Re-use Solid FT lifters?

[FlowSpecialist]

Originally Posted by old blue 75

A ? for DV. David can a guy with access to a surface grinder and spin fixture
(hint hint) grind a 1 or 2 deg. angle on used lifters instead of the large rad., or will that not work.
I,m thinking of some used GM hard face hyd. lifters. Maybe do the figure 8 pattern on emery afterwords.

old blue 75

The angle, if you want to approximate a dome to an angle, is nowhere near 1 or 2 degrees. The dome is only 2 to 3 thou high so across a 7/8" lifter that would only be about 0.4 degrees to generate a similar angle with a straight line. If you can set up a grinder to that accuracy it's worth a try.

My own method is much more simple. Reface them flat then put them in a lathe and apply some 80 grit to the face. Because the surface speed will be greatest at the rim and falling to zero in the middle you remove progressively more material towards the rim. That very quickly generates exactly the shape you're after with little effort. Keep moving the grit paper about so you don't just create circular grooves. I move it about in strokes from the edge to the centre applying more pressure at the edge and tailing off as I move in.

You can check the metal removal and curvature with a dial gauge and once you've got a feel for how long you need to polish each one it's a very quick operation. Perhaps a light lick over with finer paper just to remove any scratches and job done.

As I say aim for 2 to 3 thou higher in the centre than the rim.

Dave

[old blue 75]

quote (The angle, if you want to approximate a dome to an angle, is nowhere near 1 or 2 degrees. The dome is only 2 to 3 thou high so across a 7/8" lifter that would only be about 0.4 degrees to generate a similar angle with a straight line)

Dave I was just to lazy to trig. it out. I may try you method but it may have to be
on standard lifters as the GM ones I think are super hard. Do you know are lifters
thru hardened or case? How much can I grind off?

[Cammer]

Solid cam followers are designed with a spherical shape on the surface contacting the camshaft. The sphere is about 0.002" higher in the center of follower than at the edges. The slight spherical shape keeps the camshaft from digging into the edge of the follower.

As followers are round and rest in round bores they are free to turn. This turning is fundamental to maintaining good follower life. Turning is facilitated by grinding as much as 0.002" taper over the width of camshaft lobes. The camshaft lobes rub slightly off-center on the followers causing the followers to turn in their respective bores.

IMHO, if you are not bound by rules, a roller lifter camshaft is the best choice for most applications. Roller camshafts can be designed with profiles not possible with solid flat tappet camshaft designs and hydraulic roller lifter designs are available for milder engine builds.

There are not many quality solid flat tappet manufacturers left in the world and engine builders often report quality problems. Some engine builders will not warranty engines built with solid flat tappets.

Flat tappet camshafts are often used with healthy springs and metal to metal contact is difficult to avoid. I do not want to get too far into the zinc issue with motor oils but will cover some of the basics. Zinc only comes into play when there is metal to metal contact. This is significant in the fact that metal to metal contact should be avoided in an engine. Every time the engine sees metal to metal contact, the zinc (and other similar ingredients), become sacrificial lambs. Yes, this means you are using them up.

Diesel oils are used by many but may be the wrong choice. A quart of oil contains many packages of ingredients unique to its specific use. A diesel engine runs hotter than a SI engine and it also runs dirtier. Adding packages to diesel oils to address these specific needs leaves less room in our quart of oil for packages which may better address the needs of our SI engine.

Racing oils have different packages than street oils, requiring frequent oil changes. Given the prices of racing oils this can be expensive for street driven vehicles.

[Mwilson]

I got scared and bought lifters! Cam is going in tommorow, and they sent me the wrong cam which is a blessing because its the one I wanted after I hung up.

252/260
106 lsa
.579 (1.6) .573 (1.5)