five7kid

iTrader: (14)

Anybody got an example of each they can put side-by-side?

When I put the XS282S in the 396 last year, I knew the rockers had to be tightened a lot farther down on the studs than they were on hydraulic cam. What I didn't realize at the time is it would lead to valve float, especially on the intake valves.

So, if someone could compare the two and let me know, I'd appreciate it. I've never heard of having to have different length pushrods for solids vs. hydraulics. This is driving me nuts.

(As I'm sure you know, SBC and BBC use the same non-roller lifters.)

Damon

Agreed that the pushrod cup on many solid lifters sits lower than the cup on many hydraulics. Informal observation..... probably about the same as if you pushed the plunger in the hydraulic down about 1/2 way into it's travel, give or take.

Now, when I set up the valvetrain on my 454 with the same Comp 282 cam I ended up with much longer intake sticks than I would have expected. These are AFR heads in my case, so probably not a direct comparison to what you're working on, but I'll let you know that AFR recommended sticks that were +.200" over stock, so that's where I started. On the exhaust, pretty close (ended up +.250" for proper exhaust geometry). But on the intake, nowhere near right (I ended up a whopping +.400" to get proper geometry). If the sticks were much shorter than that it put the pushrod at a very odd angle to the rocker arm and I could forsee some problems with that down the road.

I use multiple different methods when checking rocker geometry/pushrod length. One is contact pattern on the valve tip- I actually WATCH what it's doing through the whole travel, not just the mark it leaves on the valve tip. I also use a cheap Mr. Gasket plastic rocker geometry tool (pushes on the rocker stud). And finally I pay attention to the location of the poly-lock in it's slot in the rocker arm to make sure it never gets too close to either end of the slot from valve-closed to max lift. If all 3 methods agree, I know I'm close. Which in my case they did, but only with considerably longer intake sticks than recommended.

five7kid

iTrader: (14)

The lifter cup is a lot farther down in the lifter than 1/2 the travel of the hydraulic plunger - 1 turn on the adjusting nut centers the hydraulic plunger, which is one thread on the stud. It's more like 3 or 4 threads on the stud down.

Silly me, I didn't see this as a "custom" installation. Live & learn.

Where did you get your pushrods? I'm seeing prices close to $200 for a set.

F-BIRD'88

Just compared two new solid and hyd lifters. Don't see how there would be much if may difference in the running pushrod seat height once adjusted right.
Not enough to require different length pushrods.

A high lift cam has a smaller backside, not a taller lobe peak. This is the difference in the net pushrod top tip height when the cam is on its base ( lifter down). Even then it does not usually require custom pushrods. But could if you're using a non-stock rocker arm combined with a thicker than stock (.022") head gasket.

five7kid

iTrader: (14)

What brand of lifters? My hydraulics were General Kinetics, looked like every other Chevy V8 hydraulic I've seen. The solids are Elgin.

I should have taken pictures. I put the hydraulic lifter that was coming out and the solid lifter I was putting in side-by-side on the bench, cam side down, and the solid lifter push rod cup was significantly lower than the hydraulic relative to the bench surface. Every "reliable" photo I've been able to find on the internet showed the solid lifter cup down in the body of the lifter as well.

I understand about the base circle with higher lift cams. That just added to the problem. I used a steel shim head gasket, so those shouldn't have added anything. The block deck is stock, stock unshaved heads, which would not help the problem.

F-BIRD'88

I have comp solids and Speed pro Ht817 hyds. the hyd lifters appear to have the seat higher but remember the lifter is adjusted so the seat is depressed so appearance is decieving.
I just checked again. When side by side, with the hyd lifters plunger depressed
half way down its travel, the push rod seats are the same height in the lifter body.

What rocker arm are you using. Some have a non standard pushrod seat height location. Crane gold race and Comp pro magnum come to mind.
Crane modifies the geometry of the push rod seat on their rocker. Part of their "quicklift technology" with those rockers I can see you needing a different pushrod length than stock.

five7kid

iTrader: (14)

I'm using Comp Magnum rockers. Same as I did with the hydraulics.

Damon

I found Trick Flow makes some decent sticks for street/strip type applications- certainly good enough for a solid flat tappet and the price was pretty reasonable.

F-BIRD'88

What does your rocker arm/ valve tip geometry look like?