1972 225 v6 timing issues

[hunt2labs]

This old Buick (OMC) engine was running wonderfully until recently. A mechanic friend believes the timing belt jumped and it's time to rebuild.
Here's what's been done: Replaced condenser, points, plugs. (Wires fairly new and distributer cap looks good.)
Here's the symptoms.

Starts and runs at idle. Bogs down with throttle up.

If we advance the distributor to the position that the engine runs smoothest, the timing position is past the scale stamped on the engine.

Gaps are correct.

Set cyl. 1 to top dead center, and we are way off the marks on the timing scale.

Advancing or retarding the distributor does not help engine runs smoothly when throttled up.

Does this sound like the chain jumped timing and I have to crack it open?

Thank you again for all your great input over the years.

 

[alldodge]

Does this sound like the chain jumped timing and I have to crack it open?

No, sounds like you need carb and timing work. Bog during throttle up would be accelerator pump

Since the timing mark does not line up your vibration damper probably slipped. Can get a piston stop bolt and find TDC on number 1 then use timing tape, or get another damper.

 

[Scott Danforth]

I agree with AllDodge that the carb needs cleaning/rebuild and the timing needs to be set correctly.

what was the dwell when you set the points? the dwell has to be in spec prior to setting timing.

 

[kenny nunez]

I hope you are using genuine Delco ignition parts, if not NAPA is a good source. That big box auto store stuff is Chinese trash. If the harmonic balancer is off and you cannot locate one there is a service advertised in Hemming's that can rebuild yours. Get a dwell meter to set the points @ 40*.

 

[hunt2labs]

Thanks Guys-
Delayed response.
Timing chain did slip. Replaced cranks and seals. Ran ok at idle, rough when throttled up. Checked oil- water getting in somewhere.
Much bigger problem going on now.

I am done with this project boat.
It was a free boat 5 years ago-now, not so much.
Last year winterized but did not get all water out and plugs popped. Probably cracked block as well that finally showed itself.
It had several runs this year before all this occurred.
Oh well.
Salvage perhaps?