Paradox

iTrader: (1)

I have the RB holley 600 on a '85 13b engine, pacesetter long-tube header to straight through exhaust to a crappy burned out muffler.

i cant seem to get the Holley to stop massive backfires between shifts, its not just the little pops that these engines normally make, its a full out explosion in the exhaust.

i've set the timing multiple times now, and tuning it by ear or advanting it a tiny bit seems to give less backfires, but its still prominent

adjusted the float bowls many times aswell. having troubles keeping those where they should be tho. is there only one sight-hole on the 600? i cant see one on the primary side

also when driving it doesnt feel like my secondaries are opening up, altho they have been set to mechanical with the "screw trick" both float bowl screws are adjusted almost as lean as they can go.

right now im pretty much stumped, any idea's?

i had a appointment setup early next week to put on a new muffler since its obnoxiously loud right now, but its really not worth putting on a new one if its going to continue backfiring like this. i'll blow it out in no time.

thanks

Rx7carl

On a Holley you adjust the fuel level by removing the plugs and the level should be at the lower part of the hole IIRC.

Paradox

iTrader: (1)

yeah, but what about on the primary fuel bowl? i dont see a sight hole/plug...

rmriggin

Check your power valve, make sure jets are providing enough fuel, and set your floats. I used to have the same problem because my floats were not set right, and the jets were too small. So I am now running 62 jets and have an 8psi power valve. I have not been backfiring, and I haven't had any issues with dead spots either.

Ultralights

get rid of the burned out muffler! mine runs perfectly untill i get any hole in the exhaust or gasget, then its fireball explosion heaven! holes usually occure on a regular basis once all holes a fixed, including bad muffler, she runs smooth as and no backfiring

Paradox

iTrader: (1)

doesnt RB block the power valves on the RB prepped carbs? i heard they did, but im still learning about Holleys, dont know much at all right now...

Alak

iTrader: (9)

Your running lean. Check the exhaust for leaks. No leaks in exhaust and you know its a carb problem.

Try a 1" open spacer and remove the secondary diaphram spring and put the litest one in. try that. then start the process of jetting.

I had to put on one of the largest power valve nozzles on my N/A to get it to run right.

on a 650CFM Carb I have .31 sized power valve/accelerator pump nozzle and the primaries were .70 jetted from .65. On a side note, Im like 1000 feet above sea level respectively.

Oh and a Wideband Helps too.

Paradox

iTrader: (1)

my buddy dan said to talk to you actually. he's also in calgary.

i'm trying to do as much as possible before i start changing jets. since i am at sea level (vancouver island). i will have to check for exhaust leaks first then perhaps go from there. far as i know my exhaust setup is pretty sturdy, but who knows. would a exhaust leak really make that big of a difference?