I am speaking for Tim, but this is the reliefs in the first brick 258 cu. in. engine.

It is my opinion that of the many variables in the success of that engine, the quench area and these reliefs played a major role in developing approximately 310 hp.

Charlie Burns Laton, Ca (South of Fresno)



BurnsRacing981@gmail.com

I did it on my engine based on the Carroll Miller article.  However, I think that Ted has right idea and that the only thing necessary is notching for the intake valve with a big cam and small bore.  The gains are probably not much if anything especially with a blown engine.

BTW what are those radial slots in the pistons of Ted's engine?

Doug T

The Highlands, Louisville, Ky.

The thing about the overhang-shrouded area on that side of the cylinder is that it isn't a quench area at all (even if Ford incorrectly believed it to be at the time), and I think it's a poor design because they were building off of the flathead, and still figuring out the OHV idea. It essentially acts like a dam for air flow. I don't know if it's a good thing or a bad thing to radius that edge. I'm no expert.



All I know is that if there was a huge edge damning the air stream like that in a cylinder runner I'd knock it down. Same principles of airflow hold up in the cylinder.



You will loose compression, but for your build you need low compression and high flow- you are forcing air in. You want more flow, and sacrifice compression to avoid detonation.

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie

I did it to my block and haven't thought twice about it since. You won't ruin your block if you're patient, and slow. Make a mark as to where your top ring land will be, stay above that, and carefully radius the edge to allow for a better flow into the cylinder on your intake stroke. I'm already beyond what most people consider acceptable compression on iron heads- but the loss of one totwo cc's didn't bother me. I ended up at 10.1:1 compression. Here are the pics of my block, and my cylinder heads. And I develop fairly decent power with my motor.







The only pics I could quickly find were when I was measuring piston to valve clearance. But you can see the reliefs.

Heber City, UT (15 mins outside of Park City- basically it's in the mountains)

55 Effie

I believe that the overhanging shrouded area was considered by Ford to be a "quench area." Because the design of the Y-Blk heads is somewhat different than many other engines, there's ample indication that they were misunderstood by many engine builders. How many times have we read that "you can't do much with these heads." People like our moderater, Ted & in particular, John Mummert, have proven those statements to be wrong.. Anyway, Rono, you already have low compression 471 heads, that much removal of material will likely lower compression significantly. As I said earlier, my buddy did that to his Y-Blk Drag engine years ago, and as far as we could tell there was little if any benefit...

Paul

I think that everything else being equal, yes you will loose power. You'll notice in that article that domed pistons were also used to account for the increased combustion chamber volume. But I'm no expert and it does not seem that anyone really knows. The increased flow potential could out way a decrease in compression... or it may not. Karol could have had that wrong, at the expense of a mph or 2.


Lawrenceville, GA

Charlie;

What a great article! Thanks for posting it. I'm still flip-flopping on whether or not to relieve the block, basically because I am using the lower compression 471 heads to start with. So, even though I could possibly be generating 9 psi boost with the modified VS57,could I be loosing power by lowering the compression even more by relieving the block? If just a minimal HP gain, I don't know if it's worth the risk and the work.

Rono

  Ron Lane,  Meridian, ID

If this article about Karol Miller is accurate, it is one of many things he did to get that 150.097mph record.



"Carefully, the top of each cylinder bore was chamfered from the chamber outline to a point just above the top of ring travel."



http://yblock.blogspot.com/2007/07/ford-success-stories-karol-miller.html





Lawrenceville, GA

Mike: you can't equate the Ford flat head situation with a Y-Blk. It's a different setup totally. And Ted did the small reliefs on the illistrated engine for valve clearance... A buddy of mine years ago did the reliefs on his Y-Blk gasser. As far as we could tell, it made little difference. Probably offset any gains by loss of compression.

Paul

Oh yeah!!

Forgot to add one thing.

I don't have the nerve or a steady enough hand to for something like this!!!!!!!!!!

Just stirring the pot.

Missouri Mike

I'd rather be lucky than good.................

    but good ain't bad!!