timing weirdness, what to try next...?

[Jonnyuma]

I started muckin' around with my timing the other day in an attempt to find/fix an extremely high idle condition that couldnt be traced to the carb. When i manually turned the engine to TDC, the damper's timing mark was at 0 but the rotor was pointing at about 6 o'clock when it should have been at 5 o'clock (sm block 360). I pulled the distributor figuring the gear had somehow gotten 1 tooth off. With a telescoping magnet-y thing i got the slot pointed at the #1 tower (about the 5 o'clock position) but now the thing wont start at all. It got dark and i had to put my toys away so i never got around to checking for spark and all the other no-start troubleshooting, but im wondering if maybe i screwed it up worse than it was. If it was running with the dist so far advanced, but wont even start with it in the correct position should i be looking at the cam phasing and/or valve timing? The engine was rebuilt at some point by i-dont-know-who before i got ahold of it. Could the weird dist position have been used to compensate for something internal? Im gonna feel like a dolt if i find something crazy-simple when i get back to it, but to the best of my knowlege everything is hooked up correctly, i triple checked all my connections. Anybody been down this road. And if you have, did u have to push the car back? HA!

 

[HitIt]

You might have gotten your distributor 180 degrees out. I would find TDC on the compression stroke on cylinder #1 and make sure your distributor rotor is in the ballpark of cylinder #1. You may have found TDC on the power stroke which would have been 180 off.

an easy way to find tdc is to remove the plug and put your finger on the spark plug hole. Crank the engine. When your finger blows off, that the compression stroke. Then just get it to TDC on the balancer.

Your balancer might be off too, after some time the outer rings are known to loosen up and spin- making the timing marks useless.

Any funny timing stuff can't really compensate for a cam that is not installed right.

 

[Jonnyuma]

Oddly enough, or maybe not, balancer slippage was what i was originally going in to check for. I found TDC with my finger over the plug hole, then did it a couple more times to be sure, then checked it again with a screwdriver through the hole, turning the engine slowly by hand until it stopped rising. Each time the balancer's mark was on 0. How can i check to make sure the balancer is in the right spot? It seems to be, but i can be kind of dense sometimes and miss stuff. I wont even mention the time i spent an hr checking for spark on an engine, cranking it with a remote starter. I got tired of messing with it so when i reached inside to get my keys, and found them...in the off position...well, I'd rather not talk about it.

 

[Meep-Meep]

So it was running fine except for the high idle? What was the timing when you first checked it? Finding TDC by blowing your finger off then rolling the engine until you feel or measure the piston at its highest point is pretty good and should be within a few degrees - or enough to make the car run.

 

[Jonnyuma]

It seemed to be running strong, but it was idling at over 2000 rpm. The idle screw wasnt even touching the throttle lever and the idle adjustment screws had no effect. I think it was so high that it was pulling it off the idle circuit, rendering the screws useless. Although, to answer your question, I had the screws turnd to 1 and a half turns out and the timing set at 12 deg BTDC static with around 35 mech (vac can disco) coming in by 2500 rpm. I thought maybe the throttle cable was bound up or some other mechanical reason was the cause for the freaky idle speed but couldnt find anything like that. With the trans in gear it drops to 1000 to 1100 rpm. Driveable yes, but putting it in gear was a scary moment.

 

[HitIt]

Once you get it started again maybe check for vacuum leaks? The high idle in neutral and then dropping a lot once it's in gear sounds vacuum related to me.

 

[Jonnyuma]

I don't doubt there's some small vacuum leak(s), but my vacuum gauge reads within specs and the engine will die if I close or cover the choke tower. If anything, it seems to be running rich, if my sense of smell is still working properly. I can see both floats thru the sight glasses (good), fuel pressure is a steady 6psi. The carb is new-ish, maybe 10 hrs of run time, and isn't sporting any leaks. I would think it'd have to be a pretty major vac leak to cause that kind of trouble, right? I is most bewildered on this one.:black_eye:

 

[Meep-Meep]

Not sure if this was mentioned already but are the secondaries cracked open a tiny bit? If you have a Holley there is a tiny set screw facing the throttle side. It's kind of sneaky.

 

[Jonnyuma]

A good question...I haven't really investigated the 2ndaries. Something I'm gonna check on when I get back to it. Thanks.