I know cost is an issue many times with rebuilding an engine but it seems like a really good idea to me to use nice light forged pistons in any rebuild better than stock... Never enough money to do it right in the first place, always enough to do it again later... Has anyone weighed a stock 350 piston? I keep forgeting and I am out of town or I would list the stock weight... If anyone has one off a rod please weigh it for me! I almost fell off my chair when I found out my custom pistons were 154 grams EACH lighter than my TRW forged pistons!!! yes it was worth it to tear the engine down and re-balance it with the better pistons... one phone call to Diamond (9.5:1), Ross Racing (11:1), Weisco (10:1), etc can set you right up... They have all ready made these pistons for people and can make more on request... Venolia even says that for no extra cost they will give you ANY compression ratio you want, a SBC pin diameter so you can use cheep strong forged rods off e-bay etc.... I do not have any proof but I bet the weight loss is worth a few HP AND for sure it makes the engine more reliable and boosts the RPM capability AND the raises the HP limits of the stock rods due to less stress (weight on the rods)... PLUS you can get the nice light forged rods for cheep when you use a piston with a SBC pin diameter... Bob is now offering top of the line forged 350 pistons too so call him: http://www.finishlinemotorsports.com/ Here is a Diamond custom piston at 555 grams. These are set up for running nitrous and turbocharging at the same time and Daimond says I should be safe to about 1000 HP with these babies.... Plus they cool sexy!!! Look true love in the shape of a heart on em: Here is a TRW forged piston at 709 grams: A quote from a reputable piston manufacturer: I found a interesting article at CHP web site about their SRP Professional piston line : "The most recent example of this is our SRP Professional piston line. We integrated features such as a new lightweight forging design, an advanced low-friction ring package, shorter wrist pins, a unique skirt profile, and ultra-flat ring grooves. On our Chevy 383 test engine, the new design resulted in a weight reduction of 63 grams per cylinder and a 13hp gain!"
Hey Sean,take a look at these; http://www.buyracingparts.com/pisto...totec-forged-350-buick-dished-piston-kit.html Here's the 455 pistons,they show the bottom veiw of what the 350 piston looks like too. http://www.buyracingparts.com/pisto.../autotec-455-buick-forged-dished-pistons.html
Thanks, so stock pistons are about 200 grams heavier than my pistons that are good to 1000 HP. Thanks, these ARE the pistons that Bob Mackley is selling at finishline motorsports and he might give u a deal if you say you are friends with me...:TU::TU: ---------- Post added at 06:17 AM ---------- Previous post was at 06:13 AM ---------- Holly crap!!! $208 for a custom camshaft!!! Sign me up! I will order through Finishline though! http://www.buyracingparts.com/valvetrain/camshafts/buick-camshafts/custom-buick-hydraulic-cam.html
Sean can you give me a call at the shop at some point when you have a minute? We are starting to get the parts together for Jenn's 350 turbo dragster and we want your take on a few things.
PM sent with my work number ---------- Post added at 08:00 AM ---------- Previous post was at 06:51 AM ---------- 3. Eagle SBC rods Engine builder Brian Leibee used an off the shelf Eagle rod at 6.30 long and had Ross make custom pistons for the application, after slight machining this combo has been track proven reliable and the cheepest option so far for forged piston and rods combo:The rod used for the Buick 350 is the CRS6300SLW http://www.sciontist.com/ProductDeta...x?id=100005865 or http://www.cnc-motorsports.com/produ...177&CtgID=8085 Just spoke to Troys Engine builder Brian Leibee and he said that it would be no problem to do another setup liek this for someone. The rods are VERY slightly narrowed, bearing tang moved and stock buick 350 bearings are used, the piston is custom made anyways so no problem to go with the SBC pin diameter. Info on the pistons again: The piston builder Ross Racing Pistons. Job card # off the order sheet was 115793. Should help speed the process of ordering. Waited about 5 weeks. Pistons are a true flat top with 4 cc valve reliefs. Engine builder Brian Leibee with Leibee Precision Machine,Phone# 307-362-5049. Tell him Troy sent ya hill take care of ya. http://www.v8buick.com/showthread.ph...ghlight=casper
You too man, I can not wait to swap alum heads on my twin turbo 350!!!!! I think I need to build another car with a better roll cage so I can run faster than 10.00 in the quarter.... Something light like you run.... Would not take many PSI of boost to run 8 second miles with a light car!:Brow:
Yeah, we need some critical information to be added to this thread. I can point it out but I don't have the numbers. When you talk about applied stresses and acceleration loading in a reciprocating assembly the forces go up dramatically with speed increases. I'm sure it is at least by a factor of the increase in speed squared. Could be cubed? Not sure about that one, though it does apply to vehicle speed vs drag I've been told. So if anyone has the formula we should have it where we're talking about piston weights. What kills pistons is piston speed, and obviously the speed reversals at both ends of the stroke but much more so at the top than the bottom because the acceleration of the sideways component from the big end travel is additive at the top but subtractive at the bottom. So the top on the exhaust stroke is the very worst. (no compression/firing to cushion the reversal) and means the piston is most likely to fail in tensile and be pulled away from the wrist pin, separating at the ring lands. This is a special concern for us because of the long stroke, making these engines more rpm limited than shorter stroke motors. But we can fight back with lighter pistons and rods, (a smaller diameter piston is generally lighter than a larger one) and with a longer rod/stroke ratio. Jim
Since there is not much we can do to change the piston speed, I am not worried about it. Higher quality pistons raise the tolerance to really high piston speeds to a level that we need not worry about it... Info about piston speed: http://www.cartechbooks.com/techtips/pistonspeed http://www.csgnetwork.com/pistonspeedcalc.html From Probe Pistons: Q: What will lighter pistons do for me? A: Light pistons have several benefits. They reduce stress on the rotating assembly and block, especially at high rpm. They allow quicker wind up of the engine, much the same as a lightweight flywheel would. They make balancing easier, reducing or eliminating the need for expensive Mallory metal. Q: How much RPM can Probe pistons handle? A: There is no practical limit for RPM. In general, the higher the RPM the lighter the piston should be (33 ounces at 10,000 rpm is 20 TONS). For the SRS Series pistons 8,500 rpm is common.
There's the matter of material to consider when chosing a forged piston also. The 4032 alloy can be installed with tighter piston to wall clearance,and is typically lighter than others,but,it isn't meant as an all out race piston.Here is a explaination from the company in the link I posted earlier in this thread; "AutoTec is a High Quality, Precision Manufactured piston option. That comes at a very respectable price. Our Design Specific Forging allows us to manufacture our parts with less machining time, thus allowing us to keep production cost down. Then pass that savings on to you, the customer. Made out of 4032 High Silicone Aluminum Alloy, it has great wear resistance, a low expansion rate, is very durable, and is very low in friction. These pistons accommodate multiple uses including,your local auto shop, muscle car restorations, performance street rods, as well as many spec racing classes. They can also withstand mild nitrous kits and small turbo or super chargers. Just about everyone can benefit from the excellent value the AutoTec line carries. Keeping in mind these pistons were originally designed for about 600 Horsepower. In Small Block applications, we have customers that frequently fine tune engines that yield 850+ Horsepower with a bit of Super Charger boost. Bore, Ring Pack, and Compression Distance changes can be made to any shelf part at no extra charge. Meaning that if you do not see your application listed in the guide, we can make what you need without charging a custom price. Every part is made with same high quality machines and tools as our RaceTec line including diamond turned ring grooves, and skirts. Not to mention our parts are 100% made in the USA." Then there is the 2618 alloy,this alloy is more suitable for a racing applications,but requires more piston to wall clearance(because of it's greater expansion rate),which will be louder before warmed up,but will handle a lot more abuse,such as more PSI in a forced induction app,and larger shot of NoS than the 4032 alloy would be able to withstand.(Which says a lot because the 4032 alloy can handle some power!) The 2 alloys mentioned are usuallly from after market higher end pistons,with the 4032 being a more street friendly choice,and the 2618 being more for extreme racing conditions(but still can be used on the street if someone wanted to). I hope this was helpfull,chose wisely,and enjoy. Sean,which material are your pistons? I would assume that they are the 2618 alloy if they are rated at 1,000+ HP,but not sure?
I would have to look at the paperwork which is about 300 miles away at the moment... I do know that the pistons are designed as a street strip piston for use with nitrous and they are not a race only type of material. I should not have said they are "rated" for 1000 HP. The Diamond tech on the phone said "that these are typically fine to about 1000 HP", so that put my concerns to rest. Every aspect of my Skylark was tilted towards the street side of the street/strip spectrum. Mild camshaft, switch pitch torque converter, auto shifting trans, mild 3.42 gear etc. I plan to idle it around town and drive it on the highway so there was no place for "race only parts".
Hey Sean,I didn't say that the 2618 was race only,my point was that they are more up to the task of an extreme engine.The 2618 alloy is used in nascar engines,where they run up to .010"(.005" per side) piston to wall clearance because of their expansion rate and the high temperatures those engines can run. Of coarse on a mainly street driven car where the temperature stays in check,and even blasting down the QM it won't see nascar temps.So when this alloy is chosen for a street,or a street/strip car(even a QM race car),the piston to wall clearance will be around 1/2 of what nascar runs.You just need to be aware that the pistons should be "warmed up" somewhat before WOT is applied,so they have time to expand in the bore for better sealing,and less piston rocking.(with quiet exaust,can be heard,when cold) And like the tech info I posted said about the 4032 alloy; "Made out of 4032 High Silicone Aluminum Alloy, it has great wear resistance, a low expansion rate, is very durable, and is very low in friction. They can also withstand mild nitrous kits and small turbo or super chargers. Just about everyone can benefit from the excellent value the AutoTec line carries. Keeping in mind these pistons were originally designed for about 600 Horsepower. In Small Block applications, we have customers that frequently fine tune engines that yield 850+ Horsepower with a bit of Super Charger boost." "Keeping in mind these pistons were originally designed for about 600 Horsepower. In Small Block applications, we have customers that frequently fine tune engines that yield 850+" So I would think your app needs the stronger 2618 alloy for the amount of HP and cylinder pressure your going to be sporting.:Brow: Can't wait to read how it runs for you!:TU:
I would be lucky to hit 700 HP so I am sure they will be fine... I am pretty sure the Switch Pitch TH400 is the weakest link in the drivetrain right now, but if that goes I have a regular TH400 built for more than I need ready to swap in.
