[jrgoffin]

Great looking piston, Ed! From a glance, I thought it had a resemblance to the JE 314631 (shown below), but the skirt here is definitely beefier. Since this is still an early sketch, did they - or you - see an advantage or disadvantage to an asymmetric skirt? Probably one of many questions on the way.

The JE's were ones I looked at seriously, but they came it at over a 9.5:1 C/R - definitely a bit on the high side. It will be nice to give the "new guys" (I won't give it away) the exact specs now, and if this package is going to be complete with the tool steel pins and good rings, it should be a real score. Thanks again for your efforts!

 

[eschaider]

SCHWING!:rock:

Yea I thought so too, Bob.

Great looking piston, Ed! From a glance, I thought it had a resemblance to the JE 314631 (shown below), but the skirt here is definitely beefier. Since this is still an early sketch, did they - or you - see an advantage or disadvantage to an asymmetric skirt? Probably one of many questions on the way.

The JE's were ones I looked at seriously, but they came it at over a 9.5:1 C/R - definitely a bit on the high side. It will be nice to give the "new guys" (I won't give it away) the exact specs now, and if this package is going to be complete with the tool steel pins and good rings, it should be a real score. Thanks again for your efforts!

View attachment 128833

It is going to be a soup to nuts package for us Joe. It will literally be a bore size and c/r. The rings, pins, locks etc will all come pre-packaged. If someone wants to go ala carte that is equally possible. Gibtec will make anything, for anybody, any way they want it. Whatever your heart desires (practically) their CNC manufacturing process can provide. Remember these guys roots are in ProStock, ProMod, Blown Alcohol and Top Fuel. They build the very best stuff available for the toughest pro classes.

The reason for the slipper skirt instead of the asymmetrical skirt is part cylinder wall loading. The asymmetrical skirts are plenty strong. The asymmetric design is geometrically quite rigid and produces high localized cylinder wall loadings. The slipper skirt has some flexibility or spring and spreads the load over a wider area of cylinder wall. It is going to be easier on pieces. The additional surface contact area also provides opportunities for additional heat xfer to the cylinder walls.

 

[Helomech74]

I had a sneaky suspicion that you were going to use Gibtec for these pieces, excellent quality stuff. I like the .200 thick full slipper skirt design. I've never spec'd a piston with that thick of a skirt trying to keep weight down, but if they come in at 394 grams, that's not bad at all. What material are they going to use, 2618 I would imagine? Looking forward to the final details.

 

[eschaider]

I had a sneaky suspicion that you were going to use Gibtec for these pieces, excellent quality stuff. I like the .200 thick full slipper skirt design. I've never spec'd a piston with that thick of a skirt trying to keep weight down, but if they come in at 394 grams, that's not bad at all. What material are they going to use, 2618 I would imagine? Looking forward to the final details.

I figured you and a couple of other guys on the site had already figured it out Jim. You didn't let me down. You are correct about the material it is 2618. 2618 just makes more sense for a maximum effort piston like this. No reason to shortcut a premium piece material-wise.

My own forged versions of this piston came in right around 420g w/o pins - I want to say they were right between 419g to 421g with the heaviest less than 423. Not bad for a forging but heavier and not anywhere near the precision available with a billet piston. These pistons were designed in Solidworks so as to leave no wasted material in the finished piston while maintaining maximum strength in all the areas we most highly stress the piston. They will be much more consistent weight-wise. My expectation is right around a gram perhaps less weight difference per piston. I am quite pleased with the final design. Like I observed earlier there are little items like the intake valve reliefs that have to be added but other than that sort of window dressing it is a complete design.

Next step is to get the package pricing put together and we should be ready to go.

 

[oldmodman]

Looks great Ed.

But a question. I know that given the best of all possible worlds you want the rings as far down as possible. But is there a longevity trade off to having the oil ring unsupported where it crosses the pin gap?

Or is there a secondary support ring below the lower oil ring?

And will they be supplying the ring pack? Tool steel top, total seal second (gapless), high tension oil? And is the gapless total seal second a modified napier? Or is that face profile not available in a gapless?

 

[Helomech74]

Looks great Ed.

But a question. I know that given the best of all possible worlds you want the rings as far down as possible. But is there a longevity trade off to having the oil ring unsupported where it crosses the pin gap?

Or is there a secondary support ring below the lower oil ring?

And will they be supplying the ring pack? Tool steel top, total seal second (gapless), high tension oil? And is the gapless total seal second a modified napier? Or is that face profile not available in a gapless?

Whenever the oil ring intersects the pin hole, we use oil support rails that sit below ring. Most all of my custom pistons wind up in this configuration due to the design and I've never had an issue with them. No noticeable oil consumption or longevity issues at all.

 

[SlowSVT]

Ed

I'm impressed. Send me the part file I wanna look under the hood.

 

[eschaider]

Looks great Ed.

But a question. I know that given the best of all possible worlds you want the rings as far down as possible. But is there a longevity trade off to having the oil ring unsupported where it crosses the pin gap?

Or is there a secondary support ring below the lower oil ring?

And will they be supplying the ring pack? Tool steel top, total seal second (gapless), high tension oil? And is the gapless total seal second a modified napier? Or is that face profile not available in a gapless?

Whenever the oil ring intersects the pin hole, we use oil support rails that sit below ring. Most all of my custom pistons wind up in this configuration due to the design and I've never had an issue with them. No noticeable oil consumption or longevity issues at all.

Jim is spot on Drew. In years gone by (~15 or more) the pin and oil land intersection was a real no-no except on a race only engine with other stuff like buttons instead of locks. Today the support rails that the piston manufacturers use make the design every bit as reliable.

That said the piston can be made w/o the pin in the land. To do that you need to use Saleen rods, and set the rod journals to SBC 2.000" diameter. When you do this the crank will relax and the mains will need to be cut 0.010" undersize to get a straight crank again. When you are done the finished crank needs to be sent out for nitriding again because of the depth of the rod journal cut. I actually did this on an OEM crank. It works but in the end the mods I wanted to make to the crank snout needed a billet solution.

This is the same piston design in the pdf and screen shot below but with all the Saleen rod mods;

 

[eschaider]

Looks great Ed.

But a question. I know that given the best of all possible worlds you want the rings as far down as possible. But is there a longevity trade off to having the oil ring unsupported where it crosses the pin gap?

Or is there a secondary support ring below the lower oil ring?

And will they be supplying the ring pack? Tool steel top, total seal second (gapless), high tension oil? And is the gapless total seal second a modified napier? Or is that face profile not available in a gapless?

I'll, call tonight Russ.

 

[jrgoffin]

Next step is to get the package pricing put together and we should be ready to go.

Definitely looking forward to those details!

Considering a good piston set with the TS pins and quality rings can get on the pricey side, hopefully Gibtec is really going to make this attractive.

Didn't want to give it away earlier, and considering their site isn't up yet, this video clip is good intro to them for anyone curious:

http://www.gibtecpistons.com/

 

[eschaider]

Apologies for the delay Joe. The day job has been demanding this week. I'll get something going with them by email this weekend and I suspect we can have a package part# within a week or hopefully less.

You, Jim (Helomech74) and a couple other guys figured it out right out of the box and set my PMs on fire with your suspicions about who the manufacturer was. As you guys already noodled out, Gibtec is the company! BTW thanks for posting the Gibtec link, it is a great look at who these guys are and what they are about. Most guys outside of the Pro classes do not know of them.

Gibtec specializes in extreme service supercharged engine pistons for ProMod, Blown Alcohol and Top Fuel. They also have a cutting edge n/a piston for the ProStock cars. The pistons they make (IMO) the very best available for supercharged applications. While I do not have any ProStock engine experience with them I would expect the n/a versions of their pistons to have a comparable level of attention to detail and application specific design innovation.

The company and their custom piston manufacturing mission fit our application needs like a glove. The best part of this is it will give end users, like many of the guys on the site here, the ability to order an optimized, finely tuned piston design for a blown Modmotor without all the hassle of hoping they properly learned custom piston design, ring packaging, selection and the myriad of other considerations that go into the design and design preparation prior to production.

As the end user all you will have to know is what bore size you want to use and what compression ratio you want. All the structural design and engineering for sinking heat out of the piston, optimizing ring packaging, pin boss strength and pin offsets (when requested) has already been done for you. The piston will look like a piece of fine jewelry everywhere, have an unprecedented weight consistency from piston to piston and be physically as strong a piston and as light (at that strength threshold) a piston as is physically possible to be made.

We often look at F1 engines and their componentry as sitting at the top of the high performance design and engineering pyramid. These pistons are kissing cousins — except for use in a supercharged Modmotor.

 

[Quicktime_GT]

Awesome!

I'll soon start on my bottom end build and will completely trust in this Piston and its design choice.

Thanks For working on this Ed.. Thanks all who supported.

Neil

 

[eschaider]

Looks great Ed.

But a question. I know that given the best of all possible worlds you want the rings as far down as possible. But is there a longevity trade off to having the oil ring unsupported where it crosses the pin gap?

Or is there a secondary support ring below the lower oil ring?

And will they be supplying the ring pack? Tool steel top, total seal second (gapless), high tension oil? And is the gapless total seal second a modified napier? Or is that face profile not available in a gapless?

I'll, call tonight Russ.

Ed

My response to Russ was not intended to be in my response to Drew. Apologies for not responding to the last points you had raised Drew. Here is the response;

Gibtec will be supplying the pistons with the rings, pins and locks. We have designed the piston so the wrist pin towers are just barely wide enough to fit the pin end of the rod between. The reason for this is to get as much bearing surface for the pin in the left and right pin tower bosses with a 2.5" long pin as humanly possible. The motivation is obviously rigidity. The base ring package that will come with the piston will be a 1.5mm nodular iron top, a 1.5mm napier cut iron second and a 3.0mm oil ring. The piston can be had with any combination of Totalseal rings that are commercially available today.

The nodular iron top is done in the interests of an easier seating ring with excellent performance characteristics. The napier second is there for its oil control which is so important in a supercharged application. The 3mm oil is just the standard blower motor offering. the oil is not a low tension ring again for oil control reasons in the blown application.

The pistons can be had with the steel and tool steel options for the top ring but you start adding break in complexity and cost when it is not necessary. The second ring can be replaced with a Totalseal gapless ring. In fact that is the way I spec my own pistons. Again it adds cost but it is available and does work very well. The pins are heavy wall H13 tool steel. You get your choice of pin locks either the OEM style Circlips or the double Spiroloc solution.

The ductile iron top ring sounds like a wimpy solution at first. Let me assure you it is not. If you take anything but a steel ring and twist it you will break the ring somewhere before you get a half a turn on it. If you do the same thing with a ductile iron ring you will have to make several revolutions before you finally break it. I have a close friend and client in my daytime business that runs a twin turbo 12.5:1 compression ProMod that has tested and used the ductile iron top ring at up to 60 psi of manifold pressure. They typically run the engine in the high 40 low 50 psi range and the rings are not quite one season old right now and leak down like they were new. Ductile tops are very impressive rings.

The ability to upgrade the base package's component parts will always be possible. The base package however, will hit the bullseye for 99% of everyone who will be needing pistons.

One of the very attractive benefits to this design approach is the ability to order just one replacement piston if you got a little frisky with your tune and actually did get a piston. The replacement piston would arrive in a condition that allows you to put it right back in the engine w/o even rebalancing! No more need to buy a whole new set of pistons.

 

[eschaider]

Awesome!

I'll soon start on my bottom end build and will completely trust in this Piston and its design choice.

Thanks For working on this Ed.. Thanks all who supported.

Neil

Glad you like them Neil and thanks for the good words.

This piston was long overdue. The number of "custom" piston choices out there that are merely warmed over n/a designs and or are missing important design considerations is disappointingly high. Our engines cost two boat loads of money to build and there is no reason why we should have to settle for anything other than the best when it comes to our pistons.

This initiative will give anyone access to a premium quality, blown Modmotor specific, piston design they can have confidence in. We should have the last pieces of the package together this coming week. I will be traveling Wednesday through Saturday but checking mail as I go. As the last pieces come together i will post them up.

 

[speeddemon2000]

Looks Awesome! Are you going to have a version for the stroker guys?

 

[eschaider]

Looks Awesome! Are you going to have a version for the stroker guys?

Sure will Bobby.

 

[jrgoffin]

Giving Ed's thread a nudge, I mean "bump", for those of us anxiously awaiting more good news!

 

[Tractionless]

Ed,

Will the pricing for the initial buy be lower than if we need a set down the road?

Is there any coating options?

I'm not need a set at the moment but don't mind having them sit on the shelf for future needs if there's a initial discount.

Thanks

 

[eschaider]

Ed,

Will the pricing for the initial buy be lower than if we need a set down the road?

Is there any coating options?

I'm not need a set at the moment but don't mind having them sit on the shelf for future needs if there's a initial discount.

Thanks

The run up to the holiday has been challenging Keith so I am a little behind in driving this project but the answer to your pricing question is no.

In fact there are coating options but I have not included them in the basic piston package. The general market awareness of surface coatings is driven by magazine articles and some piston manufacturers. The coatings add considerably to the price of a set of pistons and have a very narrow target market - they are not needed by more than 99% of the buyers. If you decide you want the coatings however, they are readily available for both crown and skirts.

 

[eschaider]

OK, guys, the deal is done, and the numbers are in. Here are a few PDF views of the piston from different perspectives;

Angled Top View,

Angled Bottom/Side View,

Bottom View,

Angled Top and Side View,

Thrust Face View,

To allow you to look to your heart's content, I have also attached a 3D PDF file of the piston to the bottom of this post. The file is named Gibtec.pdf. Download it, and you can spin the piston around to your heart's content looking at it from all sides.

What you see is basically 99% finished. Little elements still need to be added, like the double pin oilers, but the design is essentially complete.

I can tell you with virtual certainty this is the finest Modmotor piston you can buy anywhere at any price. It just doesn't get any better than this. The best pistons I could build using forgings fall decidedly short of this design. These pistons fall into the F1 class of piston. You do not have to order in standard, 0.010, or 0.020 oversize. These pistons can be available in any bore size you want in 0.001" increments!

The Complete Package Will Include the Following;

• Eight billet 2618 aluminum pistons with pin fitting,
• TotalSeal Ring set 1.5 x 1.5 x 3.0 mm
  • Ductile Iron Top Ring
  • Standard (non-gapless second ring)
  • Standard tension oil rings
• Eight 0.866 x 2.500 x 0.180 wall H-13 Tool Steel Pins (if you want a heavier wall, it is also available)
• Sixteen 0.866 wire locks (If you prefer Spirolocs, specify at ordering time)
• Eight oil support rails.

That is the entire ModFords Terminator Piston Package. The actual part number is not yet established in the Gibtec computer system but will be very shortly. All you need to know to order is the bore size you want and the compression ratio you want; Gibtec handles the rest for you. You do not have to know about skirt cam, skirt thickness, ring package design or placement, valve reliefs, etc. The work has already been done for you.

The Price for The Entire Package is $1,138!

Remember, these are custom billet pistons explicitly engineered for our supercharged engines. These are not warmed over n/a forgings masquerading as blower pistons.

If you ever hurt one, you can order an exact replacement or an exact replacement 0.001 or 0.002, or 0.003 bigger and not have to step up for a whole new set of pistons. The shirts on these pistons are 0.200" thick; the rings are 0.280" down from the crown, the ring land depth, clearance, and finish have been optimized for the TotalSeal ring set. The piston you see with the (essentially) flat top will produce a 9:1 c/r with two country miles of PTV clearance on cams as big as 0.525" lift.

For those who would like a Moly coated dry lubricant on the skirts, you can add it for $160!

OK, guys, you finally have the ultimate blower motor piston expressly designed for our engines.

Say some words at me.