Engine down of pulling power - need ideas

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Model T Ford Forum: Forum 2012: Engine down of pulling power - need ideas
Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Bowker on Friday, November 09, 2012 - 02:02 pm:

For the past year the engine in my 1914 touring (which is actually a 1922 dated motor) has lacked pulling power on hills. I revs fine but once down to about 25 mph in top, the power drops and the speed falls rapidly.
I have checked the timing, about 11 degrees BTDC and now the compression, about 70 pounds on all four cylinders, it has a Z head. I have checked the valve timing and seems to be correct with the exhaust just closing and the intake opening at just about TDC on the none-power stroke.
The speedster has essentially the same motor and pulls all the way down to 15 mph.
What am I missing?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill dugger on Friday, November 09, 2012 - 02:21 pm:

TonY:
When I set my timing on my '17 and my '19 I set it to fire just past TDC. 11 BTDC sounds to early. See what some of the other guys say. Setting it at 11 would cause a heating, kicking back when you try to start it. On a fully retarded timing it could break your arm if it kicked back. Try resetting the timing and try it and see what happens. Cannot hurt anything.
Good luck and Happy T'ing.
Bill D


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Sosnoski on Friday, November 09, 2012 - 07:05 pm:

The timing should be set to 15 degrees AFTER TDC with the spark lever all the way up. I would start by resetting the timing and see how it runs.

Dave S.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Bowker on Friday, November 09, 2012 - 08:53 pm:

When I said 11 degrees BTC I meant with the timing lever down, with it up it is timed a little after TDC.
I rather suspect I have the camshaft gear one tooth off. To verify I looked in the on-line Encyclopedia and checked the valve opening, however I'm not sure I understand the timing instructions which read:

VALVE TIMING
(Revised during 1912, and typical through 1927)
Intake opened with piston down 1/16" After T.D.C. (1/4" above) *
Intake closed with piston up 9/16" After B.D.C. (3-1/8" below) *
Exhaust opened with piston up 5/16" Before B.D.C. (3-3/8" below) *
Exhaust closed with piston at T.D.C. (5/16" below) *
* Piston position from top of cylinder.

When they say piston down 1/16 After TDC (1/4 above, just what are they refering to on the measurement. Is it piston position from the exact TDC or from the top of the block.
Then is the exhaust closing at TDC 5/16 below. That doesn't make sense, its either at TDC or 5/16 below TDC
Can any experts help with a better explaination?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Friday, November 09, 2012 - 09:55 pm:

Tony, When you find out what was causing the problem, please post. I have a similar problem with the 26 touring. Both roadsters pull much better. It might not be the engine though, because the touring is a heavier body and it also has bumpers. You and Justin rode in it the day we went to the Lions, Tigers, Bears. Remember the hills I went up in Low low? Once the car gets to moving about 25 or 30 it moves right along, but when shifting from low to high it is very slow in high.
Norm
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Saturday, November 10, 2012 - 02:22 am:

Tony,
In "Intake opened with piston down 1/16" After T.D.C. (1/4" above)" the 1/4" measurement is from the top of the block to the top of the piston. At TDC the piston is 5/16" above the block.

In "Exhaust closed with piston at T.D.C. (5/16" below)" the "below" is clearly a typo. It should be "above" and that would calculate correctly with all the other measurements as well as with other descriptions of valve timing on this forum.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Richard Bennett on Saturday, November 10, 2012 - 02:34 am:

Tony, I am a little puzzled. You say 'for the past year'. Has the pulling power changed in this time? If you have not re-timed your timing gears for some reason, they will not be in a different mesh, and thus will not throw the timing out.

Your symptoms are a little like the effect fitting 3:1 gear set in the diff wil have. The car will run well when able to rev but will not lug under low revs as it tries to push taller gears.

If you have change neither the timing gears or diff ratio, then you need to look elsewhere.

Hope this helps.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By William Rowles on Saturday, November 10, 2012 - 04:12 am:

As speed decreases going uphill you should retard timing for best power.....are you doing that? If not try that to see if it helps.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill Robinson Salty Bottom, AL on Saturday, November 10, 2012 - 07:07 am:

Norm, I had the exact problem in the summer of '11. Come to a slight hill, have go to Ruckstell, then to Ford low, just to get to the top.

This summer I fixed it. This is what I found.

The 2 pins on the camshaft had "wallered" themselves to a point that they were no longer extending at 90 degrees to the camshaft. The pins were actually angled to almost 45 degrees and the gear and shaft were still tight.

This angling allowed the fiber timing gear to rotate on the shaft which greatly retarded the timing.

A new cam and a new gear and she pulls hard, again.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill Robinson Salty Bottom, AL on Saturday, November 10, 2012 - 07:18 am:

or.....was it advanced?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Saturday, November 10, 2012 - 09:25 am:

You have more than 1 T so I'm assuming you have quite a bit of driving experience especially involving spark lever setting. Your compression is, frankly, better that most I've seen posted here and you've checked timing and such. If all that's OK how about fuel delivery? As some one posted earlier: is this a new development?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd on Saturday, November 10, 2012 - 11:30 am:

Worn camshaft?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Bowker on Saturday, November 10, 2012 - 09:35 pm:

I did remove the motor earlier in the year to add the Texas T oiling system, big vanes and a large tube. I don't remember the pulling problem prior to the motor work and even though I don't remember re-timing the camshaft, however my memory is not as good as I remember, I may well have made adjustments to the main bearings and lost the timing. The problem now is that I have a proper oil seal on the crankshaft and it is not easy to remove the front cover plate without removing the crankcase. This was the reason to more clearly understand the timing by looking at the valves. If there is a typo, then I think I understand, I'll have another attempt when I have completed a few more honey doos....


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