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Old 04-17-2021, 01:39 PM   #1
kcstreetracer
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Engine doctor needed!!! Help 😆

Ok guys I have a 68 I've been restoring for a yr. Finally to a point of starting it. Here's what its doing. Go easy im not a real great troubleshooter.

73 350
New top end. HEI, Cam, lifters,rockers, pushrods, holley mechanical secondary carb( supposedly rebuilt ready to go)

Got everything buttoned up last night amd fired it up. Started for a second and died. Let go till this morning as it was late amd didn't want to disturb the neighbors. Today it won't start and once in awhile sounds like it'll start but won't. Periodic backfire no flames just a puff of smoke

Last night I checked valves. It has spark. 6.5 psi fuel pressure. Pretty sure timing is right as it fired last night. Has spark but won't fire with starting fluid now Today

Its a new flat tappet cam and I don't want to wipe the lobes out trying to get it going. Any direction for a newbie is greatly appreciated

Also is a new factory wiring harness and using the hei conversion wire repinned in harness.
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Last edited by kcstreetracer; 04-17-2021 at 01:49 PM.
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Old 04-17-2021, 01:53 PM   #2
custom10nut
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Re: Engine doctor needed!!! Help 😆

Did you set the lash on your valves? Itís sounding almost like you have them too tight, so when the lifters get pumped up with oil, your valves arenít seating.
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Old 04-17-2021, 01:58 PM   #3
kcstreetracer
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Re: Engine doctor needed!!! Help 😆

Yes the initial setup. Pushrods had all up and down movement gone but still could spin.
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Old 04-17-2021, 02:07 PM   #4
morepwr
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Re: Engine doctor needed!!! Help 😆

Sounds like timing to me. Even it fired and died the distributor might be a tooth off. You might be able to advance or retard the timing if there is room to move it a bunch and get to run. But I know HEI are fat and if there is a vacuum advance there isn't much room.
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Old 04-17-2021, 04:57 PM   #5
truckster
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Re: Engine doctor needed!!! Help 😆

It's timing. Verify TDC and #1 are aligned on the compression stroke.
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Old 04-17-2021, 05:08 PM   #6
03BlkZ
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Re: Engine doctor needed!!! Help 😆

I agree it definitely sounds like a timing issue. Pull the distributor. Make sure #1 is TDC on the compression stroke and then drop the distributor where the rotor points to the #1 cylinder when it's all the way seated. I just fired my 70 C10 with 350 yesterday for the first time since full rebuild. She fired right off and I had to just tweak the distributor and went right into break in. Good luck fella!
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Old 04-17-2021, 05:50 PM   #7
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Re: Engine doctor needed!!! Help 😆

I'm with all the others;
"Sounds like timing to me. Even it fired and died the distributor might be a tooth off."

Mark #1 on the distributor using the cap to get it correct. Easy to loose a few degrees in the translation.
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Old 04-17-2021, 08:09 PM   #8
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Re: Engine doctor needed!!! Help 😆

+1 on "it's the timing". Plug wires correct?
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Old 04-18-2021, 04:20 PM   #9
Wrenchbender Ret
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Re: Engine doctor needed!!! Help 😆

Check to see if the carb is flooding. You may have gotten a foreign object in one of the needles & seats.
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Old 04-19-2021, 12:21 AM   #10
GASoline71
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Re: Engine doctor needed!!! Help 😆

timing might be 180 out...

Gary
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Old 04-19-2021, 06:37 AM   #11
Minkota
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Re: Engine doctor needed!!! Help 😆

I too think it may be timing. did you double check the timing of the Cam before closing it up? also, as mentioned above it most likely is just 180 out.
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Old 04-19-2021, 08:45 AM   #12
AussieinNC
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Re: Engine doctor needed!!! Help 😆

Little known fact...when you install the cam and chain and have the dot on crank at 12 oclock and dot on cam at 6 oclock, the engine is actually on compression point for cylinder # 6...not #1.....

If you installed the distributor to fire#1 without rotating the crank one turn the distributor is 180 degrees out of position.

Simple to check....remove spark plug from cyl #1, have a helper bump the engine over slowly while you hold your finger over the spark plug hole...when you fell compression building, manually turn the crank to align the timing mark on balancer to timing tab...remove dsitributor cap and rotor should be pointing directly to cyl #1....if its pointing at #6 lead post, the distributor is 180 out....

You can either pull the distributor and turn rotor to correct position, or some folk just move the leads around, placing #1 lead on #6 post....

Double check firing order...18436572....
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