337cc kits vs 'standard' vs 'Wiseco' pistons

wombat200 · Post by **wombat200** » Mon Sep 01, 2008 3:35 am

Hi All,

I'm finally embarking the engine for my C77-based special (as well as another Dream project I'm working on). This engine will be a performance engine, with a few mods such as bigger carb & hi-performance cam (either CB or megacycle cam).

I have a few piston-related questions.

I have some 3mm oversized pistons/rings - they are 'MC' brand, but have 'ART' cast on them, so I can take it that they are OEM quality.

I also have some forged 'Wiseco' pistons, 0.50 oversize. These are obviously very good quality high-performance pistons.

Can anyone offer opinions on the pros & cons of either choice? Obviously the Wisecos would allow further over-boring if neccesary, but beyond that, I'm leaning towards the 337cc kit simply for the extra capacity. Has anyone run a 337cc dream? Will the Wisecos be better in a higher-revving motor?

All ideas / theories / speculation welcome!!

e3steve · Post by **e3steve** » Fri Sep 05, 2008 4:29 pm

I have a pair of OEM pistons in their boxes in the garage; I'll look 'em out tomorrow, Rob, & let you know about the ART bit.

wombat200 · Post by **wombat200** » Mon Aug 03, 2009 6:27 pm

More comment welcome, this engine is going together shortly.......

davomoto · Post by **davomoto** » Mon Aug 03, 2009 8:18 pm

Rob, I've done a couple engines with the wisecos, and really no perform'ance gain. I have a set of 3mm overs, and a cylinder bored to fit ready to install on my upcoming street tracker CL77 project. My experience from big bores in the past tells me the engine will be tourqier, and less rev happy. ART is the OEM manufacturer of Honda pistos, so you know the quality is good. You may want to have the pistons balanced.

Davo

e3steve · Post by **e3steve** » Tue Aug 04, 2009 6:36 am

Hey Rob, sorry mate, I dropped the ball on this thread! My new Art pistons are +0.5, beautifully cast and machined and the box is stamped 13103-275-000. I read that Art manufactured for Honda (as did Tec, Stanley, Nippon Seiki, etc,) and Dave has confirmed my belief in what I read. I'm sure Ed may be able to corroborate that.

I passed up on some cheap, new hi-comp pistons last year, as I remember from my youth (when tuning meant as much as a Motorola quadrophonic 8-track player!) how raising compression adversely affected tractability, requiring higher octane fuel and made for an uncomfortably 'lumpy' idle. That's not what I want of my CB, so I'm opting for 'flowing the ports. My first foray into such 'tuning' was with a pal's '61 MGB (most cars in UK back then varied from 850cc to less than 2-litre; not exactly 'big block'!) and then my own 1275cc Mini Cooper S; the difference in smoothness, revvability and acceleration was very noticeable. Standard valves but in turned-down phosphor/bronze guides, uprated valve spring sets, polished chambers/ports/inlet manifold, balanced pistons, rods & flywheel. My old Mini gained around 800rpm, over its previous 6500 ceiling, before valve bounce; that equated to almost a 12mph (19km/h) hike in top speed. It would pull max-rpm in top, downhill, sails up & with the little 10" wheels balanced! The most significant increase was in standing-start and midrange acceleration: almost 2 seconds shaved off the 0-60mph benchmark, 50-70mph in top took less than 6 seconds; and all on standard gearing, carburation and exhaust system. It was quiet, smooth-revving (for a 4-cyl) and it idled!

Bored yet?

Anyway, the reason for my wittering on here is to show that, with smaller motors, opening up the bore and/or raising compression isn't always the way to go. Your requirements obviously may differ.

Just a thought......