Bent Pushrod

**cowstandmoto** · 04-28-2013, 08:42 AM

Ok folks. I just figured I would start a new thread for this. Just a quick refresher; mine was the new build that wouldn't start at first, and then after that, when I got it to run, was making a sound around the no. 6 cylinder area. And then discovered that the exhaust rocker on no. 6 was pushed over, thinking maybe I had forgotten to torque that bolt. Well, as you can see from the title, I have a bent pushrod. Here's the weird part; it is the intake pushrod on no. 6 that is bent. Do you guys have any idea what might be causing this?

**cowstandmoto** · 04-28-2013, 10:33 AM

I forgot to mention that the pushrods are hardened.

***SMWS6TA*** · 04-29-2013, 07:10 AM

Many things could cause this, over rev, incorrect timing, floating a valve, PTV clearance out of tolerance, hydrolock......

**cowstandmoto** · 04-29-2013, 09:14 AM

Hey Scott. Well, a little clarification is needed here. I'm sorry I didn't say anyhting before, but the car is still on jack stands. It hasn't been on the floor since I started this build. So it couldn't be over rev. And probably not floating a valve. One of my buddies, kinda thinking out loud a colapsed lifter. Does that sound feasible to you?

***SMWS6TA*** · 04-29-2013, 09:37 AM

Yes it's possible, did you reuse the lifters?

If you changed them what lifter did you go with?

**cowstandmoto** · 04-29-2013, 09:46 AM

Yeah, I used the old ones.

***SMWS6TA*** · 04-29-2013, 10:09 AM

how many miles on the them (block)?

**cowstandmoto** · 04-29-2013, 10:20 AM

They had 54000 on them

***SMWS6TA*** · 04-29-2013, 12:54 PM

not sure then....well GM has stated that the LS7 is the stock lifter for replacement on LS1's.

For my 6L build I'm going with a set from BTR. They cost more then the GM lifters but I have my reasons for going with the BTR's.

**cowstandmoto** · 04-29-2013, 01:05 PM

Oh really? Well, I guess I'm going to pull off that head and look. Damn it! I hate that I'm going to have to do that.

Are you really? What does BTR stand for?

***SMWS6TA*** · 04-29-2013, 01:34 PM

Ok, let's go over this again...Please bear with my questions.....Your answers will help others that would add input.

You had a rebuild that wouldn't start, correct?

Did you rebuild it yourself?

How much of a rebuild was it? Total or partial (what exactly)?

Why did you need to rebuild it?

***SMWS6TA*** · 04-29-2013, 01:35 PM

BTR - Brian Tooley Racing

**cowstandmoto** · 04-29-2013, 01:51 PM

Let me give you all the poop this evening

**cowstandmoto** · 04-29-2013, 04:21 PM

Ok, sorry about that Scott. Alright. First off, it wasn't a rebuild, I just added a bunch of performance stuff on it. ARP
5.3L heads, 239 .595"/.605"-111 comp cam, 102mm FAST LSXR intake, 102mm Nick W. TB, Fast 100mm MAF, 7.375" hardened pushrods, LS-6 ported oil pump, Texas Speed 1 7/8" long tube headers, scorpion 1.7 ratio rockers, SLP underdrive pulley, LS-3 coil packs. Now originally it wouldn't start. But I saw that one of the coil pack wire harnesses was upside down. After that it started for the first time. It immediately started making that banging sound around cyl. 6. And that's when I took of that passenger side valve cover off and saw the no.6 cyl. exhaust rocker knocked over toward the no. 6 intake rocker. And that's where I am now. And as I said before, I started this build with 54,000 on the clock.

***SMWS6TA*** · 04-29-2013, 05:43 PM

Ok, I see,

Did you measure for correct pushrod length or did you get the length from the place you ordered your parts?

Not doubting your skills or knowledge, hell you could be better then me....I'm just going over everything just to get a clear picture.

As best as I can tell sounds like your on the right track. I would try replacing the push rod first before I tear off the heads. You might get lucky and that was all you had wrong. If you still have valve train noise You're going to have to dig deeper....meaning pull the head and hope it's a lifter and not a bent valve too.

**cowstandmoto** · 04-30-2013, 01:26 AM

Good morning Scott. Yes sir, the pushrods came as a set with the heads and the cam. But I did check the length of them to make sure they were 7.375" long. I tell you what though, I called Texas Speed yesterday(where I purchased the heads/cam/pushrods/oil pump package), and told them about the bent pushrod. And they were blown away by the fact that I bent a hardened cromoly pushrod with the car sitting on jack stands, and that it did it with car at idle! They said that just doesn't happen. I think they believe me, but I think I knocked there socks off!

***SMWS6TA*** · 04-30-2013, 06:59 AM

Yeah it blows me away to.....I just thought of this and you aren't going to like it.

When you installed the heads and push rods did you turn the crank over 2-3 times to check for any binding? I ask because sometimes when you install a lifter it can get side ways and will cause binding as the cam rotates.

**cowstandmoto** · 04-30-2013, 09:50 AM

Yeah, in a way I did. Not exactly like that. What I did do (when I was putting in the rockers) starting on no. 8 cylinder, with the intake and exhaust pushrod in their holes, I would press the pushrods down to make sure the lifters were all the way down. And then I would have one of my sons manually turn the crank over. And at the same time always keeping pressure on the pushrods. And I'm sure you know the rest of the procedure for installing rockers. Keep pressure on the both pushrods until the intake pushrod gets to it's highest point and then when it just starts to look like it is about to start going down. And that's when you bolt down the exhaust rocker. And then you do the same for the other rocker on that cylinder.

**cowstandmoto** · 05-19-2013, 07:17 AM

Good morning everyone. I have an update. I got a chance to take off the passenger side head (the side that had the bent pushrod) yesterday, so I could check all the lifters on that side. And to check to see if the lifter under the bent pushrod might have collapsed. But it was fine. And the rest of them were fine. I bought a whole new set of lifters and trays a week and a half back. So I went ahead and replaced all of them on the passenger side.

**cowstandmoto** · 06-02-2013, 08:47 AM

Giving you guys a quick update. I went ahead and replaced all the lifters with the new GM stock replacement lifters. I've got the drivers side head on and bolts torqued. I'm waiting for the passenger side head to come back from Texas Speed. I sent them the head so they could repair the rocker arm hole where the bolt threads got blown out of. So maybe by the end of next week I will be able to start the car again and see what happens.