Bent / broken push rods

Posted By: 73rrak

Bent / broken push rods - 02/09/12 05:49 AM

I'm working on a new 440 that bent the intake push rods just after break in and I'm trying to figure out why. I made a push rod length checker and these are the numbers I came up with :

Stock push rod = 9.292

Rod checker results from lifter cup to rocker cup :

intake = 9.203
exhaust = 9.210

Is this enough to cause all of my intake push rods to bend / break? were should I look now ? I checked the pistons with a bore scope through the spark plug hole and I don't have any damage on my pistons at all so the valves never touched them.

Posted By: 340SHORTY

Re: Bent / broken push rods - 02/09/12 09:04 AM

if thats the case,,, how/what bent them??? Wht did you use/get unequal lenght PRs? HEMIs are the only Mopar engine that I know of that has unequal length PRs..

Posted By: 73rrak

Re: Bent / broken push rods - 02/09/12 12:50 PM

I re used the push rods that were in the motor. The motor was out of a 77 motor home with 48,000 miles on it and from the looks of it it had never been opened before I opened it. Although I never heard the motor run before I took it apart it was super clean inside and in completely stock form. I don't know if the push rods were all the same size and now it will be impossible to tell being that all of the intake rods are bent. I didn't mark them or separate them when I took them of the motor so the chances of getting all long ones on the intake only are pretty slim. There has got to be something else wrong in this motor.

Posted By: drew72

Re: Bent / broken push rods - 02/09/12 02:42 PM

Coil Bind

Posted By: dogdays

Re: Bent / broken push rods - 02/09/12 05:57 PM

MODS!!!!!
This guy has two open threads on this same topic in this forum and one in the race forum.
I'm getting tired of opening a thread and reading the same old whining and guesswork answers.

To the OP:
Take the doggone heads off, but before you do, check valve to piston clearance using a light spring and degree wheel. Get V/P measurement at every 5 degrees from 20 degrees BTDC to 20 ATDC. While you've got the spring off measure its compressed height. Also check the valve stem seal to retainer clearance. Measure the actual pushrod diameter between an end and the bend.
If they all check out it's valve guides.

Between now and the time you get that done don't start another thread about the same thing.

R.

Posted By: 64Post

Re: Bent / broken push rods - 02/09/12 06:57 PM

Quote:

MODS!!!!!
This guy has two open threads on this same topic in this forum and one in the race forum.
I'm getting tired of opening a thread and reading the same old whining and guesswork answers.

To the OP:
Take the doggone heads off, but before you do, check valve to piston clearance using a light spring and degree wheel. Get V/P measurement at every 5 degrees from 20 degrees BTDC to 20 ATDC. While you've got the spring off measure its compressed height. Also check the valve stem seal to retainer clearance. Measure the actual pushrod diameter between an end and the bend.
If they all check out it's valve guides.

Between now and the time you get that done don't start another thread about the same thing.

R.

Never mind...

Posted By: 73rrak

Re: Bent / broken push rods - 02/09/12 07:39 PM

Dogdays.... I don't have a post in the race section I've never even been to the race section. I don't have 3 threads going on this same subject. One is for a carb issue that thread lead into the all of my intake push rods are bent one. The 3rd one I have going is me trying to find out what the stock rocker ratio is so I can eliminate that as a possible cause of the problem. I didn't mean to upset anybody I was just trying to solve a problem and have people read 2 pages of posts to get to a question on another part of the problem although it was in the same category.

Drew. and whoever else guessed coil bind I think you might have it. I have a spring off and the valve seal looks fine but I can see area where the spring hammered into the spring perch. I'm working with the machine shop that did the head work I will let you know how that goes.

Posted By: GomangoCuda

Re: Bent / broken push rods - 02/09/12 08:36 PM

If it is coil bind and the shop knew the cam specs then let them fix it(if they know how) and never go back. NEVER.

Posted By: HemiRick

Re: Bent / broken push rods - 02/09/12 08:39 PM

Was the gas it ran on new? Old gas will leave tar in the intake tract and when the engine cools it cements the intake valves in place. When you crank the engine again the pushrods bend.

Posted By: 73rrak

Re: Bent / broken push rods - 02/09/12 09:08 PM

It looks like it was coil bind I only have .375 travel on the valve. I found an extra spring that was installed that the machine shop says is not supposed to be there. I have the outside spring the damper and a spring inside the damper. I'm taking the extra spring out and checking it again. I will let you guys know what I find.

Posted By: JohnRR

Re: Bent / broken push rods - 02/09/12 09:14 PM

Quote:

It looks like it was coil bind I only have .375 travel on the valve. I found an extra spring that was installed that the machine shop says is not supposed to be there. I have the outside spring the damper and a spring inside the damper. I'm taking the extra spring out and checking it again. I will let you guys know what I find.

How do they know it's not supposed to be there , the Hughes spring may be a double spring and if it is the spring seat on a factory head is not cut to accept that type of spring arrangement ....

Are the heads off yet ?

Posted By: stumpy

Re: Bent / broken push rods - 02/09/12 09:40 PM

Pull the heads and check things correctly. Even in the driveway with hand tools it's only a two hour job.

Posted By: 73rrak

Re: Bent / broken push rods - 02/09/12 09:41 PM

No the heads are still on and they are staying on. The extra spring was the problem for some reason Hughes shipped them with the extra spring and Hughes says it's not supposed to be there. The machine shop just installed them the way they received them. Yes they should have checked them but right now I'm just happy to have the problem solved without having to take this thing back apart. Now I just need to get the camera out of the cylinder and maybe I can drive this piece of crap.

Posted By: JohnRR

Re: Bent / broken push rods - 02/09/12 09:44 PM

Quote:

No the heads are still on and they are staying on. The extra spring was the problem for some reason Hughes shipped them with the extra spring and Hughes says it's not supposed to be there. The machine shop just installed them the way they received them. Yes they should have checked them but right now I'm just happy to have the problem solved without having to take this thing back apart. Now I just need to get the camera out of the cylinder and maybe I can drive this piece of crap.

now that you have said that you will be pulling that head to get the camera out ...

good luck ...

Posted By: 73rrak

Re: Bent / broken push rods - 02/09/12 10:01 PM

I gave up worrying about saying bad things about this car months ago. It can't get back at me any more than it already has...... hhahahahha

Thank you everybody for all of the help

Posted By: 64Post

Re: Bent / broken push rods - 02/09/12 10:10 PM

Quote:

Quote:

No the heads are still on and they are staying on. The extra spring was the problem for some reason Hughes shipped them with the extra spring and Hughes says it's not supposed to be there. The machine shop just installed them the way they received them. Yes they should have checked them but right now I'm just happy to have the problem solved without having to take this thing back apart. Now I just need to get the camera out of the cylinder and maybe I can drive this piece of crap.

now that you have said that you will be pulling that head to get the camera out ...

good luck ...

If it went in through the plug hole why wouldn't it come out the same way?

Posted By: JohnRR

Re: Bent / broken push rods - 02/09/12 11:14 PM

Quote:

Quote:

Quote:

No the heads are still on and they are staying on. The extra spring was the problem for some reason Hughes shipped them with the extra spring and Hughes says it's not supposed to be there. The machine shop just installed them the way they received them. Yes they should have checked them but right now I'm just happy to have the problem solved without having to take this thing back apart. Now I just need to get the camera out of the cylinder and maybe I can drive this piece of crap.

now that you have said that you will be pulling that head to get the camera out ...

good luck ...

If it went in through the plug hole why wouldn't it come out the same way?

The issue will be grabbing it to get it out thru the plug hole, I'm guessing it wasn't much smaller than the plug hole.

If it were me I'd almost be tempted to pull off the intake , pull the intkae valve spring , make sure the exhaust is closed , put the plug back in , lower the piston some and open the intake valve to the point that the retainer with locks is sitting on top of the guide and use a shop vac to try to suck it out the intake port ...

Posted By: Twostick

Re: Bent / broken push rods - 02/09/12 11:36 PM

Kevin

Posted By: zrxkawboy

Re: Bent / broken push rods - 02/10/12 12:48 AM

So what did all of this do to the new cam?

Posted By: Mr.Yuck

Re: Bent / broken push rods - 02/10/12 01:23 AM

Dude that motor needs to be torn down, sorry. The heads have to come off, the cam needs to come out and the pan needs to be dropped. No getting around it. You could have bent the valves, wiped the cam and damaged the pistons. You can't see much w/ those little "scope" cameras. It would stink to heck to put it all togther and have the same thing happen at fire up or to find out the cam was wiped.
I've been where you are I had 200 miles on a brand new engine when it dropped a valve(I/we think the cam walked) At least you can fix yours. I ruined 2 cylinders, 2 pistons, filled the crank case w/ water and toasted 2 valve seats on a super nice set of iron heads.
Grab a 12 pack and get rolling.

Posted By: 73rrak

Re: Bent / broken push rods - 02/10/12 01:37 AM

The angle of the piston keeps the camera on the cylinder wall just below the plug hole but perpendicular to the hole. The camera is 9 MM X about 1" to maybe 1-1/2 so the only way to grab it is by the ends to take it out but I can't grab the ends because it keeps rolling to the bottom of the plug hole. I tried jacking on side of the car up to relieve some of the angle of the piston it helped but not enough. I'll get it out and it should be easier now that the valve train problem is out of my head.

Posted By: 73rrak

Re: Bent / broken push rods - 02/10/12 01:41 AM

Quote:

Quote:

Quote:

Quote:

No the heads are still on and they are staying on. The extra spring was the problem for some reason Hughes shipped them with the extra spring and Hughes says it's not supposed to be there. The machine shop just installed them the way they received them. Yes they should have checked them but right now I'm just happy to have the problem solved without having to take this thing back apart. Now I just need to get the camera out of the cylinder and maybe I can drive this piece of crap.

now that you have said that you will be pulling that head to get the camera out ...

good luck ...

If it went in through the plug hole why wouldn't it come out the same way?

The issue will be grabbing it to get it make out thru the plug hole, I'm guessing it wasn't much smaller than the plug hole.

If it were me I'd almost be tempted to pull off the intake , pull the intkae valve spring , make sure the exhaust is closed , put the plug back in , lower the piston some and open the intake valve to the point that the retainer with locks is sitting on top of the guide and use a shop vac to try to suck it out the intake port ...

I like this idea I'm gonna try it ....... Thanks

Posted By: JohnRR

Re: Bent / broken push rods - 02/10/12 02:03 AM

Quote:

Quote:

Quote:

Quote:

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No the heads are still on and they are staying on. The extra spring was the problem for some reason Hughes shipped them with the extra spring and Hughes says it's not supposed to be there. The machine shop just installed them the way they received them. Yes they should have checked them but right now I'm just happy to have the problem solved without having to take this thing back apart. Now I just need to get the camera out of the cylinder and maybe I can drive this piece of crap.

now that you have said that you will be pulling that head to get the camera out ...

good luck ...

If it went in through the plug hole why wouldn't it come out the same way?

The issue will be grabbing it to get it make out thru the plug hole, I'm guessing it wasn't much smaller than the plug hole.

If it were me I'd almost be tempted to pull off the intake , pull the intkae valve spring , make sure the exhaust is closed , put the plug back in , lower the piston some and open the intake valve to the point that the retainer with locks is sitting on top of the guide and use a shop vac to try to suck it out the intake port ...

I like this idea I'm gonna try it ....... Thanks

Actually after reading your other post it sounds like it's on the plug hole ... I assumed it fell completely into the cylinder ... put the vacuum on the plug hole first , release the valve train so the valves are closed.

When you get it back together , with the valve train off do a leak down test on all the cylinders , this will tell you if you have bent valves .

Posted By: 73rrak

Re: Bent / broken push rods - 02/10/12 02:26 AM

I'll be able to tell tonight if it has leaking valves. I'm using air to hold the valves up while I take the extra spring out. So far I can hear air going past the rings but none from the valves. I have 6 more to go so the car still has six more chances to show it's evil side .... Hhahahhaha

The camera is "in" the cylinder but with the piston up all the way it sits just below the spark plug hole against the cylinder wall. I wish it was just in the spark plug hole it would be out by now.

Posted By: bboogieart

Re: Bent / broken push rods - 02/10/12 02:28 AM

I don't mean to be a jack a$$ but I think I would have had that head off by now.

Posted By: 73rrak

Re: Bent / broken push rods - 02/10/12 02:34 AM

I hope it doesn't come to that but if it does I'll take the heads off. I have a new camera coming it should be here tomorrow this one has a hook attachment with it that goes in front of the lens I hope that will work better.

Posted By: 471Magnum

Re: Bent / broken push rods - 02/10/12 04:19 AM

Quote:

I don't mean to be a jack a$$ but I think I would have had that head off by now.

No kidding. Only takes a couple hours to pull a head.

Posted By: wicked

Re: Bent / broken push rods - 02/10/12 03:55 PM

Any time I have seen coil bind like that , it has done some very ugly things to the bottoms of the lifters. I'd want to pull the lifters and look at them and the lobes very carefully.

Pushrod measurements should be the same unless you have a lobe wiping out.