What have you done to your Land Cruiser this week? (17 Viewers)

[pb4ugo]

I have no idea. How can I determine that?

My question was intended for @wchevron. If he's running a stk driveline then his numbers don't add up.

Matthew, how are you determining your speed? What size are your tires. Do you have a tach? It seems something is restricting your RPM or power.
Timing, Mechanical advance, valve adjustment, vacuum leak or maybe the carb. Suck on the vacuum canister hose and see if the canister holds vacuum. If you can suck air then its bad.

 

[Pitter Patter]

I have no idea. How can I determine that?

Put one tire in the air. Mark it and slowly rotate it one time around. Have another person under the rig counting how many revolutions of the driveshaft.

 

[MatthewMcD]

My question was intended for @wchevron. If he's running a stk driveline then his numbers don't add up.

Matthew, how are you determining your speed? What size are your tires. Do you have a tach? It seems something is restricting your RPM or power.
Timing, Mechanical advance, valve adjustment, vacuum leak or maybe the carb. Suck on the vacuum canister hose and see if the canister holds vacuum. If you can suck air then its bad.

Thanks, I'll test this.

Put one tire in the air. Mark it and slowly rotate it one time around. Have another person under the rig counting how many revolutions of the driveshaft.

I assume this is the rear tires. I'll check this too.

I don't have a tach, but I could rig up my shop tach for a test drive.

@pb4ugo " vacuum canister hose" do you mean the brake booster? That is the only thing on this truck connected to vacuum aside from the distributor.

 

[mef0629]

Thank you, they are always a work in progress!!


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That color combo rocks! I don't take the top off because I don't have anywhere to store it. Not too mention I need help...

 

[wchevron]

Are you running 4.88:1 gears in your di

My question was intended for @wchevron. If he's running a stk driveline then his numbers don't add up.

Matthew, how are you determining your speed? What size are your tires. Do you have a tach? It seems something is restricting your RPM or power.
Timing, Mechanical advance, valve adjustment, vacuum leak or maybe the carb. Suck on the vacuum canister hose and see if the canister holds vacuum. If you can suck air then its bad.

Truck is a 1977 4 speed with 2F. Tires are 33x10.5x15 BF Goodrich KO2 all terrain. At some point the engine and transmission were replaced. I'm assuming it's a stock transmission but not positive. Saw a note in the folder of paperwork I got when I bought it that both has been replaced. Speedo bounces back and forth until 40 mph then smooths out after 40. (Planning on pulling it this winter and greasing it up to hopefully stop the bouncing) On the highway, typically the speedo is reading about 50mph-ish and the tach is between 2700 and 3000 rpm. Have a speedo app on my phone. When the speedo is reading 50ish the app is saying 60 so somewhere between 8-10 mph off.
Was searching the max rpm I should be running and found an older thread, the general consensus seemed to be 3600 was a safe max rpm. Was out earlier, the tach was about 3300 rpm and the speedo was at the 60mph mark.

 

[pb4ugo]

Truck is a 1977 4 speed with 2F. Tires are 33x10.5x15 BF Goodrich KO2 all terrain. At some point the engine and transmission were replaced. I'm assuming it's a stock transmission but not positive. Saw a note in the folder of paperwork I got when I bought it that both has been replaced. Speedo bounces back and forth until 40 mph then smooths out after 40. (Planning on pulling it this winter and greasing it up to hopefully stop the bouncing) On the highway, typically the speedo is reading about 50mph-ish and the tach is between 2700 and 3000 rpm. Have a speedo app on my phone. When the speedo is reading 50ish the app is saying 60 so somewhere between 8-10 mph off.
Was searching the max rpm I should be running and found an older thread, the general consensus seemed to be 3600 was a safe max rpm. Was out earlier, the tach was about 3300 rpm and the speedo was at the 60mph mark.

You can find RPM calculators on the web. If you have a stk 4 speed the final drive ratio is 1:1 in 4th gear, stk diffs are 4.11:1 pre 79 and 3.70:1 on later 40's. If you measure advertised 33" tall tires you will find they are actually smaller. Lets figure they are 32". If you enter these numbers into a calculator you will find your RPM's are going to be closer to 2600 using 4.11 diff gears, 32" tires, and going 60 mph, if they are 3.70:1 gears then the RPM's will be less. A slightly smaller tire will increase rpm's slightly.

 

[wchevron]

You can find RPM calculators on the web. If you have a stk 4 speed the final drive ratio is 1:1 in 4th gear, stk diffs are 4.11:1 pre 79 and 3.70:1 on later 40's. If you measure advertised 33" tall tires you will find they are actually smaller. Lets figure they are 32". If you enter these numbers into a calculator you will find your RPM's are going to be closer to 2600 using 4.11 diff gears, 32" tires, and going 60 mph, if they are 3.70:1 gears then the RPM's will be less. A slightly smaller tire will increase rpm's slightly.

Thanks. I'll pay more attention to the rpm and speed on the way home and see where I'm coming out at on the calculator.

 

[mrboatman]

Thanks. I'll pay more attention to the rpm and speed on the way home and see where I'm coming out at on the calculator.

I’m running a 84 2F in a 69 40 with the same tire and at 3000 rpm (on a tach) I’m running 70 ( gps ). I also have a H41 4 speed which doesn’t matter still 1 to 1 ratio in 4th gear. With the old F engine 2 pistons with small holes in them I could still do 70 at 3000 rpm it would just smoke you out with blow by.

 

[Chilkoot]

Put one tire in the air. Mark it and slowly rotate it one time around. Have another person under the rig counting how many revolutions of the driveshaft.

Is the ratio of the driveshaft spinning to one wheel revolution indicative of the gearing? IE 3.7 vs 4.8 spins on the driveshaft to one revolution of the wheel?

 

[wchevron]

I’m running a 84 2F in a 69 40 with the same tire and at 3000 rpm (on a tach) I’m running 70 ( gps ). I also have a H41 4 speed which doesn’t matter still 1 to 1 ratio in 4th gear. With the old F engine 2 pistons with small holes in them I could still do 70 at 3000 rpm it would just smoke you out with blow by.

Just drove home. At 2600 rpm I'm about 58-59mph on the gps on a fairly flat highway. At 3000 I'm between 63-64. Speedo is reading about 10 mph low. Measured the tires, 31.5". Based on the calcuator I'm about 200-250 rpm high.

 

[pb4ugo]

If your speedo is bouncing, it'll be a good idea to grease it.

 

[wchevron]

If your speedo is bouncing, it'll be a good idea to grease it.

That's on the winter project list

 

[MatthewMcD]

My question was intended for @wchevron. If he's running a stk driveline then his numbers don't add up.

Matthew, how are you determining your speed? What size are your tires. Do you have a tach? It seems something is restricting your RPM or power.
Timing, Mechanical advance, valve adjustment, vacuum leak or maybe the carb. Suck on the vacuum canister hose and see if the canister holds vacuum. If you can suck air then its bad.

I decided to create a separate thread for this discussion.

I can't drive 55

I moved this to a separate thread to apply some focus. My original question is, why is my top speed in 4th gear ~45-48 mph? Background: 5/75 chassis with an estimated 68-70 F (PO said .5F but others have doubted that). 4 Speed transmission 32" tires Vacuum advance on the distributor appears...

forum.ih8mud.com

 

[fireflyr]

I have no idea. How can I determine that?

With the 4:10 gears, 4 speed and 33’s I was running 3000 at 60. With the overdrive 4L60e I’m at 2100 at 65. Same tires.

Got the top set back on. What a pain in the arse to do it solo. Now I remember why I bought that top from Pakistan. Anyone heard from Eshan in the last 10 years? I loved that green canvas top.

Think that’s it for the week.

 

[fj40fillet]

Out and about getting parts. Construction on the back roads made it an offroad experience.
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Current top speed is about 48mph. Not a problem in Austin traffic, but I am curious what I should expect with a 4 speed transmission and an older engine. I have a replacement 2F on the way.
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My 79 with the 4 speed easily does 65 on the highways. It was scary at that speed until I replaced all the tie-rod ends. Now it's tight and steering control is as it should be like a new car.

 

[ryanwk628]

Yes, many of the distributors for these engines vacuum retard. I converted to a vac advance distributor.

I did the same when I went to a later style carb. I capped the vac advancer (retarder?) on the dizy and ran it on mechanical advance only until I got a DUI which I am now running off ported vac on the carb. Mechanical advance was fine at revs on flat roads, but was wanting when under load like steep hills.

 

[Goldbug]

Thank you, they are always a work in progress!!


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Can I ask where the sliders came from? Both the ones below the side steps and on the back corners? I'd like to do something similar for my infrequent, but impactful, wheeling trips.

 

[wchevron]

My 79 with the 4 speed easily does 65 on the highways. It was scary at that speed until I replaced all the tie-rod ends. Now it's tight and steering control is as it should be like a new car.

I was surprised how much my steering improved once I got the zerk fittings working and got some grease in the tie rods.

 

[Chuckha62]

That's on the winter project list

Be careful "greasing" a speedo. Ideally, your speedo should be clean, dry and debris free, then "lube" it with powdered graphite.

 

[wchevron]

Got the green led lights installed in the cluster and tach.