Bent Push Rod and Timing
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Laughing Gas
Joined: Jan 2002
Posts: 1,008
Likes: 1
From: Tucson
Freightrain, I didn't expect an answer in the middle of the day. Thanks. I read your response and I want to make certain I understand. If a plug fires too early there is no way it could result in a bent pushrod but if the cam timing was a bit off that could indeed cause a bent pushrod.
Here's what happened. I had my 390 rebuilt with a pretty big cam (Crower, 222 and 228 at .538 and .552) with the matching springs. I fired it up at TDC, advanced it until it was running better, ran it for 15 minutes between 2,000 and 2,500 revs and shut it down. I drove it around the block a few times and up to the exhaust shop. On the way back from the exhaust shop, a terrible banging or tapping (metal on metal) started. Then it stopped. It then seemed to run perfectly. On the way home form the parts store, it started again. I took off the right valve cover this morning and number 4 intake was bent bad.
What is you best guess on this? Thanks.
jor
let's say timing was as far as 25 or 30 BTDC
Here's what happened. I had my 390 rebuilt with a pretty big cam (Crower, 222 and 228 at .538 and .552) with the matching springs. I fired it up at TDC, advanced it until it was running better, ran it for 15 minutes between 2,000 and 2,500 revs and shut it down. I drove it around the block a few times and up to the exhaust shop. On the way back from the exhaust shop, a terrible banging or tapping (metal on metal) started. Then it stopped. It then seemed to run perfectly. On the way home form the parts store, it started again. I took off the right valve cover this morning and number 4 intake was bent bad.
What is you best guess on this? Thanks.
jor
let's say timing was as far as 25 or 30 BTDC
Post Fiend
Joined: Mar 2004
Posts: 6,056
Likes: 8
From: Union, Washington
Dist. timing (when the plug is fired) can't bend push rods. I would susupect that with the amount of lift you are running that either the valve spring are binding at full lift or the valve is hitting the piston. Pretty much the only two things that will cause your problem. Well, there is always the valve springs are so strong that the push rod can't push that hard and bends. In any case it is a valve train problem.
Thread Starter
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Laughing Gas
Joined: Jan 2002
Posts: 1,008
Likes: 1
From: Tucson
Thanks, Bear. I took a week off of work and thought I had done a good job on this engine swap. Everything all clean and painted, new clutch and pressure plate, new peripherals. Anyhow, my machinist assured me that he had this thing set up right (they build lots of race engines). It is what it is; I just wanted to be certain that I didn't do anything to cause it. Thanks for your answer. I guess this one's on him.
jor
jor
Lead Driver
Joined: Jan 2003
Posts: 9,893
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From: Ohio
I wonder if actual piston/valve clearance was checked?? Spring bind is a possibility, floating is another.
That cam sounds about just like the one I have in my 390. I have stock(real stock, original Ford) pistons and have no piston/valve clearance issues.
For whatever reason...#4 got hung up on something.
I wonder if it ate something?? Check the bottom of the carb for missing screws? anything? Since it was the intake valve that leads me to believe something might have come through it.
My race car ate a carb screw once..it left actual thread imprints in the top of piston and head! It was a Holley, and it was the bottom screws that hold base to throttle plate.
That cam sounds about just like the one I have in my 390. I have stock(real stock, original Ford) pistons and have no piston/valve clearance issues.
For whatever reason...#4 got hung up on something.
I wonder if it ate something?? Check the bottom of the carb for missing screws? anything? Since it was the intake valve that leads me to believe something might have come through it.
My race car ate a carb screw once..it left actual thread imprints in the top of piston and head! It was a Holley, and it was the bottom screws that hold base to throttle plate.
Last edited by Freightrain; Jul 27, 2005 at 02:12 PM.
Thread Starter
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Laughing Gas
Joined: Jan 2002
Posts: 1,008
Likes: 1
From: Tucson
Thanks for the advice, Freightrain. It's a brand new Edelbrock 750. I looked at it last night and didn't see anything amiss. The pistons are Speedpro L-2291-F. There is no possibility that I dropped something in there myself as I was super careful. I have it back now at the machinist's and I am waiting for him to call. I am hoping I don't get jerked around on this as it sounds as though it was not set up right (assuming your ate-something idea didn't happen).
jor
jor
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Lead Driver
Joined: Oct 2004
Posts: 8,062
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From: Central Oregon
Had my 428 build at a shop in Bend, OR. and they used NAPA lifters on my engine and another 428, both went into 64 Galaxies and both had problems with bent push rods. I pulled the intake off mine and pulled out a lifter to check it, it would not compress. So I put in a in A new set from differant parts house and I had no more problems. I bent a total of 8 push rods before changing them. The other guys engine did the samething and he changed his and had no more problems.
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Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
Ya, if the hydraulic valve sticks...then it will not compress and thus holding the valve in the OPEN position !! Not good!!
I've always run solids so never had to deal with issues like this. But, with the all the tiawanese junk running around today I would not be surprised.
I've always run solids so never had to deal with issues like this. But, with the all the tiawanese junk running around today I would not be surprised.
FE "Freakin Expensive"
Joined: Dec 2003
Posts: 6,461
Likes: 4
From: Smith Mountain Lake, VA
Originally Posted by Freightrain
Ya, if the hydraulic valve sticks...then it will not compress and thus holding the valve in the OPEN position !! Not good!!
I've always run solids so never had to deal with issues like this. But, with the all the tiawanese junk running around today I would not be surprised.
I've always run solids so never had to deal with issues like this. But, with the all the tiawanese junk running around today I would not be surprised.
Thanks,
Russ,
Lead Driver
Joined: Jan 2003
Posts: 9,893
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From: Ohio
Oh...everyone's a commode-i-an..............LOL!!
The valve INSIDE the lifter.........for those that don't actually realize what I was actually talking about! The little ball that rattles when a hyd. lifter has never had oil in it.
The valve INSIDE the lifter.........for those that don't actually realize what I was actually talking about! The little ball that rattles when a hyd. lifter has never had oil in it.
FE "Freakin Expensive"
Joined: Dec 2003
Posts: 6,461
Likes: 4
From: Smith Mountain Lake, VA
Yeah Larry I knew what you were trying to say!!! LOL....
No actually I thought you developed a Hydraulic Valve incase your lifters pumped up??
Therefore the Valve still wouldnt slap the piston!! LOL....
Yes you are refering to the Check Ball Sir!!
Russ
No actually I thought you developed a Hydraulic Valve incase your lifters pumped up??
Therefore the Valve still wouldnt slap the piston!! LOL....
Yes you are refering to the Check Ball Sir!!
Russ
Lead Driver
Joined: Jan 2003
Posts: 9,893
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From: Ohio
I have no need........since I run solids! None of that quiet, non-adjusting crap for me..LOL!!
Don't think there is enough room to build all that into a lifter. Even though Rhoads did make the bleed down type. Basically a "leaky" lifter! I never saw the need for that either? Why would you go thru the trouble of using them?? Guess I never had the need to make a cam seem "smaller"
Don't think there is enough room to build all that into a lifter. Even though Rhoads did make the bleed down type. Basically a "leaky" lifter! I never saw the need for that either? Why would you go thru the trouble of using them?? Guess I never had the need to make a cam seem "smaller"
