Re: Engine Problem-Need Your Ideas Please
[Re: dennismopar73]
#1489181
08/22/13 10:37 PM
08/22/13 10:37 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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Quote:
Vacume leak on the intake, possible miss adjusted valves, or both!
The intake needs o be checked put it on dry checkit with feeler gage top bottom side to side, do not use cork end gaskets if it is aluminum just use gasket sealer . nice 1/4 bead will work great.
If intake checks out, use small amount o sealer around the intake ports top bottom of gasket .
Most small blocks love to leak on the valley side
 A sure test to see if you have a manifold to head port vacuum leak on the crankcase side is to block off all the openings on the valve covers ( breather, PCV, Oil fill cap, Etc. ) and see if the idle improves with everything blocked off. If it does, you have a vacuum leak to the crankcass.
Fastest 300
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Re: Engine Problem-Need Your Ideas Please
[Re: Rodder]
#1489183
08/23/13 12:28 AM
08/23/13 12:28 AM
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Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
cheapstreetdustr
master
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master
Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
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just start it up and let it idle..
then spray some carb cleaner around the areas you suspect may have a leak...like intake gasket area.
carb base ect...
if the idle changes drastically you have found the source of the vacuum leak
365" Iron J heads,,3480lbs best 1.39 60ft on SS springs.10.54,124 mph ...6.67 1/8th et.average 60fts 1.46 w/ small cam &.063 no2 pill tagged & insured
[image][/image]
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Re: Engine Problem-Need Your Ideas Please
[Re: Crizila]
#1489185
08/23/13 08:10 AM
08/23/13 08:10 AM
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Joined: Apr 2006
Posts: 46
Ohio
blown71duster
member
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member
Joined: Apr 2006
Posts: 46
Ohio
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Quote:
Quote:
Vacume leak on the intake, possible miss adjusted valves, or both!
The intake needs o be checked put it on dry checkit with feeler gage top bottom side to side, do not use cork end gaskets if it is aluminum just use gasket sealer . nice 1/4 bead will work great.
If intake checks out, use small amount o sealer around the intake ports top bottom of gasket .
Most small blocks love to leak on the valley side
A sure test to see if you have a manifold to head port vacuum leak on the crankcase side is to block off all the openings on the valve covers ( breather, PCV, Oil fill cap, Etc. ) and see if the idle improves with everything blocked off. If it does, you have a vacuum leak to the crankcass.
With everything blocked install a vacuum gauge on the dipstick tube and see if you have vacuum with it running from the valley side of the intake.
Also use a water bottle and spray on the header tubes after it runs for a little bit and make sure each tube is getting hot, great way to find a cylinder down.
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Re: Engine Problem-Need Your Ideas Please
[Re: blown71duster]
#1489186
08/23/13 10:44 AM
08/23/13 10:44 AM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
|
Quote:
Quote:
Quote:
Vacume leak on the intake, possible miss adjusted valves, or both!
The intake needs o be checked put it on dry checkit with feeler gage top bottom side to side, do not use cork end gaskets if it is aluminum just use gasket sealer . nice 1/4 bead will work great.
If intake checks out, use small amount o sealer around the intake ports top bottom of gasket .
Most small blocks love to leak on the valley side
A sure test to see if you have a manifold to head port vacuum leak on the crankcase side is to block off all the openings on the valve covers ( breather, PCV, Oil fill cap, Etc. ) and see if the idle improves with everything blocked off. If it does, you have a vacuum leak to the crankcass.
With everything blocked install a vacuum gauge on the dipstick tube and see if you have vacuum with it running from the valley side of the intake.
Also use a water bottle and spray on the header tubes after it runs for a little bit and make sure each tube is getting hot, great way to find a cylinder down.
 2 good ones 
Fastest 300
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Re: Engine Problem-Need Your Ideas Please
[Re: VernMotor]
#1489187
08/23/13 11:28 AM
08/23/13 11:28 AM
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Joined: Jan 2003
Posts: 10,001
Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,001
Frostbitefalls MN (Rocky&Bullw...
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Quote:
How much timing does it have at idle ?
You said you had light springs in it, if they advance too quickly, and you try and set your idle it will either run fast or the timing will fluctuate, reducing idle speed, which lets the timing back off, motor stumbles and dies. If this is the case (check with timing light) Find a bit stiffer spring that won't let advance start till 1200 rpm or so, and the bigger the cam you have in it, the more initial advance you will need and the less coming in through the advance plate. A moderate street strip cam may need 12 to 16 initial degrees timing, to a race cam demanding a locked distributor for best results.
This may be a problem along with a large vacuum leak. Check both.
Last edited by gregsdart; 08/23/13 11:31 AM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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