Did i collapse a lifter or bend a pushrod? Floated valve? H/C Z06
12-14-2005, 06:57 PM
#1
Did i collapse a lifter or bend a pushrod? Floated valve? H/C Z06 Today i was doing one of my normal runs and at the top of 3rd gear (7,000rpm) i noticed a power drop, then shifted and noticed there definately wasnt as much power as before even though the car still pulled. So i slow down and put it in 6th gear to cruise and notice right away my car is missing. Its vibrating slightly in gear and at idle i can hear it "squeak squeak" almost like a belt squeak but when i put my head closer i can definately hear more of a metallic sound. My valvetrain has always made noise, but this is definately something wrong. It's a loud tick and squeak. I lost absolutely no oil pressure, at idle its 38psi @ 196 degrees which is what i recorded when this happened. Same as it always has been so i know its not a bearing. Or atleast i hope its not.
What i plan on doing next is leaving it running and pulling wires to see which cylinder it is. I know is on the drive side bank, i can definately hear the difference. Any ideas? I tried to make a video but all you can hear is the transmission/headers hitting which sounds like horrible rod knock but it wont capture the sound its making, although i am only using my camera.
What i plan on doing next is leaving it running and pulling wires to see which cylinder it is. I know is on the drive side bank, i can definately hear the difference. Any ideas? I tried to make a video but all you can hear is the transmission/headers hitting which sounds like horrible rod knock but it wont capture the sound its making, although i am only using my camera.
12-15-2005, 04:53 AM
#7
Eh i been out winterizing pools in this weather breaking ice to blow out the lines so cold doesnt bother me that much, but i didnt feel like it last night. Nice SUFI btw.
So whats the worst case scenerio for my situation and the best case?
So whats the worst case scenerio for my situation and the best case?
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12-15-2005, 12:51 PM
#10
Sweet i hope its something like that. I'll take a look at it tonight. The heads are brand new with springs that should be good to .630 lift. I forget which kind. The are ET 2.055 ported LS6 heads. The first set did get bent because of how close the pistons came to the valves, so i was thinking that is probably what happened to this but on only 1 cylinder? I still have ALOT of power too so i dunno. I'll check it out, my mechanic did reuse the stock lifter and rockers.
12-15-2005, 01:17 PM
#12
It would show me exactly which cylinder has the broken valve, pushrod, lifter etc. You pull the plug wire the idle goes down, you know that cylinder is firing correctly. I pull the plug wire the idle stays the same, i know that's the cylinder that isnt firing correctly. Even though i have to pull off the entire valve cover anyway, i could atleast determine which engine bank, though im 99% sure its on the driver side, and i could atleast narrow my search down with the cover off.
12-15-2005, 02:01 PM
#14
FYI, unplugging the fuel injector instead is a good way to avoid getting zapped. Of course the SES light may come on, but so long as you have a scanner of come kind, it's not a big deal.
Eric
Eric
12-15-2005, 02:33 PM
#16
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Find someone with a TECH II, they can turn off cynlinders while its running and you'll definitely tell whats going on. Dealers have them, some shops have them. Wonderful little diagnostic tools.
Much better than pulling the plug wires or the wire harness to individual cylinders.
If the sounds is coming from up top near the head, then I would be willing to bet you took out a lifter, presuming you have hardened pushrods. Spring failure is a possibility too, but you mentioned springs good for .630. If you've been taking care of them, they should be ok.
Much better than pulling the plug wires or the wire harness to individual cylinders.
If the sounds is coming from up top near the head, then I would be willing to bet you took out a lifter, presuming you have hardened pushrods. Spring failure is a possibility too, but you mentioned springs good for .630. If you've been taking care of them, they should be ok.
12-15-2005, 04:13 PM
#18
Eh i always let the car warm up before i drive it so i dont think that was the case. It broke after being driven at 60mph for 30 minutes so i assume it also got the springs worked in pretty well. It's raining right now and i dont feel like getting wet so i'll wait to check it out. thanks for the replies.
Last edited by Shawn MacAnanny; 12-15-2005 at 05:46 PM.
12-15-2005, 05:50 PM
#19
Ok i removed the valve cover and you guys were right on the money. Did you know that these engines can run on only 4 cylinders? I went to crank it over to watch the rockers and it started right up and idled. I was amazed and no SES lights lol.
Anyway i turned it on and off about 3 times and it happened to stop just like this and i was able to see the broken spring. Here's a pic. It's on the drive side, all the way to the front of the car.
http://home.earthlink.net/~01z06/sit...alvespring.jpg
Also i noticed my rockers can all be moved side to side when they are in the position that the rocker is in on the broken spring. Should they be tighter or anything? Also how do i go about replacing this spring? Do i have to remove the heads to compress it? Where can i get just 1 spring from?
Anyway i turned it on and off about 3 times and it happened to stop just like this and i was able to see the broken spring. Here's a pic. It's on the drive side, all the way to the front of the car.
http://home.earthlink.net/~01z06/sit...alvespring.jpg
Also i noticed my rockers can all be moved side to side when they are in the position that the rocker is in on the broken spring. Should they be tighter or anything? Also how do i go about replacing this spring? Do i have to remove the heads to compress it? Where can i get just 1 spring from?
