Racingjunk Forums

Racingjunk Forums (
-   Engine Tech (
-   -   motor poping (

jl4020 06-20-2007 06:55 PM

motor poping
can some one help me mind my easy fix. i have inquird a poping noise at high rpm. i thought i might have water in fuel but carb,fuel pump and filter was clean. iam think that if it was a bad valve spring it would do it threw out rpm.? right or wrong? any way to test msd box? it a big block chev

topsportsman1 06-20-2007 07:07 PM

What MSD Ignition box you got? How high rpm are you talking about?

jl4020 06-20-2007 07:14 PM

msd 7al well some where around 6000 and up i have a 7000 it

topsportsman1 06-20-2007 07:20 PM

7AL?? 2 or 3?

jl4020 06-20-2007 07:25 PM

my bad it a 2

topsportsman1 06-20-2007 07:43 PM

Its possible the 7al2 could be going away,the 7al2 is about the same caliber box as the 6al,which is about half the caliber as a 7al3

I'd sooner think you was having issues with your box,or the add on box for the rev limiter,maybe unplug the rev limiter and see if the problem goes away,other than that,I'd say either upgrade the box or ship it back to MSD and have it checked out

Also you could be having tachometer issues causing it to cut out at higher rpm's

davis419b 06-20-2007 08:10 PM

What kind of fuel do you run? I know you said it was clean but i still want to know. Also what compression do you run?

billhendren 06-21-2007 05:19 AM

You may want to check your valve springs,also make sure your mag pickup wires are separated from the coil orange and black leads.also check the polarity on the mag do this look at where your timing is set,unplug the dist and take two short wires.plug one end into the dist and cross the wires before plugging them into the wire loom.start the engine and see if the timing advanced or retarded.the correct position is the retarded one.Bill

jl4020 06-21-2007 01:08 PM

vp 110 it 13to1 it just started it last weekend never had a prolbem till then . ithought if it was valve spring it would do it all the time?

bjuice 06-21-2007 03:24 PM

i have to ask..what did you run before then ?...(fuel)

thanks brian

jl4020 06-21-2007 03:30 PM

ive ran the same as last year this was my second 5 gals used. didnt chage anyting.

davis419b 06-21-2007 04:28 PM

Drain the fuel and put new fuel in from a different source. Its the chaepest thing you can try. I had the same problem the beginning of this year. I run alcohol but it would only pop at the top of low & high gear. It was a brand new barrel. I tried and changed everything and it still popped. I was at Memphis and had to buy fuel and believe it or not it quit popping. Try It! Don

jl4020 07-05-2007 06:05 PM

well i know it would be someting easy. i think we found the prolbem. 7000 rpm pill in my box. took it out and ran wed and ran with just a little pop. fuel pressure set at 8 but fall down to 6 psi order new regulator .hope that get the old girl going i dont like to see her sick 8). thanks for all the nput

SST4530 07-06-2007 08:08 PM

Popping out exhaust or through the carb?

All times are GMT -8. The time now is 11:29 PM.