Engine pushrods

[loco28]

Hi,
Got a new 5.7 vortex put into my bayliner 2052 Capri,
I used it 6 times and it broken 2 push rods what could be doing this??
Please help thank you

 

[HT32BSX115]

Re: Engine pushrods

Hi,
Got a new 5.7 vortex put into my bayliner 2052 Capri,
I used it 6 times and it broken 2 push rods what could be doing this??
Please help thank you

Howdy,


Welcome aboard!

There's only a few things that can bend/break pushrods.

Top of the list is stuck valves. Stuck valves are usually caused by water getting there and causing corrosion.

Water getting in there is usually from cracked/leaking risers/manifolds.....leaks can be due to leaking riser (to manifold) gaskets......

cracked riser/manifolds is usually from freeze damage.

There's other reasons but I would check the risers and manifolds first.

Regards,


Rick

 

[John_S]

Re: Engine pushrods

Welcome to iBoats.

Assuming you purchased a complete engine, most things would/should be covered by the supplier. If you installed the exhaust and it is hydro-locking or water intrusion, then maybe not. Hydro-locking would typically occur on start-up, and be accompanied by starter grinding, etc. If you purchased a short block, and assembled the heads, etc, than a completly different scenerio. In that case, the more details you can provide, the better. What cam, lifters, pushrods, rockers, etc, etc you used. How you adjusted the valves, and checked other key clearances.

What cyl and valve (I/E) have you broken the rods on?

When did it occur? start-up, cruise, wot, rev in neutral, etc?


PS. A vortec engine, unless purchased a replacement/reman from mercruiser can mean a large combination of parts, the only known quantity is the heads, and even those are sometimes not genuine GM.

 

[loco28]

Re: Engine pushrods

Hi bought the engine from the mechanic he did all the work, I got the boat back and after one use it snap a pushrod, they fix it at no charge got it back second use it done it agin,they did find a little bit if water in the fuel tank but it was drain out, it happen after using the boat for about 20 minutes and it sounded like it was backfiring, they used all the top parts of the 5l engine that come with the boat,they told me they tested the manifolds and they were ok he telling me there nothing wrong that they have done to make thus happen.
I start the boat at home before I used it to make sure I had no trouble at the ramp,hes telling me I the one doing something wrong?? s

Welcome to iBoats.

Assuming you purchased a complete engine, most things would/should be covered by the supplier. If you installed the exhaust and it is hydro-locking or water intrusion, then maybe not. Hydro-locking would typically occur on start-up, and be accompanied by starter grinding, etc. If you purchased a short block, and assembled the heads, etc, than a completly different scenerio. In that case, the more details you can provide, the better. What cam, lifters, pushrods, rockers, etc, etc you used. How you adjusted the valves, and checked other key clearances.

What cyl and valve (I/E) have you broken the rods on?

When did it occur? start-up, cruise, wot, rev in neutral, etc?


PS. A vortec engine, unless purchased a replacement/reman from mercruiser can mean a large combination of parts, the only known quantity is the heads, and even those are sometimes not genuine GM.

 

[loco28]

Re: Engine pushrods

Hi the engine is new they tell me they put a vortex block and heads,and used the top parts of the mercruiser 5l engine,this is the second time it happen the 1 st time they fix it the boat lucky to have done no more then 4 hours on the new engine???

 

[John_S]

Re: Engine pushrods

he telling me there nothing wrong that they have done to make thus happen.

I think the question to your mechanic is "What possibly could I be doing wrong to cause a push rod to bend?"

Did he tell you what cylinder and what valves? Repeat offender, or different?

Look at the plugs from the offending cylinder(s).

 

[HT32BSX115]

Re: Engine pushrods

If there's no valve corrosion from leaking risers or other water intrusion (or stuck valves for any other reason), then I would be talking to the "mechanic" that installed the valves, pushrods and rockers.

Push-rods that are too long and/or rockers that are "screwed" down way too tight can bend/break pushrods.........They just do not break for NO reason......

 

[solareclpse2000]

Re: Engine pushrods

If there's no valve corrosion from leaking risers or other water intrusion (or stuck valves for any other reason), then I would be talking to the "mechanic" that installed the valves, pushrods and rockers.

Push-rods that are too long and/or rockers that are "screwed" down way too tight can bend/break pushrods.........They just do not break for NO reason......

^^^^^ exactly the thought! i have seen engines do this many times. due to improper valve adjustment procedures. also from an aggressive cam grind profile on stock valvetrain but being a hydraulic cam that wouldnt be common in your engine.

i would recommend gettin a new "mechanic" to fix it and take a look. or if you got a buddy that knows engines well

 

[joewithaboat]

Re: Engine pushrods

Valves are probably too tight. Are the push rods bending when you run it under load at higher rpm? If so the lifters are likely pumping up and bending the push rods. Could also be the wrong combination of parts. If they used rocker arms that require guide plates but don't have them?? Or it has guide plates and self aligning rockers???

I would start by checking the valves, set them running.

Maybe find a different mechanic.

Post pictures of your heads, and rocker arms. Quickest way for us to have a look because you don't know what vintage it is.

Also... you said you used it 6 times and bent pushrods only 2 times...
Are you possibly over revving the engine?
What rpm are you operating at?

 

[Scott Danforth]

Re: Engine pushrods

if its a new engine with new exhaust with good exhaust flappers (no water reversion issues, etc), then I am leaning toward your mechanic does not know how to set up hydraulic lifters and I would get another mechanic.