Our '13 starts very easy, many times getting a free start. It idles nicely and runs just great going down the road slowly. However, at higher speeds---25-35 mph or so it runs a little rough. Not too bad but I'd sure like to smooth it out. I've drained the carb, checked to make sure all cylinders are firing, cleaned the plugs and messed with the mixture from so lean it staggers to very rich. It seems to run the best with the mixture about 3/4 turn from full lean. In other words, I turn the mixture knob all the way closed then open it about 3/4 turn. Running richer makes it run more rough. I'd appreciate your comments.
May want to replace the needle. it could be scored
Mine ran rough at higher rpm's because the communicator had some wear spots in it and apparently when the roller went over those dips, it would bounce. I replaced the communicator with a smooth one and it run much better.
Four things I would suspect, and a fifth one not likely. Sometimes 2 or more things could be wrong at the same time, so you don't find the problem, so check them all.
The commutator has been spoken to above. Try a new one. (if that's not the problem it's a good idea to have a spare anyway)
Partially plugged fuel line. The sediment bulb has a screen in it and might be partially plugged with rust particles or varnish or other sediment. Thoroughly clean. If you have any other fuel filter other than the original type sediment bulb, remove it. The gravity flow doesn't give enough pressure to flow through filters other than the original type, especially true of the cars with tank under the seat.
Running on battery instead of magneto. T's tend to run poorly at higher speeds on battery than on a good functioning magneto.
Coils. Do they have good condensers and points? Have they recently been adjusted using a coil tester or strobospark?
This last one I don't suspect, but it would be a good idea to do a compression test. Should be around 50 PSI on all 4 cylinders. They should all be within 5 PSI of the same. Sticking valves could cause a problem, but usually worse at slow speed or when pulling.
Norm
The other obvious thing that no one have mentioned is the ignition timing. The ideal timing will be different at higher speed then lower speed.
Jim
Are you running on magneto?
Or simply running on 6 volts?
If I forget to turn the switch to MAG, the the car develops a faint miss at the speed you mention, plus top end is reduced. When I switch to MAG, then the missing stops and I can move on.
The car runs on 12 volt battery only as the magneto isn't installed. An alternator maintains the battery. A T engine but has halogen lights front and rear---but rarely use them.
There you go. A 12 V battery doesn't put out enough volts to run the coils at higher speeds.
Like John Dolittle said above, if I forget to switch to mag after cranking the car on battery, it runs rough at higher speeds. I look down, realize the switch is still on battery, switch it over to mag, and it runs smoothly.
Get your mag fixed and installed and it will run better.
I forgot to add. . .it's a shame to have a car that nice and not have it run on mag!
All that makes sense to me. Thanks for the comments. The car is still the way it was when we bought it---no mag. We bought the car in May. Being fairly new to the Model T hobby I wasn't aware of the battery versus mag question. I do have all the mag parts in a box however so I might have to do some work there.
Thanks again.
John:
While I certainly agree that you should get the magneto working for best performance, I still kinda think you have a coil or timer problem that could result in your car not running much better than it does. Many people run their T on 12V when the magneto goes south on them and they don't have rough running at 25-35 speed. Since getting the car to run perfectly on magneto requires the coils to be properly set up and a good timer installed, my bet is that if you have your coils adjusted by someone who knows how to use either a Strobo-Spark or a Hand Cranked Coil Tester (HCCT), your car will perform a ton better even on 12V while you await getting the magneto going. The poor battery performance that most folks are referring to is 6V battery operation and that for sure won't allow you to have much performance in the 25-35 MPH range because of the slowness of the coils. A 12V battery will overcome that problem but only if the coils are properly adjusted. If your coils were adjusted using a "buzz box" type of tester, then I am even more sure that your problem is in fact a coil or coils. When running on battery you need to have a very good timer. Magneto operation is forgiving of a poor timer somewhat since the magneto pulse is what actually fires the coil. Hope this helps.
Actually running coils on 6 v or 12v should work just fine up to 45 mph with standard gearing (1400 RPM). After 1400 RPM the 12v has been shown to do as well (actually a little better in the linked test) as running on the mag but the 6v power performance does drop off at higher RPM.
Here is the dyno test comparing different ignition systems.
http://www.mtfca.com/discus/messages/257047/Ignition_Dyno_Testing__1_-267231.pdf
Jim
Jim:
I respectfully disagree. It is true you can set the coil for way less current than 1.3 amps and thus get it to run better on 6V but a coil that is properly setup on a HCCT will not run very well on 6V since it will be retarded timing wise. You cannot simply compare 6V to 12V unless you are talking about a standard coil adjusted normally on an HCCT. There is a clear and noticeable struggle for the coil timing to try and keep up and the car will most notably feel retarded timing wise.
John R.
Nothing to really disagree about. I was just pointing out that in one actual dyno test that the 12V did about as good a mag and the 6V performed okay up to 1400 RPM (45 MPH). Of course that was just one test and others with different settings may get different results.
I do agree with you that, "A 12V battery will overcome that problem but only if the coils are properly adjusted. If your coils were adjusted using a "buzz box" type of tester, then I am even more sure that your problem is in fact a coil or coils. When running on battery you need to have a very good timer. Magneto operation is forgiving of a poor timer somewhat since the magneto pulse is what actually fires the coil."
Given a choice between DC power or mag, I think that magneto operation is the most trouble free.
Jim
If you read the text of that dyno test the timers were adjusted for optimum horsepower on the dyno. If you could do that to a running Model T while going down the road then you might see similar results. The people performing the test were adjusting the timers beyond the limits of the factory linkage.
If you set the timing properly in your car you can't get enough advance to achieve very good top speed when running on 6 volts. The linkage doesn't have enough travel to achieve the amount of advance you would need.
If you set the timing to achieve best power on 6 volts while at higher speeds it would be too far advanced when cranking, leading to broken bendix parts or broken person parts.
The higher voltage afforded by the magneto advances timing as voltage climbs. A 12 volt battery is better than a 6 volt battery in this regard, but a magneto is still better.
Now you may consider this a dumb question---I'll preface my question by saying I really don't understand electricity/voltage, etc---anyway, what would happen if I used two 12 volt batteries? Don't laugh---that's a real question. I really appreciate all the response to my problem---not a big problem since the car does run down the road "okay" but I'd like it to run better. Thanks again
John M.
You might want to search and read previous posts on this subject of 6V and 12V operation of coils. Also Ron Patterson and Steve Coniff authored some fine articles on this. Those are available at my web site document library and are free. Go to www.funprojects.com and look in the document library.
As to your specific question. There is very little if any further useful gain in coil speed beyond 12.6V Battery. Don't confuse magneto voltage (28-30V) with Battery voltage since the magneto is AC voltage and it has different timing characteristics when powering the coils. If you increase the coil voltage to 24V when using a battery you will very likely destroy your coils if you are not very very careful and you will gain mostly just heat in the coil and shorten its life. Even when raising the voltage to 12V battery one must be careful not to let the coils site and "buzz" on 12v since they will quickly overheat.
Maybe another dumb question, however as a follow up to my original question----would a distributor be a possible remedy for my running rough problem? I drove the car about 15/20 miles this afternoon and it runs just fine at 5 or 10 mph. It starts great but gets rough when I get more speed, and at around 30 mph or so it's pretty rough. I do have all the magneto parts but thinking this would be less expensive. Thanks again for your help
4 tested and rebuilt coils $40 ea = $160
New timer if needed = $50 = total $210
New Distributor, single 12v coil, new distributor wires to the plugs = $365
Singing sweetly four Ford coils in the dash mount box, and if one fails you can get home on 3 cylinders.
Distributor, no lovely Ford sounds, one coil failure, tow truck.
My '14 was running off a 12V battery at the 2008 Centennial and when the battery was low on juice, it ran rough until it quit. Found out my battery was totally dead and my mag was working, which the last time I tried it, it didn't work. Started it on the mag. Got me home and is still working.
John, and others, Don't try to improve your performance by adding one of those Diffy things that don't look proper on a Model T!!
Simply research the E Timer option. You'll enjoy a Stock looking car with improved performance and eliminate the need for any maintenance of the timer.
This seems especially true if you are trying to operate on a 6 V battery. You'll be impressed.
Problem is the E timer disables the magneto, making your model T solely dependent on the battery for ignition, thereby defeating the car's redundant and utterly reliable factory ignition system.
That is a poor solution in my opinion. The stock ignition system is the soul of a Model T. Get rid of that and you have lost my respect.
It all depends on why your car is running rough. If the valves are bad, no ignition system will fix the problem. Likewise if the fuel system is partially blocked and you are running lean at higher speeds. Magneto runs better than battery, but your car will run fine on just a 6 volt battery if your coils are in good condition. It will just not be quite as fast on battery as on magneto.
We just got back from a trip to Yosemite, and I ran all the way up to Glacier point without a problem on my coils and magneto. Some cars with distributor had a hard time.
A distributor is one fix for a car with a bad magneto, but it won't make it run any better than it runs on coils if the coils are good.
You say you have all the parts for the magneto but it isn't installed. Has the magneto ring been rewound? If you are going to install the magneto, you need a good ring, and the original ones ALL of them have very fragile insulation from years of being oil soaked, and should be rewound or you might find that you would be wasting your time installing it. The magnets, likewise must not be cracked or you have possibility of throwing them and causing damage. The magnets should be re-charged and the clearance between flywheel and magneto ring correct.
The last paragraph is not intended to discourage you, but to instruct you so that your work will not be in vain. I have 3 Model T's and all 3 have good magnetos and run on coils. That is one of the fun things about a Model T.
Norm
If the timer is a roller type, pull it and check it inside. I bet you'll find a wavy, uneven raceway. This causes a high speed misfire as the roller bounces along. At lower speeds it is able to maintain contact better and you don't have the miss.
"The car runs on 12 volt battery only as the magneto isn't installed."
I don't know what I'm reading into your first entry. The above quote makes me think your figuring a magneto is something that gets bolted onto the car somewhere. Now don't get bent out of shape when I ask this but are you aware of where the magneto is and how it operates?
Sorry Royce, You are not giving John very helpful information....
He said that he doesn't have a mag installed on his car. I hope you don't disrespect him for That?
You know that simply using an etimer doesn't disable a working mag also.
Since he is running his car on battery only a T will perform great using the E Timer. It may be a great solution for him, of course Not for You.
John take my advice to you to get your beautiful car running great down the road.
Dan is correct but he left out the fact that you have to pull the engine out of the car to install a mag. You may not be ready for that now.
I'm betting RV is correct about your timer making your car not perform properly But,
In the mean time do check out the information about the E Timer by Mike Kossor. This will keep you car looking and sounding like a T is supposed to but More important you'll be driving it and loving it. Someone posted above that a T will not perform as well on 12V but this is Not the case with an E Timer. There are so many guys now that are using this trouble/maintenance free timer for many thousands of miles that someone in your situation should not over look this option.
Well, many times problems are simple things but we don't always go there first. This morning I removed the timer, wiped the inside of it clean with a nice clean rag, put the timer back on and did a test run of 10 miles or so. The car ran well this time through a wide range of speeds. While I really appreciate the helpful comments to help me fix my problem I think there are many who post here that have been at this hobby for many years and don't realize that some of us are new and we have to be "helped along" with our car challenges. I'm not sure where "respect" fits into the hobby, I just want my car to run well and to be as stock/original as possible when I can do that. Thanks again for your help. We're headed to College Station/Bryan, Texas tomorrow to join in the Texas T Party. Lookin' forward to our first one. Thanks again
Enjoy the drive John, Those are a great bunch of guys.