Guys;

I've built a couple of other Y-Blocks, but never have tried this before so I'm a bit nervous. Anyway, before I put the carbide to the iron I would like your advice and even "is this trip even necessary"?

This is my 331 cu.in. blower motor project using a modified VS57 supercharger with a high output impeller that John Erb says should produce 7-9 psi boost. I got some pictures and info on how to do it and I'm posting a couple of pictures here of what I'm planning;

Using new Fel-Pro Permatorque head gaskets I set scribe lines in blue dye. The cylinder ring ridge is about 0.300" from the deck so using an old (borrowed) piston I set it in the hole about 1/2 way to the ring ridge(0.150") as a guide. The black duct tape on the piston is so I won't gouge it by accident. USing a carbide burr I'll SLOWLY cut out these areas being careful to stay inside the scribe line. I'll buff the cut outs with tapered rolls and cross buffs so carbon doesn't build up. That's basically the plan. I'll be using ported 471 heads and also planning on drilling a new road draft tube hole in the block where they were on the 56-57 motors to relieve crankcase pressure.

So, what are your thoughts? Is this step really necessary. I'm not proud, I'll stop right now if the benefit is minimal.

 Rono

  Ron Lane,  Meridian, ID

Why?

Frank/Rebop

Bristol, In ( by Elkhart) 

I'm not sure why you would want to do this. Is this a speed "secret" that you saw somewhere? Are you confusing Y-Blocks with Ford Flatheads, where the block is relieved for better flow from the valves that are in the block to the cylinder?

"The Master Cylinder"

Enjoying life at the beach in SOCAL

Okay, Gord McMillen has been providing me the info and pictures. He has built and raced quite a few supercharged Y-blocks and is manufacturing the blower kits for y-block set-ups. His rationale for the block relieving is so the motor can breathe better under boost considering the typical valve shrouding of the Y-Block heads. Maybe the 471 heads I'm using pose less of a problem than the "G" heads or Mummerts new aluminum heads, I'm not sure, but if you guys think I can skip taking the risk on doing this (one bad slip and the block is toast), I'll be happy to pass on it. below is one of the pictures that Gord sent me.Rono

  Ron Lane,  Meridian, ID

I have done this block relieving on y blocks for years and see no problems if you go carefully. Many of us have little pecularities/features that we like to do when building engines, After being on here for a fair while it sure is obvious that a majority of relative newcomers seem to want to reinvent the wheel or y block. Go with your idea carefully and doubt you could toast your block. Just my opinion. regards bill.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Hi

Im new to the forum, but this is my 2 cents.  If you understand the risks and you can afford to possibly ruin this block, then i say go for it.  Remember that buy doing this you will be lowering the compression ratio.

Hope this link helps

http://www.streetrodderweb.com/tech/0905sr_ford_flathead_myths/index.html

Another opinion. If the purpose of grinding on your block is to unshroud the valves then I say don`t do it. Most sources I have seen recommend that the heads should be relieved not the block. Since you are using a blower that may not be very important anyway. And modern theory is that swirl of the intake charge is more important than absolute airflow. And the valves are really only shrouded at low valve lifts so what do you hope this will gain. Like I said, just an opinion. Pete

The value of some things done in modifying an engine are hard to measure (unless you have a dynamometer). IF you look up the bore of a y-block with the cylinder head in place the valves are significantly shrouded. Relieving the block (flathead Ford terminology) is an effort to improve volumetric efficiency not unlike porting cylinder heads.



Yes, you are modifying the combustion chamber shape. Yes, you will slightly increase the effective combustion chamber size, you will slightly decrease the compression ratio, and you will change the turbulence in the combustion chamber.



When I have done this, it has been on normally aspirating engines, not supercharged or turbocharged. I mention this because some feel that even cylinder head porting is of less value when the air fuel mixture is pushed into the combustion chamber rather than merely drawn in by atmospheric pressure and the 5th cycle of the 4 stroke engine.



Make sure that the depth of the material removal is less than the top ring groove of the pistons you will actually be using. Although time consuming, I have finished the material removal by using a hand file to ensure a uniform taper from the gasket ring to the top of the cylinder bore.



IF you look closely at the pictures of Ted Eaton's EMC entry in Y-Block magazine earlier this year, you'll notice that the deck of his engine had the same relieving that you are proposing to do.



I think that little things do make a difference in the building of an engine. I like the way AussieBill put it.



Regards,

NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

Here are some pictures of what I do.  This simply gives a bit of room around the intake valve when it’s fully depressed.  When using higher than normal lifts at the valve, this notch becomes mandatory in that it keeps the intake valve off the edge of the cylinder.  When notching the cylinders, make sure the notch does not get into the top ring area of the cylinder.

 

 

 

 

 

Lorena, Texas (South of Waco)

I want to thank everybody for their comments and thank Ted for his pictures and advice. I'm glad I checked the distance from the piston top to the first compression ring on the new forged pistons because that only measured about 0.250" as compared to the stock piston which was about 0.330". So, my relief will be shallower and I don't plan on going any deeper than 0.125" max. I'll post more pictures when I get it done.

Rono

  Ron Lane,  Meridian, ID