D24 NA Piston Options

[DieselScout]

Anyone have experience with either or both of these brands?
1. https://www.autohausaz.com/pn/068107091D
2. https://www.hansautoparts.com/16Pistons1mm.aspx

What are the notable differences between the Kolbenschmidt pistons and the Hans Auto Parts Pistons? (The latter were recommended to me)

Is there a reason that there is such a large price difference?

Are there any other decent pistons on the market?

[v8volvo]

I would recommend NEVER buying anything from "Hans" or his handful of other shady businesses (he frequently shuts down old online businesses as they gain bad reputations and opens new ones, in an endless cycle of BS). These are all owned by Pete Rothenbacher of North Carolina who is a known crook. His game is reselling junk quality parts from unknown knockoff manufacturers, bought by unfortunate folks who have forgotten (but will sadly soon be reminded) that "low price" and "good value" are not always exactly the same thing. Those parts of his are responsible for thousands of destroyed VW diesel engines, mostly TDI engines. Timing belts that shred after a few hundred miles.... injection pumps that seize and throw the timing belt.... etc.

Read about folks' experiences with his parts on tdiclub.com and get a feel for what this guy's sense of ethics is. Nobody has ever been able to get him to help with the massive costs of repairing the damage done by his parts, at least to my knowledge. Those folks who bought his con discover that the few dozen dollars they saved on the cheap parts need to be repaid orders of magnitude greater to get their ruined car back on the road.

Even if you did happen to identify a low-risk part (which to me would not include pistons or any other internal or moving component or any part of the fuel system) to buy from him that you thought you could experiment with safely, I would still recommend against it, simply on principle of not supporting his enterprise.

The difference between the two parts you asked about?
- Kolbenschmidt pistons are known to be excellent quality based on decades of market experience. Kolbenschmidt is an above-board parts manufacturer with quality control policies, a distribution network, a warranty department, and relationships with vehicle OEMs. They are sold by retailers who are sufficiently confident in the product to disclose who manufactured it -- in fact they are proud to do so.
- "Hans" pistons are.....?????? All you can know for certain about them is that they are being sold by a guy with a well-earned reputation for selling dangerous junk that he will not stand behind after it destroys your asset. You know nothing else. No brand. No assurances about quality metallurgy. No info about where and by whom they were produced. No info on warranty performance, other than Rothenbacher's own claims which are unverifiable. Nothing.

You can probably guess my personal view of this choice. I know Tom Bryant has gotten lucky with some parts from Hans and I have seen him recommend them before. I always thoroughly respect Tom's opinions and I know he doesn't reach them without a lot of careful consideration and data. But in this particular case, I strongly disagree with his perspective, and point out that his positive view is ONE opinion, pretty much the only verifiable positive opinion of Rothenbacher's parts you will find. I refer to you to the hundreds of tragic stories referenced above as the counterpoint to Tom's solitary, small-sample-size positive view.

Mahle pistons are also excellent quality, similar to KS.

[DieselScout]

Do you have a link to where I can find the Mahle pistons?

Any idea what brand Parts Place sells?
https://www.partsplaceinc.com/vw-1-6...040-21029.html

[v8volvo]

The Mahle parts seem to come up on ebay from time to time, try there? They may no longer be in production as they seem to be less common. But there is a lot of old stock out there, all around the globe, for these engines thanks to the millions that were produced over the decades. So even after end of production, NOS parts seem to be quite prevalent.

I don't really think you can go wrong with KS pistons though, if you have a source for those. I know Tom is not partial to them because he has found that they tend to be slightly "short" (distance from wristpin to piston crown less than factory) and thus the piston protrusion out of the block deck is less and headgasket selection options become more limited. But I believe the reason KS pistons are built this way may be that they assume if you are installing oversized pistons, you likely will have also had the block surface milled. If that is the case then some material will have been removed and that will partially compensate for the shorter pistons, which may be shorter by intentional design for that purpose. You could even decide how much block material to take off based on your piston measurements (comparing what is removed from the engine vs the intended replacement parts) if you wished to control it directly. So in short, it's a solvable problem, if it's a problem at all.

I don't know what Parts Place stocks but they are a longtime reputable retailer. I am sure you could call them and ask.

[DieselScout]

I think I found some specs on the KS pistons (this example is the "standard" option): https://www.kmotorshop.com/en/articl...103101e-076069

If I am reading this correctly, the height is the same as the green book spec (71.7mm) but the weight of 690g is much heavier than the green book spec of 455-465g.
Is that an acceptable difference? Would it have any noticeable impact on engine performance?

[v8volvo]

Originally Posted by DieselScout

I think I found some specs on the KS pistons (this example is the "standard" option): https://www.kmotorshop.com/en/articl...103101e-076069

If I am reading this correctly, the height is the same as the green book spec (71.7mm) but the weight of 690g is much heavier than the green book spec of 455-465g.
Is that an acceptable difference? Would it have any noticeable impact on engine performance?

That would be a very large weight difference, enough that I would be concerned if it were really true. However I cannot really see how it could be true. The pistons are the same size/shape/profile and made out of the same material. I don't know how KS could increase the weight by over 50%.

Here is my guess: the greenbook spec is for a bare piston, whereas the info you linked for the KS piston probably includes the piston plus the wristpin (and perhaps the rings and wristpin clips although those don't weigh much). It's probably the weight for the entire little box that they ship you, since all of those parts are included.

A good way to test would be to weigh a factory piston (even a used one) with and without the wrist pin and see if that theory adds up. I have a few kicking around that I could try that with if you don't. Tom probably has plenty as well.