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AllRi5e 05-01-2011 07:17 PM

Won't idle under 60 degrees timing
 
I've been viewing this forum for about two years now, and have found the solutions for many of my cars issues by reading old posts. Well, I've searched and searched but can't find a good thread for this issue. Any help would be greatly appreciated!

Background.

I have a sbc 383 with 500 miles on it
hydraulic flat tappet, w/ 1.6rr
Aluminum heads 210 runners, 68cc chambers
MSD 6a, Msd wires, Blaster 3 coil, msd tach adapter, pro billet distributor
Professional Parts Typhoon intake
Holley S/A 770
Optima red top in the trunk

Problem
I can't get the car to idle under 40 degrees advanced. It actually pulls better vacuum and idles better at 60 degrees. It doesn't sound good at all and it shakes quite a bit. I've let it idle like this for about a total of 30 minutes. I pulled the plugs to run another compression check and the plugs were very carbon fouled.

I have checked the distributor position no less than 20 times. I cranked the balancer to TDC, took the valve covers off and verified both rockers on #1 were closed on the compression stroke. With the dizzy locked down at 60 degrees advance the rotor is now pointing to the next cylinder in the firing order when the balancer is on TDC #1.

I've built this car from the frame up and I'm about to give up and tow it to shop just to save my sanity. Help!!

68NovaSS 05-01-2011 07:41 PM

Has it been like this from day one? If the pointer is at TDC and the rotor is pointed at #8, and you're sure the piston is actually at TDC, sounds like you need to move the wires one tower clockwise or reposition the distributor.

If that doesn't fix it, maybe you have the wrong balancer or timing cover/pointer, do you have a timing tape on it or just the factory markings?

AllRi5e 05-01-2011 07:52 PM

Thanks for the reply!
No, in its first incarnation it ran at 13 degrees initial. Since then I've installed new heads, the 770 carb and put the battery in the trunk. Next time I'll change ONE thing, check it and move on to next thing.

I added a timing tape the other day so I could use a cheapo timing light instead of my digital. Same reading with both lights.

If I stabbed the dizzy incorrectly, couldn't I just rotate the cap until I found normal timing on the balancer?

dgcantrellsr 05-01-2011 07:58 PM

Quote:

Originally Posted by AllRi5e
Thanks for the reply!
No, in its first incarnation it ran at 13 degrees initial. Since then I've installed new heads, the 770 carb and put the battery in the trunk. Next time I'll change ONE thing, check it and move on to next thing.

I added a timing tape the other day so I could use a cheapo timing light instead of my digital. Same reading with both lights.

If I stabbed the dizzy incorrectly, couldn't I just rotate the cap until I found normal timing on the balancer?

I think the heads are too big & the carb is too big. JMO That's what was changed.
What intake ?

68NovaSS 05-01-2011 08:00 PM

Quote:

Originally Posted by AllRi5e
Thanks for the reply!
No, in its first incarnation it ran at 13 degrees initial. Since then I've installed new heads, the 770 carb and put the battery in the trunk. Next time I'll change ONE thing, check it and move on to next thing.

I added a timing tape the other day so I could use a cheapo timing light instead of my digital. Same reading with both lights.

If I stabbed the dizzy incorrectly, couldn't I just rotate the cap until I found normal timing on the balancer?

Well, the cap won't rotate without the distributor, moving the timing. Just moving the wires one tower should would do it.

AllRi5e 05-01-2011 08:02 PM

Too big, eh? I thought the carb might be too big but I didn't think the heads would be an issue. Any suggestions?

68NovaSS 05-01-2011 08:03 PM

Quote:

Originally Posted by dgcantrellsr
I think the heads are too big & the carb is too big. JMO That's what was changed.

Those aren't the problem and aren't going to change the timing. Too big or not, the rotor is in the wrong position.

AllRi5e 05-01-2011 08:05 PM

Quote:

Originally Posted by 68NovaSS
Well, the cap won't rotate without the distributor, moving the timing. Just moving the wires one tower should would do it.


I thought about doing that but isn't that the "one tooth off" thing?

68NovaSS 05-01-2011 08:06 PM

Quote:

Originally Posted by AllRi5e
Too big, eh? I thought the carb might be too big but I didn't think the heads would be an issue. Any suggestions?

210 might be a little large, and slightly effect intake velocity, not a show stopper IMO. You can jet the 770 down if you're running rich.

bubbahotep 05-01-2011 08:09 PM

That carb seems ok to me assuming its the vac secondary it'll size itself accordingly

Your sure that timing light is any good with the MSD? Used it before on any msd systems? Some lights cant read multispark correctly

At 20' (for example) timing what exactly happens? Does it just stall out, sputter, or rpm drops?

The rough idle and fouled plugs you describe sounds like a carb or spark issues. At 60' timing what are your rpms at idle? It sounds a little like your using the timing to compensate for bad fuel mixture or even a dead spark on a cylinder.

Custom10 05-01-2011 08:19 PM

Have you double checked your valve/rocker adjustments? what is the engine pulling for vacuum? maybe a leaking intake gasket. Is the dist power and ground OK?

AllRi5e 05-01-2011 08:20 PM

Quote:

Originally Posted by bubbahotep
That carb seems ok to me assuming its the vac secondary it'll size itself accordingly

Your sure that timing light is any good with the MSD? Used it before on any msd systems? Some lights cant read multispark correctly

At 20' (for example) timing what exactly happens? Does it just stall out, sputter, or rpm drops?

The rough idle and fouled plugs you describe sounds like a carb or spark issues. At 60' timing what are your rpms at idle? It sounds a little like your using the timing to compensate for bad fuel mixture or even a dead spark on a cylinder.

At 60* it idles roughly at 1300

I used my digital light with this MSD before and it worked fine. I thought the gun could be wrong after I relocated the battery so I bought the cheap one and got the same reading.

Is it possible to compensate bad mix with advanced timing?

20* is a no go. Once I get below 40 the rpm starts dropping, it starts shuddering and dies.

I was thinking weak spark but I didn't think the MSD could "do" weak spark.

AllRi5e 05-01-2011 08:26 PM

Quote:

Originally Posted by Custom10
Have you double checked your valve/rocker adjustments? what is the engine pulling for vacuum? maybe a leaking intake gasket. Is the dist power and ground OK?

Carb has vac secondaries. Suppose to be plug a play for cars under 450hp. I think someone messed with it and returned it.

Would tight valves cause this? I did install the rockers myself and it was my first shot at it.

Vacuum 17-19", the gauge shakes back and forth.

I spray the carb base plate and intake with carb spray and listened for any change in idle. No change.

curtis73 05-01-2011 08:30 PM

First I would do is verify TDC. Its pretty common for balancer rings to slip on the rubber ring, so the timing mark isn't always a good indicator. Don't worry about being a tooth off... that is only a problem with points ignition. With more modern ignitions, it doesn't matter what tooth its on you just turn the dizzy until its lined up right.

Second I would verify the carb tune. Look down the throats while its idling. Is there liquid fuel dripping from the boosters? If there is, chances are its a blown power valve or a needle/float issue.

This is assuming that you have the firing order right. I know, its a stupid thing for me to say, but I have chased all kinds of issues only to find out that I skipped the basics.

Help us out.... cam specs and compression?

68NovaSS 05-01-2011 08:31 PM

Quote:

Originally Posted by bubbahotep
That carb seems ok to me assuming its the vac secondary it'll size itself accordingly

Your sure that timing light is any good with the MSD? Used it before on any msd systems? Some lights cant read multispark correctly

At 20' (for example) timing what exactly happens? Does it just stall out, sputter, or rpm drops?

The rough idle and fouled plugs you describe sounds like a carb or spark issues. At 60' timing what are your rpms at idle? It sounds a little like your using the timing to compensate for bad fuel mixture or even a dead spark on a cylinder.

I recall some lights aren't compatible, and require use of an Equus type digital light. Yours might be that, but like he says here...check to be sure.


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