Brians1

Gurus,
On my Stock 81, I am under full CCC control, no error codes/CEL

The following is occurring:

• Timing set to 12 BTDC (Timing light verified on #1 Cylinder)
• base timing set by disconnecting the Dizzy pigtail
• Idle is great, smooth and strong
• Drive on road - starting at 5 MPH I get terrible knocking (sounds like hammers banging rapidly on the block)

I Advance the timing to 16-18, even 22.....the knock is less present until higher mph and I get a tiny bit of perf..tiny....so to me going that far advanced tells me the CCC/ECM is not really calculating correctly and thus I’m getting the terrible perf/bad timing....

thoughts??

My setup:

• Freshly rebuilt Q-Jet (the E4ME electric controlled / CCC) ** Built by national Carb’s in Jacksonville Fl
• MSD Coil, Cap, Rotor, Accel Ignition Module (MSD doesn’t make one for the 81 CCC)
• MSD 8.5 MM plug wires
• Corvette central true dual exhaust (no cat – straight to Magnaflow mufflers)
• Stock TH350 trans with stock 2.87:1 Dana 44
• 86K miles on the original 350 motor

qwank

is your distributor installed correctly? could be off a tooth.

Brians1

Qwank,
This could be entirely possible....I purchased the car with a Vacuum Adv dizzy and a crappy edlebrock....E4ME was in a box.

I put the ccc dizzy in.....and all I did was try and align it like the vacuum one as I made marks....

How should I go about ensuring the dizzy is on the right tooth?

qwank

put the #1 cylinder at top dead center (line the timing mark on the balancer up with the timing tab) and see where the rotor points. if it's not pointing to the number one terminal, it's off.

Brians1

So if I understand correctly....
The timing mark (line) on my harmonic balancer should be in the center of the open circle on my Timing Tab..this indicates TDC (? yes?)...then look at the orentation of the rotor...if the pointed end with the metal contact is not pointing at #1 cylinder (i.e. the front driver side cylinder) then I need to pull it out and align it so it does... ??...if i were to take a yard stick and lay it on top of the rotor to the cylinder...its should line up yes?

My timing Tab is like this....

Jig A Low

in general the rotor should be pointing towards the #1 cylinder, but it's more important that it's pointing to the #1 spark plug wire on the dist. cap.

Brians1

Thank you ...like this..yea?

Amorget

I don't understand how if the timing is correct the distribution could be off? Unless you guys are saying timing is off AND the harmonic balancer has slipped...

Brians1

So I got the motor to #1 cylinder TDC, took off the cap and the rotor was pointing at #8 cylinder!
I guess I know what I will be doing tomorrow night after work

Amorget

You are fine, it is probably pointed at #6 which fires opposite of #1. Turn the motor over one more time and it should point at #1.

Brians1

Honestly Im going to start from scratch for peace of mind.
Im going to pull the valve cover, get it to TDC...and then insert the dizzy correctly

** and the rotor was really pointing almost directly at the passenger seat vs directly at #8...it was def off.

Amorget

If it was pointed at #6 on the cap then you are probably ok (which is basically the passenger seat) . Turn the motor over one more time and see if it is pointed at #1 then. If it's 180 out the car probably wouldn't start and if it did it would idle horribly. Just do that before you pull it all apart.

However, in saying that, you might want to verify that the timing mark on the harmonic balancer is at 0 when you are at TDC. If it isn't you need a new harmonic balancer.

I am trying to recall, did you buy a scan tool to see the values the ECM is seeing? If so, make sure your MAP value seems right along with Coolant Temp Sensor and RPM.

Brians1

Ok got an update just not a good one.....
1st attempt ..... Aligned the mark on the harmonic balancer to TDC...put the dizzy in with rotor and cap pointing to #1 cylinder.....won't start and very bad backfire

Second attempt
Took off valve cover and watched #1 cylinder exhaust and intake open and close....took a look at the harmonic balancer....no line.....
I used a marker and drew a line for TDC...turned it over a few more times and every time my mark hits in comparison to #1 valve action. I placed the dizzy back in and it all lines up to #1 cylinder

I haven't attempted to start it yet because I'm in fl...it 96, hot as hell in my garage and the damn bugs are insane ! So I'll try and crank it in the AM

To me this looks suspect to a bad harmonic balancer....looks to be the original so I guess over 30 years it could have slipped ?!?! Doesn't the "inner ring" of it have a notch which gives it the static position of TDC??band the outer portion may have slipped... See options from summit...pretty cheap and 1 piece I think...

qwank

Sounds like a bad balancer. I replaced mine with a stock one from GM.

LannyL81

A gree....sounds like the outer ring has slipped. Balancers are not all that difficult to change-out, just be sure to use a puller/installer.

Good luck.

Brians1

Yes I've got the tools so changing it out today....I'll report back

jotto

Interested in how the change went, pics if possible with a write up!
I have the tools and the balancer.........

LannyL81

Balancer is pretty easy to swap-out as long as you have the puller / installer.

Take fan out to give you some room.
Then with trans in gear, remove the center bolt. I made a bolt that slides into the crank snout; ground all the threads off it and it is long enough to bottom out against the crank.

Install the puller and let the puller bolt push against this "bolt" so the no chance of damaging the threads of the crank....dab of grease on "bolt" head. Leave trans in gear and let the puller do its job.....balancer comes off.

Once balancer is off look to see if there is a groove on the sleeve, hopefully not as the seal may need to be replaced. Now I have never tried to replaced the crank seal with the timing cover in place....I take the water pump off and remove the timing cover...seems to be easier than trying to drive the new seal in with cover on the engine....but am sure others have.

Anyways installation just requires a coating of engine oil on the seal and on balancer sleeve, inside and outside. Then using the Installer the balancer is pressed onto the crank snout. Just need to ensure that the crank threads and Installer threads are clean first, then a dab of grease on them and proceed carefully as you do not want to strip the crank threads.

Let me know when you want to do this and I will pop-over and help.........if only I could!!

Brians1

Ok so I got the old balancer off (see pic).... I have stopped for the day because the Florida heat in my garage is terrible!!

Once I get it back on..to get to TDC when I put the dizzy in, do I just need to rotate the balancer until is lines up right on the line, no need to pull the valve cover again ??

jotto

As there is a key way on the balancer/crank it can only go on in one position and this will either be TDC for no1 or No6 iirc.
Can you post a pic of old vs new, had the original slipped?


Lanny, come on over, we'll have a ball!