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New cam and a rough idle...

  #1  
Old 08-26-2008, 08:05 PM
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Default New cam and a rough idle...

An exhaust valve cracked on my 00 Civic EX D16Y8 so I pulled the head and bought a rebuilt. I put this cam in it ( http://www.nopionline.com/nopistore/...0HONDA%20Civic ), using the stock rockers/lifters/valves/springs.

The car was up and running last Thursday night. I took it on about a 300 mile trip over the weekend while always changing the speed. It was running decently, but not as well as I was hopping it would. It was extremely doggy. I slowly advanced the timing until it was as far as it would go. That seemed to help but it's still doesn't seem to be as quick on accelerating like it was before. I cleaned and gapped the plugs to 1.1 mm. I used a new spark plug to check that the coil is good on the no 1 wire - nice white hot.

It's idling rough. Today I went around a clover leaf taking a right and it died. It's been starting a bit hard when it's warm and likes to idle around 250 till I push the gas. Is there something I can do? I'm going to check the valve lash tomorrow to make sure it's within spec. It's supposed to be .007 intake and .009 exhaust but I only had a gauge with .006 & .008 on it so I used that. What are the symptoms of too small of valve lash? I know this is a big post and a lot of questions it's just that I haven't stopped thinking about my car for the past 3 weeks.

Any help/insight with a beefier cam would really help! Thanks!
-Norbster
 
  #2  
Old 08-26-2008, 08:14 PM
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It seems possible that your timing belt is off by one tooth with respect to synchronization of the cam and crank at TDC1.

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Last edited by RonJ; 08-26-2008 at 08:17 PM.
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Old 08-26-2008, 08:30 PM
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I looked at that about 3 times. It seemed like it was right on the money, but it's hard to tell from the angle you get with the motor in the car. I'll check that tomorrow again when I check the valve lash. If it was off a tooth, the way I advanced the timing would need to be the way I slip the belt forward one, then retard the timing - right? Both would be toward the firewall.

And thanks RonJ!
 
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Old 08-26-2008, 08:41 PM
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Dang it! That's gotta be it! I remember the left side looking like it lined up okay, but the right seemed a bit too high. I bet it is off a tooth... ^^@%^*@$^@#%^@$ it! Do I HAVE to take the crank pulley off to move the T-belt one tooth?
 
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Old 08-26-2008, 08:47 PM
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Originally Posted by norbster86 View Post
If it was off a tooth, the way I advanced the timing would need to be the way I slip the belt forward one, then retard the timing - right? Both would be toward the firewall.
I also hope that I am thinking about this correctly. Facing the cam and crank as shown in the diagram, I believe that you should shift the timing belt clockwise one tooth on the camshaft gear. I think this can be done without removing the crank pulley. Just be sure first to loosen the belt tensioner. Be sure to check whether visually this better synchronizes the cam and crank at TDC.

When the timing belt is reinstalled, adjust the ignition timing (jumper wire on the service connector and warm engine idling to spec) so that the crank pointer aligns with the middle mark (red) in the group of three on the crank pulley.
 

Last edited by RonJ; 08-26-2008 at 08:49 PM.
  #6  
Old 08-26-2008, 09:24 PM
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I'm thinking if the fully advanced timing needed a bit more counter clockwise motion (looking at it from the passenger side). Doing a 180 on that should mean the cam needs to move clockwise one tooth (looking @ it from driver side). Then the timing can be backed off a bit clockwise. That would move the right side mark on the cam gear down & hopefully dead on.

So a beefier cam would still use the stock cam's ignition timing? I thought it would need to be advanced or retarded at least a bit...
 
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Old 08-26-2008, 09:33 PM
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Facing the crankshaft as shown in the diagram, advancing the timing would require movement of the crankshaft in the clockwise direction. For example, the three marks separated from the white TDC mark on the crankshaft are increasingly more advanced with respect to timing.
 
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Old 08-28-2008, 07:28 PM
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It's dead on. Yesterday the temp was into the upper 60's and my car ran fine. Today it was warmer out and it was running rough again at idle. 2 days ago when it was 85+ it was running like crap. Normally when you go to start the car, even if warm, it will rev up to 15K then back down to normal 600 rpm or so idle. On that 85+ day it would turn over a bit harder then normal (2 sec instead of .9 or so) and then run about 250 rpm then slowly make it to about 450. Tapping the gas peddle seemed to help a bit. But it still wasn't running like it should.

Could this be an ICM? I hope I'm remembering that correctly. I read something not long ago about a module that had really low quality solder on it from the factory that was known to go out. I couldn't find it though... for some reason searching for ICM returns zero results.

I'm gonna drive about 250 miles + this weekend to the cabin and will report back if it's still acting up (probably will be! it, like a typical woman, likes to tease).

Ron - thanks for your help on this. I'm pretty sure the timing on the car is dead on for what it is.

Any ideas from anyone?

Thanks,
-Norbster
 

Last edited by norbster86; 08-28-2008 at 07:32 PM.
  #9  
Old 08-29-2008, 05:25 AM
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If you are sure that the mechanical timing is correct, then use a timing gun to set the ignition timing so that the pointer for crankshaft pulley aligns precisely with the red mark on the crankshaft pulley (middle mark in group of three). Note that the service connector above the ECU must be "jumper wired" and the engine must be warm and idling to specification to set the ignition timing (see diagram below).

Prior to setting the ignition timing verify that the spark plugs are in excellent condition (see diagram below) and that the contact points of the distributor cap and rotor are corrosion free.

I think you should find out whether or not the new cam requires stock valve clearance settings. If addition, it would be a good idea to check whether the valve clearances are properly set on the rebuilt head, as you mentioned earlier.
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