Bruce Amacker Posted March 9, 2011 Share Posted March 9, 2011 I'm helping someone write an article about PSD pistons, I provided him with 7.3, 6.0 and 6.4 pistons for research as I don't have my 6.7 torn down yet. He's looked in all of the service literature about piston manufacture and asked a question I can't answer: Are PSD pistons forged or cast? Is there any service info regarding the construction of the piston? Any input is welcomed, sources are encouraged. Thanks! Quote Link to comment Share on other sites More sharing options...
iceman Posted March 10, 2011 Share Posted March 10, 2011 The piston is: made of an aluminum alloy. fitted with an upper keystone compression ring. fitted with a lower rectangular compression ring. fitted with oil control rings. this is according to the wsm on fmcdealer for a 2007 f-250 with a 6.0 Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted March 11, 2011 Share Posted March 11, 2011 The 7.3 uses a cast aluminum alloy piston with a Ni-resist insert. Sometimes referred to as bimetallic pistons. The insert is located at the top compression ring area. It is harder than the piston material and, from what I can tell, two of it's advantages are improved piston life and the insert allows the top ring groove to be located closer to the top of the piston reducing the shrouded area. Since the VT444 was such a successful engine, one might assume that the same piston technology was used in the VT365 and the 6.4 since these pistons appear to be cheaper to manufacture than forged types. As for the 6.7... I can 'see' Ford using this same architecture as long as the materials play well with compacted graphite iron cylinder walls (look what they did to the modular engine pistons). I'm glad you posed this question as it has opened my eyes to developments that I just never imagined (or dared to imagine) regarding something as basic and old as piston design and materials. Trunk pistons.... articulating pistons... time to do some reading..... Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted March 11, 2011 Author Share Posted March 11, 2011 Since the VT444 was such a successful engine, one might assume that the same piston technology was used in the VT365 and the 6.4 since these pistons appear to be cheaper to manufacture than forged types. As for the 6.7... I can 'see' Ford using this same architecture as long as the materials play well with compacted graphite iron cylinder walls (look what they did to the modular engine pistons). There IS considerable difference between the 7.3 and the 6.06,4 pistons. The later pistons use a Teflon or similar insert in the skirt where the 7.3 did not. I supplied my friend 7.3, 6.0 and 6.4 pistons for his article, but I don't have a 6.7 piston out yet. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted March 12, 2011 Share Posted March 12, 2011 The presence of an insert in the skirt is an interesting factoid... My own reference to the modular engine pistons is partly due to the insert in the side of the piston... I hesitate to use the word skirt since the mod motor pistons I have seen do not have a traditional slipper skirt design. I am more than a little surprised that these engines aren't a lot noisier when they are cold - unless, of course, this particular design allows for less noticeable "cam". We both realize that the demands placed on the typical diesel engine piston are more severe than anything we generally see in gas engines - 'up until now' might be an appropriate disclaimer at this point since the 3.5 ecoboost has, we are told, piston cooling jets... something that indicates that the pistons may be subject to temperatures beyond the capabilities of the materials they are built of. Still and all, I'm glad you brought the subject (of pistons) up.... Piston technology has, apparently, been in a state of flux and the results appear to be nothing less than (with apologies to Mr. Spock) fascinating. Quote Link to comment Share on other sites More sharing options...
Matt Saunoras Posted March 12, 2011 Share Posted March 12, 2011 well we all know in the world of gassers that high compression and boost generally don't mix too well for pump gas. how the ecoboost accomplishes all of this is beyond me at this point Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted March 13, 2011 Share Posted March 13, 2011 With the ecoboost, the fuel is injected directly into the combustion chamber...it is injected just before the combustion event is intended (injection pressure under high load conditions is something like 2200 PSI). This reduces the chances of preignition and/or detonation. Additionally, all ecoboost engines have variable exhaust cam timing - and some have variable intake cam timing as well. Exhaust cams are retarded to reduce cylinder pressures (ergo reducing cylinder temperatures) and are used as emissions controls. Intake cams are advanced and are used to increase cylinder pressures (ergo performance). If at all possible, sign up for the EcoBoost class (31S30T0). It's only two days and there is stuff to learn. FWIW, I had to take it to keep my diesel cert..... Quote Link to comment Share on other sites More sharing options...
rlchv70 Posted March 17, 2011 Share Posted March 17, 2011 The 6.0L and 6.4L pistons are cast hypereutectic pistons. One difference between them is that the 6.0L is spray cooled and the 6.4L is gallery cooled. If you look at the underside of the 6.4L, there is a passageway (gallery) that the piston cooling jet squirts into. 6.0L doesn't have that. Quote Link to comment Share on other sites More sharing options...
lmorris Posted March 18, 2011 Share Posted March 18, 2011 The 6.7L piston also has the oil gallery. So does the ecoboost piston. Quote Link to comment Share on other sites More sharing options...
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