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Finally on the road.Need some help.

1K views 6 replies 5 participants last post by  -SS454- 
#1 · (Edited)
First time out since resto.didnt go good.Need some help.

Well after ten years and a lot of work my 70 is ready for the road again. So i thought. I took it out today and have some engine problems. Engine is a 406, basically stock, a little work to the heads,mild cam,Edelbrock RPM intake,Edelbrock 600 carb and HEI.Auto trans. No real road miles since rebuild. Just a lot of moving it around running time. Engine idles good but when i take off it boggs pretty bad then will accelerate bog a little higher in the RPM range then just runs real rough.After it cools off and i come back the next day I notice a little anti freeze will come out around the front of the intake where it seals to the block and a little around the the gasket by the valve cover.But its gelled up, not liquid. Also notice white smoke when i first start it up. I am thinking maybe an intake leak that is also leaking internally? I also notice that when setting the mixture screws the car will run better with one of the screws turned all the way in,then gets rougher as i back it out.Only back it out about 1.5 turns. What does that mean? I had the car running very good with a different carb (that i dont have anymore) i bought this carb new and am wondering if there is a problem with it. Im going to change the intake gasket first and go from there.Another symtom is that the idle will vary a lot.For example i had it idling around 1000 RPM. Took it for a ride and when i came back and put it in park it was up around 1500RPM. I backed it down to 1000RPM. Another ride.came back and it was idleing so low it wanted to stall.So i adjusted back to 1000 RPM.Timing is set to 8 degrees BTDC at idle.Vaccum advance is blocked off. Any thoughts?
 
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#2 ·
Sounds like a big vacuum leak.
After you fired the motor, make sure you retighten the intake bolts. They will loosen quite a bit. Make sure you use sealer on the bolts as they will leak if you don't.
 
#3 ·
Also,i noticed you said your running a mild perf cam with only 8 deg btdc intial timing which is VERY RETARDED for an aftermarket mild perf cam.

What are the specs on your cam?

Most if not all perf cams need approx 15-18(MAX) deg btdc initial timing so your wasting fuel,loosing power,and causing the motor to run hotter than it should by running 7-10 deg too retarded for the intial timing.

Bump up the timing before you try to tune out your problem because it may fix it all together or at least reduce the problem some.

But listen for detonation after you bump up the timing.

Scott
 
#4 ·
The cam is a Summit 1103. Specs are -
Cam Style: Hydraulic flat tappet Basic Operating RPM Range: 2,000-4,500 RPM Intake Duration at 050 inch Lift: 214 Exhaust Duration at 050 inch Lift: 224 Duration at 050 inch Lift: 214 int./224 exh. Advertised Intake Duration: 272 Advertised Exhaust Duration: 282 Advertised Duration: 272 int./282 exh. Intake Valve Lift with Factory Rocker Arm Ratio: 0.442 Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.465 Valve Lift with Factory Rocker Arm Ratio: 0.442 int./0.465 exh. lift Lobe Separation (degrees): 112 Intake Valve Lash (in): 0.000 Exhaust Valve Lash (in): 0.000
Do you think the intake leaking antifreeze could be a sign of where my vaccum leak is? I tried spraying the whole intake and carb base with carb cleaner with the engine running but it showed no effects. I will try playing with the timing.
 
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