[smartparts312]

Hello I am new and thanks in advance!
I have searched high and low to find a similar situation but can’t seem to find anything like this? Trying to learn!!!

76 Chevy K10 350
81 front end and cab
GM replacement crate
Accel HEI
Road Demon 625
Eddelbrok performer intake

My problem is I am trying to set base timing so I can adjust my carb.
When I put a light on it with the vac adv disconnected and plugged at even 15* it runs like crap and pings and backfires through the carb?????
When I was setting the disty I pulled tdc on #1 and the marks lined up.
So to get it to even run and go I need to advance the crap out of it to where it looks like it would be at maybe 25* or more base time??????
When I do that it runs ok but is super sluggish down low but goes ok to good up top???

I know a little about this stuff but thats it a little and everyone I ask has no idea (maybe your light is broken) but it works fine, or set it where it runs and just run it but that’s not what I want to do.

Could the cam be out of time????

Like I said I am trying to learn here and all input will be greatly appreciated

[SSedan64]

Sounds like you need to recheck & make sure the distributor isn't a tooth off.
http://www.chevytech.com/3c1o1.html
http://www.chevytech.com/2c44o2.html
Pull the plugs, turn the engine over until it blows your finger away from the #1 plug hole, then turn the engine over manually until the timing marks line up on the balancer. Make sure to disconnect the coil 1st. Or here>> http://www.corvette-restoration.com/...stallation.pdf

[smartparts312]

Ok thanks for the reply!
Even if the disty is off one tooth I would have to advance it really far but it would still fire at tdc (or 15* before) and read that with the light right?
So thats still not going to account for the extra 10-15* it needs to run???

[smartparts312]

Am I totally wrong and this could never happen unless I was missing something I can triple check everything. put #1 at tdc check the timing mark on the timing tag and the balancer line up at 0 and check the rotor is pointing at the #1 plug wire.

Anything else that I am missing and ssedan64 said disconnect the Coil but how do you check the timing without a coil (its on top of the disty anyway not just an extra plug wire?????)

Someone must know something even if its so simple please help

[Tech @ BG]

Typically when one pings and backfires it is usually a sign of being lean or it does not have enough initial timing. Have you gone back through and checked the firing order? As one of the other guys posted it does sound like it may be a tooth off.

When you brought tdc up and checked the balancer and the timing tabs did they all line up right? I know from working at a dealer years ago some of the balancers and timing tabs were different even for the same size motors.

edit.. just saw where you posted they did but may want to pull the valve cover off and bring the piston up and double check it that way.

[454C10]

could be a mis-match in the timing tab and balancer.

did the crate engine come with a timing tab and balancer? or did you use your old engine stuff on the new engine?

a back fire out the carb typically means retarded ignition timing or lean.

[cobalt327]

Originally Posted by smartparts312

Hello I am new and thanks in advance!
I have searched high and low to find a similar situation but can’t seem to find anything like this? Trying to learn!!!

76 Chevy K10 350
81 front end and cab
GM replacement crate
Accel HEI
Road Demon 625
Eddelbrok performer intake

My problem is I am trying to set base timing so I can adjust my carb.
When I put a light on it with the vac adv disconnected and plugged at even 15* it runs like crap and pings and backfires through the carb?????
When I was setting the disty I pulled tdc on #1 and the marks lined up.
So to get it to even run and go I need to advance the crap out of it to where it looks like it would be at maybe 25* or more base time??????
When I do that it runs ok but is super sluggish down low but goes ok to good up top???

I know a little about this stuff but thats it a little and everyone I ask has no idea (maybe your light is broken) but it works fine, or set it where it runs and just run it but that’s not what I want to do.

Could the cam be out of time????

Like I said I am trying to learn here and all input will be greatly appreciated

Start at the beginning by determining true TDC, then if you want, you can make an inexpensive timing tape to see where total is at, etc.

DETERMINING TDC

MAKE A TIMING TAPE

Good luck!

[smartparts312]

when I checked, the timing mark on the balancer and the tag lined up at tdc on number 1 cyl!!! (carfuly with a screwdriver in the plug hole for tdc) also the rotor was pointing tward number 1 cyl????

Thanks for all the replys I am going to triple check marks tonight but i am sure they are right!!

also tech@BG it seems rich at idle and it fouled the plugs once (with the timing advanced so it would run???)

Is it even possable to run at a true 25* base time (if something wasnt wrong?)

THANKS FOR ALL THE REPLYS

[454C10]

sure you can run 25 degrees at idle. make for a snappy throttle response.

loner durations cam require higher timing, like 25 or even 35.