396 misery - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

 
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post #1 of 4 (permalink) Old Oct 20th, 99, 12:53 PM Thread Starter
 
Join Date: Mar 1999
Posts: 5
I just rebuilt a 396 and put the performer rpm heads, intake, and cam.(240-246, .560-.573) I also installed a new Holley 750cfm doublepumper, and msd ignion, with the lightest springs installed. I can't get the thing to idle right, when I get it going, it eventually stalls, got the secondaries cracked, used a vacccum gauge to set idle curcuit. The engine seems to want more timing than usual. 10-1 compression. I have alot of steam blowby coming from the valve covers, at mid throttle,2000-2500 rpm, the engine pops and surges, have dual 2.25 exhaust, (too small?) also, doesn't seem to me it has 450hp as it should, very little take off power, (stall converter is 2600, but feels much lower, also wants to stall when in gear (3.55-1), how much timing should I be shooting for? am My jets to small?, plugs look brown, but ok. any help would save a sane man.
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post #2 of 4 (permalink) Old Oct 20th, 99, 05:33 PM
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Bill
 
Join Date: Aug 1998
Location: Waldorf Md. USA
Posts: 3,300
68,
Did you buy a vacuum advance distributor, or a all emchanical. My experience is that any street driven car needs a vacuum advance. That is the only way you can get enough advance at low to mid rpm without having way too much total. You can verify this by increasing your timing to around 25 deg and see how the car responds. Just be carefull because you will have way too much total when you do this.
I hate to burst your bubble, but there are very few TRUE 450 hp street engines out there. You are talking about over 1 hp per cubic inch and that is generally a fairly stout motor. I know what all the "desktop dyno" crowd and other bench racers have to say, but I have had them on the dyno, believe me 450 HP out of 396 cu in is a stout motor.
Please don't take this the wrong way, but judging by your questions you need to ask around and find someone close to you with the experience to help you set the car up properly. It really is not something that can be done "long distance" I am also concerned with your blowby problem. If the motor is fresh, there really should not be any thing coming out of the breathers. Sounds like the rings are not sealing properly. You said you rebiult the motor?? Was it bored, new pistons etc, or just a "re-ring and bearing job" not really a rebuild.
Try bumping the timing up and see what happens.
Hope this helps,


------------------
Bill Koustenis
Advanced Automotive Machine
Waldorf Md


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post #3 of 4 (permalink) Old Oct 20th, 99, 06:05 PM Thread Starter
 
Join Date: Mar 1999
Posts: 5
thanks for the reply, yes, I did purchase a vacuum advance distributer, I have it timed right know 16 initial, 38 total, all in before 3000rpm, and it runs good there, it also all but eliminated the steam from the head cover vent holes, does that make sense? The block was bored .030 over with forged pistons, arp bolts complete bearing job, line honed, etc. by a reputable shop. The idle problem still exsists, it idles at 2000rpm for about a minute, then drops down to 750rpm and holds there, wanting to die. My vaccum at idle flucuates between 8 and 10 inches, maybe I should check my powervavle #, the idle adjustment screws do little. Maybe i should try to crack the secondaries alittle more? Thanks again.
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post #4 of 4 (permalink) Old Oct 21st, 99, 12:31 PM Thread Starter
 
Join Date: Mar 1999
Posts: 5
ok, here I go again, came out this morning and the car would not fire on that timing setting, so I advance it a little more, 20 initial, 42 total, runs good, got a 45# (had a 65) powervalve, idles great!!! I misread the vaccum gauge, I had only 6 inches at 1000rpm, now I idle at 800rpm, and is steady with good thottle response, now I need a 2800 stall and we'll see.
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