Thread: Lighter engine
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Old 01-22-2015, 01:19 PM   #1
jsceash
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Lighter engine

Some times I wonder what Porsche was thinking?

I have my engine apart again which started life as a 2004, 3.2 L. I had it modified in winter of 2012-2013, to a 3.6L by LN. I ran low of funds while assembling it so a couple of things I wanted to do didn't get done. Consequently I didn't replace the tappets and ended up with a tap this summer which seem to be getting louder this fall. While apart the first time I had the crank balanced but skipped replacing the rods.

I removed the motor and started by removing the cams to check the tappets finding 4 that did not seem to pump up and were lower in the tappet housing than the others. The tappets at this point had 65K miles. The rebuild has 18K and I calculated 4500 of those were on track. So there are now 24 new tappets being installed. In the end I wanted to check how the rest of the engine looked and so I took it down to the crank. There was no wear measureable on the lower end. The thing that gets me is the weights variation of parts. Why would they have so high a variation on moving engine parts. The original part 3.2. 93 mm pistons with rings and connecting rod pins. Compared to the LN JE piston 3.6 99 mm pistons with ring and moly connecting rods, No comparison.

Stock piston------------- Stock -----------JE pistons/W --------------Carillo
/W rings & pins....... Rod /W bearing .....Rings & pins ..............Molly rods /W Bearings
1. 649 g................ 635 g. ......................491 g. ......................565 g.
2. 649 g................ 639 g. ......................491 g....................... 564 g.
3. 656 g................ 638 g....................... 491 g. ..................... 565 g.
4. 653 g. .............. 639 g. ..................... 491 g. ..................... 565 g.
5. 654 g. .............. 638 g. ..................... 491 g. ..................... 564 g.
6. 650 g. .............. 638 g. ..................... 491 g. ..................... 565 g.

Stock moving weight 7738. g. The low total assembled rod 1284g highest 1294 g.
Modified moving weight 6333 g. The low total assembled rod 1055g highest 1056g.

Previously the crank was out of balance as well by over 20 g. No wonder you need a 34 pound sprung flywheel
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2003 Black 986. modified for Advanced level HPDE and open track days.
* 3.6L LN block, 06 heads, Carrillo H rods, IDP with 987 intake, Oil mods, LN IMS. * Spec II Clutch, 3.2L S Spec P-P FW. * D2 shocks, GT3 arms & and links, Spacers front and rear * Weight reduced, No carpet, AC deleted, Remote PS pump, PS pump deleted. Recaro Pole position seats, Brey crouse ext. 5 point harness, NHP sport exhaust

Last edited by jsceash; 01-22-2015 at 01:27 PM.
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