Timing issue's

[CamaroAdam73]

Got a couple timing questions.

It's a Chevy 350, HEI vac advance.

First off, when you twist the cap COUNTER CLOCKWIZE is that advancing or retarding the timing?

Second, when you connect the vacuum advance should the timing mark on the balancer jump up way above the tab??

My car recently started doing allot of funny sh*t out of the blue, and i'm at a loss here.


With everything its doing, the only conclusion i can come to is that it jumped a few teeth on the timing chain, but awnsering theese questions will be a very very big help, thanks guys!

 

[jrm81bu]

Turning the cap counter-clockwise will advance the timing. Depending on whether you are using a vacuum port that has constant vacuum(ported?) or only vacuum under load(switched?) will move the timing when its hooked up.

 

[CamaroAdam73]

I'm using the Ported side of the carb for my Vac advance, on the edelbrock 750 the Right vac port is the ported(constant vac) and the left side is the switched(under load) and as far as i know the switched port should ony be used for emissions controlled engines.

And thank you, that awnsers allot of questions and doubts in my mind.

The only remaining possibility is that it somehow skipped a tooth on the timing chain, because the engine WAS running great, and smooth. Now it runs like dirt sh*t, backfires through the carb, and when it throttles up the engine trembles BAD.

And it's perfectly in time, according to the balancer and timing tab. 10 dagrees above 0 on the tab.

Luckily for me, a few months back i bought a new double true roller timing chain and gears + new timing chain cover, because i started out on buying piece at a time to rebuild my cam/valve train in the engine.

So the game plan here is to check/ replace the timing chain and cover, and i'm going to re-do the valve lash to eleminate that being the problem.

Also im going to junk both distributors and drop the NEW moroso.

 

[megaladon6]

what i'd do is set it to TDC by feeling the spark plug hole (ie air is pushed out when cranked) or using a piston stop. then see where the balancer is along with the #1 rockers. if both valves are closed and the timing marks line up, you may have a fuel/carb problem. your problems can also occur from a lean condition.

 

[jrm81bu]

As far as the left port being for emissions-that's the one i'm using 🙂 .
To me its more of what the motor wants. I tend to go back and forth and test drive it each way, then leave on which ever one it wants.

 

[CamaroAdam73]

Yeah i'm going to get some help with this before i rip the front of this motor apart.

Finding TDC is for some reason harder for me than others, and thats because most of the time im doing all this work by myself, so holding my thumb over the whole, isen't always an option.

But i now have a new nifty resource to my advantage, a VISTA cam.

My brother installs medical equipment in dentists offices, and picked them up, they are cameras on a pole with a bright light, and a very very close view, best part is, they fit inside a spark plug hole!

So i'm literaly just going to watch for the piston to stop moving and reach TDC.


Also, just to rule out valves, i did a compression test on every cylinder and i'm getting between 155 - 175 on all cylinders.

And if anybody can awnser this, maybe its a clue as to what the ****s going on in this engine, yesterday i pulled into a gas station, shut her off and fueled up, i started it back up, and 10 seconds later, at idle, in park, it cut out to 0 on the tac, engine stopped, and then started back up on its own, not with the starter of course, but i just ...bounced back to life? I didnt touch the gas, nothing, just did it all on its own, what the hell?

 

[megaladon6]

that's the ignition system. it may be a loose wire or a module. i was working on a customers car that used to be perfectly fine for us, but would randomly cutout when the owner had it. as i'm checking the usual crap i brushed a wire and it died. when i pulled my hand out (i didn't know that i'd hit the wire yet) the wire went back and the car fired over. the weird part was that the engine had been off for about 7-10sec. i just kept thinking of the movie christine!