Coupe not pulling hills like before

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Model T Ford Forum: Forum 2017: Coupe not pulling hills like before
Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew Atchinson on Thursday, June 22, 2017 - 04:24 pm:

The other post on hill pulling reminded me of this question I had. Sunday I took a drive with my grandfather in the 26 Coupe. On the way there it pulled every single hill out here in 2nd, no problem. On the way back we heard a "clang" pulled over, nothing fell off or appears to have broken, but the cap of the muffler is currently detached from the rest of the unit so we figured that was the noise of the exhaust pipe moving some. It got real sluggish on the hills after that and I had to switch to low band a lot. Things that changed: 1) I tightened the bands up some when we stopped before turning around. 2) The cap part of the muffler popped off again (loose exhaust pipe, planning to fix the whole unit when I replace the exhaust manifold). 3) I do have a slight exhaust leak on no. 1 cylinder but it's not bad (again, replacing the whole manifold soon). 4) I noticed a large amount of water vapor build up on the intake when we stopped, it was very humid out and about 82 degrees. Any ideas why it's not pulling the hills in second like before? Would any of the above factors cause that?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Thursday, June 22, 2017 - 04:56 pm:

The only thing I see is the bands - maybe you tightened them a little too much?

Regarding the water vapor (I assume you mean condensation?), are you running a factory hot air pipe into the carb?

Without a hot air pipe, condensation can form on the outside (and inside the air passage) of the carb during humid conditions. Not a problem unless it starts turning into ice! :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew Atchinson on Thursday, June 22, 2017 - 04:58 pm:

The hot air pipe is off as that's how it was when I bought it. I do have a couple of them laying around though and have been considering adding one to the motor. The bands probably are the likely culprit. they are worn and need changing. Honestly the only reason I drove it Sunday was my grandfather hadn't ridden in it yet and really he really wanted to make a local show. The new kevlars are in the trunk haha. I've never done a band change with a completed motor so will likely be seeking advice and help.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bruce Compton on Thursday, June 22, 2017 - 07:48 pm:

I've experienced a similar situation after blowing a muffler on my '36 coupe. I'm guessing that the extra exhaust noise makes it seem like the engine is working harder than before the muffler came apart. Besides, tightening the bands shouldn't make the car less sluggish and a restriction free exhaust (no muffler) should in theory increase power. Keep us informed. Cheers : Bruce


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew Atchinson on Thursday, June 22, 2017 - 07:55 pm:

It's definitely weaker. I'm almost stalling out and having to switch to low on hills I was pulling the whole way before. Not just pulling, but usually doing a healthy 15mph or so on fairly big hills. I'm wondering if maybe the muffler hanging down is perhaps obstructing the actual exhaust pipe some. I failed to mention the muffler is still on, just drooping since it's not beign held firm/straight by the lid that bolts to the frame.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chad Marchees _____Tax Capital, NY on Thursday, June 22, 2017 - 08:02 pm:

I think I would start with the hot air pipe.

But to further that, I wonder if you took it out right now if it would "seem" like it regained the power (being the condonsation / possible frosting of the intake is gone).

Henry put them there for a reason.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, June 22, 2017 - 09:07 pm:

Were the hills on the way back steeper than the hills on the way out? If not, have you driven this route before with a passenger? I can tell the difference in hill climbing with one, two, or three passengers.

I would suspect the bands are too tight. Sometimes you can even have a loose pedal with the bands too tight if the cams are worn. If that is the case re-lining the bands won't help unless you repair the problem. Be especially careful not to have the bands too tight if you are using Kevlar.

An easy way to tell if it is too tight is with the engine warmed up put the car in neutral. It should not move forward or reverse in neutral. You can also try putting the parking brake in the neutral position on a level surface with the engine off and push the car. The engine should not turn. Then turn the crank while in neutral, the car should not move. When you push the low pedal it should move about an inch into the neutral position without clamping the band. Then as you push it farther the shaft will move to the right until you clamp the band. at that point the pedal should be about 1" to 1 1/2" above the floor. If you have worn cams, the shaft will not begin to move to the right until it is almost to the floor.

The reverse and brake work the same way except the shaft moves to the left to clamp the bands. They too can have worn cams.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dick Fischer - Arroyo Grande, CA on Thursday, June 22, 2017 - 09:20 pm:

Chad may be onto something.

You mentioned high humidity and condensation on the intake pipe. If it was cold enough to make condensation on the outside of the pipe, then it was probably cold enough to make frost or ice in the carburetor venturi. Venturi ice restricts the flow of fuel/air into the engine and can cause a significant loss in power.

I have experienced enough of a power loss on takeoff in a light airplane to warrant aborting the takeoff.


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