41 Woody Low Power

[bacelaw]

Hi all:  thanks to everyone here I have my 41 Woody stopping well with no brake leaks.   She starts immediately, runs smooth, but I have to floor the gas pedal up a moderate hill.  I'm not looking to drag race, and I get it - she's an 80 year old heavy wood vehicle. But I can't get her comfortably over 40mph without absolutely mashing the gas pedal, and hill climbing is the same.

 

Timing is at TDC.  Points are new.  Carb is new.  Gas is fresh. Compression test checks out okay.  

 

I won't be offended if the response is - that's normal.  Any thoughts?  Thank you!

[Dave72dt]

Couple of thoughts and neither may be applicable.   Clutch may be slipping or the brakes may be dragging a bit.  How free does it roll if you were to push it?

[bacelaw]

4 minutes ago, Dave72dt said:

Couple of thoughts and neither may be applicable.   Clutch may be slipping or the brakes may be dragging a bit.  How free does it roll if you were to push it?

It's not that easy to push... I've adjusted the rear brakes and the rear wheels spin in the air but not that freely.  I thought I had rear brakes adjusted well, but should they spin really easily with no brake drag at all?

[Dave72dt]

My thoughts are if you can hear them drag, it's too much.  Some of these other people who've spent a lot of time with these particular brakes can give you a better answer.  If they are new brakes, just installed, you're probably OK.  How about the front brakes?

[Bob Riding]

On 2/7/2023 at 6:43 PM, bacelaw said:

Hi all:  thanks to everyone here I have my 41 Woody stopping well with no brake leaks.   She starts immediately, runs smooth, but I have to floor the gas pedal up a moderate hill.  I'm not looking to drag race, and I get it - she's an 80 year old heavy wood vehicle. But I can't get her comfortably over 40mph without absolutely mashing the gas pedal, and hill climbing is the same.

 

Timing is at TDC.  Points are new.  Carb is new.  Gas is fresh. Compression test checks out okay.  

 

I won't be offended if the response is - that's normal.  Any thoughts?  Thank you!

Is it the stock motor? Stock Carter carb?

[FarmerJon]

Seems like you should have more power than that.

How is the exhaust? Could it be possible the muffler is plugging it up? 

Does your heat riser move correctly?

Have you checked that your throttle linkage is adjusted correctly, and pedal to the floor equals the carb butterfly being all the way open?

Does it have a vacuum advance on the distributor? If so, is it working? Check that it isn't leaking air, and that your points plate isn't seized.

Edited February 9, 2023 by FarmerJon

[Tom Skinner]

bacelaw,

All good advice above. First pump tires to max pressure allowed, try pushing her out of the garage she should roll, get a helper if need be. Wheels should turn by hand after brake work (raised up of course) with minimal drag. New Breakes will settle in after 10 -20 miles driving.

I like the Vacumm Advance check idea above, along with the Distributor Plate turning freely. Also I have found setting the timing about 5 - 6 Degrees advanced helps with the new gas octanes with ethanol. Originally gas back in the 1940's was about 76 octane not 87 octane, this may account for the reason our cars run better with the Timing advance a little more than usual. So say your Service Book calls for 2 Degrees BTC, then try 7 - 8 Degrees BTDC. That is the sweet spot for my 1948 Royal (250.6cu.).

Good Luck, let us know what you find.

Tom

[bacelaw]

Hi all:  this is really great stuff; the motor is stock, 55k miles or so.  Tomorrow I'm going to check all your suggestions.

 

I had no idea there was a heat riser between the manifolds - I'll check to make sure that functions.  

I'll use the minor adjustment bolts on all four brakes and make sure there's no drag at all on the shoes, and push her out of the garage.

I'll check the points plate, and also that I'm getting full throttle with the pedal - all great ideas.

I'll definitely advance the timing a bit more than TDC. 

 

How do I tell if I have an exhaust restriction in the muffler?  Other than smacking the muffler with a hammer, is there another way to determine if it's restricted? Vacuum gauge?

 

[Sam Buchanan]

The 218 in my '48 P15 runs great at 10* BTDC. The manual suggests advancing the timing until there is a little pinging under heavy load then retarding enough to eliminate the pinging. I've never tried this so don't know how close my timing is to the 'ping setting'. But the engine is very responsive at 10* on cheap gas.

[FarmerJon]

3 hours ago, bacelaw said:

 

How do I tell if I have an exhaust restriction in the muffler?  Other than smacking the muffler with a hammer, is there another way to determine if it's restricted? Vacuum gauge?

 

A vacuum gauge that you can see while driving is always helpful for tuning.

It won't tell you Whats wrong, but will certainly tell you IF something is wrong. It will also tell you if you make an improvement. 

As far as testing the exhaust: check your heat riser first!

I don't have anything close to stock under my Plymouth, so it is hard for me to say exactly,  but here are a couple things I have done on other vehicles:

What is the visual appearance of the muffler? Is it badly dented, rusty, swollen?

Is there a bolted flange between the exhaust manifold and the muffler? If so, you could unbolt the muffler from the down pipe, and take it for a drive with no muffler.. The vac gauge would be helpful here. If it feels like a real car again and you have noticeable increase in vacuum at most ranges, you have found your problem.

If you don't have a bolted flange before the muffler,testing gets a little more....complicated. If you don't have a welder, maybe talk to a muffler shop ( that deals with old cars) about how to diagnose, and cost of various operations...you could Sawzall the muffler off and have a muffler shop weld it back in if it isn't a problem. Or you could have the shop weld a "test pipe" in place of the muffler. 

There may be other, better ways but that would be my go to...well actually...

My go to would be to split the exhaust and run duals to steelpack Brockman Mellowtones out to pencil tips, regardless of if the stock muffler was good or bad... 

[Sniper]

3 hours ago, bacelaw said:

How do I tell if I have an exhaust restriction in the muffler?  Other than smacking the muffler with a hammer, is there another way to determine if it's restricted? Vacuum gauge?

 

https://www.onallcylinders.com/2016/03/31/vac-visual-quick-guide-vacuum-gauge-readings/

[bacelaw]

2 hours ago, Sniper said:

 

https://www.onallcylinders.com/2016/03/31/vac-visual-quick-guide-vacuum-gauge-readings/

 

I had a feeling vacuum gauge could show restricted exhaust.  Thanks everyone!  I have a full day to test all these issues and I'll report back.

 

[bacelaw]

Hey everyone:  I adjusted rear brakes, because they were dragging, and advanced the timing a few degrees before TDC - she now rolls better, and has much more pickup.  I think that was most of my low power issue...Once I added some advance, the vacuum test was steady at 18in. or so.  It didn't slowly creep down, so I don't think the muffler or exhaust is restricted. 

 

But, I did find that the heat riser is completely seized, probably in the closed position.  If I remove the carb, can that flapper be removed from above the exhaust manifold?  Or, do I need to buy a new manifold?

 

 

 

 

[Tom Skinner]

bacelaw,

The Flapper may be freed up with PB Blaster and the carb off. Remember a Temp sensitive Spring also belongs on the post as well.

If not removing the manifolds one may make repairs that way to it as well. The Gaskets for the manifolds cost in the $25 - $30 range.

Remeber to drain the anti - freeze first as some manifold bolts go into the water jacket. Also use sealer on those same bolts while re-installing to prevent leaks.

Good Luck trying to free it up with PB Blaster - you may very well suceed in this manner. The Spring should wind 3/4 of a turn upon installing to provide proper tension.

Good Luck!

Tom

[bacelaw]

45 minutes ago, Tom Skinner said:

bacelaw,

The Flapper may be freed up with PB Blaster and the carb off. Remember a Temp sensitive Spring also belongs on the post as well.

If not removing the manifolds one may make repairs that way to it as well. The Gaskets for the manifolds cost in the $25 - $30 range.

Remeber to drain the anti - freeze first as some manifold bolts go into the water jacket. Also use sealer on those same bolts while re-installing to prevent leaks.

Good Luck trying to free it up with PB Blaster - you may very well suceed in this manner. The Spring should wind 3/4 of a turn upon installing to provide proper tension.

Good Luck!

Tom

Thanks Tom.  I don't ever plan on driving the wagon in cold weather, so I'm not concerned with the flapper being functional. I just don't want it to restrict the exhaust flow... I'll try to work it free with the carb removed.  

[Bryan G]

I've found you can dial in quite a bit of timing advance on these engines. Even regular grade gas is higher octane than these engines were designed for. I tried cranking my distributor as far as it would go and it finally had some spark knock under moderate acceleration. 

[capt den]

one question. if you advance the timing how will it affect engine temp under normal operation. i was told that more advance equals hotter engine temps.  bacelaw can get a new vac advance unit on ebay. not too expensive. maybe even at the parts store. i got mine on ebay, it came from turkey. apparently chrysler had some operations there at one time. new brakes when adjusted should have a very slight drag, which as stated here will go away after 10 to 20 miles of driving. i welded my heat riser to allow free flow of the exhaust gas. personally i think the heat riser is one of the stupidest things i have ever seen on a car. i know---- carb icing. i have never experienced that.anyway, they always rust shut, so maybe they just should be made of higher quality components.     capt den

[FarmerJon]

I have always found good results with bumping up initial ignition timing, in both flatheads, pushrod OHV engines, and OHC engines (the good '80s ones that you could still adjust). The reward is always a more responsive engine and an increase in fuel economy. 

I have never seen over heating problems that weren't caused by typical cooling system flaws, or plugged emission equipment. If the system is healthy, it won't make a difference in temp.

Maybe exhaust gas is hotter, idk, it has never mattered to me. 

OP- does your distributor have a vacuum advance canister?

If so, did you check it for leaks and for free movement of the plate?

I am glad you are making progress. Hopefully getting the exhaust riser freed up or removed will make another big difference. 

 

[Sam Buchanan]

18 hours ago, bacelaw said:

Hey everyone:  I adjusted rear brakes, because they were dragging, and advanced the timing a few degrees before TDC - she now rolls better, and has much more pickup.  I think that was most of my low power issue...Once I added some advance, the vacuum test was steady at 18in. or so.  It didn't slowly creep down, so I don't think the muffler or exhaust is restricted. 

 

But, I did find that the heat riser is completely seized, probably in the closed position.  If I remove the carb, can that flapper be removed from above the exhaust manifold?  Or, do I need to buy a new manifold?

 

 

 

 

 

It's just a matter of semantics but a "closed" heat control valve is a good thing, that allows exhaust to exit directly through the manifold. An open flapper directs exhaust up through the intake manifold. I doubt you can access the flapper through the carb port but if it is free to rotate you can wire it closed from outside the manifold. By the way, the purpose of the heat control is for atomizing fuel when cold for smoother running, not to prevent formation of ice.