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Topic Review (Newest First)
04-22-2013 11:54 PM
Originally Posted by techinspector1 View Post
I seem to remember reading in an engineering mag several years ago that the crown thickness of most any piston will be about 7% of the bore. So, on a 4" bore piston, the crown should be about 0.280" (over a quarter of an inch).

With my thumb and pointer it feels like maybe 1/8" here. Ill have to measure it..
04-22-2013 08:26 PM
Originally Posted by 0trbo4myCHEVUICK View Post
The head of the piston is real thin.
I seem to remember reading in an engineering mag several years ago that the crown thickness of most any piston will be about 7% of the bore. So, on a 4" bore piston, the crown should be about 0.280" (over a quarter of an inch).
04-22-2013 07:13 PM
0trbo4myCHEVUICK The pins are the only thing that's thick on these! Jeez! The head of the piston is real thin. What else to expect with a 1.125 compression height and 26cc d dish! Heres some pics of the engine mocked up. On the stand, in the living room. Yes ive got an awesome wife.
04-22-2013 05:06 PM
ssmonty Congratulations! I hope you like yours as much as I do mine. Almost a shame to put works of art like that into a spot where you can't show them off to your friends for bragging rights.
Is it just me,or do the pins seem overly thick, or extremely heavy to you? One thing for sure, you know they won't fail. I'm probably used to some thin tapered pins on some Speed Pro's I have on a shelf. However the quality of the piston isn't nearly that of the Mahle's.
04-22-2013 01:58 PM
0trbo4myCHEVUICK Pistons arrived today, stoked. The guys at MAHLE are great to work with.
04-15-2013 01:00 PM
0trbo4myCHEVUICK thanks guys. will post pics when the new pistons arrive. +26cc for 6" rods. Should be interesting.
04-15-2013 10:41 AM
Originally Posted by camaroman7d View Post
Dish piston and inverted dome are different ways of saying the same thing. These pistons in your link a what is often called a D dish or D cup. This design combines the advantages of a flat top with a compression ratio controlling dish of some volume. There is a related design called a Step Dish where the wall of the dish is cut away making a step.

These designs compared to the OEM's favored use of an enclosed or circular dish is that the D dish/cup, step, or inverted dome maintains a closely closing surface between the piston and head on the side of the head's squish/quench step. By keeping these surfaces with a clearance of about .040 inch detonation resistance and operating effectivity is greatly improved. The dish or stepped side under the valve pocket is a volume added to the combustion chamber, clearance volume of piston to block deck, and head gasket in order to keep overall compression inside a range the fuel can optimally tolerate.

04-12-2013 10:58 PM
1Gary We have bought those quantities I guess.The relationships I think we have created along with a clean customer record has played a huge role.

Anyone who has CNC machines involved in their business has hundred of thousands invested and the small money we talking here isn't significant.Don't get me wrong,the high performance end doesn't have a big margin so those businesses are not a cash cow.Many machine shops earn their bread and butter in production runs of industrial parts and the high performance end of the deal is just some cream on top of that.Again not the main source of income.10,000 wiggets is worth a ton more than a bore on a block.

When I said we aren't anything special I meant if we have been able to do what we have,anyone follow the same formulas could as well.
04-12-2013 05:36 PM
Originally Posted by 1Gary View Post
Parts direct to the end user is often not a option due to distributor contacts and often at a much higher costs to the end user.
Some manufactures screen end sales for a dealer with a point system in customer satisfaction.If there is enough negative feedback pull their line out of the dealership.
That is what I was saying here: Then you seemed to have been saying the opposite of what you're saying here.

I had said:
Many if not all manufacturers do not offer price breaks to individual buyers. They instead offer the price breaks to vendors who buy in quantity.
Your reply was (bold mine):
We have networked manufacture direct purchases for yrs.Well really we have met many face on face and created those contacts.We aren't anyone special,so if your willing to do some leg work,you would be amazed at what you can get done.
04-12-2013 03:08 PM
1Gary Parts direct to the end user is often not a option due to distributor contacts and often at a much higher costs to the end user.
Some manufactures screen end sales for a dealer with a point system in customer satisfaction.If there is enough negative feedback pull their line out of the dealership.
Wiseco happens to be one of the brand names that sells it's self not needing any dealerships.

CNC motorsports is a member on this forum.From the posts I have read,their posts have been correct.I am guessing the source of that info is coming from the owner of the business.I am also guessing you have yet to talk to him directly on the phone.If you where a customer of ours,I too would refuse to deal with this private matter on a open forum out of common respect for each other.

I suggest your might be one phone call away to talk directly to the owner from finding a better solution to your issue.
04-12-2013 12:35 PM
AutoGear This is why I hate buying through intermediaries. A whole lot of fingerpointing and in the end you're the one thats gonna get reamed. Sucks.

And Im still the 'kid' at the parts business; so I see both sides, Im lucky that my boss tends to under-promise and over-deliver, especially if customers with returns are nice about it.

Is CNC that WISSOTA-based roundy-round company thats in MT or SD?

If you dont live within a couple hundred miles of them; Im sure theres a local guy who would be more than happy to have your business.

Hell if you insist on buying parts from a guy you don't know; theres always Mike Lewis in CA. Hes a super nice guy, a straight shooter and a wizard at oddball combos.
I can't say Id build the motor the same way you are; but theres nothing that would scare me off. Just different strokes for different folks.
Stay upbeat, positive and polite; eat the shipping if you have to and take it as a learning experience. Keep us posted.
04-12-2013 10:59 AM
0trbo4myCHEVUICK Okay, MAHLE is swapping out the pistons for some 6" rod pistons with the D shape and no rail. They are very nice about the situation and paying for shipping both ways.
I have to swap my 5.7 rods with CnC motorsports, and I have to pay for shipping both ways. Would have been nice of them to pay atleast one way, Since I did not get the product they assured me I was getting. No biggie I s'pose, as long as its getting resolved.
I will defiantly think twice before ordering from CnC again. Customer service is very rude, they don't care about correcting their mistake unless its no cost to them. Also, I did the math, Really didn't save hardly any money at all going with the full kit through them. Sure didn't save any money now that im having to pay shipping costs to correct their mistake.
04-10-2013 06:35 PM
PatM Now, THAT sounds like a solution! Shame you've been worked over like this.

04-10-2013 03:38 PM
0trbo4myCHEVUICK I am going to hit with some nitrous.
This has been a pretty big mess I think im going to return it all and buy this 468 bigblock for 3000$
04-10-2013 03:25 PM
Originally Posted by 0trbo4myCHEVUICK View Post
Well the tech for CNC motorsports is SERIOUSLY trying to talk me out of the D shaped dish. Said the only reason the D shaped dish is common right now is for COST reasons, it is cheaper to make the D shape.
Sais the quench pad will make absolutely ZERO difference for flame travel or chamber mirror. Actually he said the full circle dish is the best for flame travel and efficiency AND detonation resistance. The MAHLES that I want are NOT available apparently.
Also the wisecos are 650$, the MAHLES are 750$. He said its going to cost me MORE to get the wisecos over the mahles because they are not a dealer for wiseco.
Then he told me that he could issue a 400$ credit for the return of the mahles. FOUR HUNDED DOLLARS! Lets do the math, My total bill for crank, rods, pistons, bearings, rings, and shipping was 1,783$ that makes 1,383 with the 400$ credit for pistons.
Minus 650$ for crank makes 733$, minus 418$ for rods makes 315$

315$ for some bearings? I relize they need to make some money but seems like this is starting to look like a bad deal. Really? you send me the wrong pistons and I have to pay for return shipping?

Also I gave him the part number for the wisecos and he said he couldn't get them. He told me that they are putting out over 25 engines a month and I shouldn't have any worry about the full circle dish. Thing is, that's what I want, and what I called ahead to ask for, specifically.
Thanks for letting me rant as I just got off the phone with CnC, Now I get to figure out what to do next
If David Vizard or one of the engine builders on this forum told me what this kid is tellin' you, then I would believe what they said. But a kid on the phone is the same to me as a kid at Autozone or Summit or any other parts supplier. What the hell do they know? They're just tryin' to stuff parts down your throat and make a profit.
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