Opinions: Which model Zenith is the better one?

[armybuck041]

Hi guys,

I'm still plunking away with my 74A2. Getting close to doing the reassembly very soon.

I've been reading a ton of info, and Carbs and their problems seem to be the hottest topic.

So, with my A2 I have 4 different Zenith Carbs:

12848 (external mixture)
13660 (sealed mixture)
13660A (unplugged mixture)
13660B (unplugged mixture)

They are all pretty much in the same condition, dirty, old, but far from gone. I'm not concerned with which one is "correct" but rather, which would most likely be the best performer.

If it were up to you, and based on historic performance, which one would be the better one, if I chose to rebuild one?

Thanks

Scotty B

[Horst]

13841. Unfortunatly not in your list. A2 pre-emission. But performance differences will be quite small anyway. You will find the differences about those carbs in the wiki in the fuel section.

[rickf]

12848, early A1 carb. Keep in mind that the internals of this carb are not the same as the later carbs but in my opinion it is a better carb. The one thaat Horst listed is the best of both worlds but I have never seen one. I am running the very late "Aftermarket" Zenith and although a lot of people say they are junk I have had good luck with it.

Rick

[raymond]

I have had extremely good luck running a sealed emissions type carb. I "unsealed" the idle mixture screw and set the mixture to where it runs the best, not where the TM says to set it. I also set the valves and timing every spring when I bring my M151 out of hibernation. I think some of the problems blamed on the zenith carb are caused by other factors. I suspect one of the biggest problems with some peoples engines is that they are out of time. A lot of people are either intimidated by timing an engine or can't figure out how to use a standard 12 volt induction light on a 24 volt shielded system. Another thing I suspect people have trouble with is the ignition itself. If you suspect your ignition is bad but don't know much about points or are intimidated by them, buy an electronic ignition kit. They are a simple drop in install and require no adjustments. Setting the valves is pretty easy on an M151 also. The valve cover is held on only by 2 bolts and the PCV valve and is thus easy to remove. I adjust the vallves while the engine is running. It doesn't spray oil all over the place like one would think, and it really doesn't take much time. Have someone show you once how to get the "feel" of a properly adjusted valve using a feeler gauge and you will wonder why you did not do it before. Didn't mean to hijack this thread, I just have always thought a lot of problems are blamed on the zenith carb when it is really a pretty good carb.

Sorry for the hijack

[baios]

what about the patent that Mil-plus the company in Itally says about the M151carb????Does anyone use those carbs??How they perform????

[Horst]

I have tried the modified venturi from Mil-plus. I had posted pictures of it. Waste of money.

[armybuck041]

Thanks for all of the tips fellas...

Just got back from putting the new Battery Box Floor in... Getting closer.

Any chance that just the Gasket Kits from later models will work with the earlier 12848 Carb?

Scotty

[rickf]

Thanks for all of the tips fellas...

Just got back from putting the new Battery Box Floor in... Getting closer.

Any chance that just the Gasket Kits from later models will work with the earlier 12848 Carb?

Scotty

Yes they will. The accelerator pump is said to be different but I have had no problems with any of the ones I have done.

[Rainman]

Hey rick,

Reading this post I decided to take a look at a few I have laying around, to see if I have either of the "good ones". On my kitchen table, the first carb I grabbed was the early 12848 that came on my 64 Kaiser M151. The second carb I picked up was one of the elusive 13841's! Now I'm looking forward to looking in my parts room tomorrow to find a few others.

Rainman

[armybuck041]

Looks like i'll get the old dog 12848 pulled apart and cleaned up then...

Hopefully the guts are good, and a good cleaning and some new gaskets brings her back to life again.

Scotty

[Ralph Fuller]

Rainman said, ". I adjust the valves while the engine is running. It doesn't spray oil all over the place like one would think."
Using an old valve cover...couldn't you cut out the top, install it temporarily to catch the oil while you adjust the valves?

[rickf]

Ah Ralph, You must have worked on Corvairs! I would cut a set of valve covers across the top and partially down each side and bend the top out to adjust the valves. As far as all of the other vehicles, I had a set of cut down valve covers for every engine hanging on the wall of my shop. Along with a couple of sets of the rocker clips to keep the oil from squirting out of the oil hole in the rocker. That is not a problem on the mutts which are oiled from the rocker arm and not the pushrod.

Rick

[raymond]

Ralph

You would be surprised at how surprisingly easy it is to adjust the valves on a M151. It is nothing like my old 1965 Ford Mustang, which is the only other automobile I ever owned with solid valve lifters. if you have never adjusted the valves on a M151 engine, I would guess that the only hard part would be finding someone to show you who actually knows how to use a feeler gauge. It is easy to do, but with modern engines, it is becoming a lost art.

[rickf]

Ralph

You would be surprised at how surprisingly easy it is to adjust the valves on a M151. It is nothing like my old 1965 Ford Mustang, which is the only other automobile I ever owned with solid valve lifters. if you have never adjusted the valves on a M151 engine, I would guess that the only hard part would be finding someone to show you who actually knows how to use a feeler gauge. It is easy to do, but with modern engines, it is becoming a lost art.

There were only two 65 Mustang engines that had solids, a 271 horse 289 Hi performance and the super rare 427 tall block Nascar engine! I am guessing you had the 289, there were only something like 35 of the 427's made.

Rick

[armybuck041]

Thanks again for all the replies fellas.

No issues on setting the valves. I did mine running with the cover off. Aside from shaking the hell out of my arms, it was pretty easy. Much easier than my M38A1 was. At least both intake and exhaust are done on top. I'm going to have to get a good Timing Light mind you. I havn't actually set the timing yet.

The Carb thats on it, 13660B works OK, but I wanted to clean up and restore one of the others to make sure when it goes in for inspection, everything is in tip top running condition. Will the emissions vent lines still connect to the 12848 if I swap over the fittings?

Scotty