New engine pushrods coming off rockers

[Calif240]

Hey guys.. one more issue...

I've gotten my new engine all broken in. It was assembled by a professional. '67 440 with all aftermarket parts except the block and head. The valve-train is comp except for the scorpion lifters. All of it is new. The cam has .540 lift and is a roller hydraulic. It has the nice big black comp rocker arms in the standard ratio... Anyway, there was a noise today when I started it. It didn't sound good so I pulled a valve cover. I had a pushrod completely split in two at the center. I also had about 5 more pushrods that had jumped off of the seats. I'm sure one or two had done it a while ago because I was having an issue with my #8 cylinder that I couldn't figure out (turns out both of these pushrods had jumped whereas two other cylinders just had one valve. Surprisingly, the lifters and camshaft look brand new and don't have anything wrong with them... I'm wondering if the geometry is wrong on the pushrods or if the engine builder maybe sized the pushrod length wrong? They are tight in the seat, but can barely spin.... anyone run into this type of issue before?

Thanks... as always, all of your all's advice and experience is greatly appreciated... definitely helps a young novice like me out.

[Kern Dog]

Pictures, Pictures !!!

If the engine was built by someone else, you'll never know for sure what was done. There are people I trust but nobody more than myself! When an engine is built in a shop but never started or ran, it may be hard to know for sure that everything is kosher.
If the correct pushrods are in there, they should never come out on their own. If oil pressure is fine and they haven't galled or overheated, they should have been fine. Most aftermarket rocker arms require a pushrod that has a traditional ball on the bottom and a cup on the top end. The ball end sits in the lifter and the cup provides a seat for the ball/adjuster in the rocker arm. Look at the pushrods for blue heat marks or cracking. Ever taken apart a dead engine and seen a BLACK connecting rod? That is the result of heat and failure due to a loss of lubrication. If the pushrods show any signs like this, it could be something to discuss further.
Never heard of Scorpion lifters but I'd figure that they are "paired" with a link bar? That keeps them in position and prevents rotation within the bores. If so, your okay there. Is there adequate clearance where the pushrods pass through the heads? Once I made the bonehead move and installed my rocker arms out of order with some RH and LH ones backwards. This made the pushrods rub but didn't bend anything.
Some lifters have a wide oil band that can become UNcovered as the lifters reach full lift. This will cause a momentary reduction in oil pressure. If this is the case your only cure is to replace the lifters with a brand with a narrower oil band. I had a set of Lunati solid flat tappets that looked like barbells. I was worried about them so i returned them for a set of Howards lifters.

[Kern Dog]

The issue of pushrod length is still a possibility. A hydraulic cam, whether roller or flat tappet, STILL needs preload. Its not as simple as a stock setup where you just torque the shaft to spec and slam the covers back on. My adjustable rockers are a chore to set and I'm not nearly as fast at setting the lash as I wish.
Yours needs around .030 preload which in most cases works out to turning the adjuster 1/2 to 3/4 turn PAST the point where the pushrod still spins. If the preload is set too deep the engine will run rougher because the valves will not fully close. If the preload is too little the engine will run smoother but you risk the pushrods popping out due to a loose fit. The pushrods will still feel tight if the lifter is on the rise or fall of the lobe. It is only when the lifter is on the lobes base circle when you can adjust it to spec. It could be that the length is wrong. If that is the case, there are adjustable pushrods you use to measure for the correct length. After measuring, you call Summit, Jegs, Mancini Racing or whoever to order the correct pushrods.

[Calif240]

Very awesome and detailed response '70RT... really appreciate it.

The pushrods have an oiling shaft through them. The pushrods are also ball/ball pushrods. The pushrods are already black because they come black (Comp magnum rods). I'm going to buy a pushrod length checker and also talk to the engine builder. Is there anything to check in terms of a collapsed lifter? They look good, but thought Id ask. Also, any reason to think that the hyd lifters aren't oiling properly?

I'll grab some shots as soon as I can and post up.

Thanks
Terry

[BSB67]

1) Pictures please
2) What is total run time on motor?
3) Any noise during previous operation?  How many times did you run the motor before the last time?
4) Exactly which cylinders and which valves were effected?
5) Do the rocker arms now w/ missing push rods spin and move smoothly/freely on the shaft?
5) What heads?, and what was done with them?
6) Any push rods bent? Closely inspect and describe the condition of the push rods.  Check rocker cups too.
7) Pull the shafts off and inspect.

It could a bunch of things.  Could be as simple as the rocker arm adjusters not being tightened.  Could be oiling issue to the shafts, clearance issue with shafts, clearance issues with the valves/guides, piston-valve contact........

Push rods just popping out with no parts damage may suggest something simple.  The "split" push rod does not sound good.

[Calif240]

1) Posting pictures in the following posts..
2) Probably 30 minutes, just a little over cam break-in
3) A small bit of clicking but it wasn't hugely noticeable and other people that heard it didn't think it was anything (probably one or two rods had fallen off but weren't bouncing badly)
4) Trying to remember from memory, but #4 Intake off, #5 exhaust off, #7 broken rod on intake, #8 both off. I'm fairly sure two cylinders went out when starting today (one breaking the rod and the other jumping)
5)Rocker arms spin nice and free, feel new
6)The broken one is bent, otherwise no. Rods look brand new other than bent/broken one. Cups feel fine.
7) Everything looks good but I definitely could have missed something

[Calif240]

Rockers...

[Calif240]

Inside at roller hydraulic lifters...

[Calif240]

Close-up of the lifters... they move freely and are smooth. Nothing looks out of place.

[Calif240]

Pushrods that are still on #3 cylinder (I took the even cylinders pushrods completely out)

[Calif240]

Top of pushrods, coming into the rockers where they hadn't "jumped"...

[Calif240]

One of the hydraulic lifters where the pushrods had jumped... everything is smooth. Doesn't look collapsed, rolls smooth, and sides are very smooth.

[Calif240]

Here is the one broken pushrod... it is hollow down the middle (should I have solid ones?)

[Calif240]

Here are the pushrods from the even side of the mill... The broken one on the right and I have it aligned so you can see the "bend" that it had when it broke. I'm wondering if it didn't jump off the seat, and get wedged between the lifter and the top of the rockers and shear because of lateral force... I've been told these shouldn't break under any normal circumstances... but this girl is far from normal.

[Calif240]

Last one... pushrods look great otherwise... they are black pushrods, but I can't see discoloration or uneven wearing on the tips thus far..

[Cooter]

Valvetrain geometry can cause all kinds of heartache. Somethin looks hinky with one of the rockers and pushrods at angle.
Something bound up cause it appears one pushrods is bent and the other just snapped.

[BSB67]

Check rocker side clearance before you take them off.
Check and report the amount of lifter plunger travel.

Double checking:  Motor seemed to run okay the first time until you turned it off.  And ran poorly/noisy (i.e. considerably different) the instant you started it up the second time, correct?

How long did you run it the second time?

[Calif240]

How do I check lifter plunger travel? Side clearance looks ok. The lifters (when pushrods are on) do not have any slack in them at all and I can't get the internal of the lifter to move any when it is taken out (at least with just pushing by hand)

The engine had a slight click before, but it didn't sound like anything was very wrong. I was getting ready to pull it out of the garage for the first time and was checking things and setting idle closer with choke. It died out hard while I was turning down the idle adjustment (which is when it broke the one pushrod I'm sure). After that I could hear it clicking and bouncing around inside. I would say that there was at least one or two pushrods that were messed up longer ago (not sure when), I just didn't know because it was still running and all.

Based on what I'm seeing with everything else looking pristine, I'm wondering if it is just pushrod geometry at the .540 lift? Either that or something with the lifters not oiling or pushing properly.


Terry

[BSB67]

Usually you measure rocker side clearance with a feeler gauge.  Not sure what "looks okay" means. 

It is unlikely the geometry causing this problem.  Even really bad geometry would not cause this to happen.

[deepockets]

I have the old comp rockers like yours, but mine are silver. mine have a 5/16th's cup on the adjusters. so I had to order pushrods that had 3/8th's ball for the lifter and 5/16th's on the rocker end. can't tell by the picture since it's a little blury, but just a thought.

[BSB67]

I have the old comp rockers like yours, but mine are silver. mine have a 5/16th's cup on the adjusters. so I had to order pushrods that had 3/8th's ball for the lifter and 5/16th's on the rocker end. can't tell by the picture since it's a little blury, but just a thought.

I think your onto something there. 

[firefighter3931]

Terry,

When the heads were machined did they trim down the valve guides and install the Viton seals ?

If the guides were not shortened then you'll have issues with the retainer to guide clearance. Just a thought 


Ron

[c00nhunterjoe]

Curious to see what the end result is. I see bradpenn though... 

[BSB67]

I have the old comp rockers like yours, but mine are silver. mine have a 5/16th's cup on the adjusters. so I had to order pushrods that had 3/8th's ball for the lifter and 5/16th's on the rocker end. can't tell by the picture since it's a little blury, but just a thought.

I think your onto something there. 

This is what the pushrod end should look like when using a Pro Magnum w/ 5/16" cup.

[Calif240]

Ron... I had told the builder that the valve guides would need to come down, but since he delivered the engine with valve covers on and all, I never verified that the guides were actually trimmed down, but that would obviously be an issue, as it would limit the ability for the pushrod to come all the way up the full .540 lift and all and the pushrod would take the resulting force. I'll stop by the builder tomorrow to see if he remembers. Is there an easy way to see if he used Viton seals without pulling off the springs and all? Maybe I should just take the heads off and take them down to the builder to re-inspect?

BSB67... I'm working to verify that one of the ends didn't need 5/16 like you've shown, but that definitely gives me something to check-off and verify. Comp paired the rods with my rockers, so I wouldn't think they're off, but you're definitely making me question it. The rods feel like they seat really nicely in both the rocker and the lifter. The side clearance is around 0.010" for most of the rockers. The biggest one is about 0.015".

I'm going to stop by engine builder and make some more calls to the suppliers and hopefully report back tomorrow evening...

Thanks again.