Motorcraft 2100 1.21 on 2.8

[kimcrwbr1]

That spacer has a gasket on both sides but they are real hard I just made a gasket to fit between the carb and spacer after I surfaced the carb. Glue a sheet of 200 grit sandpaper to a piece of glass or flat metal and slowly work the base of the carb in a figure 8 pattern until it all shines the same then slowly snug the carb down do not overtighten it. After a few complete warm up cycles snug it down again when the engine is cold. That spacer came stock with many 302s and 351s the butterfly will work just fine and you get the proper angle for the throttle cable.

 

[kimcrwbr1]

Just an idea here with a vacuum guage from idle to wot (goose. test) you dont want the vacuum to go below 2 inches Hg and then up to 20 Hg or more so run the engine around 3500 rpm and slowly close the choke until the vacuum guage reads 20 Hg. Then do the goose test again. Just something you can try.

 

[kimcrwbr1]

http://www.therangerstation.com/Magazine/Summer2003/VacuumLeaks.shtml You want it to go from 2 Hg to 25 Hg and back down to normal engine vacuum at an idle between 17-21 Hg. Adjust the timing to 10 degrees base and adjust the idle air needles for the highest possible vacuum pressure. Then count the turns in and back out on both needles they should be within 1/2 a turn between them.

 

[85_Ranger4x4]

Its all great info man, i appreciate it, but for now i need to know what did those guys with 1.21 on their 2.8's do to get it running good.

I pitched it and put the stock carb back on until I pulled the engine.

I didn't mess with the jets... it just ran really goofy. Acted like it had a vacuum leak but didn't, sometimes it would try to run away from you a little when you let off the throttle (it would keep going) Its been a couple years but that is all that really sticks out in my mind (besides spending hours sanding the insides of the stock carb spacer so the 2100 butterflies would clear )

I did pick up a 1.08 1250... actually came mounted on a '78 302. By then the 2.8's days were numbered and I deemed it not worth putting a kit in until I had a practical use for it.

 

[Psychopete]

A 1.21 is too large of a carb. When that happens, you cannot flow enough air through the venturi to make it function as it should.

^^ vacuum isn't strong enough through the venturi to draw out a reasonable amount of fuel, makes it really hard to tune. imagine the effects of different sized straws..

 

[drgrcr]

Just curious, have you ever run a compression test. Wondering how much cranking pressure a 2.8 has @ 9000' elevation

 

[PetesPonies]

Pscho . what are you trying to say different than me? Have you read my posts carefully? I'm a retired Auto instructor.

 

[fastpakr]

I think he was just giving an echo/+1 to what you said.

 

[PetesPonies]

then don't mind me

 

[BichoBII]

Sorry for disappearing, and thanks for the replies, work hasn't left me much time so haven't done any test, but i will and post asap

 

[BichoBII]

So, got some news, haven't solved the problem yet but im close, first i started going up on jet sizes and andancing the timing with no luck, so went the other way, although timing was set at 10° btdc, i retarded it a little and knock started to go away, right now i dont know the exact timing i set but should be around 6-8 btdc, guess dissy might be a tooth advanced since at this altitude i should be able to advance more than 10 without problems, but right now it is running better...