Chevy 350 questions...agan. help me!

[megaladon6]

when you timed it to 33* what RPM were you at?

 

[ERIC87442]

theres no vacuum modulater on the trans its a 200r4, and i was somewhere about 3600 when i timed it at 33, does that sound right? i set the idle screws to the highest vacuum (in gear), there out a little less then 1.5 turns i think there only out about 1 turn if i remember correctly

 

[ERIC87442]

This sounds almost like a problem that I had with my 406 Chevy, take off your valve covers and check to see if any of your rockers are loose. If any are loose you may have whipped a cam lobe. When my engine was doing this it was coming back through the carburetor(it was an exhaust lobe, yours might be an intake), I bought a new performer rpm intake and a new edelbrock 750 thinking it was slight detonation and it wasn’t getting enough fuel. I put on the new parts started it and it sounded like a train was coming through my shop. I changed it to a comp cam extreme energy cam, did the correct brake in and it ran great. We couldn’t figure why my engine with 2000 miles on it whipped a cam lobe until I did some research synthetic engine oil didn't provide enough lubrication and it was just grinding away.
It just sounded eerily similar to my issue, if it isn’t then it’s a timing issue.

your scaring me with this, haha wouldnt that happen all the time though if i did that? oddly with my valve covers on, it sounds like rockers slapping around sometimes, take the valve cover off and it sounds fine. i adjusted the rocker arms and looked at the inside of my valve covers and saw they were hitting the supports for it ever so slightly to cause that clatter noise ( they are steel stock like centerbolt valve covers) i hade alluminum tall valve covers on (before i over tightened them and cracked them) it never did that. none of my rocker arms were loose then, that was about 4-5 months ago

 

[MD13ailey]

check and makes sure that all of your plug wires are on tight. and check your rocker arms and see if any of them are to tight if the exhaust is to tight it could be holding the exhaust valve open or you could have a a flat cam that will cause the popping to. and 1150rpm when it is warm is a little high try dropping it down to about 800 and see how that works out. it doesnt sound like a vaccuum leak and I think you are close on the timing.

 

[turbo78]

its sooo hard to diagnose over the internet ya know...

 

[ERIC87442]

haha i know its hard to diagnose over the internet, its hard if your not there with the car, im just looking for input and im getting alot of great input guys thanks! it runs good enough now, it just acts like its loading up a little bit on cold start up for about a minute then its fine. and if i drop my idle down to 800 it has lower vacuum about 12-13 and it seems like the alt wont charge it enough if i remember right and it idles in gear around 500 + or - a few rpms my theory is im going to leave it now, drive it a bit, so far so good. im gonna try the advance curve kit when i get it and see what happens. and i will check my plugs again, after running it for a while with the wrong plugs the right ones whice are longer in the thread region were hard as heck to get in.

 

[custom442]

^^ a 4160 has only a primary metering block (i.e. no rear accelerator pump), you'll know the difference because you should've connected your vacuum advance to the vacuum port on the front metering block, a 4150 would have the same block(minus vacuum port) on the backside of the carb

do you have a PCV valve, is the tube connected to the correct port on the carb?

I really doubt your timing is off or your idle either.

I can really only give suggestions for your choke problem. Have you tried adjusting the fast idle cam to help with your startup issues?

my 770cfm 4160 is in decent tune and actually idles out of gear at 1300. In gear it's about 700-850 (I have a pretty radical cam for the engine, lower than that and I'm not getting enough vacuum). As long as you're getting vacuum and the right rpms in gear, it's just an inconvenience, you're not hurting anything.

Just be sure to shut your engine off in gear then shift to park, or if the engine is hot crank it in gear also. This way you're not backfiring or flooding the carb. My only other suggestion would be to take it to a holley expert in your area. Call the local machine shop and they should let you know if there's one around.

 

[ERIC87442]

yeah it is a 4160, i turned my idle down so im at about 620 in gear and its idling around 780 to 820ish out of gear, and i got about 13inches of vacuum in gear, i think im alright now, my idle screws are 1 and a half turns out now and i turned my fast idle down just a hair, thanks for all the help and all the imput, i think i have finaly gotten it better now, now just to worry about my alt. and charging issues, i think im going to try a smaller pulley if that sounds right?

 

[custom442]

If the alternator was good before, it should be good now no need to change pulleys. Just double check that you wired the 3 wire correctly.

If it's fluctuating past 14 volts it's possible that it's hooked up wrong. But if it's fluctuating, then going back to 12volts steadily this means your hot sensing line is telling the regulator to drop back down so you're good. You can get better results by rewiring the whole hot wire ignition/choke/dist. mess with a little thicker gauge and a shorter path. (make sure everything has good grounds)

 

[ERIC87442]

that was my first guess that i wired it wrong but its going the right way, they wires look old and crunchy haha so i think i may try the new wiring deal. i already cleaned up my grounds so im guessing some bigger gauge wires will do me, and as far as the car is running, its running pretty good now, idles around 850 out of gear and around 630 in gear, every now and then if i mash it it will pop back through the carb. i think i got everything pretty close now.