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sbc 355 wont idle in gear

 
kolton
V-6 Camaros rule!
Posts: 44
Joined: 04/11
Posted: 07/21/11 12:33 PM

Hey guys. I have a SBC 355 that wont idle in gear. We recently did a cam change. We went from a hydraulic flat tappet to a solid flat tapped. We got it all back together and we got it running good enough to break it in. At that point, we didnt know it wouldnt idle in gear because we had not tryed driving it. We timed it to 10 degrees and set the idle at 800-900 Rmps. When it warms up actually to the point where its running about 190 200 degrees because of this 95 degree heat, so actually hot and it had trouble idleing above 350 400. All the plugs are good and plug wires as well. New cap rotor as well. The cam card said to set valves at .016" which we did. what could my problem be? The model number on the cam is 12-677-4  

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Pontiacman2
Moderator
Posts: 8956
Joined: 09/08
Posted: 07/21/11 12:54 PM

What stall speed converter are you running?

What is it idling at in drive?
You should have it idling at 1000 RPM in park.  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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kolton
V-6 Camaros rule!
Posts: 44
Joined: 04/11
Posted: 07/21/11 01:31 PM

stock stall and in gear it rly wont idle unless i hit the throttle a bit to hold the rpms up  

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Pontiacman2
Moderator
Posts: 8956
Joined: 09/08
Posted: 07/21/11 01:40 PM

You need a 2500 stall converter for that cam.  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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kolton
V-6 Camaros rule!
Posts: 44
Joined: 04/11
Posted: 07/21/11 02:12 PM

so its normal when it wants to kill at stop signs?  

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Pontiacman2
Moderator
Posts: 8956
Joined: 09/08
Posted: 07/21/11 02:20 PM

Thats why you need a 2400+ stall converter so it don't try to pull through the brakes and want to die at a stop.

Cams like that require a higher then stock stall converter.  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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kolton
V-6 Camaros rule!
Posts: 44
Joined: 04/11
Posted: 07/21/11 02:32 PM

another question is, in this rly hot humid wheather, could that b a reason for it runnning terrible  

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Pontiacman2
Moderator
Posts: 8956
Joined: 09/08
Posted: 07/21/11 02:38 PM

Explain what you mean by  runnning terrible is it missing or what?  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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kolton
V-6 Camaros rule!
Posts: 44
Joined: 04/11
Posted: 07/21/11 02:47 PM

it seems like it runs decent but then when it warms up in starts stalling out pulling into my driveway. I have aluminum heads so im kinda worried i might have warpped the heads. i never took it over 250 degrees. The half way mark is 220. its not missing no. idk what else it would be. timing is set at 12 degrees and im running a holley 750 vacume secondarys  

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kolton
V-6 Camaros rule!
Posts: 44
Joined: 04/11
Posted: 07/21/11 03:04 PM

and also, id like to add another question. Putting in a new cam, would that mean id have to retune the carb?  

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Pontiacman2
Moderator
Posts: 8956
Joined: 09/08
Posted: 07/21/11 03:21 PM

The temperature has reach as high as 250 degrees if so that is more then enough to cause plenty of damage. Crazy

You shouldn't have to re adjust the carb.  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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1980elcamino
I have an SS396 tatoo
Posts: 295
Joined: 09/10
Posted: 07/21/11 06:25 PM

dang. 250! I have never gone above 200. Sounds like its time to upgrade your cooling system. I have $200 in my cooling system. It consists of dual electric fans I got at a junk yard for $30, A four core radiator from Auto Zone, 180 thermostat with two tiny holes in it, all new hoses and fresh coolant. Definitely a worthwhile investment. I went out driving today (95) and had no problems. (similar engine)  P man is right about the torque converter for that engine. I don't think it should drop to 350 to 400 rpm and stall though. Maybe 650-700 and run a terrible quarter mile. Check for vacuum leaks and double check your idle air fuel ratio screws.  

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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 07/23/11 10:19 PM

Hi there,
 Mechanical cams are sneaky and that is why I would
 try 14*38* total advance at 3000 rpm.
 and set the idle at 850/900 rpm. What plugs have you got
 with what heat range? What jets are in the primaries of
 the 750 holley??  There could be a lot trial and error
 depending on the inlet manifold you are using..Skyeking  
skyeking

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