# Timing issue



## NDExpat (Mar 20, 2016)

My 1967 GTO 400 4V AT is starting to get my goat (pun intended). It seems to want to idle & run best at ~40 deg BTDC but bogs down & stalls when I put it in gear. I've looked at the post by 69 267 originally posted 2/18/18 because I seem to have similar problem. I went through the diagnostics/solutions posted there without getting any improvement.

I had the block rebuilt by a reputable machine shop, experienced Pontiac builder. He installed new rings, bearings, valve job and installed a 9779068 grind cam. I verified the timing marks were correct before I started re-assembling the engine.

I rebuilt the carb myself as per Cliff Ruggles book using his rebuild kit. There's a good chance it's a carb problem since this was my 1st attempt at rebuilding a QJet. I may look for an inexpensive, new carb to run temporarily & send my QJet off to Cliff Ruggles so he can go through it (if new carb makes a difference).

I've played around with indexing the distributor, moving it 1 gear cog in either direction, but that seems to make matters worse. I rebuilt the distributor as per Lars tuning tips posted in this forum. New coil, condenser, points, rotor & cap. Dwell is dead on 30 deg.

I've checked the valves according to some of the posts on this forum and everything seems to be correct. There doesn't seem to be much adjustment for the stock hydraulic lifters/rocker arms.

It's only pulling about 10" vacuum at idle so it could be a vacuum leak, but I've checked the intake as suggested in the thread started by 69 237 it seems ok. I've installed all new vacuum lines, PCV valve & grommet.

I'm stumped. Any advice is greatly appreciated.

Alternatively, can anyone recommend a good mechanic/diagnostician/tuner in the North Texas area (Fort Worth)?

Thanks


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## integrity6987 (May 10, 2017)

new harmonic balancer? Sure mark is at zero degrees TDC, rotor at #1 ?


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## NDExpat (Mar 20, 2016)

Original harmonic balancer. Rotor points to #1 position on distributor @ TDC with mark on 0. I rolled it around with a compression gauge in #1 spark plug hole to verify.


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## Bob Young (May 27, 2018)

Idle speed? If out of the idle circuit it will do stuff like that. Even with the 068 cam it should idle down to 500 in neutral, with timing set per spec. If not, you/or somebody did something to the carb or worse case the cam wasn't ground right if the marks line up.

Are you using an aftermarket roller chain? I remember some have 2-3 key ways for altered cam timing. Running 10.75 comp?
with the timing set at 6 the centrifugal advance should be 0-2 @500 and will run up to 10.5-12.5 @ 1000

Here's the correct placement of the keyways.


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