Cammed Z28 sounds terrible
08-02-2011, 09:43 PM
#1
Teching In
Thread Starter
iTrader: (1)
Join Date: Jun 2011
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Cammed Z28 sounds terrible I was driving my Camaro the other day and got on it, all of a sudden at about 5 or 6 grand it lost power. It idled really rough then died and I could not get it to restart. It sounds like it wanted to start but it would only run for a second or 2 and it sounded terrible.
I was by a parts store so I went ahead and rented a fuel pressure gauge and that checked out fine. I had to have it towed home and I checked for spark, and that was all good as well.
So today I talked to my neighbor who is a mechanic and he said he thought it might be a crank position sensor, so I went ahead and put a new one in, and it didn't help at all. So he jumped in it and got it to start but would barely run and it sounded terrible. It would only run with the throttle to the floor, but it would hardly rev up at all. It knocks and clatters really bad like it is the lifters or something. Almost sounds like it has no oil in it, but I just changed the oil about 100 miles ago and it is still at the full mark on the stick, and the oil pressure gauge is showing that it has oil pressure. I pulled the driver side valve cover and everything looked normal, but it got dark before I could get to the passenger side.
All engine mods were done by the previous owner, this is what I was told was done to it: LS6 block that had about 30,000 miles on it, he re-ringed it and put new bearings in it, it has a TSP Torquer V.2 cam in it with dual valve springs and hardened push rods, and it has pacesetter long tubes. Other than that, I'm not too sure what else the motor has done to it ( timing chain or oil pump). It only has about 4-5000 miles on the rebuild and I have never had any problems with it for the 3000 miles I've put on it.
I'm not too sure what could be wrong with it, but I have a feeling its gonna be pretty expensive. I was thinking maybe somehow it jumped a tooth on the timing set or something like that. Tomorrow I'm gonna bring cylinder #1 to TDC and look at the valves to see if they're where they should be, but other than that I need some suggestions.
I was by a parts store so I went ahead and rented a fuel pressure gauge and that checked out fine. I had to have it towed home and I checked for spark, and that was all good as well.
So today I talked to my neighbor who is a mechanic and he said he thought it might be a crank position sensor, so I went ahead and put a new one in, and it didn't help at all. So he jumped in it and got it to start but would barely run and it sounded terrible. It would only run with the throttle to the floor, but it would hardly rev up at all. It knocks and clatters really bad like it is the lifters or something. Almost sounds like it has no oil in it, but I just changed the oil about 100 miles ago and it is still at the full mark on the stick, and the oil pressure gauge is showing that it has oil pressure. I pulled the driver side valve cover and everything looked normal, but it got dark before I could get to the passenger side.
All engine mods were done by the previous owner, this is what I was told was done to it: LS6 block that had about 30,000 miles on it, he re-ringed it and put new bearings in it, it has a TSP Torquer V.2 cam in it with dual valve springs and hardened push rods, and it has pacesetter long tubes. Other than that, I'm not too sure what else the motor has done to it ( timing chain or oil pump). It only has about 4-5000 miles on the rebuild and I have never had any problems with it for the 3000 miles I've put on it.
I'm not too sure what could be wrong with it, but I have a feeling its gonna be pretty expensive. I was thinking maybe somehow it jumped a tooth on the timing set or something like that. Tomorrow I'm gonna bring cylinder #1 to TDC and look at the valves to see if they're where they should be, but other than that I need some suggestions.
08-02-2011, 10:01 PM
#2
Look for stupid simple stuff like disconneted pigtails and burnt or broken wiring, sensors etc. If you find no problems there then try pulling the valve covers and checking things out. May want to have a look at the oil to check for metal shavings. Sounds like it could be bad. Good luck dude.
08-02-2011, 10:19 PM
#4
pull the passanger side valve cover and inspect, maybe a broken valve spring, but sound like you may have broken a valve itself, or even broken a rod if it will not rev. pull the pass side valve cover and go from there, pulling the heads will tell all, if there is any damage to the motor.
08-02-2011, 11:07 PM
#7
Teching In
Join Date: May 2006
Location: south dakota
Posts: 25
Likes: 0
Received 0 Likes
on
0 Posts
pull the passanger side valve cover and inspect, maybe a broken valve spring, but sound like you may have broken a valve itself, or even broken a rod if it will not rev. pull the pass side valve cover and go from there, pulling the heads will tell all, if there is any damage to the motor.
Trending Topics
08-03-2011, 04:30 PM
#9
Teching In
Thread Starter
iTrader: (1)
Join Date: Jun 2011
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Alright, so I was pulling out my spark plugs to do the compression check and when I pulled out the number 4 plug, it was all beat to hell. Looks like I'm gonna be pulling the head off, so I might as well just pull the engine and throw a new cam in,a good set of heads, and get her all cleaned up. Sorry for the crappy picture, my phone camera is terrible.
08-03-2011, 06:45 PM
#11
first before you go and buy all the fancy parts, go ahead and pull the head on the side with the broken spark plug. that is a sign of a broken valve, if your cylinder walls are ok, then maybe the motor is usable. but a compression test should tell you if #4 is busted or not. anything under 180 is bad, 190 for norm (10.1:1 compression on stock LS1 heads)
08-03-2011, 07:41 PM
#12
Pulling the head is little more than curiosity-satisfaction at this point, there's no way the piston survived whatever happened. Engine comes out regardless of your findings.
08-14-2011, 10:58 PM
#13
Teching In
Thread Starter
iTrader: (1)
Join Date: Jun 2011
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
I finally got around to pulling the passenger head off. The piston has a hole in it and the valve is wedged sideways in the head. The cylinder wall has a nick in it so I don't think I will be able to reuse it.
Here are some crappy cell phone pictures:
Here are some crappy cell phone pictures:
08-14-2011, 11:54 PM
#15
Teching In
Thread Starter
iTrader: (1)
Join Date: Jun 2011
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
08-15-2011, 09:28 PM
#18
Teching In
iTrader: (1)
Join Date: Apr 2007
Location: Winston-Salem,NC
Posts: 36
Likes: 0
Received 0 Likes
on
0 Posts
Is that the first time you had gotten on it that hard? I would say it looks like a shotty build to me but kinda odd if you've been driving it that hard for a few thousand miles. I'm curious to know if he checked for the correct length pushrod before installing new ones after the cam. Although, that isn't a hugh lift cam so they may have been fine. I'm curious to know the cause as well......
08-16-2011, 01:45 AM
#19
Teching In
Thread Starter
iTrader: (1)
Join Date: Jun 2011
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
As of right now I'm not quite sure of what caused it. Pulling the head off is as far as I've gotten so far and I'm hoping to have time to get the motor out by then end of this week.
I've been driving it hard since the day I got it and it has never given me any trouble and it had no funny noises. It had TSP 7.4" hardened pushrods in it but if that was the correct length, I don't know, I never checked. But then again who knows if the engine only had 30,000 miles on it and who knows if he redid it all. I should be able to find out the root cause by the end of this week.
I've been driving it hard since the day I got it and it has never given me any trouble and it had no funny noises. It had TSP 7.4" hardened pushrods in it but if that was the correct length, I don't know, I never checked. But then again who knows if the engine only had 30,000 miles on it and who knows if he redid it all. I should be able to find out the root cause by the end of this week.
