Problems after cam change

streetstang67

Member

Mar 5, 2003

573

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16

Lexington, SC

May 22, 2005

#1

• May 22, 2005

• #1

I installed a Comp XE256H cam yesterday and roughly set the timing and somewhat adjusted the valves.

Problem 1: Oil leak somewhere causing #8 cyl. header to burn oil
Problem 2: Engine misses under accleration
Problem 3: Car is not any faster.
Problem 4: While idling, car will randomly cut off, without any fore-warning.

Overall, I would think these problems are results of bad valve adjustment, bad timing, or bad carb. adjustment. What do you think, and how can I fix this?
Thanks

 

rbohm

Founding Member

Apr 12, 2002

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tucson,az

May 22, 2005

#2

• May 22, 2005

• #2

1: sounds like a valve cover leak to me.

2: vacuum leak likely, bad plugs or plug wires also.

3: gotta tune the new combo, timing, jetting, etc.

4: how smoothly does the engine idle? if not at all then likely a carb and timing adjustment are in order. as for valve adjustment, loosen each rocker in turn untill you hear the valve clatter, then tighten the rocker up untill it just goes away, then go 1/8 turn more.

 

Dark Knight

Founding Member

Feb 1, 2000

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Chandler, Az.

May 22, 2005

#3

• May 22, 2005

• #3

correct firing order? cam isnt ground with the late model firing order, is it?

check the back of the intake manifold too, for leaks..

prob 4 sounds like a loose wire somewhere.. check the coil connections etc..

 

dennis112

15 Year Member

May 15, 2005

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Amish Wonderland of Central PA.

May 22, 2005

#4

• May 22, 2005

• #4

Problem 3: Car is not any faster.

The XE256H doesn't sound like much more than a stock replacement cam so I doubt if there would be much of a perceivable difference in performance. You should probably work on your "tune" a little more--Perhaps try advancing the cam.

 

1

10secgoal

Active Member

Dec 1, 2003

2,801

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49

San Diego

May 22, 2005

#5

• May 22, 2005

• #5

Yeah. I has to be a major gain to feel anything in the butt dyno/ I made one mod, didn't really feel a difference. But picked up 2 tenths and 2.5 mph in the 1/4. So the butt dyno is about as accurate as a g-tech.

 

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

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Salt Lake City, Utah

May 22, 2005

#6

• May 22, 2005

• #6

DO NOT ADVANCE THE CAM. Compcams builds in an advance into their cams so they need to be installed straight up.

 

streetstang67

Member

Mar 5, 2003

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Lexington, SC

May 22, 2005

#7

• May 22, 2005

• #7

Isn't the cam and timing two different issues? How would I advance the cam?

 

D

D.Hearne

New Member

Sep 29, 2000

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south louisiana

May 22, 2005

#8

• May 22, 2005

• #8

Problem 2 sounds like a full tune up is in order, if the valves are adjusted correctly. Problem 4 could also be a short in the ignition. If you've got an aftermarket tach, the green wire, even though it's a ground, will short against metal and kill the engine, look for bare wiring where it goes thru the firewall if that's the case.

 

streetstang67

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Mar 5, 2003

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Lexington, SC

May 22, 2005

#9

• May 22, 2005

• #9

D.Hearne said:

Problem 2 sounds like a full tune up is in order, if the valves are adjusted correctly. Problem 4 could also be a short in the ignition. If you've got an aftermarket tach, the green wire, even though it's a ground, will short against metal and kill the engine, look for bare wiring where it goes thru the firewall if that's the case.

Click to expand...

The tach is broke...good thinking.

 

69Rcode_Mach1

Active Member

Apr 20, 2004

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Salt Lake City, Utah

May 22, 2005

#10

• May 22, 2005

• #10

streetstang67 said:

Isn't the cam and timing two different issues? How would I advance the cam?

Click to expand...

This refers to the camshaft itself you can install it so that your cams timing marks are aligned differently from your crankshaft this is how you can advance or retard your cam. This is NOT necessary with a comp cams product however.

 

D

D.Hearne

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Sep 29, 2000

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south louisiana

May 23, 2005

#11

• May 23, 2005

• #11

streetstang67 said:

The tach is broke...good thinking.

Click to expand...

Not good thinking, rather this was gained from actual experience, way back when I ran an aftermarket tach for the first time, and did the wiring half assed. No grommet thru the firewall. and after a period of time, it came back to haunt me when that green tach wire shorted. :damnit: