RTB Posted January 14, 2014 Report Share Posted January 14, 2014 Are there any dished pistons that work with 6 inch rods? 85-87 mm in size? Also I have 2 options. I can either run flat top pistons with a ported u67 head. Or I have run dished pistons with a 219 head. Which would be the more optimal set up? Also this is with 44mm Mikunis and a datsun comp intake. Time sensitive. Quote Link to comment
H5WAGON Posted January 14, 2014 Report Share Posted January 14, 2014 www.Ozdat.com/ozdatonline/enginedesign/ Start punching in your info! Quote Link to comment
RTB Posted January 14, 2014 Author Report Share Posted January 14, 2014 www.Ozdat.com/ozdatonline/enginedesign/ Start punching in your info! I don't know which pistons work with 6 inch rods. Also, Just because something works on paper doesn't mean it will work well in real life. So its sort of which is better, dished pistons with a peanut head or flat tops with a open chamber. They probably will have very similar compression ratios. Quote Link to comment
H5WAGON Posted January 14, 2014 Report Share Posted January 14, 2014 The ozdat deal will tell you if over deck height...also draynor just built a Hybrid LZ block.... Z22e pistons. Check his thread...What motor are we building...? Quote Link to comment
Draynor Posted January 14, 2014 Report Share Posted January 14, 2014 The Z22e pistons work with the 6" rods, 87mm stock size. What I have, using a L20b crank, and W58 peanut head.A Z20e block has the 6" rods with flattops already, 85mm.VG pistons can also work, but need to search on which ones, as some years are pressed onto the rods and others are fully floating.There is also what "MetalMonkey" has, I believe Mahle forged pistons, made for a Mitsubishi? I think they come in 85mm and 86mm.I can't tell you which combo is the best, cause I don't know. But those are some of the options for pistons. Quote Link to comment
RTB Posted January 14, 2014 Author Report Share Posted January 14, 2014 l20b with stock crank. 6 inch rods. Originally I was going to use 85mm NAPS-Z pistons and a ported u67 head with a don potter cam, datsun comp intake, and 44mm Mikunis. But now I have the option of getting a 219 head but I want to stick with my long rod set up but I don't know if there are pistons at work with that set up and if there are, which set up would be more advantageous. Also the link isn't super helpful because I try to enter the current set up im building now and it says that my piston goes above the deck and I know that isnt true. Quote Link to comment
RTB Posted January 14, 2014 Author Report Share Posted January 14, 2014 Draynor, in your experience is it better to have a peanut head with dished pistons or a open chamber with flat tops. Thats the gist of what im asking Quote Link to comment
Draynor Posted January 14, 2014 Report Share Posted January 14, 2014 Well I did the Z22e pistons with the long rods, because it's what I had, it all just basically fell into my lap.I don't have much experience, just saying.But if you did the flattops with the rest of the stuff your mentioning. You will basically have a stock z20e bottom end. Which is something like 8.8 compression. the Z22e pistons, which really don't have very much dish, with the 6" rods and L20b crank is 10.016 according to OZDAT. But "DatzenMike" calculated my motor build at like 10.4.Like I said I don't have much experience with either. But my motor before my head started having a problem, screams and have had no pinging, long as I use premium gas. Quote Link to comment
RTB Posted January 14, 2014 Author Report Share Posted January 14, 2014 91 octane gas is fine? and so we are clear you are running flattop pistons with a peanut head and you have about 10.4 compression? And i have the NAPS-Z pistons so I have no dish at all. They just have slight valve reliefs. Also, Did you have to stack gaskets? Quote Link to comment
Draynor Posted January 14, 2014 Report Share Posted January 14, 2014 Thats what I have been using, just fine.I am runnig Z22e pistons (Not flattops), Pictured below. W58 peanut. No stacking gaskets, just drilled the coolant holes in the Z22 gasket, needed since I used a Z22 block. Quote Link to comment
RTB Posted January 14, 2014 Author Report Share Posted January 14, 2014 I think I am going to end up calling rebello this morning to try and figure this out. Because when I use ozdat they dont have a NAPS-Z piston option but I know that its perfect deck height and maybe a cc or 2 for the valve reliefs. When I change the piston so that it matches the deck and use the v91 head on there and use a 3mm head gasket it gives me a compression of 9.4. But theres no way the compression would be that low with flat tops and a peanut head. Quote Link to comment
datsunaholic Posted January 14, 2014 Report Share Posted January 14, 2014 With a 3mm head gasket? Yeah, it'd be that low or lower. Head gaskets usually crush down to around 1.2mm. Quote Link to comment
datzenmike Posted January 14, 2014 Report Share Posted January 14, 2014 The Z22e pistons work with the 6" rods, 87mm stock size. What I have, using a L20b crank, and W58 peanut head. A Z20e block has the 6" rods with flattops already, 85mm. VG pistons can also work, but need to search on which ones, as some years are pressed onto the rods and others are fully floating. There is also what "MetalMonkey" has, I believe Mahle forged pistons, made for a Mitsubishi? I think they come in 85mm and 86mm. I can't tell you which combo is the best, cause I don't know. But those are some of the options for pistons. The Z22E pistons used on 6" rods would work actually, just. But only on the Late Z22E pistons not the early or 720 truck ones. With mods the VG30s will also work. Quote Link to comment
Laecaon Posted January 14, 2014 Report Share Posted January 14, 2014 There are no other pistons that will work with 6" rods. Late Z22e or modded VG30 pistons. All other nissan/datsun pistons are too tall and wont clear. You might have to go looking elsewhere, like mitsu pistons or something. Check out the Silvolite Catalog. But it would be luck to find anything else. Quote Link to comment
Draynor Posted January 14, 2014 Report Share Posted January 14, 2014 Whoops, yeah forgot to specify late Z22e pistons. Quote Link to comment
RTB Posted January 14, 2014 Author Report Share Posted January 14, 2014 Second question. Ok, what if I keep my 85mm flat tops and get the 219 head. Then I get a metal head gasket or stack gaskets to get to about a 2.5-3mm thickness. according to ozdat that drops my compression below 10-1. Quote Link to comment
datsunaholic Posted January 14, 2014 Report Share Posted January 14, 2014 Stacking head gaskets kind of defeats the purpose of the peanut head, which is to have a small quench area. A 3mm gap there is pretty much like having an open head at that point. But with all the disadvantages of having stacked gaskets added in (more prone to blowout, and absolutely screws up the timing chain to the point you'd likely need an adjustable upper sprocket) Quote Link to comment
RTB Posted January 14, 2014 Author Report Share Posted January 14, 2014 If z22e pistons work that would be perfect. Slight dish. No reason to stack gaskets. how do i tell the difference between the early and late model piston. Quote Link to comment
Draynor Posted January 14, 2014 Report Share Posted January 14, 2014 Z22s and early Z22e. 35.5 pin height. Z22e late 82 and 83. 32.1 pin height. I got mine on Rockauto. Brand new ITM's with rings for $120 I believe. Ordered them for a 83 200sx. Quote Link to comment
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