While installing the XS282S in the 396, I thought I'd check the relative weights of the hydraulic flat tappets I've been running and the solid flat tappets for the new cam. Now, this wasn't a chemist's scale by any stretch, just a 16 oz food scale. But, the hydraulic came in at 100 grams, the solid at 80 grams.

I should weigh the pushrods as well (didn't think of that last night). Should be less than the lifter, I'd guess. Of course, I have no clue what the rocker arm rotating mass would be.

But, I'd think any reduction in valve train mass is a step in the right direction.

 

your solid lifters weighed less then an EMPTY hydraulic lifter? (or full?)
interesting...

That's probably better for performance than yellow caliper paint

 

I didn't take the lifter apart to wipe out all of the oil, but it did drain some after removal.

 

Take it as you will, but according to Smokey Yunik, any drop in valvetrain mass will allow more reliability and performance from the engine. However, accoding to smokey, the mass reduction on the pushrod side of the rocker arm is significantly less important that the reduction on the valve spring side.

 

Interesting. The valve spring has to keep everything loaded so the lifter stays on the lobe. We all know that a rev kit keeps rollers on the lobes, relieving the valve spring of that responsibility, and increasing rev capability.

Valve bounce/float has more than one source. But, I'm sure Smokey had a strobe light on a lot more valve trains than I have.

 

Mass on the 2 sides of the rocker fulcrum has different effects.... even though reducing it on either side is a good thing.

On the push rod side, it keeps the lifter from following the cam on the closing ramp; sort of "lifter toss".

On the valve side, it causes the valve to bounce off the seat at closing.

Both things are very bad, but their exact effects, and their cures, are quite different. IMO the valve bouncing is more serious as far as how the engine runs, but the lifter getting flung off into space can break parts. Neither is a good thing.

Personally I think you'll get more of a difference just from the different cam ramps, solid to hydraulic, than the lifter weight.

I've often wanted to take a hyd roller cam and just stick solids on it, and tight-lash them, and see how much difference it makes. I've done that lots of times with flat tappets, but never a roller. Hmmmm.......

I have that same cam on hand actually (on a small base circle ) for a buildup in a 400 block that I'm working on. I'll be using it with Isky Red Zones, a rev kit from AFR with Comp pucks for the lifters, Crower 7/16" stud 1.6 stainless rockers, stud girdle, Dart heads with 2.05" and 1.625" valves, Comp 999 valve springs, Ti retainers.

I'm actually thinking it's not enough cam for the rest of my situation, but hey, I've already got it; it seemed like a good idea at the time.

Let us know how you like it.

 

Oh.... except mine is a small block. It'll be a good bit bigger than your big block. You know what she says, inches is inches, no matter how big the block....

 

At .030" over each, you'll have about 5 cid over me.

I'm comforted by 260 cc intake ports pre-porting, actually. . .

(I'll be sure to post the results - once it's running and I can provide quantitative data.)

 

No actually, I think there's more to it than .030" of bore. Hence the small base circle cam.

Als, don't forget, BB intake ports are alot longer; so the port volume for any given flow, will always be a MUCH higher # than a small block. That's one of several classic unknowns that FUBARs a direct SBC vs BBC comparison.

All the same, let us know how it turns out. I'm certainly hoping for the best!!! Because if yours works good, mine likely will too; and vice-versa.

 

Have I ever mentioned the both of you are engine geeks? No? Well now I have.

So how long do we have to wait for these things, huh? C'mon, times a wastin'!

 

I think I've just be accused of being a bench racer who's all and no walk . . .

(Believe me, I know time's a'wastin'. 1st T&T is 6 weeks away, and I've got at least 4 weekends' worth of work to do on the two cars to get them ready for the season.)

 

Pfff... would I ever intimate such a thing?

Besides you didn't seem too happy with the end of last season so any kick in the *** has to be a good one.

 

Last season was a weird one, that's for sure. But, the car kept getting quicker, so that was encouraging. The new cam should make a difference, allow me to drive around that '71 Charger 440 that has always been a thorn in my side (I got paired up with him in the 2nd round and 1st round on consecutive race nights last mid-season, took me out and basically killed my season points - last race of the year, he was in 1st place by something like one round, we got paired in the 1st round again, this time I took him out - he ended up in 5th place).

I'm chomping at the bit, no doubt! (Probably explains this chatter. . . )