Hi guys, In doing the new 482 combo, I decided to offer both a race piston, and a Street strip Piston. The race piston is a new version of our tried and tru Diamond 2618 piston, which we have used successfully now for the last 8 years in many 470 combo motors. It has these specs: 4.350 bore 1/16 compression and 3/16 oil ring (smaller rings with gas porting available at extra cost) Maxi-light ring belt and pin boss internal milling (aprox 615 G) .990 pin with dual spiral locks (.185 wall - 177g) Pin Fit No pin offset 1.725 Compression distance Flat top with 9 CC valve reliefs. .300 deep to fit any cam or valve size. You may opt to go with a lighter tool steel pin at additional cost coatings are also available Cost is $779 for the set, with pins and locks _______________________ For the Street/Strip 470 and 482, I am now offering a 4032 material piston from Autotec. Recommended for Street use, with occasional trips to the drag strip- up to 600 HP 4.350 Bore 1/16 compression/3/16 oil rings 25cc dish with valve reliefs Straight pins (no offset) 4032 material 1.775 (470) and 1.725 (482) Compression distance Pin fit with .990 pins (pins and locks included) Standard 1.85 wall pin weight (TBD) Cost is $679, that represents a $100 savings over the current 470 diamond piston (prices just went up) Any questions?.. just ask Thanks JW
Can they be made shorter,with a thinner stack,for longer rod or strokers? I run an .043,.043,3mm in my street and street-race engines. I also run a .927" Chevy pin.It allows me to have a very short piston,and not get into the oil ring. Has anyone done anything like that with a Buick?
Sure, any CD you want, plenty of ring options available. Yes, there was a 7.1" rod 494 combo around for a while... I built a few of them.. that took a 1.335 CD. The consensus among most folks that ran that combo was that ring seal suffered from piston rock.. and most of us went back to the 6.700 rod, to keep some skirt on the piston. But some guys really love that light piston (534g rings a bell) and still run the long rod. On the buicks, because of the big bore, and "flexible" block, I am a fan of piston skirt.. I get less scuffing better ring seal, and longer engine life between freshen ups, even on the race motors. Just did a freshen 6.7" 494 after 9 seasons of racing, was very happy with how the bores and pistons looked.
on the floating pins , which locks do you prefer? spiral, or regular ? Do either one of the two styles tend to dig into or wear the piston whare it rides in the grove?
Pins and locks with the pistons. I prefer the spiral locks, they dig into the piston much less than the dual tru-arc snap rings do.
Mr wise. if I wanted to purchase a set of the autotec street pistons. would I need to call the 1-800 number, your web site doesn't appear to support parts purchasing. one the 470 kits what con rods do you recommend.
No 800 number, you can call me at 320-629-8999 or we can do the whole deal right on the board here, with a "conversation" which is private, or email me at jim@trishieldperformance.com The 470 piston is designed to work with any 6.8" long BBC rod, if you widen rod throws. Built the first 20 or so like that.. now we have a new BBB 470 rod from Molnar Technologies.. a superior piece, that is specifically designed to work in this combo. JW
Thank you sir. So I take it they are 2.20 big end Does the crank throw still need widened to fit the Molnar rod.
No, the new rod has our Buick width, that, and having the correct bank offset, are the differences between our 470 rod, and the BBC rods. JW
Jim, Would either of these pistons be ok for a street/strip setup that sees an occasional 150 shot of nitrous? (Just gathering ideas at this point)
Ya, as long as that 150 shot does not turn into a 300 shot... we should be just fine. I assume we are talking about a 450HP or so base build..
Haha, 300, fair play Jim. Afraid not on the 450hp, so I may have to explore other avenues. My current setup dyno'd comfortably over 500, and I want the next one to be a bit hotter. Thanks for the answer Jim, I'll do some poking around and get with you when the time comes, dont want to sidetrack the thread. I'm just in the early info gathering stages now. Back to your regularly scheduled program.....
In that case, you need the 2618 Diamond piston for that combo. Not really that much more expensive in the grand scheme of things. I recommend these 4032 Autotec pistons for up to 600 HP street or street/strip applications. JW
