Broken Pushrod on maiden voyage

[PC Rat]

After being torn down for almost 2 years I finally got my Daytona back together. I got the engine started at noon on Thursday. We took off for the lake on Friday to get the boat wet. Friday went fine, about 30 minutes of 2700 to 3200 rpm cruising. Saturday we went for a ride and after about 4-5 minutes heard a pop then the engine started clattering pretty loud. I shut it down and got towed back. I pulled off the valve cover and found the tip of the pushrod laying on the head and the rocker was spun sideways and you can see where the rest of the pushrod (which stayed in the lifter) worked itself into the body of the rocker.
Any ideas what could have caused this???????????
http://www.***boat.com/image_center/data/520/3256Rocker_and_Pushrod_Post.JPG

[PC Rat]

Also, I haven't found any other damage yet (probably the lifter is junk) but just the aluminum debris from the rocker all over inside the engine.
Will I need to tear the engine completely down and get it hot tanked to clean it all out?
Brian

[MikeF]

Looks like the pushrod was rubbing against the "passage/tube" in the head by seeing the marks on the pushrod just below the "pushrod guide marks". Prior to the damage once broken?

[rrrr]

I'm not a math expert, but it looks like you have a geometry problem. :rollside:
Did you check to see if the pushrod length was correct for your cam/lifter/rocker arm combination?
If it was my engine, I would tear it down and clean it.
Sorry you are having problems, that sucks.

[cstraub]

Looks like the pushrod was rubbing against the "passage/tube" in the head by seeing the marks on the pushrod just below the "pushrod guide marks". Prior to the damage once broken?
Brian I agree with Mike. Looks like there is some contact.

[steelcomp]

I third that...looks like the push rod was getting side-loaded. If that's the case, you're going to have to pull that head to do some clearancing. I'd check and see if there are any others doing the same thing, and at that point, probably tear it down just to be safe.
Bummer.

[PC Rat]

The other marking on the pushrod is from when the rocker spun and the pushrod moved toward the center of the engine (trying to come out of the guide) until it hit the head. There appears to be plenty of clearance when everything is where it is suppose to be.

[obnoxious001]

What are the chances that the valve adjustment was wrong, loose enough to let the pushrod out of the cup,, causing the damage to the rocker arm, and ultimately the pushrod? Food for thought, I have seen that senario before.
I found a pretty loose one on a superstock at Long Beach on Saturday, not sure who had done the previous adjustment,, but the polylock was good and tight. Needless to say, the boat was faster once it was correct.

[jkh04200]

I Agree with obnoxious.
Its hppened to me, twice. I hate to admit it. For some reason I cant explain, I adjusted the valves at 1/4 turn after 0 lash. It ran good for two days at Travis before it took a s^&t the second time. The pushrod broke due to the R/A coming off the valve. Just my .02

[PC Rat]

What are the chances that the valve adjustment was wrong, loose enough to let the pushrod out of the cup,, causing the damage to the rocker arm, and ultimately the pushrod?
I'd say the chances are slim, since I checked them all twice, but I wouldn't say impossible.
I do think that the pushrod broke before it came out of the rocker, because the broken piece is the exact same size as the cup in the rocker. So, could the valve stick shut and, instead of bending the pushrod, shear the tip off?
Brian

[MikeF]

Exh valves usually stick open. Which one had the problem....Int/Exh?
Is there signs of a crack before the shearing off of the tip? Possibly just a parts failure? Who's pushrods were they?

[MikeF]

Since it is the ball end of the pushrod that "alignes" the rocker, it kinda looks as though the end sheared....leading to the rocker getting out of alignment. Just a good guess. :boxed:

[GofastRacer]

I found a pretty loose one on a superstock at Long Beach on Saturday, not sure who had done the previous adjustment,, but the polylock was good and tight. Needless to say, the boat was faster once it was correct.
Damn what boat were you with??, if I'd a known I would have come by and said hello!..

[GofastRacer]

BTW, what about the pushrod guide plates, were they phased in???..

[PC Rat]

This is on the #6 exhaust.
Hard to tell of any signs of a crack.
Yes, I did modify the guide plates to center the rocker on the valve stem. I just went and checked the alignment with another rocker and pushrod - still looks good.
I pulled the head off and I see no signs of contact between the valve and piston.
Brian

[DMOORE]

Not sure who makes the rockers, but At one time I had a set of summit rollers that were also anodised blue.( looked the same), The poly locks would not stay tight. I would adjust them and sure enough, would loosen up after not too long. I would check and recheck everything, it was driving me nuts. Put a set of Harland Sharp on and never had a problem again.
Darrell.

[PC Rat]

They are Isky rockers.
Smith Bros pushrods.
Manley Nextec springs.
Manley Retainers.
Brian

[franky]

" '91 Eliminator Daytona 21 - scattered across my garage. AGAIN!!!!!!!!!! "
If I were you I wouold just sell that headache and buy something else or just get out of boating all together. It is just not worth the hassle, honestly. Please PM me with a price.

[cstraub]

Any bright notes about the voyage. . .was the oil pressure steady?

[Cs19]

" '91 Eliminator Daytona 21 - scattered across my garage. AGAIN!!!!!!!!!! "
If I were you I wouold just sell that headache and buy something else or just get out of boating all together. It is just not worth the hassle, honestly. Please PM me with a price.
LMAO.
Brians has been building this thing for a loooong time, I doubt hes gonna throw in the towel that quick, it would be a good boat to buy though.

[obnoxious001]

Damn what boat were you with??, if I'd a known I would have come by and said hello!..
I was down there with Rob and Bob DeVine. GN 47 "Fancy Dancer" and their newly purchased SS 6 "Angelfire". Saw a lot of old friends, hadn't been around the races much for a few years.
PC Rat
That end almost surely had to come off after the rocker was out of alignment with the pushrod and valve, as evidenced but the marks on the rocker arm. I don't think the end of a pushrod could "shear" off, particularly a Smith Brothers part, with normal up and down motion, being loaded against the rocker arm. Were it mine, I would pull the spring off that particular valve and check it carefully to make sure it was free in the guide, and that the tip was not damaged.

[Beer-30]

Did you stick with 1.7 rockers or were they 1.8s? Looks like a three-piece pushrod that was re-used with different angle. Tends to push against the passage tube and break off the tips of pushrods. I will only use one-piece pushrods anymore. Small or big block.
Also, you may need to "adjust" the guide plates. Have seen on here, some of the guys have sliced the center bar and aligned the slots properly - then rewelded together. Makes sense.

[obnoxious001]

Did you stick with 1.7 rockers or were they 1.8s? Looks like a three-piece pushrod that was re-used with different angle. Tends to push against the passage tube and break off the tips of pushrods. I will only use one-piece pushrods anymore. Small or big block.
Also, you may need to "adjust" the guide plates. Have seen on here, some of the guys have sliced the center bar and aligned the slots properly - then rewelded together. Makes sense.
A blue Isky rocker is 1.7 ratio, their 1.8's are purple.
Smith Brothers pushrods are known for their extremely high quality. While not impossible for them to have a bad one, I would explore other possible causes. I think he did state that he had aligned the guide plates as well.

[Beer-30]

Wow. Was hoping it was that simple.

[MikeF]

Read your original post again.
Maybe the exh valve stuck "just long enough" to cause the rocker to jump out of position. Pull that #6 exh valve (or all of them?!) and check for transfer of metal to the valve stem. That would be a tell tale. :boxed:

[GofastRacer]

I was down there with Rob and Bob DeVine. GN 47 "Fancy Dancer" and their newly purchased SS 6 "Angelfire". Saw a lot of old friends, hadn't been around the races much for a few years.
Shit I was over there checking them out too, we probably stood side by side and didn't know it, LOL..

[steelcomp]

I've assembled hundreds...probably close to a thousand two and three piece pushrods. Smith Bro's are some of the best, BUT...there's always that possibility of a bad one. The press fit between the stem on the tip, and the ID of the PR is tight, but varies. It takes a LOT or preessure to press the tips in, and if one was a little extra tight, it may have not gone in all the way. If the tip isn't seated against the top of the PR, then it can rock back and forth and it wouldn't take very long at all for it to break. It couls only be off by a couple of thousandths, but in this caase, a miss would be as good as a mile. The other possibility is a fracture right at the fillet between the stem of the tip, and the top. This could also happen during installation, and lead to failure.
Brian seems to know enough about what he's doing that I don't think it was in the assy...I'm pretty convinced it was a part failure, plain and simple. It does happen. No more pieced together pushrods. Get the Manley Pro Series one piece, and be done with it. Put the thing back together, and go boating.
My .02.

[PC Rat]

These are one piece pushrods.
Brian

[steelcomp]

Then replace that pushrod and go boating. :D

[Raylar]

I agree with steelcomp here. I would suspect a pushrod end failure here. Once the pushrod end gave way the pushrod set up shop on the one side of the rocker and moved the other end over on the valve tip. I think you should probably check the valve for a bent stem though, with that type of side loading it might now be tweeked. We use Manton pushrods and they are three piece and we have never seen a failure, but it can happen. Good Luck, don't get to discouraged.
Ray @ Raylar

[PC Rat]

I called Smith Bros to see if they had any ideas. He said to turn the engine over and watch the pushrod inside the cup of the rocker arm, with a large cam the rocker arm to pushrod angle can get so extreme that the edge of the cup could contact the pushrod. He said that the edge of the cup can act at a "pry bar" and pop the end off the pushrod.
I thought this sounded like a good idea, so I checked a couple others(obviously the broken one is out) but don't seem to see any contact. I wonder if the cup on the broken one could have been installed a little misaligned where only that rocker caused the "pry bar" effect.
I got the engine torn down tonight. There is some metal embeddment in the bearings and some scratches in the crank. The oil bypass is plugged. How does this metal get through the oil filter?
Also, what is the recommended valve guide clearance for marine applications?

[TBONE1904]

After being torn down for almost 2 years I finally got my Daytona back together. I got the engine started at noon on Thursday. We took off for the lake on Friday to get the boat wet. Friday went fine, about 30 minutes of 2700 to 3200 rpm cruising. Saturday we went for a ride and after about 4-5 minutes heard a pop then the engine started clattering pretty loud. I shut it down and got towed back. I pulled off the valve cover and found the tip of the pushrod laying on the head and the rocker was spun sideways and you can see where the rest of the pushrod (which stayed in the lifter) worked itself into the body of the rocker.
Any ideas what could have caused this???????????
http://www.***boat.com/image_center/data/520/3256Rocker_and_Pushrod_Post.JPG
I dont think I saw anyone comment on the springs......here is my .02 how cofident are you in the spring rate for the cam you are running?

[BOBALOO]

http://www.***boat.com/image_center/data/520/3256Rocker_and_Pushrod_Post.JPG
Do pushrods normally get a wear ring just under the point that this one broke? Might be the "prybar effect" Good luck, hopefully just a bad pushrod.

[PC Rat]

I dont think I saw anyone comment on the springs......here is my .02 how cofident are you in the spring rate for the cam you are running?
The spring rate is what the cam guy recommended.
Even if the spring rate was wrong, would it make much of a difference at 3000rpm?
Brian

[anger management]

man I feel your pain heres mine from last sunday .On decell from wot I heard some clatter I shut it off. Blah blah blah you know the rest.I cut the fram HP4 chevy oil filter(which has a bypass valve in it) most of the alluminum was on the outside of the element how ever a small amount appears to have gone threw the bypass So I am in the same boat.Tear it down and clean ithttp://www.***boat.com/image_center/data/520/2309Picture_388.jpg

[PC Rat]

Did you find the broken piece of pushrod? I'm curious if it is the same length as the depth of the rocker cup. What kind of pushrods are they?
Brian

[anger management]

There appears to be a bunch of small peaces some were actually inside the pushrod tube.There Bill Mitchell push rods