Valve and cam conundrum

3twinridges

3twinridges

Well-known member
Got a bit of a decision(s) on my 8BA build. Trying to decide between a Schneider 248F cam or a NOS EAB cam. Both really nice cams but the 248F recommends 85lb springs, which probably means I have to move from my NOS rotator assemblies to the 8BA type.

My first question is with that valve spring pressure (85lb), should I install hardened seats on all the valves? Right now the shop is only planning on installing them on the exhaust side.

The .350 lift on the 248F sounds great, but so does using the parts I already have and I don’t think the EAB is a bad cam. Just worried about the seats, now is the time to install them if it needs to be done before the deck is milled.

JB
 
Less than a year ago I had the same discussion about hardend seats with my machinist. He urged me to do all 16. I decided to ask how much and he said something like 230.00. I didn't discuss further, just gave him the go-ahead. You won't be sorry if you go this route.
 
I know there are folks here that said I didn't need them but I had them cut in my 53 block . I had a very bad and sad loss experience when a valve beat it's way into the water jacket on a rare and expencive later V8. I learn by experience, not always the best, but I learn. Tim
 
I can't address the seat and spring question. Think we used stock springs and seats. I have the 248F cam and it is a nice street cam. has a slight lope at idle and has lots of torque. this is in a 276.


John
 
CAM: I believe you already bought the 248F cam, so if it was mine, I'd run it (given your larger cubic inches). It will sound great and give you a bit more power over 2000 RPM.

Spring Pressure: It kind of comes down to your intentions for the engine/car. Unless you're really planning on running the thing up to higher RPMs (like over 5000), you'll not need 85 lb springs. I'm not sure how many lbs your current setup delivers on the valve seat, but if you have anywhere between 60 - 70 lbs on the seat, that will be more than you'll need.

Seats: Since you're having the machine work done, it surely won't hurt to put hard seats in all 16 locations (that is what I'd do).

If you find that your current valve, spring, retainer setup won't work out, then contact Mac VanPelt or Michael at ThirdGen for a complete package that includes stainless valves, zephyr springs, retainers and guides. These packages are not that expensive, and you'll have a whole new top-end.
 
I love the range of torque and power of the 248f in my 284" 59A/B. 70# on the seat has proven to be plenty, but I never rev over 5,000, and rarely over 4,500. I just wind it up to 4,000+ for a few seconds every time I take it out, on the theory that will blow out the carbon. Probably a myth.
 
“ I just wind it up to 4,000+ for a few seconds every time I take it out, on the theory that will blow out the carbon. Probably a myth”
Carbon be damned!!…….It sounds great at 4000 RPM’s……. don’t it!……….Mark
 
flatford8 said:
“ I just wind it up to 4,000+ for a few seconds every time I take it out, on the theory that will blow out the carbon. Probably a myth”
Carbon be damned!!…….It sounds great at 4000 RPM’s……. don’t it!……….Mark
Click to expand...

Agreed. A wound out flathead sounds glorious

At TROG, I was leaving the line in 2nd and just planked it down the course through the finish line. Had to be over 5,000K with 3.78's. I'm going to add one of those cheap digital tachs that coil around the spark plug wire to confirm.
 
Tim Ayers said:
Agreed. A wound out flathead sounds glorious

At TROG, I was leaving the line in 2nd and just planked it down the course through the finish line. Had to be over 5,000K with 3.78's. I'm going to add one of those cheap digital tachs that coil around the spark plug wire to confirm.
Click to expand...
Those cheap digital tachs can get confused unless you have some sort of supressor in your ignition cables. When I switched back from Pertronix to points and HP 404 wires the digital tach (not cheap) went flakey, as did my satelite radio. I put a one foot piece of spiral-wound ignition cable between the coil and distributor and the problems went away. And the old-time ignition parts did not have the problems that come with resistor wires between distributor and plugs; like cross firing between cables.
 
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