posi locks

[William F.]

What's the story on posi lock valve lash adjusting mechanism? A friend of mine wass looking at a solid lifter 396 Camaro. Owner told him since engine had posilocks , would be the same as having hydraulic lifters-no interval adjustment needed. From what I have read, this isn't so and would be better off with OE GM lock nuts. How about it?

[Joe L.]

Re: posi locks

What's the story on posi lock valve lash adjusting mechanism? A friend of mine wass looking at a solid lifter 396 Camaro. Owner told him since engine had posilocks , would be the same as having hydraulic lifters-no interval adjustment needed. From what I have read, this isn't so and would be better off with OE GM lock nuts. How about it?

William------

The owner that told your friend that is 100% incorrect. Posi-type lock nuts for rocker arms absolutely do not eliminate the need for valve adjustments on engines with mechanical lifters. Some folks must incorrectly believe that the only reason for valve adjustments on mechanical lifter engines is "backing off" of the factory type lock nuts. That may have some minor effect on valve adjustment, but it's not the principal reason.

The main reason to use posi-lock type nuts is in conjunction with full roller rocker arms. With this type of rocker arm there is insufficient clearance for the use of factory-type lock-nuts. Posi-type nuts can be used with stock-type rockers but you'd NEVER catch me doing it. Rather, I wish that factory-type lock nuts could be used with roller rocker arms. If I could find a way to do it (and I've given it a LOT of thought), I'd do it myself.

Factory-type lock nuts are superior to ALL other type of rocker arm nuts. Period.

[Jim D.]

Re: posi locks

Just curious Joe, if it isn't the factory nuts backing off, what causes them to go out of adjustment? Is it camshaft, lifter or push rod wear? I don't think so or those parts would require frequent replacement.

I use Posi-lock nuts on every motor I build. They must work because after the initial setting, I've never had to re-adjust them. Just for kicks I checked the lash on my 60 with solid lifters and it was still perfectly adjusted. Of course it only has a little over 10,000 miles since the initial adjustment.

As far as factory nuts being superior, hogwash.

[Clem Z.]

Re: posi locks

Just curious Joe, if it isn't the factory nuts backing off, what causes them to go out of adjustment? Is it camshaft, lifter or push rod wear? I don't think so or those parts would require frequent replacement.

I use Posi-lock nuts on every motor I build. They must work because after the initial setting, I've never had to re-adjust them. Just for kicks I checked the lash on my 60 with solid lifters and it was still perfectly adjusted. Of course it only has a little over 10,000 miles since the initial adjustment.

As far as factory nuts being superior, hogwash.

even when we had to run stock rocker arms because of the race track rules i always used posi locks BUT you must machine the top of the stud flat to get a good surface for the set screw to bite in to. with SBC the stock rocker covers may not fit because of the height of the posi locks

[Joe L.]

Re: posi locks

Just curious Joe, if it isn't the factory nuts backing off, what causes them to go out of adjustment? Is it camshaft, lifter or push rod wear? I don't think so or those parts would require frequent replacement.

I use Posi-lock nuts on every motor I build. They must work because after the initial setting, I've never had to re-adjust them. Just for kicks I checked the lash on my 60 with solid lifters and it was still perfectly adjusted. Of course it only has a little over 10,000 miles since the initial adjustment.

As far as factory nuts being superior, hogwash.

Jim-----


The main reason for adjustment is wear, including distorting conditions, in the valve train. This includes all of the parts you mention but, especially, valve head and seat recession. It takes VERY LITTLE wear to change the valve adjustment a few thousandths.

Regarding factory type lock nuts, the Chevrolet Power Manual agrees with me. See attached.

[Joe L.]

Re: posi locks

This blow-up of the aforementioned and pictured page of the Chevrolet Power Manual might be easier to read.

[Clem Z.]

Re: posi locks

This blow-up of the aforementioned and pictured page of the Chevrolet Power Manual might be easier to read.

if you don't have "dripper" rocker covers the poly locks are tall enought to keep the oil from overshooting the rocker/ball interface.

[Michael H.]

Re: posi locks

Jim-----



Regarding factory type lock nuts, the Chevrolet Power Manual agrees with me. See attached.

I agree with you too. Posi locks are only required for use with roller rocker arms, as you mention.
New, or snug used nuts do not back off.

I hate Posi Locks.

[Jim D.]

Re: posi locks

Regarding factory type lock nuts, the Chevrolet Power Manual agrees with me. See attached.

That proves absolutely nothing. What do you expect a CHEVROLET manual to say? "For better performance use an aftermarket nut because ours are crap".

[Joe L.]

Re: posi locks

That proves absolutely nothing. What do you expect a CHEVROLET manual to say? "For better performance use an aftermarket nut because ours are crap".

Jim------


In many cases in the manual they DO recommend aftermarket pieces for certain applications even though GM pieces were available.