My1st

When setting the base timing in order to get it to 6 degrees above TDC the square part on the side of the distributor cap with wires going into it was darn near but up against the plenum. Looking at other corvettes they have plenty of room for adjustment before getting close to the plenum.

Would this be a sign of having a problem with the timing chain jumping a tooth on the gears and or maybe someone was in there changing the chain and or gears and didn’t have them lined up correctly thus causing my poor running condition?

As I stated in a previous post the car ran like crap when I became the owner and with all the tune up parts and setting the timing, low idle speed, and IAC voltage it’s getting better but still not running like it should.

aklim

Stupid question. Did you disconnect the distributor advance?

powerpigz-51

Distributor is a tooth out. If you are just trying to get 6 degrees, you are fine.

My1st

Stupid question? I’d say it was if I knew the answer. As the FSM says I disconnected the wire harness to the ECM before setting the timing.

My1st

Powerpigz-51 – if the distributor is off by a tooth wouldn’t that cause a poor running condition such as a miss which I have?

aklim

IIRC it was a tan wire. Just checking because I have been to a shop where they tried to set the timing with the WRONG connector disconnected. Just checking.

And yes, if the distributor was off a tooth, it could make your car run like crap, assuming it would run at all.

Do you know how to check your valves? When it is in position 1, certain valves should be open and others closed. Someone might chime in as to which is which and I am at work so I can't access some notes I might have.

My1st

Thanks aklim, yes it was the tan wire and the car does run like crap. It doesn’t backfire but it idles poorly with a miss at 600 rpm cold start and once warm it goes up to 900
I assume I’ll have to bring up #1 and realign the distributor.

If some one could chime in on the valves that would be great.

redrose

with damper timing mark under timing tab, engine may be 'ready to fire' EITHER cyl 1 OR cyl 6...check by int & exh valves both closed on one of those cyls for the cyl actually in firing position...'quick & dirty' check is to pull spark plug from cyl, put thumb over plug hole, have helper 'bump' engine over, feel compression push air from cyl as it comes to 'fire'.

if desired to change dizzy position by 'half a tooth', remove dizzy from engine, drive out the 'roll pin' that holds the dizzy drive gear to the shaft, rotate the drive gear 180* and re-install roll pin (dizzy gear has 13 teeth)

do NOT 'shim the dizzy gear to reduce vertical 'slop', that 'slop' is reqd to 'pump' oil up the dizzy shaft to the dizzy bearings at each 'engine decel' cycle.

coupeguy2001

1.These cars have no vacuum advance.
2. The distributor is a tooth off.
3. the timing chain could have stretched, but that's not important sice the cam manufacturers usually grind the cams 4 degrees advance anyway so when the break-in stretch is accomplished, it is straight up.

My1st

Okay it's niceoutsidein MInnesota so I can work on the car agian. To fix the distrbutor problem don't I just need to pull up #1 on the fireing stroke and lift the distributor up and turn counter clockwise a bit and drop it back in?

JAKE

Yep, that's pretty close to all you need to do. There's a little more to it, though.

Here's how I do it:

I turn the engine until the mark on the harmonic balancer is at 6 degrees BTDC ON THE COMPRESSION STROKE

The then turn the rotor on the distributor until it points at where the #1 spark plug wire would be when the distributor is installed.

I then use a long screwdriver to reach inside the engine to turn the oil pump drive rod so that it aligns with the distributor shaft.

Drop the distributor in and check to be sure the rotor remains positioned where the #1 plug wire is. If NOT, I remove the distributor and turn the oil pump rod a little more and try dropping in the distributor again. You may have to try doing that several times to finally nail it.
Once I get the rotor to point where I want it and the distributor to drop all the way down, I lock down the distributor, install the cap and make all the electrical connections.

There's another way to do the same thing, but do it this way first. Let us know how you're making out.

BE SURE TO FOLLOW THESE CORRECTED DIRECTIONS.

Hope this helps.

Jake

.

My1st

Thanks Jake, before you replied I had already done the job. I got lucky, all I had to do is lift the distributor enough to turn the rotor a bet and it dropped down and everything lined up. Reset the timing and at least now it starts better. Probably need to reset the IAC and idle again and hopefully that will help the poor running condition.

JAKE

Okay, glad it worked it well for you.

Jake