good idle...no rpm
 

I have a new rebuilt engine. 1948 59AB .......
....sat for 10 plus years before I got it....and 4 years more after I bought it. Starts up and idles at 670 rpm......as I push down on the throttle it goes to 1200 rpm and then it sputters and makes cackling ,for lack of a better word, sounds out the exhaust and will not go any higher in rpm. I am very much in the learning stage and I would like to know the following....what are the symptoms of a blown power valve (Holly 94)?......what are the symptoms of a massive vacuum leak?.....I have a new Crab distributor when you set the timing, you simply loosen the screw on the side of the crab and move the little metal plate up to retard or down to advance correct? I have some e-mails out to individuals, but I need this shotgun approach as I am going crazy after working and waiting on this car for 8 1/2 years. Thank you all, who respond....Matt in Alameda

Re: good idle...no rpm
 

I'll take a stab at your questions then offer some ideas:

1. I haven't had a blown power valve so don't know thos symptoms.

2. With a massive vacuum leak you would not be able to idle so you don't likely have that.

3. You have it right on how to adjust timing. It is best adjusted with a vacuum gauge for maximum vacuum. That setting will depend on your elevation. At 5,000 feet where I live I have mine advanced as far as possible. But, bad timing is not likely to produce the symptoms you describe.

Now my ideas:

Start with determining whether the problem is spark or gas. I do that by putting my timing light on the high tension wire coming out of the coil and watch it while I increase the RPM's. The light should be steady. If it misses at all there is a problem with the spark. Put the light on each plug and see if one or more is consistently unsteady. If so, check the plug and wire. If the spark is steady check your fuel pump by disconnecting it from the carburetor and see if good powerful squirts of gas come out of the line while cranking. Also check the pressure of the fuel pump. It should be between 1.5 and 3.5 lbs. If the flow is low but the pressure is right there is a blockage in the fuel line such as a plugged fuel filter.

I have the same engine as you and have some more ideas once you post the results of some of those tests. Or PM me for more help.

Re: good idle...no rpm
 

Matt - I have a good 94 you can borrow.

Re: good idle...no rpm
 

Look for debris in the main jets.

Could be a 1000 other things, but I'd try that first. It happened to me.

Mart.

Re: good idle...no rpm
 

Check the points "dwell". If it's within spec, try putting a can of Marvel Mystery Oil in the tank or even run it through the car while turn up the RPMs.(produces a lot of smoke, so may no be an option in Ca.) Let the car sit and idle for long enough to warm up thoroughly a couple of times. This procedure is an attempt to unstick a potentially stuck valve. ("sat for 10 plus years before I got it....and 4 years more after I bought it")

If this doesn't do the job, probably the carb as wga suggests.

Re: good idle...no rpm
 

Thank-you guys, I will do the tests and report back.....Matt in Alameda

Re: good idle...no rpm
 

it is possible you have a restricted muffler (plugged), cars with bad or plugged catalitic converters act like that, if possible break it loose at the header pipe, just before it goes into the muffler, stand on the gas and see what happens

Re: good idle...no rpm
 

Matt, did you ever figure out what the problem was? I have a stock 36 and I am experiencing a similar issue. Live right near you in San Leandro.

Re: good idle...no rpm
 

NO, I am still chasing Ghosts...few things have depressed me more than this car....however call me, I sent you a PM ..........Matt in Alameda

Re: good idle...no rpm
 

That sounds like carburation to me. My 50 did that. I rebuilt the carb and it runs great.

Re: good idle...no rpm
 

You guys arnt useing those cheap little 4" paper air filters are you? They dont work worth a crap.

Re: good idle...no rpm
 

Pull a plug wire rev it, and see if it will jump to the head ,Change the Carb or blow compressed are through the secondary jets .a small vacuum leak will cause back fire .Don't touch the advance adjustment its unlikely to cause this .

Re: good idle...no rpm
 

I agree with Ted, the slight ( max 6 degrees) of timing wont cause your problems......

Re: good idle...no rpm
 

I have a 41 fordor and had just installed a new coil, condenser, rotor, caps, adjusted everything, it never started better and ran the better than it ever had.....for about 1 week when all of a sudden it developed the same symptoms as you describe. After numerous attempts to get it to run it finally wouldn't even start. After researching here on the Barn and elsewhere he only thing left to try was put the original condenser back. Well guess what...problem solved. She starts better and runs smoother than any of the other cars we own.
The new condenser must have been bad and then dead shorted so it wouldn't even run.

Re: good idle...no rpm
 

Do a compression test, you might have some sticking valves after sitting so long.

Re: good idle...no rpm
 

Just a follow up to my previous post. The attached link is to an MGA site and explains very well how the traditional coil/condenser/points systems works and the importance ot the condenser in the system. Its for a 12 volt system but the principles apply to our 6 volt system. The author indicated elsewhere that a bad condenser may allow the car to run at idle but not at higher rpms. This is exactly what happened to me and your symptons sound the same as mine were. Condensers are cheap so try a different one before assuming that more expensive problems to fix may be the problem.

A quote from his site goes something like this:

"90% of all carburetion problems are electrical"

In my case it was oh so true.


http://mgaguru.com/mgtech/ignition/ig108.htm

Re: good idle...no rpm
 

>>>I have a new Crab distributor when you set the timing, you simply loosen the screw on the side of the crab and move the little metal plate up to retard or down to advance correct?

Is that truly correct for the crab type? On the helmet type, it's UP on the plate to ADVANCE, DOWN to RETARD.

Re: good idle...no rpm
 

Do a compression test, you might have some sticking valves after sitting so long.
+1 on this.

Re: good idle...no rpm
 

Advance is up for both the crab type?and the helmet.We were flicking the points on a Model A the other day it had a new condenser on it .we were getting a few shocks (made me jump a bit ) and reasonable spark of the HT coil wire .after adding a second original Flathead condenser at the coil it started jumping almost 1/2 "
The symptoms you describe can be any number of things they can all give smilier problems .a voltage drop due to dirty Ing switch or bad low tension connections .a badly earthed condenser .leaky vacuum .secondary jets blocked ,bad coil .week points springs ,condenser ,faulty fuel pump .

Re: good idle...no rpm
 

First of all, thank-you all for your suggestions and comments. In my case, I have an converted Ford crab electronic distributor. I put a known good carb on it and it started and ran not great, but good for eight blocks, then crapped out and it had all the old bad symptoms. Good idle...no RPM above 800 ....and this morning it won't even start.....I think I will order a brand new carb,...after all, rebuilts are 75+ years old to start with......and I may get a new crab ......I am not sure what to do yet....I am real tired spending so much time and $ to get ZIP...Also I am worried about the fact that I have the Accell radio supressing spark plug wires going through Stainless Steel tubes( is this OK?), and the Pertronix flamethrower is mounted HORIZONALLY ( someone said these have to be vertical, others say horizonal is fine)in an aluminum 'cage' that is attached to the aluminum manifold with a brass mount....and in one place I have a brass support holding the plastic wire separators in place...even though all brass is isolated from the aluminum with rubber insulators...I think the voltage is so high that I may be shorting out the coil or getting a cross fire.........The irony is that everyone raves about how beautiful the engine is.....and it is,.... but as long as it does not run it is getting uglier by the minute to me.....Oh well I will figure this thing out,....Matt in Alameda