Your responses are always welcome Paul. Maybe my medication was having a bit of pre-ignition with some neurological hotspots? :laugh: My responses are way too cluttered and gibberished up because that's my brain I guess. My apologies for any headache transfers (Derek) :grin: You guys are awesome. Sean may reconsider his offer for me to add a section in his book, out of fear that it might require another book entirely. :grin: (Just to clarify, I was being a smartass/sarcastic in my last post.) Gary
It looks like there is agreement that the piston top should have symmetry about the piston pin axis. If a dish is needed the Spherical design is a good choice. AMP was looking at offering this option and is something I have proposed before but it requires some machining on in the combustion chamber. The object is to have the combustion chamber side walls look like an extension of the cylinder walls. We would set them up in the mill and cut the chambers perfectly round and the same diameter as the cylinder bore. The cutter would go deep enough to make the chamber ceiling in front of the valves (opposite the spark plug side) flat and parallel to the head surface. The chambers would also have to be concentric with the cylinder bore. The piston would be a spherical dish where the outer ring of the piston top would extend into the combustion chamber and touch the chamber ceiling without the head gasket in place. The head gasket thickness then becomes the quench distance. The piston outer ring would need the same radius on the outer edge as the inside radius of the combustion chamber. The only part of this design that is not great is the piston would need valve reliefs cut. Take it from here if you can see improvements. Paul
Great now I'm hungry for ham and cheese hot pockets... :grin: ---------- Post added at 07:24 PM ---------- Previous post was at 07:18 PM ---------- This was always a great idea Paul. Another part of that design that isn't feasible is the pricetag that would undoubtably be attached. While it's certainly an option for some, it's not something that would be considered an ideal option for most. (EDIT: Unless the new aluminum head has a redesigned combustion chamber, then this would be an entirely different conversation altogether!) Does the Buick 350 really need a quench chamber? If it had one, just how much higher could the compression be bumped to I wonder? If valve notches did need to be put in, a better rounding/smoothing of any abrupt edges would be in order (as well as putting them on both sides so the piston would be universal and properly balanced). A reflective coating/composition would be ideal for thermal reflectiveness back into the combustion chamber... What I suggested earlier still stands as my suggestion/contribution to this thread sans maybe the 'nipple' abstract that got out of hand, as an economical and versatile piston solution. Gary
Thanks guys for all the contribution into this thread. I think that I learned a lot by reading through this and as usual Paul has enlightened us! I am going to start a thread on connecting rods now...
Hey hey! THIS: http://www.livernoismotorsports.com/...A1-227125.html This is what I was talking about! Too bad I didn't see this in the other thread until now... (sans the 'nipples' that I talked about putting in the center) This piston design has my vote. Gary
There are 4 different types of Hot Pockets in our freezer. I was wondering how long it would be before someone commented. Way to go Gary. The set of piston as described is 649$. Much less for multiple orders. There is power to be gained by converting the open chamber to closed chamber using the piston and concentrating the charge closer to the spark plug while adding turbulence to the mixture by way of quench. The top of outer ring piston ring can also be designed to create swirl since it gets close to the chamber roof. In the meanwhile there will also be an increase in fuel mileage. I think it is worth the extra dollars. Paul
Well I was talking about the cost of the pistons plus the extra machine work to the head, which becomes moot if the new aluminum head's combustion chamber is redesigned... All things considered, there's probably 2 types of 'ideal' pistons then...the spherical dish with the lowered center for iron heads and open chamber, and the ones you're talking about with the new aluminum heads (if they indeed come with the redesigned closed chamber combustion chamber design), or machining the iron heads for them. Depends on how much a person's going to spend. Gary
This is the first I have heard of trying to make a "quench" area in the Buick 350 however I am interested in the idea. Looking at a set of heads here I am not sure how deep you could mill the head chamber being that the "face" of the head is not much higher than the valves themselves. This is where you are talking about making the "quench area" right? And would the piston look similar to my pic at the start of the thread except with a spherical dish? Or would you make a dome on the top of the piston to enter the Quench area?
Yes Yes I'll let Paul give you the details, since he'd be better suited with decribing the method used. Gary
Cut the chamber area you circled so it is flat and parallel with the head surface and cut the chamber walls all the way around to match the cylinder bore. We grind a piece of carbide with the radius at the end and put it in a fly cutter on the mill to do the job in one step. The piston will look like a deep spherical dish much like these 455 blower pistons with the exception of the top ring being a good distance down from the piston top so it is still at the correct height in the cylinder bore. The outside top edge of the piston will also be radiused to match the inside radius of the combustion chamber. You might consider the piston as having a dome with a dish. A Domish piston? http://www.v8buick.com/showthread.php?213591-1000-HP-Supercharged-BBB&p=1717158#post1717158 The dish will have to contain the majority of the volume since it occupies most of the chamber and will be better suited for 10:1 compression ratio or more. Is this description ok? Paul
I think Paul and Derek have the right idea with pistons and rods... Making a rod that is 'plug n play' that doesn't require a lot of extra machine work and can use existing piston selections or slightly altered custom pistons is a very user friendly way to approach this issue. Salute to you Derek. I think Paul has the right idea about the pistons. Raising the top to fit inside the head, creating a quench platform does more than just create quench. It brings the fuel/air mixture closer to the spark plug and will generate a better combustion. Aside from my half-baked ideas (which are sometimes good, sometimes not), I think there is much to be learned from this discourse. Using a deep dish (or deep bowl, more like) with nice round curves along with the raised height of the top would create an ideal, if not perfect piston for the Buick 350. If the aluminum heads have the same combustion chamber design and shape as the iron heads, then a universal set of pistons could be made to fit either head. It doesn't look like it would take too much effort to machine the heads, mainly just a single motion cutter that would even out everything: the sides of the head combustion chamber to match the cylinder walls, and to make the area near the valves parallel to the piston. How much would something like that cost for a set of iron heads, Paul? Gary
Setting the head up in the mill is what takes time. I'm thinking $125 to do both heads. It would help as a reference check to put the heads on your bare block and scribe the bore locations on the head surface. Shipping is the major expense. Paul
Thanks for the info Paul! The key would be finding a shop locally that would do the milling as shipping is expensive. I am not sure how a person could get a custom made piston like this unless they used a stick piston with modelling clay built up where it was needed and then shipped it to the piston designer. Tmrw I am going to smooth all the sharp edges on my diamond pistons... They may not be ideal but they are better than stock.
Sean On our last order to Diamond we took an existing piston, made the modifications and sent it as the model piston. The piston set should be here this week. Custom billets for max weight reduction and hard anodized to resist top ring microwelding in the event of detonation. What I would do here is simply use a stock shallow dish piston and radius the outside edge to match the radius in the machined combustion chamber. Then cut the valve pockets for clearance with the piston up into the chamber .040" from the chamber roof. Use it as a model with the understanding that the actual dish needs to be a spherical dish design. You would specify piston height above the block deck so they can figure how far down the ring pack needs to be, the spherical dish volume, pin height and diameter and cylinder bore size. Paul
