Question about Vacuum.
11-22-2003, 02:28 PM
#1
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Location: Greenville, SC
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Question about Vacuum.
I still think there is something wrong since my cam was installed. I have recently changed the opti, plugs, wires, and everything else. I still dont think Im getting any power from the cam. Next week Im planning on pulling the front of the motor apart and checking my timing chain. Before I do that I was gonna try to get some readings with a vacuum gauge. I know if its low that means I could have a vacuum leak somewhere or the timing chain could be off a tooth and not lined up properly. If the vacuum looks ok on the gauge does that automatically mean that the timing chain and dots are lined up properly?
11-22-2003, 07:03 PM
#3
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Well, I got the car on a vacuum gauge. It was reading anywhere between 8-11''s of vacuum. It was mainly staying around 9.5-10.5 but then it would drop down to 7.5 and go back up to 11. It was never a real steady reading. What do you guys make of this?
11-22-2003, 08:22 PM
#4
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I would be most helpful if you posted what rpm and what you were doing when you got those readings. 
That could be a little low for idle, depending on the LSA of your cam and spark timing/rpm.
That could be a little low for idle, depending on the LSA of your cam and spark timing/rpm.
Last edited by shoebox; 11-22-2003 at 08:49 PM.
11-22-2003, 09:02 PM
#6
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Originally posted by LT1ponykilla
The readings were taken at idle. I have the xe 224/230 cam on a 112 LSA. Like I said, the readings werent stable at all.
The readings were taken at idle. I have the xe 224/230 cam on a 112 LSA. Like I said, the readings werent stable at all.
11-22-2003, 10:34 PM
#9
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You cam's bigger than mine but I wouldn't expect your vacuum to be that low. I would suggest that you check for other vacuum leaks before you pull the timing chain cover off. Pull all the vacuum lines off the intake and plug the intake ports, then see if your vacuum improves.
11-22-2003, 10:36 PM
#10
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I would say that it is low enough to cause enough concern to dive into the motor. You could try spraying some starting fluid around the base of the intake too. If the car revs up you have an intake man leak. If it doesnt rev, still doesnt rule out intake leak completely, but its something to check.
My cam pulls about that much vacuum at 900 rpms and its quite a bit larger. Good luck.
My cam pulls about that much vacuum at 900 rpms and its quite a bit larger. Good luck.
11-23-2003, 11:15 AM
#13
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So its possible then that my timing chain wasnt setup dot to dot then or I have a vacuum leak somewhere?
As of now my car doesnt feel like its any faster from my cam. Good thing I checked the vacuum to make sure it was low. Thanks guys.
As of now my car doesnt feel like its any faster from my cam. Good thing I checked the vacuum to make sure it was low. Thanks guys.
