Stan Weiss wrote: ↑Fri Nov 11, 2022 9:35 am
Mike,
Have you ever designed a cam with a velocity curve like the green line?
Only about 100 or so.
That's what are EMV Series flat tappets are. Extended Maximum Velocity.
It's harder on the valvetrain, but when you are limited by a given fl;at tappet lifter diameter, it's the best way to get the area you need.
Mike,
Thanks I was not sure just how hard that would be on the valve train. I knew when you have a dwell lobe that has constant velocity (zero) over the nose it is very hard on the valve train.
Here's the Harmon Collins roller lifter setup. With the Y Block you didn't use the bronze guide, these look very much like a modified Harley Davidson tappet.
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Those don't look to be .500" diameter. Not doubting your word or picture, but until I see the camshaft and lifters, I will have to doubt the idea. The Y block does not have oiling to the lifter banks or pushrod oiling. I just don't see it as necessary to try to make those work in a Y when the solid lifters have worked so well for decades. Joe-71
Hi Joe, those lifters are solid, they are .500, the bronze body you see is so they can be inserted into a FE Ford lifter bore, if these were used in a Y Block the bronze body is not used, there was a tool that cut the lower part of the bore for the wheel on the lifter, the wheel is very narrow, there was also a bracket that kept them in alignment, however I don't have a picture of that bracket
Joe, have you ever investigated what would need to done, to install a SBF cam, in a Y-block? They have the same bore centers. If it could be done, you would have lots of full size cam blanks to use.
Back in the olden days, at least one builder used 239/256 cranks in the SBF so, the cams might be able to fit, also? Has anyone tried to use a SBF crank, in a Y-block?
Lots of folks used a 292 Y block steel crankshaft in 289s back in the day, but the camshaft would not work due to the distributor being in the rear of the engine, lifter angle in block, and oiling issues, timing sets, etc. There are excellent camshafts available from Isky and now Mike Jones can make them. The real drawback to the Y Block is having enough aluminum heads available to those who still need them. The Mummert aluminum heads have the combustion chamber over the bore, not outside the bore like the iron heads. You can increase the compression ratio easily with the Mummert heads, not so easy with the iron heads. Joe-71
Why? The 312 Crankshaft has a 3.44 stroke, and if you turn the rod journals down to 2.000", you can stroke them to 3.600" with a good crankshaft. Turn the mains down to the 292 journal size and you have the best of both engines. If you want more stroke, there are several crankshaft suppliers that will custom build one with up to 4.300" stroke. I have a 3.750" Moldex, 4.000" Moldex with Honda journals. Waste of time and money to try to cobble together a 351W crankshaft in a Y. JMO, but just because something can be done does not mean it should be when modern, strong, lightweight parts are available. Joe-71
Sorry, but this is not where this post should be going. A SBF crankshaft's oiling system will not allow strokes that are beneficial to the Y block due to oil passage routing. Once you start stroking by turning down the rod journals and mains, you expose the oil holes which will weaken the crankshaft. More than 3.76" stroke for the 351W and the oil passage moves out to the edge of the journal. I have a 377W crankshaft here now for a rebuild. The 302 crankshaft turned down or stroked over 3.100" exposes the oil passage about an inch in length. I am talking about stock crankshafts, not aftermarket. Joe-71