Bent pushrods... or more?
Thread Starter
Intermediate
Joined: May 2015
Posts: 25
Likes: 0
From: San Antonio Texas
Bent pushrods... or more?
Did some high speed driving the other night with some friends, might have missed a shift, I don't really remember. Anyways, now I have the loud tapping raising with rpm synonymous with a bent push rod(s). That seems easy enough to fix, however when I drove home the car would die every time I pushed the clutch in. When I started it the computer would keep it running however every stop sign and stoplight would kill it. Could I have a bent valve? Or is this possible with just trashed pushrods?
Melting Slicks
Joined: Mar 2001
Posts: 3,254
Likes: 61
From: League City TX
Back in the day on my 01 C5, we were doing some high speed runs on an old air strip.
The car was bone stock.
Grabbed what I thought was 3-4 at about 105, except pulled 3-2 accidentally. Let out the clutch and clearly over-revved the car. (B&M Ripper was installed immediately thereafter - to this day, still felt like the stock shifter went 3-4).
The Check engine light was flashing and random misfires.
- bent multiple valves
- push rods surprisingly not bent
- rockers looked fine
Upon reassembly, the valves would float on the Dyno (had before and after), so ended up upgrading to LS6 spec springs. Problem solved.
Hope that helps
It's pretty easy to pop the valve covers, remove the rockers and pull the push rods.
The car was bone stock.
Grabbed what I thought was 3-4 at about 105, except pulled 3-2 accidentally. Let out the clutch and clearly over-revved the car. (B&M Ripper was installed immediately thereafter - to this day, still felt like the stock shifter went 3-4).
The Check engine light was flashing and random misfires.
- bent multiple valves
- push rods surprisingly not bent
- rockers looked fine
Upon reassembly, the valves would float on the Dyno (had before and after), so ended up upgrading to LS6 spec springs. Problem solved.
Hope that helps
It's pretty easy to pop the valve covers, remove the rockers and pull the push rods.
Last edited by Closer_2001; Jan 30, 2016 at 01:15 PM.
Melting Slicks
Joined: Mar 2012
Posts: 2,800
Likes: 456
From: USA
I would pull the valve covers and physically look at the push rods. I would also remove the oil filter and cut it open and check for any metal that may be in the filter. I would not run the engine anymore until I checked what I could without starting it.
If you find metal in the oil filter post up some pics and let others help you with the problem.
Good luck
If you find metal in the oil filter post up some pics and let others help you with the problem.
Good luck
Last edited by zachaeous; Jan 30, 2016 at 10:33 PM.
Drifting
Joined: Jul 2011
Posts: 1,599
Likes: 398
From: Boise, ID
2022 C5 of the Year Finalist - Modified
2021 C5 of the Year Finalist - Modified
C5 of Year Finalist (appearance mods) 2019
I would pull the valve covers and physically look at the push rods. I would also remove the oil filter and cut it open and check for any metal that may be in the filter. I would not run the engine anymore until I checked what I could without starting it.
If you find metal in the oil filter post up some pics and let others help you with the problem.
It would help if you also pull and post any Codes that may be set in your DIC. If you do not know how here is a link to a youtube video:
https://www.youtube.com/watch?v=SviRjIsy9G4
Good luck
If you find metal in the oil filter post up some pics and let others help you with the problem.
It would help if you also pull and post any Codes that may be set in your DIC. If you do not know how here is a link to a youtube video:
https://www.youtube.com/watch?v=SviRjIsy9G4
Good luck
Former Vendor
Joined: Aug 2005
Posts: 16,897
Likes: 412
From: Lewisville TX
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13
Typically on a stock engine the pushrod is your "fuse" so to speak and will bend first but the thing is...what caused it to bend. Generally to bend it something has to hit it...like a piston to valve. Might have just touched it, but better safe than sorry. Easy enough to pull the valve covers and rockers and check them.
checking the oil filter is never a bad idea...I would even do a plug check. If you think something worse happened do a compression/leak down.
Safety Car
Joined: Aug 2011
Posts: 4,439
Likes: 405
From: Portland OR
Compression test will tell if you bent a valve.
If it will idle, use a stethoscope (or long screw driver etc) touching the valve covers around the areas you hear the noise from.
Then pull the cover and have a look.
The issue might be obvious
Ron
If it will idle, use a stethoscope (or long screw driver etc) touching the valve covers around the areas you hear the noise from.
Then pull the cover and have a look.
The issue might be obvious
Ron
Thread Starter
Intermediate
Joined: May 2015
Posts: 25
Likes: 0
From: San Antonio Texas
Well, I just pulled the pushrods. It seems as if they are all slightly bent if the "roll it across the table" test is legitimate. I hope swapping those out will fix the problem. Would that explain the car dying when the clutch was pushed in? That part still doesn't make much sense to me 
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Even if you find bent pushrods,, you SHOULD check for damaged valves.
Rent, borrow, purchase a compression tester and check each cylinder for proper and equal compression
If you have a slight valve seat leak, fixing it now is easy by replacing the valve. If you wit and burn a valve, you could damage the seat and that will be more money.
Bill
Rent, borrow, purchase a compression tester and check each cylinder for proper and equal compression
If you have a slight valve seat leak, fixing it now is easy by replacing the valve. If you wit and burn a valve, you could damage the seat and that will be more money.
Bill
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Racer
Joined: Sep 2014
Posts: 429
Likes: 29
From: Brooklyn, MI
At the least the heads need to come off and lifters, push rods and valves checked. Check top of pistons for hit marks from valves. Pull and cut open oil filter. If it is full of metal pull and rebuild engine.
Drifting
Joined: Jul 2011
Posts: 1,599
Likes: 398
From: Boise, ID
2022 C5 of the Year Finalist - Modified
2021 C5 of the Year Finalist - Modified
C5 of Year Finalist (appearance mods) 2019
I would pull the heads and all the components in them, if you see damage on the lifters the cam is going to need to come out and be inspected. How was your oil pressure?
Drifting
Joined: Sep 2007
Posts: 1,649
Likes: 50
From: Goldsboro NC
uh-oh
....sounds like you may have hurt the motor
. I'm sure it isn't what you want to hear but water under the bridge now. Like others have said, now that you,ve seen metal shavings, it would be best if you pulled the heads and inspect/R2 what is damaged. Hell, if funds allow, send em off for a port job.
Good luck!
....sounds like you may have hurt the motor. I'm sure it isn't what you want to hear but water under the bridge now. Like others have said, now that you,ve seen metal shavings, it would be best if you pulled the heads and inspect/R2 what is damaged. Hell, if funds allow, send em off for a port job. Good luck!
Thread Starter
Intermediate
Joined: May 2015
Posts: 25
Likes: 0
From: San Antonio Texas
Yeah! Thats the plan, i have a feeling I bent some valves. I'm checking the oil filter today. The shavings weren't big, very tiny slivers. Hoping they came off the threads from the rocker arm bolts when I removed them. The heads will be sent off to a local machine shop for porting, polishing, and a valve job. I already have a small Comp 216/220 cam and ls6 springs coming in tomorrow 
Hopefully that fixes the problem. And idk about oil pressure. Tbh my sending unit went out. At least I have an opportunity to fix that and make my baby a bit faster 
Btw, thank y'all for the great advice! This forum always comes in clutch when I need the help. Y'all are the best!
Hopefully that fixes the problem. And idk about oil pressure. Tbh my sending unit went out. At least I have an opportunity to fix that and make my baby a bit faster Btw, thank y'all for the great advice! This forum always comes in clutch when I need the help. Y'all are the best!
Team Owner
Joined: May 2001
Posts: 87,302
Likes: 1,583
From: Western NY
How does the "action" of the rocker arms seem? Is it smooth? There have been problems reported with the OE trunnions of the rockers "going south", and either damaging, or out right spitting out the needle bearings. Both CompCams and Summit Racing have a kit that replaces the trunnions and bearings with a much better set-up. There's also a kit out there, that replaces the needle bearings with a hardened "bushing"....I just don't remember, off the top of my head, the sponsor's name, but they posted a thread about their products within the last week or so...
Thread Starter
Intermediate
Joined: May 2015
Posts: 25
Likes: 0
From: San Antonio Texas
How does the "action" of the rocker arms seem? Is it smooth? There have been problems reported with the OE trunnions of the rockers "going south", and either damaging, or out right spitting out the needle bearings. Both CompCams and Summit Racing have a kit that replaces the trunnions and bearings with a much better set-up. There's also a kit out there, that replaces the needle bearings with a hardened "bushing"....I just don't remember, off the top of my head, the sponsor's name, but they posted a thread about their products within the last week or so...
Thread Starter
Intermediate
Joined: May 2015
Posts: 25
Likes: 0
From: San Antonio Texas
Well guys, I took the heads off of the motor and absolutely nothing is wrong. No sign of the valve tapping the piston even once. My sketchy table is probably more bent than the pushrods rolled on it. Anyways, a mechanic buddy of mine looked everything over and told me it was most likely rod knock 
So I'm pulling the motor and rebuilding it 
So I'm pulling the motor and rebuilding it
Thread Starter
Intermediate
Joined: May 2015
Posts: 25
Likes: 0
From: San Antonio Texas
Well I know it's been awhile. Long story short I couldn't find anything wrong so I pulled the motor out of the car. I am in the middle of tearing it apart right now. I was planning on replacing the lifters even though they appeared fine. I checked them over one more time tonight rolling them on my arm, checking for scuffs on the rollers. I thought to push down on the pushrod cups on the top to see if any of them seemed spongy. On the second lifter I checked the pushrod seat pushed into the lifter with little to no effort, I'm talking a one finger push. And now its stuck down in there. Could this be the issue I heard? There isn't any damage on the cam or the roller.