aftermarket rocker arms and poly locks for 1999 Mercruiser 3.0L

[tednv]

I'm going to be pulling the valve cover this weekend for valve adjustment, there's a slight tick on one of the valves when the engine starts cold. It goes away once warmed up, but I would rather verify that valves are properly adjusted since I don't think the valve cover has ever come off the engine. From what I've seen on youtube, this is a fairly simple procedure with the engine running and warmed up. I also have the service manual that confirms this

So I have two thoughts since I'll have to scrape + reinstall gasket and I don't feel like doing this again for a while...

1. Is there any benefit to installing aftermarket rocker arms, will these improve performance or lifespan of motor?
http://www.ebay.com/itm/Scorpion-Ro...tud-/390981086010?hash=item5b0849eb3a&vxp=mtr

2. The OEM "locking" nuts often back off, especially once adjusted. I don't want to spend money on new disposable nuts if poly locks will work. Would I be ok with installing poly locks on factory rockers or do they only work with aftermarket rocker arms?
http://www.speedwaymotors.com/Rocker-Arm-3-8-Inch-Poly-Locks,739.html

Thank you for your input folks!

 

[NHGuy]

Before you disassemble run the engine cold again and use a stethoscope or some other contact device to find which lifter is ticking. I take a long screwdriver or socket extension and put it against the suspect part, then put the other end against my upper jaw bone right next to my ear.
Move along the sides of the motor til you know where the noise is. Then when you open it you can check the adjustment on the suspect lifter.
I haven't heard of the nuts backing off, but I have heard of the lifters or cam changing. So adjust what you have.
Also, performance rockers don't matter til you have high rpms.

 

[Bt Doctur]

correctly installed the rocker nuts do not loosen. And at $2184 for no real performance gain...........................................................








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[tednv]

thank you both for wise words! i'll ditch the rocker arms idea but still thinking of those poly locks for nuts, primarily paranoia after watching this video:

https://www.youtube.com/watch?v=QAlCVA5cCQM

if you look at the crimped rocker arm nuts, i can totally see how they would loosen up after being adjusted once or twice

i'm planning on doing the "while running" procedure as described in manual, this guy has a nice demo (different engine) using poly locks. they're pretty cheap, and a lot of people swear by them
https://www.youtube.com/watch?v=xCsRPxZ2SLw

 

[DaboatnutinWA]

Tighten the rocker arm nuts a little at a time til the ticking goes away. (Quarter/ half turn.) Over tightening is bad too.

 

[alldodge]

There are a lot of nylocks (poly locks) out there and many are used. I prefer steel locking nuts because for no other reason then heat doesn't effect them. Ever noticed nylon and plastic on top your car engine over time becomes brittle. Use which ever you like, its your motor.

As others have mentioned, get it warmed up and loosen each one until you get a rough idle, then turn them in 1/4 turn at a time to quite. The give them another 1/4 turn but no more then a 1/2 turn. If the lifter goes quite more then once with another turn your lifter is collapsing and needs rebuilt or replaced

 

[Bondo]

Ayuh,...... 'n even though Apheus's video is by the book, it's misleadin',.....

Ya don't tighten 'em til the push-rods don't spin, ya tighten 'em til the free-play is gone,.....
No Liftin', pushin' down motion is what ya want at ZerO lash,....

Many guys go with no spin, 'n end up tightenin' the valves sooo tight, they won't close,... at All,....

'n I agree with AD, ny-locks are a step backwards,....

 

[fishrdan]

Poly locks might not fit under the valve cover, so they may be a moot point. If you are worried about the stock steel locknuts backing off, buy new ones.

I think you're just as apt to pull a rocker stud as loosen a nut, both uncommon. Studs can be pinned, but it's not something I would do with the head on the engine.

 

[Alumarine]

Ayuh,...... 'n even though Apheus's video is by the book, it's misleadin',.....

Ya don't tighten 'em til the push-rods don't spin, ya tighten 'em til the free-play is gone,.....
No Liftin', pushin' down motion is what ya want at ZerO lash,....

Many guys go with no spin, 'n end up tightenin' the valves sooo tight, they won't close,... at All,....

'n I agree with AD, ny-locks are a step backwards,....

I had adjusted lots of solid rockers but the first time I tried to adjust hydraulic lifters I did the no spin thing.
Ended up with zero compression on all 4.