I can't drive 55

What do you think the issue is?

  • Fuel Delivery

    Votes: 2 8.3%

  • Carburetor

    Votes: 11 45.8%

  • Vacuum Leak

    Votes: 1 4.2%

  • Transmission/Transfer Case

    Votes: 3 12.5%

  • Ignition Timing

    Votes: 2 8.3%

  • Clutch

    Votes: 0 0.0%

  • Other

    Votes: 5 20.8%
  • Total voters
    24
  • Poll closed .

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Good morning @MatthewMcD …

Just read thru the evenings posts. By elimination, both carbs do the same thing so that’s out. I like the timing advance suggestions. My DUI was properly set according to the book. The truck was running good but always sluggish. After the Holley Sniper, I was playing with that new timing light you have and discovered that I had flexibility in advancing the timing far beyond what the factory service manual dictates. And by bringing up the timing from seven to around 11° the truck woke up not that it wouldn’t do 55 or 60 prior, but it did take moments to get there, after advancing the timing, the truck just had a lot more get up and go instantaneous pep and almost makes the hyper spark seem like it performs no differently than the DUI did. Of course I know it has loads of potential I have not tapped into yet

Beyond a failing ignition, the only other option I think…. is somewhere in the gearboxes and it’s not so easy to just adjust it. i’m afraid the only option there is to pull them and physically inspect them and I know that is an awful lot of work. I’m sorry to say, but also as mentioned earlier, I am amazed and energized by your persistence and I know you will get this solved. Just sorry to see you are putting so much energy into it without a solution that seems obvious.

@RevISK you're a great friend going the extra miles to see this thru. I wish everyone so involved an immediate success.
 
Grayscale said:
It looks like one of those reconditioned heads from SOR with that enamel-like orange. There is little deposits on the rocker arms. The engine looks worked, recently.
Click to expand...
The red paint is called Glyptol.
 
knuckle47 said:
Good morning @MatthewMcD …

Just read thru the evenings posts. By elimination, both carbs do the same thing so that’s out. I like the timing advance suggestions. My DUI was properly set according to the book. The truck was running good but always sluggish. After the Holley Sniper, I was playing with that new timing light you have and discovered that I had flexibility in advancing the timing far beyond what the factory service manual dictates. And by bringing up the timing from seven to around 11° the truck woke up not that it wouldn’t do 55 or 60 prior, but it did take moments to get there, after advancing the timing, the truck just had a lot more get up and go instantaneous pep and almost makes the hyper spark seem like it performs no differently than the DUI did. Of course I know it has loads of potential I have not tapped into yet

Beyond a failing ignition, the only other option I think…. is somewhere in the gearboxes and it’s not so easy to just adjust it. i’m afraid the only option there is to pull them and physically inspect them and I know that is an awful lot of work. I’m sorry to say, but also as mentioned earlier, I am amazed and energized by your persistence and I know you will get this solved. Just sorry to see you are putting so much energy into it without a solution that seems obvious.

@RevISK you're a great friend going the extra miles to see this thru. I wish everyone so involved an immediate success.
Click to expand...
I plan to spend time today dialing in the timing, I'll try "turning it up to 11"... :)

It has always "felt" like it was the gearbox. I have always assumed that I'd need a new clutch, I know it's a lot of work, but I have done two Toyota clutches in the past, so I know what I am in for. It will also give me a change to detail the shift sequence and inspect the transfer case.

Has anyone detailed the gear rotations in 1-4 and Hi and Lo ratio? Thinking turning it by hand and counting revolutions.
 
Do you know what gear ratio the axle is?
After you test drive In “high range”,have you stopped and put it in low range and give it a test drive and confirm the reduction of gears?
 
MatthewMcD said:
I have shifted it from Hi to Low and back several times.
Click to expand...
Could you tell a distinct difference in ratio though?🤔 Low should feel like you’re driving a tractor with lots of torque. Like you said, are gears engaging correctly?

Maybe hold third gear to 3000 rpm before shifting into 4th. 🤔

My 1963 40 with 1F, 1 barrel aisin carb. 4.11gears and 3 speed tranny will take awhile to reach 60 mph, but it will. Makes me wanna take it out and document #s.

I admire your tenacity! 👍
 
Matt I'm almost thinking you might want to work from the wheels back to the drivetrain and leave the big stuff for last. It would really suck to pull a tranny, inspect and find nothing, install a new clutch and get it back together and still be here. My original clutch lasted decades and I've done nothing to my gear box and xfer case since acquiring my 40 in '85. I'm almost wondering if it could be wheel bearings, dragging brakes, front hubs that don't unlock and who knows what else that puts enough load on the drive train where it maxes out in the 4th 1:1 gear where it does? All that kind of stuff may need attention/maintenance anyway, and its easier to work through before you are dropping your tranny and xfer case.

If it turns out to be the tranny, you can find a good used 4 speed box cheaper and easier than cracking and rebuilding yours. Just my thoughts this morning...
 
MatthewMcD said:
Clutch inspection has been on my list for a year. It feels very solid but I need to see it. I opened the inspection cover for the first time and was shocked that there were no wasps or remnants of ratatouille. The interior of the bell housing is dry, the pan has some oil and I found this clip laying in the gunk.
View attachment 3748382

Pressing the clutch pedal exposed a hairline separation in the friction material.
View attachment 3748390

Is this a Napa item? Looks like I'll be dropping the tranny after I get the new carb installed.
Click to expand...
For friction material separation, are you talking about the gap between the plates (circled in blue below). If so, I’m pretty sure that’s just the normal gap where each side (clutch side and pressure plate side) are riveted to the metal in the clutch disc.

I also think if you were having clutch slippage problems, you’d notice it in the highest power/most resistance portion of driving, which I’d assume to be starting out and 1st and 2nd gears or especially in 4low. When I’ve experienced clutch slippage, rpm goes up and speed goes down, doesn’t stay stagnant.

IMG_7725.jpeg
 
Remove the rear drive shaft and lock in the hubs shift to 4H and go for a test drive. Then reinstall rear drive shaft and remove the front drive shaft and unlock hubs and shift to 2H and test drive
 
Skreddy said:
For friction material separation, are you talking about the gap between the plates (circled in blue below). If so, I’m pretty sure that’s just the normal gap where each side (clutch side and pressure plate side) are riveted to the metal in the clutch disc.

I also think if you were having clutch slippage problems, you’d notice it in the highest power/most resistance portion of driving, which I’d assume to be starting out and 1st and 2nd gears or especially in 4low. When I’ve experienced clutch slippage, rpm goes up and speed goes down, doesn’t stay stagnant.

View attachment 3749539
Click to expand...
Interesting, I thought the plate on the left pushed all that material into the flywheel. I didn't know there were two layers.

Thanks!
 
MatthewMcD said:
Interesting, I thought the plate on the left pushed all that material into the flywheel. I didn't know there were two layers.

Thanks!
Click to expand...
One friction face grabs the plate on the left while the other friction face grabs the flywheel on right.
 
1st law of thermodynamics suggests that it's neither gearbox nor clutch (I'd think you'd notice something getting hot enough to account for the missing energy).
This suggests that you're not making the power in the first place (fuel, ignition, valve clearances, blocked exhaust etc etc).
Rotating the dizzy by a few degrees is a 2 min test.
I put a brand new fuel filter in my bike and it got immediately wet from a dribble of water in the tank (blocked immediately).
 
45Dougal said:
1st law of thermodynamics suggests that it's neither gearbox nor clutch (I'd think you'd notice something getting hot enough to account for the missing energy).
This suggests that you're not making the power in the first place (fuel, ignition, valve clearances, blocked exhaust etc etc).
Rotating the dizzy by a few degrees is a 2 min test.
I put a brand new fuel filter in my bike and it got immediately wet from a dribble of water in the tank (blocked immediately).
Click to expand...
I'll advance the timing this afternoon.
 
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