump (I found out later that the trailing coil was dead.. hence dead fuel pump). She would run, but roughly, no idle and a huge dead spot.

So after a month of fiddling here and there, replacing all tune up parts and a carb rebuild, she still has a nasty dead spot off idle @ anything more than 10% throttle applied.. She does idle and rap through the RPMs after the dead spot wonderfully.. Scared me silly when that d@!mn buzzer went off @ 7K...

I thought about it for awhile, read some more info, and have come up with ether a bad/clogged accelerator pump (which is unlikely since I use a new one and short of vat dipping, the carb is brand new clean), a huge *** vaccumme leak somewhere, and/or some really bad luck.

Out came the axe and the rats nest went flying. Now that I've got it stripped, here are where my quetions come into play.

Vaccumm tree/carb baseplate/ heat sheild: Is this really nessasary? I've figured out that I have all the vaccumme soruces I need for components kept, so do I really need to keep it? Is the heat comming off of the stock exhasut manifold going to affect it that much?

Altitude Compensator: I found a thread stating that this can be ditched. Has anyone eles ditched it? I'm not going to take the car to different altitudes so thats not an issue.

Hot and cold start assits junk: Can I just pull all the pieces to these systems and thats it? Will it affect anything eles?

Second waterpump belt after smog pump removal: I read the Mazspeed guide to removing the rats nest and they use a second belt around the crank and waterpump. Is the belt for the alt. not adequate to spin itself and the waterpump?

Sorry for being so long winded, but I wanted to give the low down on whats going on with this thing. Next weekend I'm going to do the twin leading coil setup, so my ignition system will be up to par. Any ideas, suggestions, opnions, thoughts, or whatever would be greatly appreciated.

BTW, the only other mod to this car (that I can tell) is a custom exhaust. Its straight through from the exhaust manifold to the muffler.

Thanks

Ben

MosesX605

I know that the hot and cold start systems can be ditched with no detriment. I've had my cold system off during a Saskatchewan winter, and if my car can start in -30 Centigrade without the cold system, you don't need it. The hot start assist just saves you from pumping the gas before you start the car up after it's warm. Again, no problems there.

All the altitude compensator does is lower/raise idle speed, so I imagine that any idle speed change could be rectified via the idle speed screw.

As for the vaccum plate/heat shield thing, I don't really know.

Good luck.

Rx7carl

So after a month of fiddling here and there, replacing all tune up parts and a carb rebuild, she still has a nasty dead spot off idle @ anything more than 10% throttle applied.. She does idle and rap through the RPMs after the dead spot wonderfully.. Scared me silly when that d@!mn buzzer went off @ 7K...

Symptoms of a misadjusted accel pump. Dies just off idle with a little throttle, romp on it and it coughs and either dies or revs after the stumble.


The baseplate is necessary for a couple of reasons. Clearance for the linkage, and port mixing between the primary and secondary ports. Leave it be.

Alt comp can be removed and block off plate applied, also cap the 2 stub tubes above it.

Hot and cold start assists can be shitcanned. No actually they SHOULD be shitcanned.

One belt is NOT adequate to turn the waterpump and fan, itll slip above 4k. If you make it so tight that it doesnt then your putting excessive stress on the eshaft front extension, shortening front bearing life significantly.

quadman_20

Thanks for the post guys!

I didn't even think of clearance issues with the linkage. When I reinstalled the carb, I gained some height (only a couple of threads are through the nuts) because the old gaskets on the spacer fused... I scraped on them with all kinds of instruments and wasn't getting anywhere. Its really kinda weird. I took some sand paper and evened the area I scaped back out and lukily it was away from the edge and any ports. As far as sealing externally, it passed the carb cleaner test.. The spacer seems phenolic to me and I didn't want to damge it by scraping the snot out of it. Is it metal (the spacer, not the shield)?

On the accellerator pump, does it needs to "pump" later in throttle progression? Did I maybey install the spring incorrectly?

Thanks again,

Ben

mar3

iTrader: (8)

The AP needs to squirt when the throttle bracket moves. It provides the shot of gas the engine needs to fill the fuel hole between its idling circuit state and the main circuit state.

Rx7carl

The original gaskets are bonded to the spacer. And you are correct, it is phenolic. I ruined one getting the gaskets off, dont bother. And like Mario said the AP should squirt immediately when the throttle plate cracks open. Any lag and itll bog/die.

mar3

iTrader: (8)

No wonder that gasket was so hard to get off! I'll know better in the future...

Rx7carl

Yea I just stack new ones on when necessary. I learned my lesson LOL.

quadman_20

Good! I'm not going out of my mind! I must have spent an hour with that stupid spacer..

Well I think I figured out what the deal is.. Went out and started poking around and found that the return springs wern't on like they're suppose to go. The inner spring(towards body of carb) wan't sitting on the fulcrum that it shares with the primary return spring.. So the throttle wasn't closing or opening all the way.. The accellerator pump lever wasn't all the way out with the spring off, so i think that might have cured the problem. I wont know till I have my sheetmetal and ignition parts..

It does make me to think that I have another 1/4 throttle now

Thanks for your help

Ben

Rx7carl

Hmmmmmmm well if Id have known Id have pionted you to my cardomain site.

http://www.cardomain.com/member_page...=266801&page=4

quadman_20

Lol.. Thanks anyways.. Those two pics is exactly what I was talking about...

Ben

quadman_20

I went and bought the rest of the stuff I needed today and installed it. Cranked her up and immediatly noticed a "camming" like miss. Sound just like a SBC with a LOT of duration. The plates I made seem to not be leaking, and I covered all the ports. I also sprayed down everything with carb cleaner and no change in idle was detected. Is this the best way to detect a leak? Will it find even the smallest leak?

I still havn't takled the accellerator pump problem. I'm fearing the worst, and just ran outa time.

Anyone have a solution for the hot start assist linkage? It drags on the intake and binds on the shutter vavle, holding the throttle open. Just bend it?

On a good note, the fresh coil I intalled on the lead side of the ignition made a world of difference. The trailing coil died, so I replaced it with the older lead. It raps through the whole RPM range much quicker. Neighbors are starting to notice.... Man its loud..

Thanks
Ben

mechgod

When I build carbs for Pro 7 racing I either remove the parts from the throttle shaft or use a tiewrap to hold the arm up.