Because of my rough idle should i do an engine rebuild

 

Uhhhhh...
No? :)

it's a '74...
...is the engine a V8 with a two barrel carb and 5 bolts per valve cover? :)

Alvin in AZ

 

Sorry i left some info out its a 360 5.9L 2v 4x4 2 door

 

To rule out a rebuild, you need to do a compression test on the cylinders. If they are all within about 10% of each other, then a rebuild probably isn't needed unless it burns alot of oil. After the compression test, I would start with the basics like plugs, plug wires, distributor cap and rotor. It may also need a carb adjustment.

 

I've got a '75 F150 360FE Motorcraft 2100-2v T-18 4x2 that i bought new. :)

This idling-rough-business is something i've been wanting to get into.
I really need to take some pictures tho.
I drilled a 3/32" hole in both throttle plates.
Mine will, as a test, idle smooth at 380rpm now. :)
But mine's got a Comp-brand "economy" cam 252/252 and electronic ignition.
All that didn't help the idle at 600rpm tho. :/

I can see gasoline dripping from the booster venturi while it's idling at 600rpm.
There's got to be something to stop that and I want to know what that is.
At 380rpm it don't drip like that and actually idles smoother etc!

Simple fuel level ain't it, since i tried that and it was well below the level called for.
Need to try it again and go even lower to prove it's vacuum inside the boosters causing it.

Just how far into this "idling rough thing" do you want to go? :)

When i started on this carb-drilling business a couple weeks ago, mine was missing on one cylinder.
I could feel it in the single exhaust pipe, it is felt as a sucking-back of your hand.

I got the meter out and checked the resistance of each spark plug and each wire and found a bad wire. Replaced the wires and plugs, no more miss. :) But while I was at it, began tinkering with carbs again something i've been doing off and on since '75. :)

Yours got electronic ignition?

Alvin in AZ

 

Quote I got the meter out and checked the resistance of each spark plug and each wire and found a bad wire. Hey Alvin, What kind of meter and how to check?
I would be intrested in this info. Seems I have the same kinda thing hapening . With a 352 From my 1966 F100 Thanks By the way I am in NW Tucson. Bill W

 

Just a cheap analog volt-ohm meter. :)
I used the resistance testing feature.
Pulled the cap and the wires off the plugs and set in the shade with the meter.

I use Bosch-ignition wires and Autolite 45 spark plugs.

The testing was all about wanting to know, anybody else would have gotten the same results by changing out the plugs and wires. :)

Since i-am a hammer mechanic, I hammered the nose out on my rotor to be closer to the studs inside the cap. Took some careful measurements (more than once;) and hammered away. ;)

I have no idea if that helped anything or even if it made things worse. ;)

Alvin in AZ (Iola Frans:)

 

I bought a $5 meter from harbor frieght .although I did not know what the actual ohm value was, I was able to determine what wires were bad basing it off my highest reading. As for rough idle, I would take a can off carb cleaner and spray around the carb base and intake gaskets before tearing the motor apart. Also check for vacuum problems i.e. hoses, booster check valve,rusted out vacuum resivor.

 

Yeah. :) The higher ohm readings are your weaker wires.

A $5 meter is as good as a $500 meter for most of this work. :)
The meter needs to go to zero all by itself tho.
If it ain't, blow and huff on the window until the needle-zeros.
In AZ, even the expensive ones, with glass instead of plastic, can need that. :/

i happened to know what mine were new... 1000 to 1200 ohms depending on the length. But that information isn't even needed for ignition wires. :) Those readings are for the "wire wrapped type" ignition wires.

It would have been cool if i hadn't thrown my old wires away, at least kept the ones that were still good, saved me some money. ;)

I've got all kinds of resistance and voltage readings written in my shop manual.
Over the years they haven't so much told me where the trouble -was- as much as told me where the trouble -wasn't-. But either way, having that information is the easy way to go, took those readings while everything was working good and wrote 'em down, on the page in the shop manual that part's other information's on.

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Fixin to ream out some holes in one of my many 2100 booster assemblies.
Just an experiment,
Going from ~.027" to .033" on what's been called the "anti siphon holes"

The air correction holes on top, have already been reduced so on -that- assembly so it's time to find out what the anti siphon holes really do. :)

Funny thing about 2100 carb-hole-names you find on the internet, many are just plain ol' mis-named.

Alvin in AZ