bent pushrods and slight knocking after N vs. S...
Thread Starter
Joined: Nov 2001
Posts: 1,711
Likes: 6
From: Lawrenceville, Ga
bent pushrods and slight knocking after N vs. S... After my pathetic display at the N vs. S shootout my motor developed a slight knocking. I started pulling the motor apart and found a few bent pushrods, could this be the knocking or is it most likely bottom end. It doesn't smoke at all and isn't using any fluid yet either. I also found that my #8 spark plug had been hit in so hard by something that the strap was crushed flat and touching the v-groove which explains the constant missing my car was doing. So apparently I either did that when I changed them last (highly doubt it) or I've got some major issues and something fell onto the piston and was sent flying up into my plug. Are stock valves bad about coming apart at high cylinder pressures in an LS1? Any help is appreciated!
Thanks.
Jeffrey
Thanks.
Jeffrey
Teching In
Joined: Jun 2003
Posts: 22
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From: Odessa, Texas
Re: bent pushrods and slight knocking after N vs. S... No, they do not have a vavle issue if keep below 6500 rpm. If you spunn a rod bearing and the two halfs of the bearing overlapped each other on the side closest to the piston, that would make the piston stand even higher out of the hole then factory. These engines pistons do come out of the hole slightly. So you piston would then be slapping the head. I have not payed any attention to how far in the hole the spark plug extends but it could have been hit by the piston if you spunn a rod bearing. If you have towrched a valve then a piece of the valve head could have come loose and hit the plug. If you have only one bent pushrod and you have not over reved the engine I would be checking for a spun bearing. If you have several bent pushrods then you did over rev the engine and might not have known it. Over reving can cause the valves to float, which might cause a piston or several to hit the valves and bend or brake the heads off. If you do not have coolant coming out of any of the plug holes, then run compression. If the compression is good replace the pushrods and check to make sure all valves are opening the correct distance. Replace the plugs and light it up. If it does have a bad bearing it is already broke so don't be scared to light it off. Just dont sit there and rev the snot out of it. If you still have the noise climb all over it and find were it is coming from. Usually a spun bearing will knock and stop knocking and knock again changing with load changes. Just check it good before you go throught the trouble of pulling it.
Thread Starter
Joined: Nov 2001
Posts: 1,711
Likes: 6
From: Lawrenceville, Ga
Re: bent pushrods and slight knocking after N vs. S... I'm almost positive I over revved it many times this weekend, so hopefully it's just pushrods, but the plug thing doesn't sit easy with me. I was also running a plug with an inset nose, these are WAY shorter than a TR55 or TR6, so if something came up that high I would hope it was just a piece of broken valve riding on my piston and not the piston itself. I replaced the plugs with TR6's earlier and fired it up to see if it would be crushed as well but it was fine. The missing went away but the knock was still there.
I'll replace the pushrods and do a compression test and hopefully know more soon.
Jeffrey
I'll replace the pushrods and do a compression test and hopefully know more soon.
Jeffrey
Teching In
Joined: Jun 2003
Posts: 22
Likes: 0
From: Odessa, Texas
Re: bent pushrods and slight knocking after N vs. S... Good luck, I hope the nock is something minor. If it is deep and sounds as if it is coming from the lower end check your torque converter mounting bolts and look at the flexplate real good. A bolt might have sheard or the flex plat might have split. That would be a good thing, easier to fix. Also check the Balancer and bolt for it. They can make a nasty knocking noise too. If its not one of those things or the pushrods then jerk it out (or drop the pan if you can) and make her faster.
may the wind be at your back my friend!
may the wind be at your back my friend!
Thread Starter
Joined: Nov 2001
Posts: 1,711
Likes: 6
From: Lawrenceville, Ga
Re: bent pushrods and slight knocking after N vs. S... It is actually not a deep loud knock like I've heard before from a friends bottom end. It's fairly faint, more like a loud tapping I guess. It definately sounds like it's on the top end too, hopefully it is. Thanks for your help!
Jeffrey
Jeffrey
Re: bent pushrods and slight knocking after N vs. S... Jeffrey,
I was actually was looking for your post to see if how well it took the extra dose and if it still held together. I've bent and broken a couple of pushrods before and when I bent one it had a tap tap tap tap sound and it sounded like it was on the top of the motor. When I broke one in half (old motor)and drove it home, it had a louder TAP TAP TAP TAP TAP sounded like it was on the top too.
When I busted my old motor on the hose and took it apart, I noticed the spark plug gap on the cylinder that took a dump was closed, which was due to a piece of the piston breaking off hitting the spark plug and shooting out the exhaust or wherever it went.
Let me know if you need any help on that thing, I learned a lot taking it apart and putting it back together the last time around
Mike:678-427-3304
I was actually was looking for your post to see if how well it took the extra dose and if it still held together. I've bent and broken a couple of pushrods before and when I bent one it had a tap tap tap tap sound and it sounded like it was on the top of the motor. When I broke one in half (old motor)and drove it home, it had a louder TAP TAP TAP TAP TAP sounded like it was on the top too.
When I busted my old motor on the hose and took it apart, I noticed the spark plug gap on the cylinder that took a dump was closed, which was due to a piece of the piston breaking off hitting the spark plug and shooting out the exhaust or wherever it went.
Let me know if you need any help on that thing, I learned a lot taking it apart and putting it back together the last time around
Mike:678-427-3304
Re: bent pushrods and slight knocking after N vs. S... A lot of times when the gap on a plug is slammed shut, it's from MASSIVE detonation. I've seen it happen more than you might think.
On a completely unrelated side note, this is my 346th post... let's hear it for the stock displacement post!!
On a completely unrelated side note, this is my 346th post... let's hear it for the stock displacement post!!
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Re: bent pushrods and slight knocking after N vs. S... I think he was running some 118 and pulling a good bit of timing, but I'm not 100% positive though. He'll chime in and give us a heads up
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Thread Starter
Joined: Nov 2001
Posts: 1,711
Likes: 6
From: Lawrenceville, Ga
Re: bent pushrods and slight knocking after N vs. S... Yep that was my pile of crap 
I had issues all day. It was the first time I got to use my two stage setup and my timing tuner. The car just wasn't making any power, my best trap was 123. I'm wondering if it was a combination of pulling 12 degrees of timing, running 118 leaded, and spark plugs that were 4 steps colder with a less projected nose gapped down to 32. I might have not been able to fire off the mixture like I was planning. By my last run I had taken out alot of fuel and added alot of nitrous, to the tune of 3 powershot solenoids with seperate feeds and NO jets. It yeilded my best run but still didn't make near the power it should have. I'll just have to fix it and try again I guess. Hopefully with more test n tuning I can claim that stock internal record 
Jeffrey
I had issues all day. It was the first time I got to use my two stage setup and my timing tuner. The car just wasn't making any power, my best trap was 123. I'm wondering if it was a combination of pulling 12 degrees of timing, running 118 leaded, and spark plugs that were 4 steps colder with a less projected nose gapped down to 32. I might have not been able to fire off the mixture like I was planning. By my last run I had taken out alot of fuel and added alot of nitrous, to the tune of 3 powershot solenoids with seperate feeds and NO jets. It yeilded my best run but still didn't make near the power it should have. I'll just have to fix it and try again I guess. Hopefully with more test n tuning I can claim that stock internal record Jeffrey
Launching!
Joined: Sep 2002
Posts: 297
Likes: 0
From: Clinton Twp. Mi
Re: bent pushrods and slight knocking after N vs. S... Well if you need pistons I can help you out. Sounds like your piston may have hit your plug and closed the gap for you. This might of happened due to the rod spinning a bearing and that would also explain the knocking. Let me know if you need anything.
Thanks,
Chris Gelineau
Diamond Pistons
877-552-2112 toll free
Thanks,
Chris Gelineau
Diamond Pistons
877-552-2112 toll free
Thread Starter
Joined: Nov 2001
Posts: 1,711
Likes: 6
From: Lawrenceville, Ga
Re: bent pushrods and slight knocking after N vs. S... Thanks, I will definately use you guys when I do my new motor. But for now this one will stay stock internal until I either beat the current record or blow it beyond easy repair.
Jeffrey
Jeffrey
Thread Starter
Joined: Nov 2001
Posts: 1,711
Likes: 6
From: Lawrenceville, Ga
Re: bent pushrods and slight knocking after N vs. S... I did a leakdown test tonight and everything seems to be good. So I am going to replace my pushrods and hopefully try again soon. Thanks for the help.
Jeffrey
Jeffrey
Re: bent pushrods and slight knocking after N vs. S... Good luck Jeffrey. Hope it's just the pushrods. Get that thing fixed before the June 22nd shootout at SDR. You will be hauling major *** if you get the bugs worked out of the nitrous.
Thread Starter
Joined: Nov 2001
Posts: 1,711
Likes: 6
From: Lawrenceville, Ga
Re: bent pushrods and slight knocking after N vs. S... Thanks! Hopefully I can try again on the 22nd, there is a local stang that is dying to run me, but I need a GOOD pass to beat him. See you there.
Jeffrey
Jeffrey
