2.3-16 Project

[The Benz Master]

Sounds about right. On my built engine i had the deck machined 1mm to get compression ratio closer to what i wanted (11.5:1) and squish close to 1mm. And i remember the pistons were about 0.4mm too low in the bores (due to piston and rod choice), meaning that right now they protrude about 0.6mm

[Hexadeca]

10 years have now lapsed since True Compression of a 2.3-16V, and along the way I've adjusted my spread sheet to include thermal expansion of hot aluminum versus relatively cold iron.
This tends to boost the calcs a bit by boosting the crown height (aka compression height) and closing up the piston to bore clearance.
Fyi, my multiplier is set at 0.8% expansion. That gets multiplied against the ~43 height.

Unless you've gone to a significantly larger bore I'd say you've just recovered from that "piston and rod choice" and are now sitting around 9.9 to 10.3, depending on head CC.
If you've max'd out the bore and do have the gasket at 1.50mm, then I've got your CR in the 10.6 to 11.0 range.

****
BTW, my gasket measurement from back then was 0.068 (ie ~1.73mm).
The reason why so many "good numbers" is that there are so much imprecision in measurement.
Then there are plenty assumptions that negate precise measurements.
For instance...
- Are we talking a gasket laying around or a gasket under bolt torque?
- How much thermal expansion?
- Same deck height all cylinders? After torquing?
- Same head cc all cylinders? The 10-year old thread shows mine ranging from 52.5 to 55.0cc.
What a luxury to have consistency across the cylinders.

[3f05q]

Shop has since sent the pistons BACK to wiseco for additional machining, and is awaiting small end thrust spacers from JE. The head is at a second shop since the valves didn't seal on the seats. New guy did the valve guides on the $48million Ferrari GTO. I wish I had known about him sooner.

So then this happened:





Mmm... Shiny. (but what a PITA sanding in all the tight spaces)

[3f05q]

Bottom end is back... Check my numbers:

Bore: 3.780" (96.012mm)
Stroke: 80.25mm
Chamber Vol: 55cc (being confirmed)
Piston valve recess volume: 0.23cc
Zero Deck
Measured old gasket thickness: .067" (1.70mm)

Gives me a CR of 9.6:1

This is a flat top piston with minimal valve recess. 1st oversize piston has a dish to keep the compression ratio stock. How is my calculated CR LESS than what is supposed to be stock 9.7:1?

[3f05q]

Any experience with gasket kits?

https://www.pelicanparts.com/catalog..._pg1.htm#item7

Is this actually a situation where Reinz is the supplier but it's just repackaged for Mercedes?

[secretmachine]

Any experience with gasket kits? Is this actually a situation where Reinz is the supplier but it's just repackaged for Mercedes?

Victor Reinz and Goetz are OE suppliers. They'll work out a-ok.

[The Benz Master]

How is my calculated CR LESS than what is supposed to be stock 9.7:1?

that's pretty much what everybody doing the maths end up with... numbers don't match what MB was telling us. Pretty sure the problem lies within the chamber volume.

[3f05q]

Victor Reinz and Goetz are OE suppliers. They'll work out a-ok.

that's pretty much what everybody doing the maths end up with... numbers don't match what MB was telling us. Pretty sure the problem lies within the chamber volume.

Well that's... sad. I suppose a bit of boost might be in my future after all. I always planned on a Haltech Elite 1500...

[3f05q]

Is the timing chain discontinued?

001-997-71-94 - mbpartscenter tells me mercedes has no idea when they will get a supply. Pelican tells me IWIS has discontinued it. I'm hoping iwis hasn't been mercedes' supplier?

...just tried to order one on ebay. Got a refund with the message "not available".

[secretmachine]

The 16v chain has been superceded to 003 997 84 94.

https://www.getmercedesparts.com/oem...IFJlc3VsdHM%3D

[3f05q]

Thank you!

[3f05q]

The 16v chain has been superceded to 003 997 84 94.

https://www.getmercedesparts.com/oem...IFJlc3VsdHM%3D

Yeah so that's the PN that's not available here or in Germany, actually. I misread the original message from the seller.

Thankfully the old PN is available from a few people on Ebay...

[secretmachine]

well, that's not good news for 16v owners! i did a 16v chain last year for a customer, no hint of stock problems, i guess we'll have to wait for replenishment? you can also try by iwis' p/n for it - iwis 50026984, it's 134 links. autohausaz seems to have a few left - https://www.autohausaz.com/pn/0019977194

[3f05q]

FWIW there was an expectation of future availability, just not anytime soon. That said, uncertainty surrounding such a critical part isn't fantastic.

Question... Service manual states the distance from the pressure plate mounting surface on the flywheel to the friction surface should be 19.4-19.5 mm for the 102.985 motor. I'm assuming it's the same for the 983 motor?

[secretmachine]

102.98's have the same spec, yes.

16v flywheel depth


2.3 flywheel depth


early 2.3 flywheel depth

[3f05q]

Basalt fiber engine bay upholstery...