Just trying to get my car figured out.

Car is showing the following symptoms:

Running extremely rich
Runs extremely rough up to about 2400 RPM where it cleans up.
Down on power big time

Could these all be symptoms of a cam that's not installed properly. Just ever so slightly misaligned??? The car is NOT overheating, NOT backfiring out the intake (sometimes backfires through the exhaust though), and just acts plain weird at times.

 

Do you know the ceterlines of the cam installed in the motor?

If you answer yes to that, it's not in wrong. (not to spec)


Bret

 

Unfortunately I do not know the centerlines. I never saw a cam card as it was installed by a shop whom I had the cam shipped to. I'm just running out of things to check and my tuner (alvin from pcmforless) thinks that it may not be installed correctly.

 

That could be it.... if you don't degree a cam you can't be sure it's in there right.

Bret

 

Exactly, which may be my case. I didn't put the motor together, and to my knowledge the cam was not degreed when it went it. My biggest problem is that I'm not going to be able to get any specs other than what was given to me: duration @ 0.050, gross valve lift, and LSA. That's all I got.

Do the above symptoms sound like it may not be in correctly, or could be in correct but improperly ground?

 

I'll go ahead and post my experiences with this car.

The car runs extremely rough, shakes, and just is really thunky if thats a word.

The car doesn't like to lean out anywhere near storch. It is EXTREMELY picky on timing (most na cars will run in the part throttle areas + or - 5 degrees or so without any consequences other than not running at full potential) This car will not run +- 2 degrees before major bucking and popping insues.

Same deal with the fuel, its extremely extremly picky. And is not taking fuel as where a car with those type of heads and compression usually likes some fuel.

those two above statements have always been a indication of either the distributor being off a tooth OR the cam off a tooth

The Dynojet wideband stayed between 12.5-14.0 during ALL times driving up to a pull speed on the dyno. Once it made a pull it stayed in a safe low 12. I was purposely doing small runs that until all the tip-ins where ok. I didn't get to make but one tuning AFR run when the power steering pump bolts broke. After about the 2nd pull up to 4th gear for a dyno run and it still was running badly I called the guy who normally ran the dyno (i was running it) over and told him to peak at those AFR numbers and listen to the car. He agreed something wasn't right at all. The afr was golden and unless the timing was at 10 degrees (which it wasnt) it should have ran OK. It instead popped sputtered shaked etc.

The car flat out just doesn't run good under 2400rpm and the cam doesn't sound that big. I've definately have done bigger. It doesn't even clean up when he pulls moderately threw the gears



This is what I suggest to Sean,

 

Personally I disagree with the cam theory, unless his old 224/230 was also incorrectly installed. This problem didn't surface from the new cam, it has been around for longer than I can remember.

 

Have you ruled out ignition related issues yet? Opti, wires, coil ect? Those kind of issues have a tendency to dissapear in the upper rpm range when the car isn't under such a heavy load to get moving. Just a suggestion. Incorrectly installed cam just don't sound right. If it was that far off, like off a few teeth, I don't think the thing would run right throughout the rpm range, as far as popping and sputtering is concerned. If it was ment to be advanced but was put in straight up or retarded, it would just be down on power in the low end, but not pop and stuff. Keep us posted. Strange....

Ken R.

 

Lets be clear, Before he had some crushed ring lands and surging issues..

This is like a real rough popping and studdering.. to me it never really goes away.. it just gets less apparent.

It could be a crossed plug wire, but not likely.. this is alot more serous of a shake and studder.

 

Alvin, thanks for getting in here with the exacting details of what you were seeing. You can explain it better than me.

As for the ignition, I've either replaced or swapped in known working parts from my other car. The opti has about 250 miles on it, the plug wires have about 400 miles and were all thoroughly inspected for burns and came up clean. The ICM was swapped back and forth with my other car. The coil is the Accel coil that comes with the 300+ and has about 700 miles max on it.

The car is sitting at Xotic Motorsports still getting the accessory bracket heli-coiled for the power steering pump bolts and getting new motor and tranny mounts put in it.

When the 224/230 cam was in the car with the stock shortblock, the car wasn't pulling bad vacuum, but was running extremely rich. As in 10.5:1 on the dyno. But it was smooth throughout the RPM range. Just had a momentary hesitation if you goosed it under about 2400 RPM as it flooded with fuel for a moment.

With this new cam in, it's still running extremely rich, but as Alvin said, it's also very picky, runs VERY rough down low, and just isn't acting like it should. When I talked to Joe O about the design of the cam, I did say "go big" and explained the setup in detail to him. Sadly, I NEVER GOT A CAM CARD from him. The cam was shipped directly to F-Body Central in Baltimore who also did the assembly of the top end to the new shortblock and installed the cam, so I cannot say exactly how it was installed. From what I can remember the cam was supposed to have 4* advance ground in to it like almost all LT1 cams end up with. Joe also set the cam up for the car being a near full weight 3.23 gear setup. I had explained that this is what I'm currently running, but in the future the car will be seeing 4.10's with the addition of a new rear, at which point we conversed about designing the cam to where we could just advance/retard to accomodate the changes in the future.

Another thought I had was the following: The new shortblock was supposed to be internally balanced, so the counter weight from the street twin flywheel was removed. What if this is not the case, and the removal of the counter weight from the flywheel is throwing things out of whack? Could that possibly have any bearing on the rough running down low until the motor was spinning fast enough to overcome it? It seems doubtful and a long shot, and surely isn't the root issue of the running problems, but it's a thought I had.

As soon as I can get the car back into my garage I'm going to tear the sucker apart and see what I find in there. If it's not the timing, I'm really looking at no choice but to pull the cam and try another. Not my top choice after dropping $400 on a custom cam, but it's starting to wear thin considering I've been fighting this car for 19 months now. My main concern is that I go to replace the cam and run across the same issues. I'm just very concerned about that happening considering I'm 2 for 2 right now.

 

Definitely not a crossed plug wire. I've got all of them taped at both ends with the respective locations. I learned the hard way last July about that. My ears are still ringing from the intake backfire that blew apart the bottom of the ram air box with my head right there.

 

improperly balanced motor wouldn't make it picky on fuel and timing.. It really sounds like its off a tooth to me.

Usually guys who have it off a tooth will time thier cars with the distributor to where it runs ok but they usually note that its hit or miss.

I did a car here locally that backfired and carried on when the timing was anything but 7-10 degrees timing at an idle.. Guess what hte problem was?

 

Which is exactly why I'm tearing it apart when I get it home. Unfortunately, I talked to Chris today and the car isn't the priority there, I.E. they've got scheduled guys due in before they can get to me. Completely understandable too. He said probably about mid next week, so by the end of the weekend next week I should have it apart and we'll know more.

Thanks for the help Alvin. For you guys out there, this is the kind of customer service that PCMForless gives!!!! He's been helping me through thick and thin with this car for a LONG time now.

 

bad map sensors cause the same problem...Start with the easy stuff