Checking for wiped cam lobe (#3 cylinder)

[turbojoe]

How do i go about checking for a wiped/worn cam lobe? I have heard that you can remove a valve cover and just look to see if all rockers are moving up and down equally. I am trying to get to the bottom of a poor spool-up issue. Is there any other way to check for a wiped lobe? Also would a wiped lobe contribute to a rich condition (hi o2's) as well as higher Blm readings (135-138) ? I am generally concerned about the #3 cylinder (exhaust lobe) as this seems to be the most problematic on these cars from what i have read. THanks, JOe

 

[John Wilde]

Joe,

You should just pull the valve cover. Disconnect the power to the computer and have a friend turn the car over as you look at the rockers. When I lost number 3 I would get a lot of false knock that was created from the valve train issues.

 

[turbojoe]

Hey John, Thanks for reply! O.K., so if i see that #3 exhaust rocker is rising equally with other adjacent rocker arms, then this will be a good indication that I'm o.k., as far as a wiped cam lobe goes? Also, if I happen to have a wiped lobe on #3, what will that rocker do, not move much at all?

 

[John Wilde]

Yes it should be easy to see if it is bad.
When I saw mine it felt like someone punched me in the gut!
Mine rocker would almost not move at all.

 

[turbojoe]

Thanks John! I hope this is not my problem, but at least i now know what to look out for. JOE

 

[John Wilde]

Joe,

If this is the problem you should pull the motor and have it cleaned and checked out.

 

[GNX423]

While your at it you may as well check the other lobes, i had #5 exhaust go out on me. On and off valvetrain noise chatter with the occational bad idle and poor performance. One of my lifters appeared to stop spinning and was wearing in one spot.
It does not sound like you have these symptoms though.
Good luck,
Mike

 

[turbojoe]

I don't notice any strange noises except my exhaust header/crossover leak (tick tick tick) and i havn't noticed any debris or metal shavings in motor oil during draining. I do have sort of a lumpy idle (engine mounts are bad) and there is a noticeable lack in performance (poor spool-up). Car cannoty break the tires loose at all (only when applying gas against brake). The exhaust feels good and strong out the tailpipes. I'll just pull the valve cover (easy enough) seeing i'll be working on that side to replace my driver's side header (new AtR unit/nice!!). I am able to obtain maximum boost (17 lbs/Red's 93 chip) but it is a bit slow getting there. I'm hoping that it is just due to exhaust leaks.

 

[Russ Merritt]

When the weather gets better and you start drivin her again, come see me. I'm moving into a new shop in Holbrook in 2 weeks. We'll get her straightened out, no sweat!

 

[NCTURBOS]

Something else to look at if the cam is not the problem, is the torque converter. A bad or wrong converter can cause slow spool-up but still allow full boost at w.o.t.

The exhaust leaks pre-turbo don't help either.


K.

 

[stockv6]

With my stock gn I could only get the maf reading as high as 170 at 22 psi. I aswell had lobe 3E wipe

 

[turbojoe]

Thanks for all the replies guys! Russ, I will take you up on that offer, if spring ever gets here!
NCTURBOS, I checked the tourque converter by removing inspection cover. It is stamped D5 all around outer perimeter, but the stamping appears a little different than the stamping depicted over @ GNTTYPE. ORG. The stamping they show has a large D and a large 5. Mine has a small D and a large 5. Does this difference in the appearance of the stamping mean anything? Or does it only matter that its stamped D5? The converter, other than that looks like the stock converter. I tried to check the stall speed by applying throttle against brake in Drive. I think the tires start to spin at about 5-7 lbs of boost at about 2300 RPM. I found this method of checking the stall not very consistent or accurate though.