Hey all,

I have been a member of this site for several years, and a camaro enthusiast for many more. I used to post here quite often and some of the old members might remember me and my cars issues. I BEG of you experts to give me a hand with this one. (Fred )

So here it is, I’m going to take ONE last stab at trying to figure out what is up with my car, so lets make it a good one! Lol.

Anyways, some history before we get into it.

Bought the car used, 77k miles on it. Car ran VERY strong, couldn’t have been happier. I started with the simple mods first, the usual filter and catback. I could tell the difference, car ran even better!

Then after owning the car a little over a year, and doing some suspension mods and basic stuff, soundsystem, etc., I decided to go bigger. I went with Hotcam kit, headers, wires, and plugs. I had them professionally installed just because I wanted everything done right. Car sounded great, but I wasn’t impressed performance wise. I felt a bigger improvement from filter and catback then from Cam and headers.

The car seemed to have LOST top end. Torque was and still is awesome! However, it feels like the car is falling on its face on the top end, around 5600 and up, its shifts, then feels fine until it gets in the same RPM range. It makes the subtle sound of a blow-off valve when it shifts sometimes too.

Anyways, a friend of mine said I probably needed a good tune, I agreed. I tried several times to get a PCMforless tune, but had the same problems still. Went back and forth between Knock Moduls, etc. Fuel pressure was checked, it was normal. I tried going with some Pro Magnum lifters thinking is was maybe a valvetrain problem. Still no top end. Thought it was a transmission slippage. Got a race-built trans and Vigilante 3200. SAME PROBLEM.

I have NO idea why this car is as slow as it is. You can see the awful track times in my sig. And before you blame the 60 foot, I cut 1.9 and 2.0s on street tires all day long. I mean come on, I should have a low 12s car here.

My current theories (even though I thought they may have been disproved):

-Tuning: never right from the get go? But could this be soooo off that I’m losing all this power?
-Clogged Cat: The cat is the only stock part of my exhaust. Thought of this one, but many ppl, even my mechanic, have said they doubt it. My headers don't get red or anything.
-Valvetrain: Something off here from the start here as well possibly? Bad lifters right away? Bad springs? Did I break the cam in wrong some how? But again all this was professionally installed.

I apologize for the long post, but these issues with the car have really hurt my love for working on cars. I got so discouraged a few years ago with the car I put it in storage. All the money and time invested and still no results.

So anyone out there that has some constructive ideas, I would love to hear them. Please let me know if you need more information to diagnose

Thanks all

 

take your maf out and see if it looks okay. with the car running, can you hear any kind of whisle or sucking comming from the intake. Mabey a slight intake gasket leak, only other thing I would check is, your roller rockers might be too tight. Something is wrong for sure though, The hot cam is one hell of a seat of the pants gain. P.s. Get that cat out of there!!
Steve

 

Do you have good springs: Anything less than springs that will MORE than support your cam may cause problems on the top end. With even a relatively mild cam, if the springs are weak you are bound to experience problems at higher revs as the springs are too weak to adequately control the valves. When you are talking top end, you need everything working like more fuel, more air and a good exhaust, tuning, correct plugs/wires and gap, etc., but if your valve train is not stable and efficient you are not going to benefit from all the other go-fast goodies. JMHO

 

I used the springs that came with the Hot Cam Kit. I figured they would be suitable, but I haven't checked them personally. My mechanic checked them after the lifters were installed (about 3k miles after cam install) and said they were fine.

Rockers are set at I believe 0 lash. Not sure if that matters in this case.

 

0 lash on certain lifters is required, however stock lifters should be adjusted to anywhere beteen 1/2 and 1 turn past 0 for proper preset. Mybe tha's your problem: your valves are not opening as far as they should causing power loss on top. If I were you, I'd adjust those RRs properly and see if it makes any difference. Since different adjusters seem to find 0 lash at different points, it might be wise to do an initial adjustment of 1/2 turn and then adjust with engine running if too execessively noisey. JMHO

 

Well, that does make sense, but the Hot Cam Kit Rockers are 1.6 as oppossed to the stock 1.5 rockers. Does this make a difference?

 

No. Don't assume that since you used a "professional" mechanic (a person who gets paid for work) that they spent any quality time adjusting your RRS properly after installing the lifters.

You might want to take a good listen to your RRs and see if they seem too noisey. Bearing in mind tht SA adjusting RRs are noisier than non-self aligning , but at any rate all RRS are a bit noisey, however if they are too loose they probably will be extra noisey. JMHO

 

Are you sure he aligned the dots on the cam and crank sprockets correctly? Is it possible he got the splined shaft on the Opti drive off by one tooth?

 

Bubba - I understand where your coming from. But this wasn't really the typical mechanic/customer thing. This guy is a GM Master Mechanic who only really works on Corvettes and Camaros at this VERY large Chevy dealer near where I live. I met him through a friend and he agreed to work on my car on the side and I would just kick him some cash for his work. He seemed very sincere about everything and I would hate to have to doubt him. If these were a result of mechanical errors, I would be very dissappointed for trusting him and righting those issues off.

Fred - I couldn't tell you that one, that is something that hasn't been mentioned before. Anything I can check to verify this short of tearing the motor apart?

Thanks guys for your continued input

 

Point taken, however there is something apparently amiss, and if you don't plan on asking him for help in resolving the issue, then you will just have to fix it yourself....and...not to be too much of a pessimist, there are plenty of people had complete trust in their mechanics and their reputations only to wind up with catastropic engine failure because of an error/mistake or omission--doesn't mean that the mechanic did it intentionally or was slipshod, just that $hit happens, but it is the customer that winds up paying for the screwup.JHHO----AND personal experience.

 

Im going to say valve float. I bet those springs are either not the hot cam springs or they arent enough. Can you get a dyno graph or a scan of the car? I bet your knock retard is all over the place.

 

Yep, dyno graph and scan would go a loooong way in diagnosing something like this. Possible valve float and knock counts are definitely something you want to know.

I agree with the previous poster, and would adjust the rockers with the car running, just to rule it out. (are you using 3/8" or 7/16" studs?)

Also, if your cat is going out (ie: clogging up), it will definitely cause problems in upper RPMs. Did you ever have fuel mixture problems? A rich condition can cause premature cat failure. A good exhaust shop can drill small holes in the exhaust before and after the cat to check it's efficiency.

Good luck!
Thomas.

 

After reading your discription, the first thing that came to my mine is that you professional mechanic didn't install the springs from the Hot Cam kit.

Stock springs would totally fit your symptoms.

But then I got down to the part about you being buddy, buddy with your mechanic, and figured that he probably didn't pocket your springs for a different project. Perhaps some / all of your springs are out spec...every company has made some bum parts.

Perhaps you could take your car to a local engine shop, and they could pressure test like four of your springs to see if they are up to the task.

If the cam was made incorrectly, good luck figuring that one out.

That's all I've got if you've checked out that basics, and your mechanic is above reproach.

Keep the change - JM.

 

Wow, great stuff guys thanks a ton.

It seems like everyone is pretty much set on their being a valvetrain/cam issue. Nobody is opting for the tuning problem?

There is a pretty popular speed shop around here that does dyno tuning. I figured I'd give that a try. Would that reaffirm the valvetrain issues? Would they be able to come to the same conclusion on the dyno runs? Or would it still be just an "option". I'm very hesitant to spend a lot of money trying a lot of options, as I have already been down that route.

Is there a better spring option for someone with my setup that you guys would recommend? Rather then continueing to question whether the new springs are in their or not I'd rather be safe and just go with a more reliable setup. If anyone has some brands and part #s I should check out I would greatly appreciate it.

BTW, Another thing I forgot to mention: I'm getting HORRENDOUS gas mileage. It's definitely in the 10-12 mpg range on the street and barely more on the highway. This lead you all towards anything?

Again, thank you all for your insight and help. I knew I came to the right place

 

Fred,

If you've got the money to spend a dyno tune is definately worth it. If they have any idea what they're doing they should have no problem identifying a valve float issue if you have one.

As for what springs are best - I leave that up to the scholars. The springs that came with your hot cam kit should be a perfect match. Thousands of people run them everyday and have no problems.

As for the tuning, if PCMforless burned four tunes for you I doubt it's a tuning issue (unless you have mods they don't know about or some mechanical issue with your engine).
Mail order tunes are not perfect, but they do enough of them that I'd expect it to at least be close.

Good luck and let us know how the dyno tune goes. - JM