1978 F150 Lariat Build
#48
Update
Hi everyone!! Just thought id update you guys a bit. My car broke down a few months back so I got the privilege to use my truck as a daily. Now the truck had many problems at first, such as it wouldn't start right away(cranked over a lot), when I accelerated the truck wanted to die, running way to rich and high idle. But I rebuilt the carb myself, which I enjoyed surprisingly. My dad and I did a tune up, I did more tuning today. After a new fuel filter and carb rebuild the truck starts pretty well. This truck also hates reverse and always dies in reverse when cold. I played with the vacuum lines (a couple of em were plugged with bolts) and I found a spot for them all. Reverse works well and no more dying when I accelerate Now the only problem I have is that when its cold it doesn't stay running unless I rev it for a bit. but I did some more tuning so ill see if that fixed the issue. I also installed a trans cooler after I drove my lady to her grad. The tranny overheated( I think) so I installed that. Other than that, im pretty happy with it. just working out the bugs haha, Now I didn't take pictures sadly. I always forget too. I noticed the truck was very stiff when I hit bumps and I looked, it has 2 leaf springs. is this normal? also if I take one off would it lower the rear end?
#50
Very nice truck-I've got one very similar.
Looks like you have the full Ranget XLT Lariat trim. I also had the same seat design, but I hate vinyl, so when I had it rebuilt it was reupholstered in cloth.
Sounds like you need to adjust the choke. It's probably electric, and original, so the lead would come off the alternator.
Nothing wrong with the 351m/400 engines. They make good torque, which is what you want in a truck.
Here's mine:
Looks like you have the full Ranget XLT Lariat trim. I also had the same seat design, but I hate vinyl, so when I had it rebuilt it was reupholstered in cloth.
Sounds like you need to adjust the choke. It's probably electric, and original, so the lead would come off the alternator.
Nothing wrong with the 351m/400 engines. They make good torque, which is what you want in a truck.
Here's mine:
#51
#52
The idle speed when warmed up, in drive, should be 650. In park, will probably be around 800
Make sure to get the idle mixture set correctly. With the engine warmed up, choke open, in park, disconnect and plug the vacuum advance to the distributor. Throw a vacuum gauge on a full manifold vacuum port. Set the idle mixture screws at 1-1/2 turns out to start. Adjust the screws, one at a time, until the highest vacuum is obtained.
If you have a tach, do the above adjustment with the tach in place. If the idle speed goes up much, adjust the speed down and start over.
You should see a minimum of 17" of steady vacuum on your gauge at idle speed. Don't cheat by jacking up the idle speed to get a higher reading.
When you get that adjusted, we can talk about timing...
#53
Join Date: May 2010
Location: Regina, Saskatchewan
Posts: 4,436
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Great build so far! Keep it up and the pics too!
Awesome advice Yuma, as always. Would give reps, but I give them to you too often lol (again, as always)
Thanks-that's the better side...
The idle speed when warmed up, in drive, should be 650. In park, will probably be around 800
Make sure to get the idle mixture set correctly. With the engine warmed up, choke open, in park, disconnect and plug the vacuum advance to the distributor. Throw a vacuum gauge on a full manifold vacuum port. Set the idle mixture screws at 1-1/2 turns out to start. Adjust the screws, one at a time, until the highest vacuum is obtained.
If you have a tach, do the above adjustment with the tach in place. If the idle speed goes up much, adjust the speed down and start over.
You should see a minimum of 17" of steady vacuum on your gauge at idle speed. Don't cheat by jacking up the idle speed to get a higher reading.
When you get that adjusted, we can talk about timing...
The idle speed when warmed up, in drive, should be 650. In park, will probably be around 800
Make sure to get the idle mixture set correctly. With the engine warmed up, choke open, in park, disconnect and plug the vacuum advance to the distributor. Throw a vacuum gauge on a full manifold vacuum port. Set the idle mixture screws at 1-1/2 turns out to start. Adjust the screws, one at a time, until the highest vacuum is obtained.
If you have a tach, do the above adjustment with the tach in place. If the idle speed goes up much, adjust the speed down and start over.
You should see a minimum of 17" of steady vacuum on your gauge at idle speed. Don't cheat by jacking up the idle speed to get a higher reading.
When you get that adjusted, we can talk about timing...
#54
Is there a video to show a bit more on that? Also i dont have a vacuum gauge, how much would i be looking at for that. I was told there was supposed to be no vacuum at idle on the vacuum advance. Mine has vacuum 24/7. Ive switched it to different carb ports and no difference. But i did play around with aomething on the carb. It still dies when cold but it runs a bit longer. I think i just need to play with it a bit more. Also those 2 screws, i think theyre close to 2 1/2 to 3 turns out
#55
Vacuum gauge is maybe $15 at any auto part store.
With the engine running, warmed up, choke open, wheels chocked, idling in park, RPMs at perhaps 800...
Full manifold vacuum should be steady, and not less than 17"
The carb will have one nipple, usually on the passenger side, with no vacuum reading at idle. That will be ported vacuum. On the Edelbrock, it's the smaller nipple on the front, passenger side. On the Holley, it's near the front, near the top, passenger side. The ported vacuum goes to the distributor.
3 turns out is probably quite rich. Get a vacuum gauge and reset the screws to 1-1/2 out. Adjust them in or out until maximum vacuum is obtained. The idle speed will probably rise as you find maximum vacuum. It it does, lower the idle speed screw and start over.
With the engine running, warmed up, choke open, wheels chocked, idling in park, RPMs at perhaps 800...
Full manifold vacuum should be steady, and not less than 17"
The carb will have one nipple, usually on the passenger side, with no vacuum reading at idle. That will be ported vacuum. On the Edelbrock, it's the smaller nipple on the front, passenger side. On the Holley, it's near the front, near the top, passenger side. The ported vacuum goes to the distributor.
3 turns out is probably quite rich. Get a vacuum gauge and reset the screws to 1-1/2 out. Adjust them in or out until maximum vacuum is obtained. The idle speed will probably rise as you find maximum vacuum. It it does, lower the idle speed screw and start over.
#56
#57
Connect to a source of constant manifold vacuum, e.g. anything or anywhere below the carb butterflies.