Tightarse eBay rods

**old_mr2** · 24-09-2013, 10:37 AM

OK but in terms of acceleration at crank level, I believe more force is generated under boost. End hijack...

**trdee** · 26-09-2013, 10:56 AM

Actually, boost pressure serves to cushion the tension force generated by the piston trying to pull the conrod apart as it accelerates down the bore after reaching TDC. It's been discussed in a couple threads around here in the past..

edit; this article helps explain things a bit
http://www.d-series.org/forums/engin...do-i-care.html

**Sam_Q** · 26-09-2013, 11:48 AM

yes that's true, on a non boosted engine the rods are under the most stress between the exhaust and intake stroke.

**allencr** · 26-09-2013, 12:12 PM

Back to topic.
So wadda'ya gonna do?
Make'm press fit with another sleeve or circlips/buttons on the piston?

**NitroDann** · 02-10-2013, 06:07 PM

Yeah the most force derived from RPM only is on the direction change at the top of the cylinder.

But we are comparing an almost stock rpm 100whp build to a 200wKW build which does totally fine with stock hardware.

BTW cheap 'ebay' rods come from china, and like spool are simply unbranded high end rods which didnt make it into the $1200 brand name bin.

Think cans of tomatoes in a factory and different labels etc.

Dann

**dnegative** · 05-10-2013, 06:41 PM

Originally Posted by allencr

Back to topic.
So wadda'ya gonna do?

Stock rods and pistons with ARP bolts

Smallport pistons are floating which is good.

Not going aftermarket because there is no point aside from saying I have forged rods

**fixeruperer** · 06-10-2013, 12:58 AM

one of the smallports has around 10.3:1 comp too, i have the s/n number at work. ill try to remember to get it tommo when im at work.

**trdee** · 06-10-2013, 06:49 AM

standard audm n/a smallports are 10.3:1

**fixeruperer** · 07-10-2013, 02:11 PM

13103-16121 anyway, dont no which oversize.

i dont play with n/a stuff, thought they might of had a few n/a variants.

**oldeskewltoy** · 10-10-2013, 10:53 AM

Hmmm typically 4AG "H" beam rods have a mass between 405 and 420 grams each depending on the manufacturer. OEM rods for large journal cranks are well over 500 grams...... the stock wrist pin is over 85 grams.... lightening of these components, along with lighter pistons, go a LONG way for bottom end survivial... as well as snappier throttle response.

What I thought was VERY interesting was.... "Note: We also have 43mm big end diameter 4AG rods" that would seem to mean you can get 40/20 rods from these guys.... that would be nice to have so you can use a small journal crank and have many more piston options.... at least off the shelf piston options.