attworth Posted March 10, 2009 Share Posted March 10, 2009 I'm trying to decide if I want to use the AZC flat-tops, or a set of standard flat-tops. The AZC pistons combined with L24 rods make for a higher rod/stroke ratio, which from my understanding is a good thing. But is it worth it? 650$ for a set of pistons, plus 1mm over-bore at the shop. I'm running through things in my head and just trying to figure out if this is what I want to do or not. I guess I really need to call the machine shop and see the price difference between a standard bore hone and an over-bore. Any thoughts? Edit: Guess I should have mentioned that if I don't use the AZC pistons, I'd be using standard bore flat-tops. Not really looking at the performance difference due to bore size, but stroke ratio value. Quote Link to comment Share on other sites More sharing options...
blue72 Posted March 10, 2009 Share Posted March 10, 2009 Have you called AZC to make sure they've got the pistons in stock? Last time I was in the market for some pistons he was sold out and had been for a while. Quote Link to comment Share on other sites More sharing options...
attworth Posted March 10, 2009 Author Share Posted March 10, 2009 Good question. It'd be a couple months, so I didn't wanna jump the gun and waste his time. Quote Link to comment Share on other sites More sharing options...
Daeron Posted March 11, 2009 Share Posted March 11, 2009 If I am not mistaken...... .....A, they have been out of stock for several months if not LONGER (if they are still out of stock) ......B you will likely see far more increase in performance, from the increase in bore, than you will see from the rod ratio change. Remember, 280 is still more hp than 240. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 11, 2009 Share Posted March 11, 2009 Depends on what you're doing. If you're buying forged pistons anyway and you have a set of rods, it's a win/win. If you're doing nothing else other than change the rod ratio on an otherwise stock engine and you don't have rods and don't need pistons, there are much better ways to spend your ~$800. You can get those pistons from Ross through Summit Racing, just provide the specs - but you'll need to know the specs--bore, pin size, pin height ring gap sizes. I think there are threads listing the specs if you search you should find them. Quote Link to comment Share on other sites More sharing options...
attworth Posted March 11, 2009 Author Share Posted March 11, 2009 I've seen the specs somewhere, I think I book-marked it. I do have a set of 240 rods I can use, or my 280 rods. I think I want to use forged pistons, although I'm not positive. I'm still in the planning stages of this build. I'll be having a head worked through (still sorting out those details,) along with a fairly mild cam. I'd like to go with the AZC pistons, (or Ross,) as they offer a little bit of an over-bore, along with the added stroke ratio. Just having a hard time deciding whether or not the extra stroke is worth using forged, or if I should just stick with a cast piston, maybe over-bored, possibly not. Now I'm rambling. Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted March 11, 2009 Share Posted March 11, 2009 If you'll be running NA (read no turbo) cast pistons will be just fine. They can handle just about anything you throw at them sans boost. From a cost perspective, you might just do well to keep the stock L28 rods, buy a set of flat tops 1mm overbore, sell your 240 rods and that'll pay for a bit of your pistons. Unless you're going to be running more than 13:1 compression, cast pistons are just fine. Quote Link to comment Share on other sites More sharing options...
josh817 Posted March 12, 2009 Share Posted March 12, 2009 Why not just bust a Josh and go bigger and bigger? >_> Maybe even 90mm! Yah! Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted March 12, 2009 Share Posted March 12, 2009 "Bust a Josh" - now that's funny right there! Size does matter don't it!!?? Quote Link to comment Share on other sites More sharing options...
josh817 Posted March 12, 2009 Share Posted March 12, 2009 Edit: Guess I should have mentioned that if I don't use the AZC pistons, I'd be using standard bore flat-tops. Not really looking at the performance difference due to bore size, but stroke ratio value. I honestly don't think its worth your time. Using an L24 rod will give you -2.75mm deck height with an L28 flat top. You would need a piston with a pin height of 35-36mm to achieve -.65 to +.35mm deck height. Plus you are only increasing the ratio from 1.648 to 1.684 and max rod angle goes from 17.661º to 17.277º which isn't much of anything to hoot about. Might as well save your time (even though there isn't any labor difference) and your money on pistons. Quote Link to comment Share on other sites More sharing options...
attworth Posted March 12, 2009 Author Share Posted March 12, 2009 I honestly don't think its worth your time. Using an L24 rod will give you -2.75mm deck height with an L28 flat top. You would need a piston with a pin height of 35-36mm to achieve -.65 to +.35mm deck height. Plus you are only increasing the ratio from 1.648 to 1.684 and max rod angle goes from 17.661º to 17.277º which isn't much of anything to hoot about. Might as well save your time (even though there isn't any labor difference) and your money on pistons. That's what I was beginning to think. Quote Link to comment Share on other sites More sharing options...
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