P/C set for 2.7RS+ build, suggestions needed
 

Hello Everyone,

I am about to have my engine guy build my 2.7...what's the consensus on which p/c kit to use?

My engine was a CIS engine, but I am doing a 2.7RS+ spec build. Had the case work done, heads ported and opened up, will be using a DC40 cam, single plug with Weber carbs.

Which set of p/c should I get for a street engine (going in a narrow body 914)
- Mahle 2.7RS piston/cyl set listed @ 8.5:1 (but aren't hey actually higher?)
- L&N Nickies with JE pistons @ 9.5:1

Thanks for your input, I want the engine to run as cool and for as many miles as possible. SmileWavy

I'm by no means an engine expert. But was recently in a similar boat trying to decide what to build. I was told the opposite about the RS pistons, that they are actually closer to 8:1 than 8.5:1. I decided on RS pistons and DC30 cams based on cheaper access to those parts and feedback from a few long time engine builders who have had similar engines.

My dad and I are building a 2.7 with JE 9.5:1 pistons and DC40 cams for him, and were told the higher compression would make for a more fun street motor than a straight RS spec motor which is what we were going to build.

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I would have your 2.7 cylinders bored and plated to get 2,8 or 2.9l. Use JE or CP pistons to match.

With careful tweeks you may be able to get close to 9 to 1 cr with the Mahle set.

I would go with pistons that get you closer to 9 to1. I ran my friends engine below in my 914-6 for a while and loved it. I am building a similar engine but with 9.5 to 1 JE pistons in re-plated stock cylinders for another 914-6 conversion. Mod-S (DC40) cams worked great in 914 on the street.
http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/1074394-911-engine-sale.html

john

Hey a set of Mahle cylinders replated with Nikasil and honed to your pistons. JE available off the shelf at 9.5 or 10.5 to 1. Note all JE off the shelf are 2618, available in 4032 as custom.

Months of non-action on my end-bump.

Still haven't pulled the trigger, having choice anxiety and the JE allow mix is throwing another wrench into it. Any new thoughts for this street engine.

Thanks,

I went threw exactly what your contemplating with my 76 911S CIS motor. I went the 2.7 RS route. It was ok. Then I rebuilt it to a 2.8 with J&E 9:5.1 pistons with Mod S cams, aluminum flywheel, ported and polished heads and 46mm PMOs. Absolutely love it

Thanks 911 SLANT (and pocv0).

Did you guys run the standard 2618 alloy, are they loose/loud on a street engine?

Also, can the new Mahle 10.3:1 piston set be run on single plug with a stock 90mm bore? I believe these are 2618 alloy from what I've read.

Thanks again everyone with experience.

Compression is everything in a Hi Po motor. I went with 9.5 JE's but still think I should have gone with the 10.5s