Doesn't take high RPM... Need your advice.

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Model T Ford Forum: Forum 2017: Doesn't take high RPM... Need your advice.
Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Gotesman, Tula, RUS on Friday, October 13, 2017 - 01:29 am:

This issue appeared last year. Ford just refused to run more than 50 kmph: opening throttle had no effect. Now this problem became hard: the engine runs good on idle, but doesn't take high RPM. Increasing the throttle lever causes the hissing, vibration and conks (like one or two cylinders missing). It runs on the low gear, but it is almost impossible to take a speed to shift to the high gear.

We replaced the intake manifold, rebuilt the carburetor, checked coils (replaced the capacitor in one of them). Now the engine starts well and runs perfect on idle.

The compression ratio is about 2 ati (30psi) in each cylinder. It is low, but I don't think it's a reason.

Thank You for Your opinions!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Gotesman, Tula, RUS on Friday, October 13, 2017 - 01:36 am:

+ I don't use the magneto (it doesn't work): the car starts and runs with the battery


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Gotesman, Tula, RUS on Friday, October 13, 2017 - 01:53 am:

+ It is enough fuel - and it goes good from the carbureator inlet pipe


Top of pagePrevious messageNext messageBottom of page Link to this message  By Macky Mongold on Friday, October 13, 2017 - 02:05 am:

Could the valve spring pressure be so weak that the valves float at higher rpm?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Friday, October 13, 2017 - 04:31 am:

Are you getting full travel of the timer when you advance the timing?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Gotesman, Tula, RUS on Friday, October 13, 2017 - 04:36 am:

Hal, yes. It turns properly


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Friday, October 13, 2017 - 05:59 am:

What type of timer do you have?
If it's a roller timer like the one provided by Ford it may have worn an uneven surface where the roller runs, making it loose contact intermittently as the rpm increases. Usually they can be ground or turned oversize in a lathe, but it's important the roller and its pin is good too. Roller timers needs frequent cleaning and lubrication.

There are several alternative timers produced, like the TW, Anco, New Day and the recent addition, the Ideal timer.




(Message edited by Roger K on October 13, 2017)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker, Oklahoma City on Friday, October 13, 2017 - 08:07 am:

Have you had your coils fully rebuilt (new points, tested on an HCCT, ECCT, or Strobospark)? You can adjust the coils yourself and get the motor to run, but they will never run as well as properly adjusted ones.

I do agree it could be a valve spring problem too.

Have you tried tweaking the mixture at higher RPMs. Some Ts like the mixture played with a lot. For others, you can just set it and never touch it again.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Friday, October 13, 2017 - 08:21 am:

Sounds like a bad timer.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker, Oklahoma City on Friday, October 13, 2017 - 08:53 am:

Bad timer could definitely be it.

If you're using a roller timer and the ring inside isn't true and round, and/or is dirty, the roller can bounce around not make good contact.

Many other types of timer are subject to similar problems. Andersons can do if they have weak flapper springs. New Day timers can run badly if they don't have a good surface, have bad brushes, or are dirty (The older repro "S" timers are famous for not lasting) Pretty much every other aftermarket timer available back in the day could suffer from similar problems.

Perhaps you should take apart your timer and post pictures of both the rotor and the inside of the case here?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Gotesman, Tula, RUS on Friday, October 13, 2017 - 08:57 am:

Roger, I'm not sure about the type of timer. It is clean inside and seems like ok.

Cameron, for sure not: we just replaced the capacitors in 3 coils (from 2010) - we have no test equipment here in Russia.

Will valve spring problem cause the compression ratio 0?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Friday, October 13, 2017 - 09:01 am:

Michael,

Clean is good, but that doesn't mean it isn't worn out. Do you have another you could try as a test?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Gotesman, Tula, RUS on Friday, October 13, 2017 - 09:07 am:

Jerry, not, unfortunately. How to check it?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Gotesman, Tula, RUS on Friday, October 13, 2017 - 09:27 am:

Seems like I have Anderson flapper style timer.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Friday, October 13, 2017 - 12:15 pm:

Sounds like it could be spark plugs or possible spark jump somewhere in the coil box or coils. With the throttle open your compression at the cylinder is higher when the engine is pulling hard. A spark takes the least resistance to ground and with higher compression it has a harder time jumping the gap in the spark plugs and jumps to ground some place else. Try re-gapping the plugs to 25 thousandths. Preferably with new plugs. If that doesn't help, try starting the engine in the dark and look for sparks around the coil box.
You have a difficult problem to solve. Could be either electrical or fuel related.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nevada Bob Middleton on Saturday, October 14, 2017 - 04:11 pm:

I agree bad timer first place
Next valve springs
Are valves loose in the guides


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Deichmann, Blistrup, Denmark on Saturday, October 14, 2017 - 04:24 pm:

Interesting noone have commented on that you run on battery. 6 volts I presume? The coils does not saturate at 6 volts at the short time it have at higher revs, so it starts failing.
You may get a little better at proper adjusted coils but running om magnets will always be better.
The magnets may have lost the magnetism over the years. An in-situ remagnetising can make it work again. If you have an analog AC voltmeter see if yoy get just a little voltage (a couple of volts at higher revs). If you do - it may be salvagable.


Top of pagePrevious messageNext messageBottom of page Link to this message  By dale w on Saturday, October 14, 2017 - 05:30 pm:

The timer and ignition suggestions are dead on, but if they dont cure your problem, try this:

Make sure your engine can breathe.

An engine that will run fine at idle but stumble at higher RPM may have a problem pushing out it's exhaust gases to make way for a new intake charge.

See if some critters havent made a nest in your muffler or pipes restricting the flow of the exhaust gasses.

Its a simple, but overlooked solution to vehicles that sit in storage for a long time. The best part is it doesnt cost anything but your time to test it.
Take the exhaust off and try it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Eddie on Saturday, October 14, 2017 - 05:50 pm:

Sounds like timer issue.....I had the same symptoms with a new Anderson timer. I replaced it with a TW timer...huge improvement.
I suggest getting your coils adjusted by Ron Patterson or one of the other coil masters.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Doolittle on Saturday, October 14, 2017 - 10:13 pm:

I wouldn't be so sure that there is no problem. All of my cars run great on magneto. On the times that I forget to turn the switch from batt to mag, I get a reminder (slight stutter & lack of power) and these signs go away when switched to magneto.


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