Need Help for Diagnosis...

Father Mike

Father Mike

Junior Member
Hello All,

I'm new to the Ford Barn forum and this is my first post (although I've been a long time reader.) Nevertheless, not only am I new to the forum, I'm also new to Model A's, auto restoration and mechanics in general. So you could say I'm perhaps the most "wet behind the ears" as you can get.

I'm having difficulty diagnosing the problems that I see present in my 1928 Tudor. When I first got her in December there were some minor issues that needed tending but after 6 months, I'm noticing that my inexperience may be causing more problems that fixing them. Here are the problems that I've encountered and see if your collectives experiences may point me in the direction necessary for a fix (or at least better performance.)

1. For the most part, before changing out the air maze and filter that was old and dirty I noticed the car had a rough idle. It sounded like she was keeping beat with 3/4 time. (The car at idle, not while driving would sound 1,2,3 - 1,2,3 - etc.) My solution was to check the timing/tune up. Result: No change.

2. I've noticed that oil seems to be oozing out of the spark plug hole in pistons 1 and 2. The heaver the load or faster the acceleration, the more it oozes. Diagnosis: Bad rings. I check the pressure and found that all four cylinders fared extremely well. I'm at a lose.

3. After changing the air filter and only recently have I noticed that the car had gone from driving well (although running rich because of blackened spark plugs/black exhaust and not being able to exceed 45 mph) to running poorly at any acceleration. However she seems to idle better now (with the idle mixture screw turned completely clockwise), but when driving, she seems to jump when accelerating in 1st and 2nd gear. Also the slight black smoke from the exhaust that would present itself mostly while changing gears (from running rich) has now turned whitish and is much more noticeable than ever before, especially at idle.

4. The idle rpm to me seems high and there is nothing that I can do to lower it. The throttle is complete closed, the timing has been checked, and the carb is new and functioning properly (to the best of my knowledge.) The RPMs at idle are slightly over 700. BTW, I can lower the RPMs by turning the idle mixture screw c/cw but that just make the idle sound worse. It seems as well that the engine is warming up much faster than before. (Am I now running too lean?)

I'm sort of at a lose for all these symptoms and don't know where to go to next. I replaced the carb (which works better than the old one), the air filter and maze, performed a tune up (several times) checked and rechecked the timing. Adjusted and readjusted the GAV and I can't seem to the get the car to run well. Cylinder pressure is good and there are no apparent leaks in the intake manifold.

I know there is a lot going on here, but any help would be greatly appreciated. Thanks in advance for your passion and experience and patience with a novice.
 
if compression is good and oil in cylinders indicates worn valve guides, running with the gav valve all the way closed means float to high, worn gav rod or jet, or the carb is in need of a complete rebuild (contact ken ct) he does xlnt work and he posts in here and the v/8 room, cant idle engine down indicates a vacuum leak, in carb, carb base gasket, or at the intake manifold, gland rings missing or not installed correctly, intake manifold warped
 
Take a can of wd40 and with engine running spray it around the intake and exh manifolds. If leaking you will see a diff in the idle. Go on marco's site for an excellent way to set the timing. Are you losing water from the radiator? What plugs are you running? Others will chime in I'm syre. I'm not sure if Ken, CT does A carbs or not. Post a question to him on the EV8 board. Are the points set correctly and have yyou changed the condenser?
Paul in CT
Paul in CT
 
Could be a lot of things going on. Some generic advice.

1. Lose the air cleaner. The Model A carbs are not designed for them and did not have them when new. They make the car run richer--maybe imperceptibly or maybe perceptibly. Unless you're doing a lot of dirt road driving you really don't need it. Once you get the car running right without it, you can play with adding it back.

2. Join your closest Model A club and start picking brains. These guys are always eager to help out the new guy.

3. Buy some books. Les Andrews series are probably good place to start.

4. The white smoke suggests antifreeze leaking into the combustion chamber, especially if heaviest on startup. Maybe a leaking head gasket. If it's not blown, you might get lucky and fix it by retorquing head nuts. OR, maybe it's actually light grey smoke from burning oil, from worn rings.

5. 700 rpm isn't a bad idle speed. There's an adjustment screw on the carb throttle linkage. Don't use the GAV or the air bleed adjustment for this purpose. Some folks need to bend the control linkage rods.

Welcome to the hobby! Be of good cheer--they're neat old cars!

Steve
 
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Join your local Model A club and ask for their assistance. We all love a Model A that isn't running right. If I were closer I'd remove the spark plugs and check the compression with a compression guage.
 
the "oil" around the plugs is combustion by product from a leaking gasket, either loose plugs or bad gasket. The white smoke concerns me regarding leaking head gasket. It sounds as if the carb is rich with a vacuum leak in the system too. You should seek assistance from someone experienced, like a local club before the potential water leak issue develops into something worse.
 
ford1 said:
if compression is good and oil in cylinders indicates worn valve guides, running with the gav valve all the way closed means float to high, worn gav rod or jet, or the carb is in need of a complete rebuild (contact ken ct) he does xlnt work and he posts in here and the v/8 room, cant idle engine down indicates a vacuum leak, in carb, carb base gasket, or at the intake manifold, gland rings missing or not installed correctly, intake manifold warped
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SORRY guys i dont do Model "A" carbs. ken ct.:)
 
In addition to what has already been suggested, you might want to swap out the spark plugs for new ones. Your's might be "fouled out" and not firing properly because of the carb/oil problems.
 
Richard Wilson said:
In addition to what has already been suggested, you might want to swap out the spark plugs for new ones. Your's might be "fouled out" and not firing properly because of the carb/oil problems.
Click to expand...

steve s said:
Could be a lot of things going on. Some generic advice.

1. Lose the air cleaner. The Model A carbs are not designed for them and did not have them when new. They make the car run richer--maybe imperceptibly or maybe perceptibly. Unless you're doing a lot of dirt road driving you really don't need it. Once you get the car running right without it, you can play with adding it back.

2. Join your closest Model A club and start picking brains. These guys are always eager to help out the new guy.

3. Buy some books. Les Andrews series are probably good place to start.

4. The white smoke suggests antifreeze leaking into the combustion chamber, especially if heaviest on startup. Maybe a leaking head gasket. If it's not blown, you might get lucky and fix it by retorquing head nuts. OR, maybe it's actually light grey smoke from burning oil, from worn rings.

5. 700 rpm isn't a bad idle speed. There's an adjustment screw on the carb throttle linkage. Don't use the GAV or the air bleed adjustment for this purpose. Some folks need to bend the control linkage rods.

Welcome to the hobby! Be of good cheer--they're neat old cars!

Steve
Click to expand...

I AGREE!!!!!

In addition to the excellent advice that has already been posted, I would also look into the complete Ignition System. A marginal Ignition System will cause some of the problems you are having.

I would also invest in the two ignition testors made by Nu-Rex. One is for coil polarity and the other is for ignition output. These are simple easy to use testers that I have found to be very helpful and takes some of the guess out of the diagnostic process.

If you do change the points, be aware that some of the new points are made "Off Shore" and are of VERY POOR QUALITY and sometimes cause more problems than the solve.

Les Andrews has a very good set of repair books. They will definately pay for themselves in a short period of time. You will get to the problems a lot sooner and be able to repair them correctly.

If you have reasonable compression and the head is sealed up, you should be able to get your Model A should run well enough for you to drive and enjoy it.

Keep pressing on and try to find a local Model A Group. These cars can be made to run well and be very reliable. :)

Good Luck and KEEP US POSTED,

Chris
 
Father Mike

Go to Cannonsburg PA on the 4th of July. The Three Rivers Region of the Model A Restorers Club will be participating in the parade there. You will have a chance to meet some Model A guys and consider joining the club.

Roland
 
Thanks Roland, I joined the MARC about two weeks ago and sent in my information to the Three Rivers Region last week. I haven't heard from them yet, but I will be stopping by for a meet and greet. Thanks for the info.
 
Thank guys for all the great advice. I had a chance today to run up to Snyder's and get some things to address the problems. (I'm lucky enough to be within a reasonable drive to a Model A Super-Store) I started with new plugs which seemed to help greatly. My previous ones were perhaps too carbon fouled to run consistently. The rest of the ignition system seems pretty good. I get a beautiful blue spark that would rival the Blessed Virgin Mary's veil. :) I also adjusted my steering column because it was not allowing the advance to be fully seated against the distributor body. Re-timed and she seems to idle now with a lot less smoke out the tailpipe. The RPMs could now be dropped a hair as well. I also checked the radiator and found that I'm not loosing any water. (At least one system is working well)

I took the air filter off as was one of the recommendations but I'm a little nervous because I have a slight leak from the joint between the exhaust manifold and the tailpipe where the clamp is. I have a modern insert pipe that runs inside the two and the clamps (which are on correctly). Anyone else have a leak from that joint and how did you fix it? It was recommended to me to use Permitex Red and tighten that clamp for all she's worth. I also have the asbestos band that I haven't put on because I can't get it to stay in place while tightening the clamp even with the jack supporting the tailpipe. I also have a new clamp that I didn't put on because it doesn't seem to fit as snugly as the old one. I know the leak is coming from there because I closely inspected the manifold and found no cracks, splits or imperfections. Because the intake is so close to the manifold/exhaust joint I really don't thinks it's good to get that exhaust sucked back through the carb. BTW, I believe that is what killed my last air filter in less than three months with almost no miles driven. Oh, and there is not constriction in the tailpipe, I get plenty of exhaust too that exits from the back. Thanks again for the detailed and quick responses.
 
The fix you have in place between the exhaust manifold and the pipe should not allow any leakage at that point. Could the leak be from the rear port on the manifold? They tend to sag out of line and allow the gasket to not seal well.
 
The only way I could get my exhaust joint to stop leaking was a new manifold from Snyder's. They make 'em. Drive over and get one, along with new gaskets, and new brass nuts. Be careful tightening when installing. Some folks say 45 ft-lbs. I say tighten until it feels right. 45 is too much. Good way to break an ear off the manifold.
 
Father Mike, I believe that the tail pipe clamp is intended to fit a little loosely. Allows the exhaust system to vibrate without cracking a joint or pipe. That might happen if the tail pipe were rigidly held in one spot. Sound like you are making great progress. :)
 
the early repro mufflers do not fit the exhaust manifold correctly. You can have a muffler shop bend the pipe and enlarge the flange to fit, or can replace it with one designed from the Ford blueprint, which are now sold by most vendors. To tell the early muffler, look at the exhaust pipe....it will have a crimp in the bend. The Ford blueprint called for a mandrel bent exhaust pipe, which is a smooth bend without any crimps. The old pipe insert to solve the leak was a common solution, often accompanied with bending the exhaust pipe by inserting another pipe into it and pulling it, but there are some who believe the insert restricts the exhaust flow.
 
HEre's some pictures to add to Pat's comments. The poor fit between the flange on cheap repro mufflers and the manifold end was a very common problem before the new Aries mufflers became available. Similarly, the older repro muffler clamps weren't very good; the new stuff is much better and might solve your problem, unless someone has overheated the manifold so it droops, like by running on retarded spark or by placing a restriction in the pipe. Get the good parts, use muffler sealant for the final seal, and lose that pipe insert; there's a reason they made the system with its given inside diameter.

mufflersdimensions.jpg


I believe that Pilotdave was referring to the clamp to the frame. The clamp to the manifold should be tight; the clamp to the frame under the car must have some give in it. I believe that this is especially important for the new stainless muffler system. Here's a picture of the clamp I rigged using some rubber and asbestos (tsk, tsk!). Some folks say the original clamp transmits engine vibrations to the body.

mufflerclamp001-1.jpg


Hopefully, your tuning has solved the plug problems, but beware that replacing fouled plugs is often a very temporary fix.

Steve
 
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Yes I was referring to the clamp attaching the tail pipe to the frame. Interesting comment about vibration transmitted to the frame. I get a severe vibration at higher speeds that seems to be in the floor boards. Wonder if this is coming from my tail pipe clamp....it's bolted firmly to the frame and loosely around the pipe.
 
Pilotdave said:
Yes I was referring to the clamp attaching the tail pipe to the frame. Interesting comment about vibration transmitted to the frame. I get a severe vibration at higher speeds that seems to be in the floor boards. Wonder if this is coming from my tail pipe clamp....it's bolted firmly to the frame and loosely around the pipe.
Click to expand...

Vibrations are a whole another world of issues, but if it's only a high speed problem I would look first at wheel balance. Some say it doesn't matter with Model A's, but in my experience it can matter a lot.

Steve
 
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