Mack Posted January 26, 2007 Share Posted January 26, 2007 alright, finally going to take the 3.1L leap. Ive got a whole deisel block in my garage, and I want to use the LD rods with it as I dont have any L24 rods. yes, I know it probably wont be noticable and all that garbage, but, its what I have and if Im getting custom pistons, why not? o.k. so, the pin height on these pistons will need to be about 26.6mm, which is a bit on the short side, I realize. the pin will be 22mm. So, it will have to be a tight ring stack and i want to build this motor for boost. contradiction in terms, I know what are my options? Quote Link to comment Share on other sites More sharing options...
1 fast z Posted January 26, 2007 Share Posted January 26, 2007 Ring land support and adiquite rings are ALOT better things to have then a questionable noticable difference in R/S ratio, not to mention the mass increase when compared to z rods.. Z car rods can be had on ebay for 50 bux often. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted January 26, 2007 Share Posted January 26, 2007 22/2=11mm radius of pin. so 26.6-11=15.6. You HAVE to use a 4mm oil controll ring, if you want a good oil ring, with that above the pin bore 3mm. There have been people that put the oil ring below the pin but it is not recomended as oil on the pin bores is NEEDED. You could run 1mm comp rings, with atleast 3mm thickness for the lands. You will need .015" deck height. So. 1.2+1.2+3+3+4+3+.5=15.9. So basicly that is if the ring was at the TOP of the bore which you cant do, so to some up, it is NOT worth the effort and hassle and the reliablity. Not to even mention heat and detonation resistance that would be needed and for that to happen the rings should be WAY down in the bore. Quote Link to comment Share on other sites More sharing options...
Mack Posted January 26, 2007 Author Share Posted January 26, 2007 yes I see your point and all that.... for sure. I did however, find out that people are turboing the D17 honda 4 cylinders and they are getting a current max of 396whp. why is this important? well, the D17 has a 27mm compression height, which is right in line with what mine will need. granted they get forgies for 396whp and custom manifolds, but if they can hold 100whp/slug on a smaller bore (81.5mm), a bigger bore should be able to do 100whp/slug no problem. Im trying to get the piston specs from a D17 builder at the moment, Ill post them up when I get them. Quote Link to comment Share on other sites More sharing options...
Phred Posted January 27, 2007 Share Posted January 27, 2007 Mack, it can be done. You just have to pay the piper. I have been on a similar mind set, and have the hardware in hand. I chose to go with a + .040 overbore on an F54 to maintain cylinder strength. With the LD28 stroke, this combo has 2960.4cc. I have the longest rod I could fit in it, an L16 length of 5.510, made by Carrillo. The pistons are custom JE with a comp. Ht. of 1.056. You'll notice in the pics that the pin is into the oil ring land! This is handled by a thick lower oil ring support rail which is installed after the rod/pin/locks are assembled. Then a std. 3.5mm three piece oil ring is installed, followed by the 1st and 2nd rings which are 1.5mm ea. Datsuns have terrible rod/stroke ratios, and it would have gotten a lot worse if I hadn't gone with this setup. No, this hasn't hit the dyno yet, but I have built other engines with a similar rod/piston/pin layout which were sucsessfull. So I hope my own engine is too. Phred Quote Link to comment Share on other sites More sharing options...
Mack Posted January 27, 2007 Author Share Posted January 27, 2007 WOWW!!!!! thanks Phred@! thats what I was looking for!! I had heard of oil rings going into the pin bore! sounds like thats what I need!! I have also heard of the japanese building stroker motors with FJ20ET rods and honda XR500 pistons. gives almost a 1.7 r/s ratio. which, fo rthe stroker is not too shabby! EDIT> you have almost exactly what I am shooting for! a 140mm rod with the LD28 crank! btw, teh LD28 rods are 140MM, I dont know WHY people just throw them away...... nice and heavy duty. Quote Link to comment Share on other sites More sharing options...
greenmonster80 Posted January 28, 2007 Share Posted January 28, 2007 The XR500 piston combo is usually with the L14 rods. Off center bush the small end to get the rod length to 139mm. FJ20 rods have a 22mm pin size. I think that nissan actually made a sports option piston with a 22mm pin size. Possibly for the FJ but not sure. KEW and Kakimoto both have rod, piston combos with these 140mm rods for decades. Quote Link to comment Share on other sites More sharing options...
Phred Posted January 29, 2007 Share Posted January 29, 2007 A couple more pix of my JE/Carrilo 5.510 long rod. Phred Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted January 29, 2007 Share Posted January 29, 2007 Phred, Great to have you here mate. I don't get over to classiczcar much anymore, and for one, feel glad to have your wealth of expertise about. Hope the engine goes well. Got some interesting work done to the head? Dave Quote Link to comment Share on other sites More sharing options...
Phred Posted January 30, 2007 Share Posted January 30, 2007 Hi Dave, First, I have to apologize to Mack for hijacking his thread. Even though I don't post much here, I spend quite a bit of time here. There is a greater supply of tech. info here than on other sites. The people over at Classic Zcar are a good group, and I like to help out when I can. Yes, I have a fairly modified E88 I've been working on, and is about 85% finished. Mildly ported, matched and dowled to a ported TWM intake with 45DCOE's. Stainless valves, sized 44/36. I havn't made up my mind what to do with compression, so its not surfaced yet. But it will have a chamber size of around 44cc's. I'll post a few pix of it on a fresh thread when its finished. Phred Quote Link to comment Share on other sites More sharing options...
Mack Posted January 30, 2007 Author Share Posted January 30, 2007 LOL, you can hijack this thread all you want as long as you can get me a build sheet for the pistons, or an order number through JE perhaps?? please? sounds like you are going to have a bit of a screamer on your hands! Quote Link to comment Share on other sites More sharing options...
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