Loud Knock- Where to start?

[jeremy92555]

I pulled the other push rods out on that side and found what I think to be the problem. It appears the push rod was rubbing against the guide plate and completely wore away the push rod and created a lip all the way around. The side that bent has the same ring. It must have shaved so much metal that it weakened the pushrod and finally bent.

 

[73stallion]

my question is were the screw in studs tight? the left hole almost looks like the stud was a little loose letting the plate move around a little.

 

[old number 8]

Is there anyone locally that can assist as needed? I would recheck and torque everything the PO did before reassembly.

 

[Broncobowsher]

I just use an adjustable pushrod (available from Comp Cam) to find the correct length then measure it with a 12' vernier micrometer. Then you can order the correct length HARDENED pushrods from Comp Cam.
Jeremy, you said it has only 1500 miles on it? Were you pushing it a little hard for the first time? What is the valve spring pressure? May just have been too much for the stock, non-hardened pushrods.

Hardened pushrods are not for strength. The hardened is for wear resistance to the guide plates. Most stock small block fords do NOT have guideplates and thus don't need hardened pushrods. Simply put if the pushrod rubs something to hold alignment, you need a hardened pushrod.

 

[jeremy92555]

Everything was tight, i had to use a breaker bar to get them off. I would have never guessed that could happen. I dont understand why the previous owner would not use better push rods. The thing that bugs me the most is that there is two different brands of push rods used. Some had part number stamps on them so I entered the part numbers on Summit's site. They come back the same length but two totally different manufacturers. I am going to my local speed shop tomorrow to talk to them and get some parts. Thanks everybody for the help, i am anxious to get this back together.

 

[DirtDonk]

my question is were the screw in studs tight? the left hole almost looks like the stud was a little loose letting the plate move around a little.

What he said. that one hole looks awful fishy. Wonder how it was getting that wear pattern? Rough or uneven edge on the bottom of the stud?
Might check the head numbers too. LilRedBronco on here is putting his together and after buying all the parts from Summit, found that the heads (or was it rocker arms?) were not compatible with guide plates.
Could this be the same issue?

Paul

 

[motoman]

I had that happen and it broke the rocker arm too..... the valve springs were bottoming out... they were shimmed too much trying to get a higher spring weight.........

 

[windsor]

[Everything was tight, i had to use a breaker bar to get them off. I would have never guessed that could happen. I dont understand why the previous owner would not use better push rods. The thing that bugs me the most is that there is two different brands of push rods used. Some had part number stamps on them so I entered the part numbers on Summit's site. They come back the same length but two totally different manufacturers. I am going to my local speed shop tomorrow to talk to them and get some parts. Thanks everybody for the help, i am anxious to get this back together.

I have a few questions/concerns?! Everything was tight? The pushrods seem to have been overtightened. Check the bottom of the lifters and make sure they are not worn out already! (Just pull your intake off and check em. Try to leave your distributor hooked up).
Also you mentioned in an earlier thread that the motor has a 303 camshaft. Do you know what the lift is? The reason I ask is because I have a friend who has a 302 in a mustang and he is always snapping pushrods because his cam has too much lift for his valvetrain.
Also on certain ford motors you have to have the piston at the top of its compression stroke to tighten the rocker arms.
Read the book on engine assembly for your motor before reassembling your valvetrain. Having someone knowledgable on your motor will help. You can do it though if you follow a book on assembly.
I hope some of my rambling helps.

Good luck and happy easter!!

 

[blubuckaroo]

Everything was tight, i had to use a breaker bar to get them off. I would have never guessed that could happen. I dont understand why the previous owner would not use better push rods. The thing that bugs me the most is that there is two different brands of push rods used. Some had part number stamps on them so I entered the part numbers on Summit's site. They come back the same length but two totally different manufacturers. I am going to my local speed shop tomorrow to talk to them and get some parts. Thanks everybody for the help, i am anxious to get this back together.

Jeremy, there is a little boy in all of us that just wants to hear the motor run! That little boy can make us get into a hurry. If the rods looked close to the correct length the PO may have figured why spend the time or money for another set of rods. The hardened rods will cost around $100 from Comp Cam. I'd probably spring for a new set of guide plates as well. I think you've lucked-out here. Oh yea, change your oil and filter!