Bent Pushrods-Trickflow 240 Heads

[Road Grabber]

I have a 440 with Trickflow 240 heads. The rockers are 1.6 ratio Harland Sharp. These heads are supposed to allow 3/8 pushrods and are sold in kits that include 1.6 rockers.

During a dyno test on the 10th run the engine lost oil pressure. It was discovered that bent pushrods allowed two roller lifters to jump out of their bores. More pushrods were found bent too at different degrees. This happened during a couple 5500 runs.

The pushrods were a set of aftermarket Isky pushrods. I don’t know if they were 5/16 for sure but I believe they were. I’m not on location.

Any possible reason why this happened? I have ideas but I’d like to hear what others think.

We are investigating pushrod interference with the head. I didn’t see rub marks on the sides of the pushrods.

The engine builder seems to think that it wasn’t coil binding but he is going to check this again because he didn’t know the rockers were 1.6 instead of 1.5. I know he didn’t push it to the limit?

Has any had this problem before and used 3/16 pushrods with the Trickflow heads?

Thanks in advance.

 

[threewood]

Hydraulic roller lifters? Maybe pump up causing coil bind. Or straight up coil bind.

I'm not familiar with TF heads but on Stealth heads, the pushrod will rub a touch near base circle, but center up in the holes under lift.

 

[RemCharger]

Hyd / solid cam?? Lift? Correct heads for cam type? 3/8 end of pushrod in 5/16 lifter?

 

[1967coronet]

Wrong length of push rods if several bent at the same time, WAG,
Also , why didn't the builder know what ratio of rockers he installed ?

 

[Don Frelier]

Or valves hitting the pistons...

 

[dodgeboy440]

I have a 440 with Trickflow 240 heads. The rockers are 1.6 ratio Harland Sharp. These heads are supposed to allow 3/8 pushrods and are sold in kits that include 1.6 rockers.

During a dyno test on the 10th run the engine lost oil pressure. It was discovered that bent pushrods allowed two roller lifters to jump out of their bores. More pushrods were found bent too at different degrees. This happened during a couple 5500 runs.

The pushrods were a set of aftermarket Isky pushrods. I don’t know if they were 5/16 for sure but I believe they were. I’m not on location.

Any possible reason why this happened? I have ideas but I’d like to hear what others think.

We are investigating pushrod interference with the head. I didn’t see rub marks on the sides of the pushrods.

The engine builder seems to think that it wasn’t coil binding but he is going to check this again because he didn’t know the rockers were 1.6 instead of 1.5. I know he didn’t push it to the limit?

Has any had this problem before and used 3/16 pushrods with the Trickflow heads?

Thanks in advance.

Pushrods Just Don’t Bend …..

There HAS to be interference Somewhere…..

Question ?

Are you using an “ Engine Builder “. ?
OR
An “ Engine Assembler”???

Was Rotational Clearance Checked Prior
Actuation ?
What Was Your Measured Piston To Valve Spec?

IMO There’s your answer …..

Mopar2ya!

John

 

[pnora]

You also have to look close at block to push rod clearance at max lift. Lots of times the push rods will bind against the block and want to pivot out of the lifter cup. Instant disaster .

 

[INTMD8]

Can you post dyno sheets of the previous runs. May be some evidence as to what's going on.

Hyd lifter can only 'pump up' if control is lost (which is certainly possible as it seems like there were some errors here)

 

[HawkRod]

Besides coil bind, you also need to check for maximum valve travel before the spring retainer hits the seal. This value is usually large enough, but it is good standard practice to check that.

 

[Carcinogen]

Maybe the 3/8 pushrod is not compatible with lifter.

At 5:00 shows problem Nick found.

 

[Road Grabber]

He is experienced but in his older stage of life. He SHOULD have checked with me about the rocker ratio.
I will have him verify the rod diameter that failed. I don’t think they were 3/8 but if new rods are going to be ordered I will let him know about the ball size a lifter fit. Also the retainer clearance. Rolling check etc. everything mentioned.

Keep it coming if there are other thoughts.

Thank you

 

[Curiousyellow71]

We have a 440 w 3/8 pushrods w 1.6 mancini rockers TF240s heads and a 263/272@ .050 solid roller .650ish lift. Our block was decked as well, we had to do deeper flycuts to get proper clearance. Not sure if your build is similiar to ours to have a issue.

 

[Doorkicker]

post cam specs... and share the 240 part number... there are actually three different types of 240's.

Gut reaction...
- Too much lift for the spring/head, so your binding up. Especially with 1.6 rockers.
- P2V. Even minor at 5000+RPM can cause a bend and worse with 1.6 rockers.
- Wrong size pushrods. I'm less concerned about length because while important, it's really hard to do wrong. I'm thinking interface with lifter.
- Improper shimming on the rocker arms on the shaft creating a misalignment... resulting in a bind.
- Bad lifters... but even then, if they locked up, you shouldn't have that much of a lash issue to bend rods... but that's possible too.

The cam card will help a lot.
Also, how much was the cam advanced?

Keep in mind... for cams... Lift has virtually no applicability to P2V, but has the obvious impact to total valve travel, which directly relates to springs and valve stands on the head. Second, duration is a big deal for P2V. Somewhat with overlap, but general opening and closing times and valve speed. All of which are affected by increasing the ricker ratio. In other words, if the P2V wasn't tested correctly, the cam will shove the valve into the piston and bend the rod at a decent rpm... which can be missed in a "playdough" P2V test.

If you were here...
- I'd pull the springs off #1 cyl and to a P2V test (assuming the lifters weren't the obvious problem)

 

[4mulas]

3/8 end of pushrod in 5/16 lifter?

I was thinking this too. Bounced out?

 

[PRHeads]

My Wag is the pushrods just weren’t up to the task.
Particularly if there is no evidence of fairly substantial pushrod to head contact.

Use 3/8”x .080 wall, heat treated for the next go around.

 

[RemCharger]

A borescope should tell you if the valves were touching the pistons.

 

[steve340]

The other possibility is the piston notches are not big enough to clear the larger valve heads.

 

[andyf]

It doesn't take more than a few minutes to pull a valve cover and to rotate the engine over to check all of the clearances. The engine builder can tell you in 15 minutes if there is interference with the pushrod and head or in the valve spring or rocker arm area. All of that should've been double checked before the engine was fired. My guess is that someone installed a set of super cheap pushrods and they bent because they were super weak.

 

[Road Grabber]

The builder verified that the pushrods were 5/16 diameter. We did have a conversation early on about the spring coil gap having a.060 minimum gap but he didn’t go that far because it wasn’t a race application and I felt that all that pressure might cause more stress than needed but I forgot how much less he set the spring height using shims.

These heads are sold in kits with .600 lift cans and 1.6 rockers. Trickflow calls it their “top end” kit for 440s pushing 600 hp.
This cam is .530 and is more of a street mid range cam from Howard’s.

He said he did use light springs to check valve clearance and I had plenty. I don’t think valves hit pistons cause I head the heads off already with short previous starts before I gave the engine to him. I had puffs of smoke and poor head gasket sealing with felpro 1009 gaskets. I wanted the block decked, the surface of the heads cleaned up and bored .040 over with new pistons. This because a different builder DID NOT deck the block causing issues with the felpro gaskets. I am now using the cometic gaskets. He also recommended and I agree that head studs be used instead of bolts. They have fine threads that tighten on the outside.
So the guy showed some good experience.
That being said he never should have used the 5/16 pushrods. He feels that’s the problem but I did mention many of the things you all thought were things that should be addressed.

He plans to recheck everything
Retainer hitting
Spring height rotation check
Pushrod clearance at the block decked AND head
Order new 3/8 pushrods that have the correct fit on each end
Thicker wall pushrods from Smith Bros

And maybe some other things.

The lifters are roller hydraulic lifters I believe from Howard’s.

If I missed something please mention it.
This engine has been waiting for 5 years along with my CHARGER.

 

[Road Grabber]

post cam specs... and share the 240 part number... there are actually three different types of 240's.

Gut reaction...
- Too much lift for the spring/head, so your binding up. Especially with 1.6 rockers.
- P2V. Even minor at 5000+RPM can cause a bend and worse with 1.6 rockers.
- Wrong size pushrods. I'm less concerned about length because while important, it's really hard to do wrong. I'm thinking interface with lifter.
- Improper shimming on the rocker arms on the shaft creating a misalignment... resulting in a bind.
- Bad lifters... but even then, if they locked up, you shouldn't have that much of a lash issue to bend rods... but that's possible too.

The cam card will help a lot.
Also, how much was the cam advanced?

Keep in mind... for cams... Lift has virtually no applicability to P2V, but has the obvious impact to total valve travel, which directly relates to springs and valve stands on the head. Second, duration is a big deal for P2V. Somewhat with overlap, but general opening and closing times and valve speed. All of which are affected by increasing the ricker ratio. In other words, if the P2V wasn't tested correctly, the cam will shove the valve into the piston and bend the rod at a decent rpm... which can be missed in a "playdough" P2V test.

If you were here...
- I'd pull the springs off #1 cyl and to a P2V test (assuming the lifters weren't the obvious problem)

He is removing the heads again at some point. I would think if that happened there should be marks on the piston heads?

P2V - piston to valve?

Thanks for the help