Engine Backfire Diagnosis Led to Wiped cam Lobes

[350runner]

85swb "Fancy"

Summit suggest you use the GM intake torque sequence... See pic. Start with 10ft/lbs then 15, last 25ft.lbs.

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[350runner]

Get a vac gauge bud. It will tell you the what's wrong with your engine. I thought you said you had gotten one a while back for seeing the a/f screws. With out it.. it's like the blind leading the blind...

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[Skweegle89]

85swb "Fancy"

This fella helping me told me not to buy one because he had one. Turns out he doesn't so now I have to pick one up when I go back to the parts store.


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[350runner]

Good deal.

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[350runner]

http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm

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[Skweegle89]

85swb "Fancy"

http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm

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Thanks.


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[Skweegle89]

85swb "Fancy"

The beast is alive. Got it timed. Idles fine. Couple of things tho. When I hit the throttle, it takes awhile to come back down. 4 or 5 seconds. It's not instant. Also, I'm only pulling 2.5lbs of vacuum at idle and I don't have a vac leak.


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[350runner]

What's the timing set@? Have you tried audio adjusting the a/f screws? 2.5 is low

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[Skweegle89]

85swb "Fancy"

What's the timing set@? Have you tried audio adjusting the a/f screws? 2.5 is low

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Timing is at 12*. I brought the a/f screws out to 2 full turns with close to no change in vacuum.


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[Skweegle89]

85swb "Fancy"

I know this big cam won't allow for much vacuum, but 2.5 seemed low to me too.


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[350runner]

Yea you just have a cam with a Heck o lot of duration is all... have you taken it for a ride?

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[DoubleDingo]

2.5 lbs at idle? Does a ported port pull that low of vacuum at idle? I have never put a gauge on one. Could possibly be a vacuum line connected to a wrong port? Just brainstorming.

OOPS, WAS A LITTLE LATE...LOL...

 

[Skweegle89]

85swb "Fancy"

Yea you just have a cam with a Heck o lot of duration is all... have you taken it for a ride?

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Just got back from a ride. When I shift into 3rd and give it gas it stumbles and pops out the carb once and I have to let out of it to let it catch back up. Running too lean?


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[Skweegle89]

85swb "Fancy"

2.5 lbs at idle? Does a ported port pull that low of vacuum at idle? I have never put a gauge on one. Could possibly be a vacuum line connected to a wrong port? Just brainstorming.

OOPS, WAS A LITTLE LATE...LOL...

I tried it on 2 separate manifold ports.
The only lines I have going to the carb are the vac advance and the pcv valve. All the others are plugged.

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[350runner]

UN plug that vac advance till you get it limited...

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