Reproduction Parts for 1916-1964 Chevrolet Passenger Cars & 1918-1987 Chevrolet & GMC Trucks


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Joined: Jul 2020
Posts: 345
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Backyard Mechanic
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Backyard Mechanic
Joined: Jul 2020
Posts: 345
Likes: 20
Today... I had the engine running for about 1/2 hour... got it warmed up real good and adjusted the valves... boy..!! that sure is hard to get the screwdriver into the rocker adjusting slot while the engine is running... and then to put the feeler gauge in while turning the adjustment... then locking the lock nut....(got it done 6 &13)... anyway.... this is the first time I have run it that long, so I hooked my timing light up to a 12 volt battery charger and the clip on #1 wire.... shined the light in the hole and couldn't see the ball near the pointer...... so I loosened the dist. clamp and rotated it about 1" and then the ball and pointer lined up..... but I noticed that the vacuum advance arm was sucked in so the timing mark was lined up different than when cold & Not running....
So... My question.... is the timing supposed to be set (ball & pointer lined up), when the vacuum arm is sucked in...???
and did I do the right thing by turning the octane selector to zero, (while timing) then, to 8 retarded after timing is set ..???

Another question... It starts right up now after one rotation of the starter (when warm).... and several more when cold (with the choke out)..... BUT (when warmed up)... if I give it gas (accelerate quickly) it back fires ONCE, and then accelerates..... Is the timing causing this..?? or the vacuum advance causing this..?? or the mechanical breaker advance mechanism...???
How to test what is causing it.....???


1934 Chevrolet Master sedan
Filling Station - Chevrolet & GMC Reproduction Parts


Filling Station


Joined: Jan 2002
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ChatMaster - 25,000
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ChatMaster - 25,000
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the vavuum port to the vac, advance is closed off when at idle....all is well there.

To set timing set pointer to ball and marks on advance to zero. The advance setting on advance as necessrry. I always used 8 Deg advanced on mine,
Hesitation causes timing retarded
heat riser in hot position
problem with pump circuit in carb.

you retarded the timing 8 deg when you should have advanced it 8 deg.

Tp make a long story short the timing should be advanced as far as posible just so the engine does not bind up when starting with the starter,


Gene Schneider
Joined: May 2002
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ChatMaster - 6,000
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If the vacuum advance is sucked in the idle speed is too fast. Slow the idle down and reset the ball and pointer with the octane selector at 0 then when distributor mounting locked down advance the octane selector to 8 or 10. This should fix the back fire on sudden accelaration.

Tony


1938 1/2 ton Hope to drive it before I retire
Joined: Jul 2020
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Backyard Mechanic
OP Offline
Backyard Mechanic
Joined: Jul 2020
Posts: 345
Likes: 20
Great ...thanks both of you for the advice... I will try that...


1934 Chevrolet Master sedan

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