I took the 'Vette for another spin today (finally the rain stopped and dried up) :D. I cracked her open to 3/4 throttle today and wound her up to 5000RPMs (I know, I know). Man the power is out of this world.

I buttoned up all of the under the car leaks. I still have a very minor oil leak coming from the front of the intake (coming from the front rubber gaskets). Trying to get this thing to idle is rough. It seems like once she drops around 1200RPMs she keeps dropping and wants to die. The front primaries of my carburetor are really getting black. I'm not taking her out again until I hook a timing light up to her. Does it sound like maybe the carburetor is running too rich? It also seems like when I drop it into 4th gear, anything below 2000RPMs and she starts sputtering. The cam could also be part of the problem, it's pretty radical (294 solid lifter .595/.595" lift).

Other than that I'm slowly getting things straightened around and she pulls a solid 60psi of oil pressure at 50mph. This engine is really helping me become more aware. Seems like all I do is watch the oil pressure, water temperature and listen for any noises out of the ordinary.

P.S. I'm also wondering if maybe I have a blown power valve. A blown power valve would also cause these symptoms.

 

Sounds like it's running really rich. Also, if the valves aren't adjusted properly you could have bad reversion in the intake. This could cause the black residue in the carb. 292 isn't that radical for an engine as big as that. Check for a black cloud of smoke from the tail pipes, this will help determine if it's loading up. If your timing is to far retarded it will idle rough and will need more idle adjustment. You could also check the float levels. That could make it run rich too. Take your time, it will be a while before all the bugs are sorted out.

 

I don't think the cam is so radical that the car won't idle below 1200 rpms. If I remeber right you are around 245 at .050 ? Dumb question but have you set the idle circuts sp? on the carb.

I had the same problem on mine regarding wanting to die below 1000 rpms turned out to be the new msd 6al I had.

You need to time it. It could be that. If it is retarded a bunch it won't want to run. Fix what you know is wrong and then go from there.

Welcome to the world of big blocks, lots of fun and work :chevy

 

I'll probably get flamed for this but, I have not adjusted the idle circuit at all. My 850 double pumper has the 4 corner idle circuit adjustment. Do you think I should start there? This is not my first Holley, I'm pretty familiar with the double pumper, I also have a complete Hayne's book on Holleys. I'm sorry please don't yell at me :)

By the way the cam is a 294 Magnum (advertised duration) solid lifter. I can't remember correctly but for some reason I think the duration at .050" is 248.


[Modified by bence13_33, 7:29 PM 5/14/2002]

 

No. Until you get her timed (as you mentioned in your first post), you will be urinating into a stiff breeze. Time to borrow or buy a nice timing gun, dude.


[Modified by 45ACP, 8:35 PM 5/14/2002]

 

Time it first. Fix the things you know aren't right first. Do you still have open headers? Putting exhaust on it will usually result in better idle. If it still won't idle it probably needs the idle circuit richened up some. A lot of engines get ruined like this. Especially if you can't hear the detonation over those open headers.

 

Shane

Also get a vac gauge on it so you can see where you vac is at. If you are leaking oil from the front intake seal, you might have a vaccum leak.

 

Time it 1st. It's better to see when the motor is burning the fuel. Then figure out from there. You can tune the carb and tune it. Change the timing and have a totally different world.


[Modified by Aaron-74, 8:22 PM 5/14/2002]

 

I know it's way too. early to tell but how do you like the cam? I'm thinking about it for my 468ci and wanted oninions.
:cheers:

 

Fevre is right, vac. gauge can indicate where major/minor problems are. Also cylinder leakage test.