Wc or wd head for pulling?

this sux I thought that JACKWAGON was banned from here ? I was off here for 6 months and jpank is still on here ? MITCH GO BUY A JOHN DEERE AND RAG ON THOSE PEOPLE!!!  please leave this to Allis fans who want to share ideas and make good friends !!!

well that ought te be enough pankey drama for a while. He's over on ytmag now crying and showing a complete lack of comprehension to Gary Baker because someone gave praise to a half dozen or so people who know what they're doing.


Anyway now for a little usefull information. The 201 and 226 intake valves are 1.68" diameter. The seats in these heads overhang the valve bowls some so the air gets to jerk around the back side of the seat before it can find it's way to the valve. I've filled the back sides of the seats to eliminate that edge. In theory it should help. But the flowbench doesn't care what I think and the bench doesn't lie. It made no difference on the test when I tested by putting some epoxy under the seat to make a nicer transition.

On the slightly modified smaller engines like a 240 cid overbore engine a nice little upgrade is to use a slightly larger intake valve. John Deere 201, 239, 329 etc engines from the Dibuque family of engines use a intake valve that is for all practical purposes identical in length the the Allis valve. Same stem size, you can simply trim the seats and bowls large enough to accept the Deere valve which is 1.77" or so in diameter. This isn't a big change but it will get the seats trimmed out and clean up the core shift in these heads. It's a simple swap and helps gain some intake flow.

When the engines get bigger, I use other automotive valves and cut them down to size, sleeve the guides, use small diameter retainers and springs etc. Sometimes I go for a 1.85", sometimes up to a 2.08 intake valve depending on the head and application. But for most of the slow speed, 2100 and less RPM I stay less than a 1.9" intake valve. This is because on these engines the manifold and carb are to small to feed a larger valve, the velocity just dropps for a larger valve with only a given amount of air available to it. Velocity is verry important. With that nasty 900 degree corner in the head, there's only so much air that's going to bend around it. These heads peak out on flow at a fairley low lift because of that corner. When I fill the areas and cut the corner back, things improve greatly. But of course this is all done for large displacement slow running engines or smaller displacement fast running engines.   

The Deere exhaust valve also transfer in fine, but will require a little work on the seats. The Allis exhaust valve is fine for most of these applications. An engine is loud because of a sonic crack generated by high velocity exhaust gasses going past the exhaust valve. The exhaust valve is opened when there's a fair bit of cylinder pressure yet before BDC on the power stroke. This has a "blow down" effect. You don't need a verry big exhaust valve, you still want the cylinder bleeding off and fairley high velocity past the exhaust valve as the piston reaches TDC and the intake valve begins to open to help draw in a fresh charge and get the cycle started again.

:)