webber carbs on 2.9?

[the_big_2.9]

i was lookin at a lmc truck catalog and seen a carb conversion kit ... anyone try it and what do u got to change?

 

[holyford86]

the 2.9 cannot be converted to carb without a substantial investment. the conversion kit was probably for the early 2.3, 2.0, or 2.8 all of which were carbed from the factory. A properly maintained efi setup will give you superior power and driveability over the same engine with a carburetor. the 2.9 was never meant to be carbureted, it was designed as an efi engine from the beginning. you cannot use 2.8 parts to convert the 2.9 to a carbureted setup either, the engines are quite a bit different, the major differences are the heads and distributor, the distributors spin in opposite directions.

 

[almostclueless]

If LMC wants to sell many of these, they need to also sell a 2.9 dizzy with built in mechanical advance.

 

[the_big_2.9]

well i figured i should be able to use my stock dizzy but i wont have any advance i was just gonna lo
ck her in at 12* an engine dosent care where its fuel comes from as long as it gets er... in the right amounts. the stock efi system is pritty limited to mods and even if i switched it to a maf efi setup i still wouldnt give me the adjustability im after

 

[almostclueless]

Engine power and economy are going to be bad with the spark always happening at 12 degrees.

 

[the_big_2.9]

acording to ur teck page the dizzys spin the same way... maby different gear on a non tfi
2,8 dizzy could fix that problem

 

[Psychopete]

acording to ur teck page the dizzys spin the same way... maby different gear on a non tfi
2,8 dizzy could fix that problem

Where's that info (it's not right)?

The timing setup on the 2.8L is 2 gears that are touching each other - which is why the cam spins backwards. The 2.9L has a timing chain and sprockets which make the cam spin the same direction as the engine.

Switching the gears has been thought of, but I don't know if anyone has got it working.

Pete

 

[lodden758]

your rite that the cam spins backwards on the 2.8 but the gear on the distrib is backwards also making it spin the same direction as the 2.9, so if you change the distrib gear the 2.8 will work in the 2.9. still I can't see dropping 800 bucks into a 2.9 for the carb kit lmc offers.

 

[almostclueless]

your rite that the cam spins backwards on the 2.8 but the gear on the distrib is backwards also making it spin the same direction as the 2.9, so if you change the distrib gear the 2.8 will work in the 2.9.

If you have credible info that proves that (not trying to razz you; lotsa folks on the web BS about stuff they really don't know jack about), this would be good info.


Folks with early 70's colonge V6 powered vehicles could possibly drop a 4.0 into their vehicle with a fabbed intake.


I wouldn't mind having a early euro capri with a 4.0, a T-5, and a traction lok 8" rear. Tune a 390 holley using a wideband O2 setup, and thumb my nose at all the naysayers.

 

[the_big_2.9]

well i dont really no if i can be done yet but i do no if the peases are avlable i no i can make a killer 2.9 that will smoke most sbc. im not goin to go with the webber kit but maby a custom intake make out of 1/4" aluminum plate and bolt a 4bbl holly ontop. i realize this is gonna be a chore due to many factors ie. the valvecovers seal to the intake and the coolant that is supposed to flow through the intake other than that i am really looking at the high ratio rockers from camcraft and there custom cam grinding. im gonna pot my heads and run a set of pacesetter hraders the bottom end is gonna remain fairly stock except for maby a set of 2.8 pistons to up the compresion

 

[almostclueless]

"the valvecovers seal to the intake"????

do you mean the PCV hose?



Do you have both a 2.8 and a 2.9 dizzy to compare?


We need to ensure;

1. oil pump driveshaft will engage and hex size matches

2. bottom of dizzy shaft engages guide hole in block and shaft diameters are same.

3. dizzy shaft turns correct way because of mechanical and vacuum advance and oil pump.

4. ignition rotor is at tower contacts when duraspark reluctor is nearing cap tower contact (rotor phasing).

5. dizzy will correctly clamp down when hold down bolt is tight....and the gear can't bind against the block either.

Intake water crossovers wouldn't be that difficult.



Basically, if the 2.8 and 2.9 dizzys have matching dimensions on everything that is inside the block and the shafts really do turn the same direction......but the gears are backwards, it seems like everything else should be the same, and a simple gear swap would do the trick.


With a good ignition solution in place a carb and intake are all that's left.

 

[Psychopete]

"the valvecovers seal to the intake"????

The valve covers seal against the heads as well as the outer sides of the lower intake manifold. If one were to have their heads milled, but not the lower intake, this can cause a leak a the valve covers since the surfaces are not level anymore (and water in the oil as what happened to me).

IMO, I think the only way to get the power you're expecting is with forced induction, but it will still make powerful little motor. It's really going to have to pull some RPMs though - all or none.

I have a high lift cam in my 2.9L with a MAF setup and it's kind of a dog until you hit about 3,000 RPM. I have a V8 swap planned, (I was going to S/C the 2.9L), but I have having a hard time finding a good deal on the engine I want.

Pete

 

[the_big_2.9]

well in ont sayin that a stage 2 motor motor might include a custom turbo setup but for now i got my hopes set on schoolin my buddy with a 305 chev

 

[the_big_2.9]

ps, who has a couple old dizzys kickin arround that they can compare?

 

[Mutant Pony]

I have both 2.8 and 2.9 dizzys. They are completely different, no resemblance. The 2.9 is taller deck height so the dizzy is taller. I can post a pic.