Project 1977 F100 - New radiator + electric fan!

[bobo333]

They are SB acoustics SB29RDCN tweeters 5k+ @12db/oct and Tang band W4-1320SJF mids 150-5k @12db/oct, actively crossed and powered by the Alpine CDA-9887 head unit

[JRMichler]

Originally Posted by bobo333

sits on around 4000rpm at 100kmh (65mph?) my tacho is a bit dodgy and waves between 3500 and 4500 so im not 100% sure on the RPM but it sounds like its doing pretty close to 4k

Does that truck have a mechanical cable drive tach? Older tachs were driven by a flex cable coming from the transmission. The needle bounces when the cable needs to be greased. If it does not get greased, the cable breaks.

All the aero mods in the world will not help mileage if you are turning 4000 RPM.

[bobo333]

Does that truck have a mechanical cable drive tach? Older tachs were driven by a flex cable coming from the transmission. The needle bounces when the cable needs to be greased. If it does not get greased, the cable breaks.

All the aero mods in the world will not help mileage if you are turning 4000 RPM.

Nope it has an aftermarket electronic one, 1 wire to the coil, positive and negative to battery and thats it, it was pretty cheap though, i will get a new one when i have spare funds.

New gearing is defiantly high on my list of things to do, but i cant afford a new diff center or gearbox at the moment, so im doing what i can elsewhere.

Got another record fill today! ive been careful with the electric fans and leaving them off untill the engine warms up so it is getting warm much quicker now which seems to be helping, its running a bit rough again after getting the switch for petrol/LPG hooked back up yesterday but its going in for a carby rebuild and tune on Tuesday so hopefully he can fix that.

Also build a new center console yesterday, it has cup holders and a coin tray/phone holder and a 6 pack sized cooler:


I also put a new amplifier underneath the console to run the 10" subs in the kick panels:


and fitted an inverter to run my phone or laptop charger:


all done:


Thanks for lookin

[ron]

Do you have a rough Idle or rough running at speed? If its idle you can use a squirt gun full of water to spray all the vacuum hoses on at a time that should show up any leaks until the water is sucked in, then it will go back to rough idle. For rough at speed, it could be the distributor I would suspect the dist shaft bushing ,test it by removing the cap and grab the rotor and see if it moves or wobbles . just a guess

[JRMichler]

Something is wrong. With the transmission in a direct drive gear, the engine should be running about 3000 RPM at 60 MPH. Either your tach is wrong (set for 6 cylinder, maybe?) or you are driving in 3rd gear of a 4 speed.

If it's just tach error, then I suggest that whoever looks at your carburetor check it over very carefully. You might be running a full rich power mixture all the time. Most carburetors have some sort of wide open throttle fuel enrichment. If that sticks open, your mileage will about half of what it should be.

Way back when, a friend had an early 60's Chevrolet Nova 6 cylinder automatic. With his driving style, he should have averaged 20 MPG, but in fact averaged 10. His power valve was stuck open. The car started and ran great, it just sucked gas.

[bobo333]

Do you have a rough Idle or rough running at speed? If its idle you can use a squirt gun full of water to spray all the vacuum hoses on at a time that should show up any leaks until the water is sucked in, then it will go back to rough idle. For rough at speed, it could be the distributor I would suspect the dist shaft bushing ,test it by removing the cap and grab the rotor and see if it moves or wobbles . just a guess

Its rough at speed, worst at low RPM/low load, it was running great on LPG until we hooked the petrol up again the other day, i thought we may have fouled the plugs when we were switching between LPG and petrol while testing the switch, il check the dist as well though

Something is wrong. With the transmission in a direct drive gear, the engine should be running about 3000 RPM at 60 MPH. Either your tach is wrong (set for 6 cylinder, maybe?) or you are driving in 3rd gear of a 4 speed.

If it's just tach error, then I suggest that whoever looks at your carburetor check it over very carefully. You might be running a full rich power mixture all the time. Most carburetors have some sort of wide open throttle fuel enrichment. If that sticks open, your mileage will about half of what it should be.

Its a 4 speed manual gearbox so i know its definitely in 4th, it is likely that there is something wrong with the tacho, its definitely hooked up for 8 cyl though.

I have been running it only on LPG so far since i got it so the settings on the carby wont have much to do with anything (only the idle speed and throttle opening i think) the LPG has a separate mixer that could be at fault though.

Im still on the lookout for an affordable diff/gearbox swap, 351's seem to be a popular swap into Nissan Patrols so there is an adapter available for the Nissan gearbox, which has 5 speeds and much more even "car like" ratios, it should also be plenty strong enough as the Patrols are 4x4 and weigh more than my truck from the factory and have decent towing capacity too

[ron]

carb gasket, wrong plugs for fuel, lower octane LPG ? just guessing , did you use the squirt gun yet. one more thing is dist clamp loose or tight.

[JRMichler]

The LPG carb has some sort of fuel pressure regulator. Try checking the pressure from the regulator.

I'm thinking that a seriously rich mixture can explain your gas mileage. If the timing was retarded enough to cause your mileage, the engine would overheat in city driving. Or maybe low compression? Or all three?

[hotrodfeguy]

I would just forget a new gearbox and go right for a rear 3rd member 3.00 2.75's and watch that milage go right up prolly 20%

[bobo333]

Hi Guys

Had the truck at a mechanic today to get it tuned up, he found the distributor shaft was slightly bent which was causing my missfiring, he also gave everything a good going over and adjusted the timing and fuel mixtures no now it runs much better, seems to have more power and its alot smoother so i cant wait to fill up and see how it does mileage wise now

Still on the lookout for new diff gears/gearbox or even taller tires in my price range... It doesn't help that my price range isnt very much though

Thanks for lookin