Cam/Springs car sounds bad
03-13-2007, 11:10 AM
#1
Teching In
Thread Starter
Join Date: Mar 2007
Location: Streamwood, IL
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Cam/Springs car sounds bad I put in a cam about a month ago on my 99 T/A LS1 A4. We got the cam for free from a friend who is going with a bigger setup. Hes pretty sure its a GM Hotcam, 219/228 .525 112 But were not 100% (shame on me for not knowing for sure before installing).
Now the car is basically stock with a lid, and a magnaflow catback. We're gonna throw headers on it (most likely MACs).
Normally I would NEVER do a cam before headers but I had a few days off work and the cam was free. Well I did it then I found that you HAVE to change the springs too. So we were quick to get a set of Comp 918s.
Long story longer heres my inquiry. The car sounds like crap under load now, and feels just a little sluggish. It sounds like the exhaust though, the valvetrain sounds like the usual sewing machine. I've checked all the rockers, the pushrods, everything is tight under there. The only thing I did wrong was I forgot to install the rocker pedestal on the passenger side the first time around, and didnt torque the rockers in the right sequence. So instantly upon start up there was a loud POP. I also realized I left 2 plug wires off the coil. So to me, the popping could have meant one of two things, the coil was firing on the A.I.R. (spark + metal?) or, what Im worried about, could have blown a lifter. I took everything apart after this, checked the pushrods, they were fine. I put it all back together, re torqued the rockers, everything seemed fine. Now its running rough.
Could it be simply because of stock headers, the engine with the cam is trying to force out more exhaust than the manifolds will let it?
Or maybe the stock convertor since Im guessing the cam (being only .525 lift) is a rather high rpm cam?
I know this was a long post and thanks to anyone who reads it, and even bigger thanks to anyone that can help. Thanks so much!
Now the car is basically stock with a lid, and a magnaflow catback. We're gonna throw headers on it (most likely MACs).
Normally I would NEVER do a cam before headers but I had a few days off work and the cam was free. Well I did it then I found that you HAVE to change the springs too. So we were quick to get a set of Comp 918s.
Long story longer heres my inquiry. The car sounds like crap under load now, and feels just a little sluggish. It sounds like the exhaust though, the valvetrain sounds like the usual sewing machine. I've checked all the rockers, the pushrods, everything is tight under there. The only thing I did wrong was I forgot to install the rocker pedestal on the passenger side the first time around, and didnt torque the rockers in the right sequence. So instantly upon start up there was a loud POP. I also realized I left 2 plug wires off the coil. So to me, the popping could have meant one of two things, the coil was firing on the A.I.R. (spark + metal?) or, what Im worried about, could have blown a lifter. I took everything apart after this, checked the pushrods, they were fine. I put it all back together, re torqued the rockers, everything seemed fine. Now its running rough.
Could it be simply because of stock headers, the engine with the cam is trying to force out more exhaust than the manifolds will let it?
Or maybe the stock convertor since Im guessing the cam (being only .525 lift) is a rather high rpm cam?
I know this was a long post and thanks to anyone who reads it, and even bigger thanks to anyone that can help. Thanks so much!
03-13-2007, 03:57 PM
#5
Teching In
Thread Starter
Join Date: Mar 2007
Location: Streamwood, IL
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
I checked the plugs and they look fine, I mean they have 66k under their belts but if it was the plugs, more than one cylinder would be misfiring. We scanned it and its PO303, cylinder 3 misfire. At this point I'm almost convinced its a collapsed lifter. Would there be anything else to check before pulling the heads? The car has like this.... reverberating sound when your accelerating. Makes sense if a valve is not opening/closing properly. I just didnt wanna pull the heads until I had to.
Oh yea, are the head bolts torque to yield? I doubt I could reuse them but were not Rockafeller, but if it needs to be done.....
Oh yea, are the head bolts torque to yield? I doubt I could reuse them but were not Rockafeller, but if it needs to be done.....
03-13-2007, 06:06 PM
#7
TECH Addict
Wait a minute....you forgot the pedestal and tightened them down?
I'm betting the pop was a piston hitting a valve and that you bent or broke something. Start by taking the right side valve cover off and inspecting.
I'm betting the pop was a piston hitting a valve and that you bent or broke something. Start by taking the right side valve cover off and inspecting.
Trending Topics
03-14-2007, 10:10 PM
#8
Teching In
Thread Starter
Join Date: Mar 2007
Location: Streamwood, IL
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Yep 
I forgot the pedestal and tightened them down.
I inspected the valves from the top and they appear to be fine, but thats just the tip of the stem, I cant see inside the heads of course. Were taking it to a reputable shop/tuner and theyre gonna take a look at it. The guy said no matter what, 99% of cammed cars throw a misfire code. I just think its fishy because its on the same side that popped. He said it would most likely bend a valve before a lifter collapses. Problem is we just ordered 2 lifters from GM because I was convinced that was what was wrong. Either way I can return them if need be, but they charge 20% since its a special order.
Friday we go take a look at it, hopefully I didn't do toooo much damage
I forgot the pedestal and tightened them down. I inspected the valves from the top and they appear to be fine, but thats just the tip of the stem, I cant see inside the heads of course. Were taking it to a reputable shop/tuner and theyre gonna take a look at it. The guy said no matter what, 99% of cammed cars throw a misfire code. I just think its fishy because its on the same side that popped. He said it would most likely bend a valve before a lifter collapses. Problem is we just ordered 2 lifters from GM because I was convinced that was what was wrong. Either way I can return them if need be, but they charge 20% since its a special order.
Friday we go take a look at it, hopefully I didn't do toooo much damage
03-15-2007, 04:30 AM
#10
TECH Fanatic
iTrader: (1)
Join Date: Mar 2005
Location: Fort Wayne, IN
Posts: 1,237
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by DaddySS
Do a compression and leak down test, that should tell a good deal of the story and it's quick and simple.
03-16-2007, 08:37 PM
#11
Teching In
Thread Starter
Join Date: Mar 2007
Location: Streamwood, IL
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Damn Im such a ****** moron. It ended up being just the rockers on cylinder 3 were a tad loose. It fouled the plug, killed the cylinder and therefore i was only runnin on 7. New NGK TR55s and wires, retorqued the rockers, runs like a beauty! Still needs a convertor and headers but, runs so much smoother now!
Thanks for the help guys!
Thanks for the help guys!