greenmonster80 Posted June 17, 2005 Share Posted June 17, 2005 Finally got my pistons and rods balanced and fitted together. Got the tops of the pistons ceramic coated. I figured cheap insurance if nothing else. My machinists is telling me that these will now be suitable for nitros, turbo or supercharging. I know generally stock turbo pistons or forged aftermarket pistons are recommended here on this site. Is this guy setting me up for a return customer after my engine goes to crap cause I added a turbo set up? Does anyone have experience with running cast aluminium pistons in a turbo motor? To me sounds bad but this place has alot of racing history. Looking for thoughts, comments.. Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted June 18, 2005 Share Posted June 18, 2005 I read this a few times and I'm not real sure what the question is? Are you saying you did all this work and now want to add a turbo system to a motor that does not currently have it? Are you asking about the advise of your machinist? Are you asking if cast pistons can be used in a "power adder" type of motor combo? Sorry it's early maybe I just missed it? Quote Link to comment Share on other sites More sharing options...
greenmonster80 Posted June 18, 2005 Author Share Posted June 18, 2005 Sorry if I came across broken and unclear. I am building a 3.1 with aluminium pistons. I remeber reading somewhere that L28's produce some pretty hot temps. So I figured with everything apart I'd have the pistons ceramic coated. When I pick them up the comment is made that these puppies are good for turbo, nitro or supercharging. I would have never thought of using aluminium pistons in a turbo motor. But if this is sound advice I will be doing it. Looking for someone who has done this or understands more about this than I do. Are aluminium pistons safe in a turbo application? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted June 18, 2005 Share Posted June 18, 2005 All pistons are aluminum, or various alloys thereof. Forged are generally considered strongest, but factory turbo pistons are cast with stronger ring lands. If you've built a 3.1 with a normal or higher compression ratio (higher than 9:1), I would not consider any power adders with cast pistons. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 18, 2005 Share Posted June 18, 2005 "Automotive" pistons are generally made of Aluminum, cast or forged. Forged has a denser structure and is suitable for the loads from higher revs. Generally, if you are turbocharging an engine, you don't put the loads in tension that higher revving does, so you can survive with cast pistons. They are far more resistant in compression than tension. BUT if you go crazy with compressive forces, then by all means run forged, as they add a margin of safety, as well as having a higher rev limit. Generally, cast pistons are said to be useful below 7000 rpms, which is where most turbo engines make their power. But above that, and cast pistons don't hold up as long as forged units do. It's not heat so much that causes failures, but detonation! Boom, and forged or cast, things break! On the "All" comment... Not "All" pistons, however are made of aluminum. One trip to industrial repair houses will confirm that. Many larger engines use cast iron, and various other alloys other than aluminum, as they are not high revving, nor is weight a consideration in their manufacture, Durability and Longevity are their main focus. In these applications, cylinder bores are made replaceable, and it's not uncommon for many sets of liners to be replaced while the original piston simply gets re-ringed. It's a different world! Quote Link to comment Share on other sites More sharing options...
1 fast z Posted June 18, 2005 Share Posted June 18, 2005 Yea, back in the late 20's and early 30's there were alot of cast iron pistons still being used. My grandfathers V-16 Cadilac Powered roadster has FIVE TO ONE cast iron pistons in it! They couldnt get the "cam" design correct in the pistons in the early days, to accomidate for the expansion of the alloy pistons, so they used cast iron pistons, cause they didnt expand NEARLY as much as the alluminum ones. Quote Link to comment Share on other sites More sharing options...
greenmonster80 Posted June 18, 2005 Author Share Posted June 18, 2005 Ok, clears it up for me. Thanks. Going to be looking for a way to lower my compression ratio. Moving to a P90 head and possible 2mm metal headgasket. Quote Link to comment Share on other sites More sharing options...
zbuild Posted June 22, 2005 Share Posted June 22, 2005 Ive been using a set of aftermarket pistons (not forgies) with ceramic coated tops in my turbo engine for 4 years now. . . and have run up to 20psi but normally run 15psi and have had no problems with them. Pistons made specifically for turbo charging would be better in that they have wider ring lands and can take more pressure there, but sensible tuning can go a long way to allowing the use of pistons other than Forged ones. cheers - Simon Quote Link to comment Share on other sites More sharing options...
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