Original engine:
2bbl carb.
Points Distributor

Now:
​​​​​​H.E.I. Distributor
​​​​.30 over bore.
Comp High Energy Cam 268 Duration-454 Lift.
Rebuilt stock heads with roller TIP rockers
no timing marker now-did not reinstall.

Starts great/Shuts down great.
Timing Light attached to #1 plug shows mark at idle to be approximately 7 o'clock on stock balancer. Cannot rotate distributor enough to get to marker location.

Confused as timing seems to be approximately 1/4 of balancer retarded at idle.

I can attempt to move distributor a tooth.

Could timing be off this far and still run this well?
Missing any information for answer?

Please help?

 

You need a timing tab, otherwise you are in the dark about what the timing is.
7 o'clock, wouldn't that be down under the harmonic balancer on the passenger side ?
The timing mark on your harmonic balancer is keyed to the crankshaft and ultimately the camshaft. You can stab the distributor in on any tooth as long as the #1 plug wire is in relationship to the rotor. This would require moving spark plug wires on the cap possibly needing to be moved in proper rotation and turning the distributor housing to time the spark. You will need more intitial timing with the HEI.
Is your harmonic balancer defective ?

 

Could've sworn that I stabbed that distributor with the #1 cylinder on TDC of compression stroke.

I will go through procedure again to verify. This time I will mark location.

I will advance from there.

Any assistance in correct procedure would be greatly appreciated.

 

If you perform a Search of the keywords “timing mark” (with quotes) you’ll find numerous threads/posts on establishing timing mark as well as determining if the harmonic balancer may have shifted.

 

I am wondering what you are calling 7 o'clock.
TDC on #1 cylinder won't change, no matter where you stab the distributor in. Verify the timing mark on the harmonic balancer with piston at TDC. You still need the timing mark tab to time the engine.

 

You need to install the timing tab. No one can help if you do not have that.

 

Basically .... no.

First of all . . . . the obvious but I have to ask . . . . are you sure you are on number 1 ? Drivers side front cylinder ?

The next thing you need to do is verify that the outer ring of the damper has not moved. Pull the spark plug out of #1 and turn the engine over by hand until the piston is at top dead center. You might be able to see it through the spark plug hole or you can stick a piece of coat hanger wire in and turn it slowly until it is at the top. Does not have to be perfect. You just need to know if your damper is close.

I don't work on enough Oldsmobiles to know how common the damper spinning is but if you are on the correct spark plug wire then that a most has to be the problem. I just looked at one new Oldsmobile damper I have here and #1TDC will be in about the 1-2 o'clock position.

 

Please understand that I was taught old school on completely stock engines. I was taught to find the compression stroke by feeling for the rush of air pressure created by the #1 piston when rotating the engine. Then I rotate the crankshaft slowly to find when the #1 piston was at top of stroke. This is when I set the rotor to point to the #1 cylinder plug wire.

Doing this I have found that the timing mark on the balancer is nowhere near the timing tab on the block. About 50 to 60 degrees off tab.

 

I said 50 to 60 degrees off. I meant more like 100 to 120 degrees off. Instead of about 2 oclock where the timing tab is... it is between 6 and 7 o'clock.

 

Bought a new PRW Sportsman externally balanced harmonic damper to replace my stock balancer as I think it must be bad.
I assume that this damper is the same diameter as it replaces stock. I will know for sure when I pull old balancer.
Picked up a plastic 350 Oldsmobile Timing Tab from mid 70's cutlass 350 engine out of salvage yard (at the same time i took its HEI distributor). Diameter of stock balancer does not allow this plastic timing tab to bolt in.
2 questions either- or:
​​​​1) is newer timing tab located in different place?
2) are older and newer balancers different diameter?
either could cause.

 

The later plastic timing tab attaches to the dowel and the 3/8" bolt near the dowel. It should with the stock and aftermarket balancer.

 

Installed new harmonic balancer and original style metal timing tab. Found TDC utilizing piston stop method and marked zero (new balancer markedcorrectly).
Will put timing light to it now after i readjust rockers (hydraulic flat tappet with Magnum Roller TIP Rockers). I little bit of rattling.

 

All back together.

Adjusted Rocker and preloaded lifters.

Started fine. Warming engine to time.
All of the sudden engine started missing bad.

Pulled HEI distributor cap.
Carbon button burnt completely off and melted cap at button location burnt. Tab on rotor was bent too far from carbon button. Must have arced and burnt button.

Parts store today for another cap/rotor today.

 

Put the new cap and rotor in this morning.

Had to adjust the air / fuel mixture a bit. Idles great now.

WIll check the floats in the morning as I still have to full pedal to get as much air as possible to start (acting rich).

While i was in the distributor i noticed that the springs seemed awfully weak.

Do I just find out at what rpm that my advance is all in before I mess with the springs?

 

Yeah, see where your advance curve comes in and how quickly before swapping them. Usually the aftermarket springs are lighter than factory springs, at least on the factory HEI distributors.