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New engine will not idle - HELP?!?

  • Thread starter Thread starter oz
  • Start date Start date Jul 13, 2004
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2nd Mustang

Founding Member
Feb 24, 2002
2,488
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46
Southern California
Jul 16, 2004
#21
  • Jul 16, 2004
  • #21
If I remember correctly, I was reading somewhere that cam specs, not sure of which, maybe it was lobe separation can cause low vacuum readings. I have a mild Crane hydraulic roller cam, and the best vacuum I can get at idle is 14 inches. The vacuum leak would be easy enough to find, unless it was an internal carb problem. I know how frustrating it can be, good luck.
 

oz

Founding Member
Jun 29, 2000
1,079
10
58
Plymouth, MI
Jul 20, 2004
#22
  • Jul 20, 2004
  • #22
Since last reply I have changed the fuel pump (no difference) and checked cylinder leak down.
I found #8 leaks down ~7% and cylinders #3, #4 leak down ~6%. All the rest were in the 3-4% range. Since this is a newly rebuilt engine, I think these are fine numbers. Another thing contributing to #8 being the worst is that during initial cam break in, the PCV was sucking in oil that ran straight to #8. I assume it will take a little longer for #8's rings to seat.

A knowledgeable frined stopped by and said that I should readjust my valves even though my compression and leak down numbers were solid. Easy enough I guess. He also said that the engine was running reasonably well but the 10 inches of vacuum at 900 rpm was disturbing.

The cam lobe separation is 112 degrees so I should have plenty of vaccum.

I misspoke before, the Cloyes timing set i have can be installed -4, 0, +4. I know for a fact I installed it straight up.... but didn't degree the cam....

Thinking about installing the braces, fenders, and hood and calling it good enough for now... If it won't run on the street with all the advance I have in it now (15 degrees at idle to make it run decent) I will pull the front of the engine off later and change the timing set.

Sound like a reasonable plan?

Thanks.
 

oz

Founding Member
Jun 29, 2000
1,079
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Plymouth, MI
Jul 21, 2004
#23
  • Jul 21, 2004
  • #23
Talked to a guy at Cloyes and he says that all Ford small block timing sets are ground straight up (but that most FE are ground up to 8 degrees retarded for emmissions) and that the timing set I used is the same one they sell to Edelbrock.... so I guess it's not a mismatched timing set and cam....
I bet the cam is off a couple of degrees retarded.... should have degreed it I guess.
 
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