Eliminator28

I would be more concerned with Mid-lift than where the roller is riding on the valve stem. The theory that the roller has to be centered on the stem is BS. It's nice to keep it near the center, but not being there has almost no effect on Guide or stem wear like first thought.

Have you checked valve lift with the cam specs? You need to have a solid lifter to do it correctly. This is the only way to determine if VT geometry is really correct.

Was this a Merc motor originally? Are these stock length valves?

Budman II

iTrader: (1)

Going to run a dial indicator on it tonight to measure lift at the retainer.

It was not a marine engine originally, but not sure why that would matter. Stock valve lenghts were used, set at 1.90 installed height. Isky 8005 SP springs.

I have seen a little bit about the Jim Miller touted "mid-lift theory", and it makes sense. I'm going to take a look at it from that perspective tonight.

If I had to choose, would I be better off with the longer push rod shown in picture 1, or the shorter one shown in the last picture? I guess it will depend on what my measurements show tonight.

I'm probably bashing my head against the wall for little to nothing!

Eliminator28

It looks like you will end up closer to Mid lift with the shorter pushrods. But like I said, check for correct valve lift @ retainer. Changing the geometry can have a huge effect on actual lift at the valve. I assumed I needed longer pushrods with mine because I used longer valves. I assumed wrong. Valve lift was .025 short. With the stock length pushrods, it put the rocker closer to Mid Lift (not perfect but close) and the valve lift was only .004 off.

Panther

I've n ever gotten any of my engines perfect. Got them pretty close and let em fly with no issues.

Budman II

iTrader: (1)

Converted a hyd roller to solid, installed the Scorpions, and ran through it again with the stock push rods. Geometry looks much better with these rockers...



Mid lift...



Full lift...



Patterns look pretty good - close to center and looks like maybe .060 travel...





I measured gross valve lift at the retainer. Oddly enough, I got about .580 lift on the intake, although cam is supposed to have .575. Probably lack of accuracy on my borrowed gauge...



What do you all think now? I have a set of adjustable push rods to try, but at this point I don't really see the need.

picklenjim

Man don't think it will make any difference trying to get it better than that. That looks good. Just curious what brand were the other rockers you were using at first?

Budman II

iTrader: (1)

The others were Comp Cams - from my old engine. They had about 450 hours on them.

The Scorpions work well on there, but the problem is, they are so big that I am going to have trouble with valve cover clearance.

Boat1

My only concern is what you did to convert the lifter to solid configuration. You should use some test springs to check everything, that is the only way to truely check your set-up. Your results look good if they are accurate reflections, since you converted to the solid configuration.

Budman II

iTrader: (1)

Boat1, since I had the intake off, it was easy to watch the plunger on the lifter to ensure that it was not moving. I stacked a bunch of washers inside the lifter in place of the spring. Believe me, it had nowhere to go - it was a real pain getting that retainer back on.

Boat1

That was indeed a tough job, sounds like you have done everything correct to verify your measurements.