brutus

Rob just post the pictures of 100 MM S-4 pistons and the much shorter GTS vs the very short with raised wrist pin 104 mm 944 pistons which was needed to pack that much stroke into the same deck height block. And yes having skirts hit the crank counter weights was a big issue, Devek was known for using a grinder to clearance the skirts on some of their builds.

jeff spahn

Simple and elegant . . .Not

Vilhuer

This is Moldex crank and 968 pistons in S3 block. I'm not sure if one Carl is selling has equally larger counterweights or not. My crank has 8 weights so its not exact same anyway. I had to machine some material away from weights to clear piston bottoms. All shiny areas on weights have been done to give 2-3mm clearance at BDC. There were no hope in rotating crank full 360 degrees before it was done.

Rob Edwards

I don't have a comparo pic of an S4 vs GTS vs. 968 piston vs. a JE stroker piston, but I will try to get one tomorrow. In the mean time, here's the diff between the S4 and a 104 mm JE piston.


Carl, my apologies for fueling the semi-off topic-ness here, but hopefully it will help illustrate what your crank buyer will also need to source. $2400 for a Moldex crank, in stock, is a steal!

Vilhuer

More OT. Does anyone have long term experience on coated JE's? How much they are and from what source? If Carl don't like OT we can obviously move this to other thread.

brutus

This photo also answers the thread about oil drain holes in the S-4 piston. Note the two holes drilled to relieve oil trapped in the pocket around the wrist pin on the S-4 piston. Also shows the raised wrist pin and how the rings MUST be moved closer together just to get things to fit.

Vilhuer

In case someone wonders what crank balancing means this video shows whole process starting from measuring rotating assembly weight. Only difference to 928 crank is that damper and flywheel is not mounted in 928 setup as our cranks are usually internally balanced.

GregBBRD

I too thought that Oliver might be able to supply a decent rod, so I used a set in one of Joseph Fan's track engines. This particular engine got "hurt" fairly early in its life, requiring a complete "redo". After just a few hours of operation, the Oliver rods were .003" out of round...not just one, but several of them. This engine did get overreved...but not enough (8,000rpms) that it seemed like it reved high enough to "hurt" a rod.

I recently took apart one of Mark Thomas's "stroker" engines that had less than 5,000 miles on it. It also had a set of Oliver rods...which manifest the exact same problem! None of them are quite to the .003" "out of round" stage, but there are a couple that are close to .002" out of round. I can't deal with that...it's hard enough to build these engines without unknown quality parts.

My first experience cured me. The second experience confirmed my thoughts. After all, most all of the "other" rod manufacturers "hang their hat" on making "cheaper" rods than Carrillo, but they never seem to claim that they are "better" than a Carrrillo. Since I'm into "uber" quality pieces and results, Carrillo is the only way I "go", these days. A couple of dollars saved on the price of a rod just doesn't seem like the place to save money, to me.

Of course, I also realize that other people will have different experiences/expectations. That's what "choice" is all about.

Carl Fausett

I havent had a set of Oliver rods fail yet, even at 900 HP. Of course, no rod will last long if abused or installed wrong. Always easy to blame the rod, but never overlook 1) the application, or 2) the engine assembler, or 3) the engine machinist.

But, you know this.

Carl Fausett

Guys - not a problem with the thread going in direction of what else you need to make a stroker.

In broad brush strokes, here is my quick-list:

Custom pistons - either with short piston skirts or high wrist pin placement (partially into the 3rd ring groove) or both.

Rods to connect those pistons to this crank that are the right length that, with piston, arrive at the compression ratio you desire.

Clearancing inside the block for the throws.

A 928 oil pan spacer, and lengthened pick-up tube.

...and you also get to select con rod fasteners, rod bearing coatings, wrist pin retainers, piston skirt coatings, piston crown coatings, and piston ring format while doing the stuff above.

This is not a complete all-inclusive list, but just wanted to round out the items you are looking for a bit.

GregBBRD

I think you misunderstood. I didn't have one fail. I just had the opportunity to "see" how these rods were "fuctioning" fairly early in what I thought their life should be. Please understand that both of these sets of Oliver rods were SBC "offset" connecting rods, which means that they were "living a life" of complete hell, in a 928 application. The huge amount of "flex" that a connecting rod experiences with the piston not properly centered on that rod could easily "distort" the big end of the rod....that's a given in this discussion.

And I'm having a tough time "dreaming up" a situation where an engine builder could make a rod "go out of round"....with no damage to the crank or the bearings...but that's just me!

I realize that this "high output" engine building experience is fairly "new" to you and you've got a "long way to go" and a lot of lessons to learn, before you perfect this art...that's also a given, in this discussion.

Unfortunately, if people ignore what others have found out...they have to "learn" as they go...and pay the "price" for these lessons.

Understand that I have nothing to gain in this discussion....it's just a discussion, for me. I'm just the small guy building engines...you are the giant marketer of all things 928.

I'm actually completely overjoyed that you want to use SBC offset Olliver rods in your engines....and completely encourage you to continue to do so!

I'm just hoping I can "help" the other people, with my knowledge/experience.

Again, nice wiring loom! Great product!

Carl Fausett

Sure you do. You want to say that Carrillo rods are superior to Oliver rods. You want to imply your engine builds are better than mine because you use Carrillo rods.

I'm not going to argue one rod manufacturer against another. I did point out that although all rod failures are blamed on the rods, there are other factors.

Carrillo makes and excellent rod. But a Google search for "Carillo Rod Failure" or "Carillo Rod Problem" will show that no matter who you are, there can be issues.

Now - can we talk about the crank?

Carl Fausett

It is also a given that 500 HP engines are less likely to have a rod failure, than the 650, 750, or 900 HP 928 engines that I have built. So I would expect you to have fewer rod failures... that's just a given in this discussion too.

I haven't had a rod failure in one of the engines yet, although at these performance levels, I certainly might. Let me just say, we are waiting to see what the next failure mode will be at this level.

Bill Ball

Carl said:

"I have Oliver rods of the correct 928 offset..."

Greg then said:

"I'm actually completely overjoyed that you want to use SBC offset Olliver rods in your engines..."

Speedtoys

The same thing that keeps me -well- employed and in demand as a consultant.


Doing it wrong.