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  #1  
Old 12-12-2002, 03:14 AM
George G. Leverette George G. Leverette is offline
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Default 360 short block

The last 360 short block blew #8 piston with only 486 miles on it. The short block was replaced by Mopar within a week and installed with Edelbrock RPM heads and intake topped with a Holley 750CFM carb. The engine runs like it has a major vacuum leak no power until about 2500 RPM then it performs fine. At idle it will hunt up and down approximately 200 RPM without throttle input. The carb shop says the Holley seems OK, the engine shop says the push rods seem to be holdoing the valves open and recommended a shim, adjustable rockers or Adjustable push rods. What other trouble shooting steps should be taken before more cash outlay?
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Old 12-12-2002, 10:24 PM
ohioDemon ohioDemon is offline
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george, i think i would do a compression test on the cylinders.
if you have a valve holding open,it should show up
are you running stock valvetrain?
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Old 12-13-2002, 02:23 AM
George G. Leverette George G. Leverette is offline
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I will do a compression check to try and determine if a valve is hanging open. I am running the stock valve train.
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Old 12-14-2002, 04:24 AM
George G. Leverette George G. Leverette is offline
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Checked the compression and it averages 165PSI with no more than 10PSI reading betrween cyclinders. The low vacuum is still a concern and although it starts easy it appears to be ignition related.
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Old 12-14-2002, 11:30 AM
ohioDemon ohioDemon is offline
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ok, i don't think its a valve problem.
try this, warm your motor up get some wd40 and spray around the bottom of carb and intake manifold. check all your carb and intake bolts to make sure they're tight.
unplug your pvc and plug where it goes into carb.


try this , ohiodemon
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Old 01-11-2003, 03:39 AM
George G. Leverette George G. Leverette is offline
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Tried the spray method and nothing changed. Changed the intake manifold gaskets and still getting 5 inches, need about 20 degrees initial to keep it running. Will try the PVC tomorrow.
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Old 01-11-2003, 05:25 AM
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dwc43 dwc43 is offline
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How big is the cam in this thing ??
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Old 01-11-2003, 10:56 AM
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rumblefish360 rumblefish360 is offline
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I had the samething. Low vacuum. The stock shortblock cam MoPar gives you is a Purple 292/,509.
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Old 01-12-2003, 01:07 AM
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Something in that short block did the same thing with me. I also had the Eddy heads. I finally went to a Holley 830 with the annular boosters and the four corner idling to get it straightened out. PRO had the same exact problem with his.
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Old 01-12-2003, 01:17 AM
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rumblefish360 rumblefish360 is offline
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Ya might have something there Dart. The cam is a stout lil'bugger.
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Old 01-12-2003, 09:28 AM
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Smile Unplug the vaccum advance diaphram

Do you have the vaccum advance type distributer? This will make the engine surge due to constant retard/advance at low vaccum.
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Old 01-13-2003, 11:45 AM
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With a cam that size we normally recurve the distributor for the correct total advance and disconnect the vacuum advance. I personally think that cam is a bit much for the 360 on the street. That is one of the things I do not like about that shortblock. I think the .484/.284 is a better selection for that set up. A Demon carb may be a good solution also.
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