1.6 rockers vs 1.52 rockers - pros and cons (Page 3/6)
RayOtton JAN 30, 03:47 PM
Thanks for the info.

I'm still getting mixed signals as to the wear problem with 1.6 rockers.

Some folks think it's a problem but then one poster has had them installed for 10 years.

Also, I don't have any intention of pulling the engine to install a better cam. The performance rocker option is about the most digging into the engine that I want to do.
E.Furgal JAN 30, 09:49 PM

quote
Originally posted by RayOtton:

Thanks for the info.

I'm still getting mixed signals as to the wear problem with 1.6 rockers.

Some folks think it's a problem but then one poster has had them installed for 10 years.

Also, I don't have any intention of pulling the engine to install a better cam. The performance rocker option is about the most digging into the engine that I want to do.



Some have issues with 1.6 rockers and they can be
1) piston to valve clearance.. not an issue on a stock 2.8v6
2)putting more pressure on the cam lobe, lifter face , todays oils have has the zinc al but removed, flat tappet cams need this zinc the wilder the cam the more it becomes a fast showing wear, as the lobe ramps are faster,taller and require stronger springs, the more pressure pushes the oil film off the lifter/lobe face and the parts run with less of an oil film, the zinc builds up on parts so the lifter nose and cam lobe face have a layer of zinc so even with the oil film being pushed out the zinc layer is still there, and gets renewed as the oil flows over the parts.. adding the 1.6 rockers won't add that much pressure as the stock springs are weak and after all this time are even weaker.. and the cam in the engine is mild, but that doesn't mean you shouldn't use oil made for flat tappet cammed engines, The biggest problem is people think they can add a zinc additive to todays oil and call it good,you can't todays oils are very high detergent that stuff cleans off the layer of zinc as fast as the zinc layer tries to build up a layer.. you have to use low detergent or non detergent oil.. and why the so called high zinc race oil is not always what it seems as many are high detergent oils,and ya they have high zinc levels the high detergent makes it's level a mute point.. 10 years ago you could just use diesel oil as it was high zinc.. but as soon as the epa added converters on diesels the oils had to become low zinc just like they did for cars.. to find the good oil diesel high zinc oil you are going to a big rig fleet part store, as the stuff on the local chain stores are for new diesels..
3) non roller 1.6 rockers add side loading on the valve stem and guides as the stock geometry is set up if it was to blueprints, to not sweep across the valve tip,but to stay at the center, the 1.6 require different length push rods to get the same small movement at the center of the tip.. so they end up making the rocker tip sweep across the tip of the valve.. the farther from the center of the tip the more side loading on the valve stem and guide..

The good thing is the stock springs and cam are so lame the extra side loading isn't that big a deal.. but add a cam with fast lobe ramps and higher lift that require stronger springs and then it becomes a big issue.. the fast ramp ,high spring pressure is the reason ball and socket rockers have the same issues as flat tappet cams/lifter and need zinc.. or they blue from heat and the rockers then fail at the ball area..
RayOtton JAN 31, 06:43 AM
Ok, thanks for the explanation.

Couple of things -

1 - The car only has 48K miles and it was owned literally by a little old lady. I doubt the engine ever saw more than 3K RPM's and I know it was maintained according to the recommended schedule. So the valve train probably isn't too tired.

2 - Any oil manufacturers make "old style" oil or would a high end synthetic be acceptable?
Arns85GT JAN 31, 09:37 AM
I haven't used it, but I am told that Royal Purple produces an oil used in diesel motors that has zinc.

However, a good non-detergent synthetic will also work, however you will want good seals with synthetic.

I dyno'd my 2.8 at 132 at the wheels with 1.6 roller tips. The engine pulled very strong even with less than stellar rings.

The stock springs is all I ever used, and they worked fine right out past 6k rpm.

Watch the full roller rockers though. I used Scorpions and they did not clear the stock valve covers. I had to use S10 covers to get the clearance.

The fact is that unless you are doing high rpms the roller tips work just as well, albeit if you want that "little extra" top end you likely will want full rollers.

You'll want to port your exhaust logs and Y pipe if you are doing this work too. That frees up a good 6 hp.

Arn
RayOtton JAN 31, 09:43 AM

quote
Originally posted by Arns85GT:

You'll want to port your exhaust logs and Y pipe if you are doing this work too. That frees up a good 6 hp.

Arn



Done.

Plus a ported throttle body, upper intake manifold, lo-restriction cat and about an 80 lbs weight reduction.

I'm please with the performance enhancements so far.

The rockers are the last thing on the list.
DandRauto JAN 31, 11:21 AM
Did the ones from Summit also required different valve covers from the stock ones?
Arns85GT JAN 31, 12:44 PM
All the aluminum rockers are too fat for the stock covers.
lou_dias JAN 31, 12:59 PM

quote
Did the ones from Summit also required different valve covers from the stock ones?


Nope.


quote
Originally posted by Arns85GT:

All the aluminum rockers are too fat for the stock covers.



No they are not. The ones I listed from Summit worked fine. They are "narrow body" style.

My motor:


If you are truly worried about clearance, you can always run the gasket from other 2.8 motor as an "EXTRA" one - I'm talking about the thin flat one that looks like someone scrammbled cardboard and rubber together...

[This message has been edited by lou_dias (edited 01-31-2015).]

edfiero JAN 31, 05:14 PM
Can't speak to the 2.8 V6, but I use to have an Impala SS with an LT1. Guys would always swap the stock 1.5 rockers for 1.6, without batting an eye. No one ever mentioned any problems as a result of this.
Notorio MAR 02, 07:14 PM
So what did you end up getting? I can't find the 1.6 ratio, 10 mm stud, Comp Cams rockers kit that includes the pushrods, at any price.