10.5:1 or 9.5:1 wiht DC20 cams?

[RichHawk]

I'm getting my 3.2L replacement engine next week. It's essentially brand new in nearly ever way, disassembled with lots of new shiny parts.

1987 stock injection, and stock exhaust... so far. I'm expecting a Steve Wong chip as well. Street / occasional track engine that must idle well, but Does not need to meet any emission standards.

Some of the oohh ahh parts are:
brand new DC20 cams and brand new JE 9.5:1 95mm pistons.

So I'll start with a simple question: Should I sell these pistons and by some 10.5:1 JEs? I haven't read any downside to the 10.5:1 CR. But I'm not sure if the JE pistons are going to have enough relief for the DC20 cam lift.

Thanks,
Richard

[304065]

Keep the 9,5 if you are going single plug.

[longhornchris04]

Is it twin-plugged??? If not then running 10.5:1 is probably out of the question, based on what I've read here and on Steve's website.

Not that I'm an expert. Hopefully they will be by soon.

[RichHawk]

Ok,
Keeping with single plugs, the European 3.2 was a 10.3:1 CR.
I just had misremembered it as 10.5:1

Is 10.3:1 acceptable (JE pistons) and will it clear the valve lift of the DC20 cams?
Wayne's book has the 10.3:1 European P&C as one of the easy power bumps when rebuilding.

Why would this be a bad idea?

Richard

[88-diamondblue]

Richard,

I asked the same question several years ago on this and this thread covers it pretty well. Carrera Rebuild 10.3 Pistons & Cylinders

I did a rebuild on my Carrera and used 98mm JE pistons at 9.5:1 with the DC-22 cam which is higher lift than the DC-20 and have had no problems with it. Just didn't get it timed right the first time around and the JE pistons deep valve pockets saved me. More to come on this in the next couple of days. Have fun on the build. I would love to do another.

Make sure to use steel head studs on the exhaust side or an aftermarket solution like Supertec studs and ARP rod bolts, as that is a weak point with the Carrera engine.

[RichHawk]

Thanks Michael!
That's exactly the kind of thread I was looking for.
I knew it was out there, and in that thread they mentioned that this had all been hashed over time and time again. But for me, it's all brand new and buried under years and thousands of posts. I dug plenty looking for it, but just did not dig in the right place, with the right key words.

So, I'll stick with the 9.5:1 JE pistons I have, and put the best gas in that I can find.

Richard