Motor does not pull properly, has no power ...

DRG-ler

DRG-ler

Senior Member
Hi folks, we are currently looking at the bug.

It's about a Tudor with a 4Banger, where the engine doesn't pull properly. There is a lack of power, so that the car can only drive 70/80 km / h. Far too little!

What has been done so far: We found sand in the tank. I have no idea how it got there, but we dismantled and cleaned the entire gasoline system, including the gasoline tap, sight glass, all filters and carburetors. That was unsuccessful!

The gasoline flow was controlled. Unsuccessful!

A complete replacement carburetor was installed, from a Tudor that runs at full power. (Would drive 95Km / h if he had to.) That didn't change anything either. Unsuccessful!

The ignition system was set using the Nurex Precision Timing Kit and ignition flash gun. Also brought no change, unsuccessful!

It was recognized that sparks flash over on the distributor body. An intact one was installed, but that did not lead to any improvement either. Unsuccessful!

New spark plugs were installed. Unsuccessful!

What could be the reason for the lack of performance? The engine runs very smoothly and smoothly, starts very well, but it is already evident when accelerating from the lower revs that it lacks power. I'm slowly running out of ideas.

Greetings from Berlin

Andy
 
Hi Andy,


the next step I'd take would be a compression-test on all 4 cylinders.

Is the car stock?
It performed well before the sand got into the tank?


Greetings,


Daniel
 
I think the car ran better than it was procured. However, that was about 2 years ago, and it was rarely used in between. I don't want to judge whether the whole thing can be connected to the sand.

I also had no direct comparison at the time. It's really hard to say. How much bar should the compression tester then show?

What are reasonable values for a series engine?

Stupidly asked: Would it be possible that the sand could get through the carburetor and into the cylinders? It was very fine sand, like from a bird cage, but in total "only" about a tablespoon full. Most of it in the Bulb sediment.



Greetings Andy
 
Hello Andy,


if the sand was fine enough to get through the jets then I think it would be possible.
A stock engine has a compression of roughly 4.2 : 1, So I guess you should read around 3,5 to 4 bar. (pressure in the inlet is a bit lower than 1 bar)


If it sat for such a long time, there's also the possibility of a sticky valve. Have you poured some oil into the cylinders and let it sit for a day? Or you could just remove the valve cover and take a look. :)


Last but not least, is the fuel 2 years old as well? If so, then empty it and put a few litres of fresh fuel in the tank. I've had that problem with motorcycles as well, after putting some fresh fuel in the tank the bike ran fine.


Greetings,


Daniel
 
How much sand got into the other carburetor ?

I too would recommend a compression test.

Is the distributor advance working correctly ? [ I know you set the base timing]

Has the camshaft timing gear been replaced ?
 
so you are expecting more then 45mph?
we have no idea what condition your engine is in. do a compression test. many As will not go faster then that, though some om this board will argue a model A engine should go 65mph from the factory, very few do without mods of high compression heads, overdrive
or even a better carb. consider these motors as to about 40 hp.
 
What makes a Model A run well:

The engine must have good compression which requires that the rings and valves be in good condition. The camshaft must also be in good shape.

The fuel mixture must be right which means adjusting the GAV for best engine performance while driving.

The ignition must be right which means adjusting it for best engine performance while driving.

There must be no parasitic drag such as the brakes dragging.

The rest of the engine must be in good shape including no leaks at the intake or exhaust manifolds and a free flowing muffler.

A higher compression head helps. That plus other modifications to the engine have the potential to double the horsepower.
 
Hello Ronn, yes I expect more than 45 miles. My own Model A runs 55 miles with a production engine without tuning without any problems, would even run 60 miles (1x tested). However, I don't do that kind of thing with this old car anymore. The trucks here in Germany are limited to around 80 km / h. If I can ride comfortably there without slowing them down or letting them push me, that's enough for me. It gets uncomfortably loud in the car for over 55 miles. But I consider 45 miles to be too little. That would perhaps be a useful value for a German Model A engine with 30PS and 2.3L displacement. This car comes from Denmark / Scandinavia and should have a 3.3L engine with 40 HP.

Indeed, poorly closing valves valves should be noticed during a compression test.

There was very, very little sand in the carburetor itself, only in the float chamber. (Maybe 3-4mm³)
Is the distributor advance working correctly?
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I mean yes. The ignition advance can be adjusted from approx. 8 ° after TDC to approx. 22 ° before TDC. That should be the usual 30 °.

Has the camshaft timing gear been replaced?
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No, no one was on the tax times. They also fit. The notch in the camshaft sprocket corresponds to TDC cylinder 1. I did a visual test.

I'll see that I can borrow a compression tester. If the result is bad, I will probably need an endoscope.

As already written, the lack of performance is not only noticeable in the lack of top speed. Even when accelerating from lower revs / speeds, the engine pulls significantly worse than my own.

Greetings Andy
 
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Check to see if the carburetor throttle plate is opening wide open, the linkage can be bent out of adjustment, check the foot control as well as the hand control.
 
Three things I'd check: compression, clear unrestricted exhaust, and timing. You should be able to advance the ignition enough so the engine pings when pulling. Then retard just enough to stop pinging. If you cant get it to ping, your timing is too retarded. Just like a piano, you cant beat tuning by ear.
 
DRG-ler said:
Hello Ronn, yes I expect more than 45 miles. My own Model A runs 55 miles with a production engine without tuning without any problems, would even run 60 miles (1x tested). However, I don't do that kind of thing with this old car anymore. The trucks here in Germany are limited to around 80 km / h. If I can ride comfortably there without slowing them down or letting them push me, that's enough for me. It gets uncomfortably loud in the car for over 55 miles. But I consider 45 miles to be too little. That would perhaps be a useful value for a German Model A engine with 30PS and 2.3L displacement. This car comes from Denmark / Scandinavia and should have a 3.3L engine with 40 HP.

Indeed, poorly closing valves valves should be noticed during a compression test.

There was very, very little sand in the carburetor itself, only in the float chamber. (Maybe 3-4mm³)
I mean yes. The ignition advance can be adjusted from approx. 8 ° after TDC to approx. 22 ° before TDC. That should be the usual 30 °.

No, no one was on the tax times. They also fit. The notch in the camshaft sprocket corresponds to TDC cylinder 1. I did a visual test.

I'll see that I can borrow a compression tester. If the result is bad, I will probably need an endoscope.

As already written, the lack of performance is not only noticeable in the lack of top speed. Even when accelerating from lower revs / speeds, the engine pulls significantly worse than my own.

Greetings Andy
Click to expand...







Advance. The full range should be 40*. If you are starting at 8* retarded and only going to 22* you have 22* BTDC not 30*.
While I think 40* is too much, 22* is not enough.
If the timing is set at TDC and the travel is 30* rather than 40*, the 30* should be fine.

I agree with a compression test. It doesn't have to be high, just has to be somewhat even. Mine has had 45# for the 45 yrs I owned it.

The size of engine is something most wouldn't think of. Many folks think the Ford 9N and 8N engines are the same as the A and have installed them.
 
Just like a piano, you cant beat tuning by ear.
Click to expand...
But this only works if you know the sound you have to watch out for !!

Check to see if the carburetor throttle plate is opening wide open, ...
Click to expand...
Banal problem with great effect. I will check!

How can you tell if the silencer is blocked?

Thanks Bavarian for the link. I will check too. Sometimes you can't think as stupidly as it comes. Perhaps the previous owner actually installed a small engine. Then all work would be pointless, and you could probably only achieve a comparable performance with tuning.

Greetings Andy
 
The size of engine is something most wouldn't think of. Many folks think the Ford 9N and 8N engines are the same as the A and have installed them.
Click to expand...

Yes, that happened to a friend. This one had an engine failure and he had an exchange engine installed in a highly acclaimed workshop for many thousands of euros. Unfortunately, the workshop failed to pay attention to the displacement of the newly installed engine. Now he only has 30HP with the small engine. My friend is no longer doing positive advertising for the workshop!

The degrees were now only mentioned from memory. The adjustment was made a long time ago and I found the adjustment range excessive at the time. It is quite possible that it was actually 40 °.

Greetings Andy
 
I don't know if Marvel Mystery Oil is available in Europe but it is the common additive used for sticky rings and valve on an engine that will actually run. It can be used in the fuel to help free up hard carbon and light corrosion that may cause lower than normal compression levels.

Nothing will correct for worn engine components. A person should also insure that drive train friction problems aren't a possible cause. Wheel bearings, brakes, and tire condition can affect friction causes. A slipping clutch can have an affect but it usually is more apparent during shifting of gears.
 
I did not think of the smaller displacement engine used in Europe. That is very possibly it. Without taking the head off and measuring the bore, I know of no easy way to check. Maybe filling up the cylinder with a measured quantity of oil when the piston is down and then sucking it out. Or measuring it after it is sucked out.

As far as restriction in the exhaust system is concerned, you may be able to tell with a large vacuum cleaner (shop vac). The vacuum cleaner should have almost no restriction in airflow going through the exhaust system.
 
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