akeboshi Posted February 4, 2012 Share Posted February 4, 2012 I just finished building my new motor and I was thumbing through the How to Rebuild your Datsun Motor and I saw that there is a particular way the rods need to face. I dont remember which way mine were so I dropped the oil pan and come to find out they are the opposite way the book says! The motor spins freely and I have the correct crankshaft thrust so how imprtant is it to have them installed one way or the other? Is my engine gonna bind up? Im alittle worried now. I could use some insight please. Marcus Quote Link to comment Share on other sites More sharing options...
johnc Posted February 4, 2012 Share Posted February 4, 2012 Take it a part and assemble it correctly. Quote Link to comment Share on other sites More sharing options...
akeboshi Posted February 5, 2012 Author Share Posted February 5, 2012 OK.... By the way, I installed ARP stuff on this motor, would it be ok to retorque everything or should I consider these ruined after lossening them up? Also has anyone had any firsthand experience doing this on their engines? Just curious as to why they have to be one orientation vs another as they look to be symetrical. Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 5, 2012 Share Posted February 5, 2012 ARP are re-usable studs, but if you read their instructions, the nuts are expendable. A set of nuts from ARP and some more Lube and you are set for reassembly with repeatable torques and clamping forces intact. The rods have offset in them for thrust under power stroke. Generally this is oriented when you install the pistons on the rods. The pistons have a notch that faces forward, and the rods are installed to be correctly oriented then. I'm at a loss how the rods are backwards but the pistons are the right way if they were installed correctly when paired. Quote Link to comment Share on other sites More sharing options...
akeboshi Posted February 5, 2012 Author Share Posted February 5, 2012 The piston/rod assemblies came from another motor. I didnt catch this when I was putting them in the new motor, then I saw the section in the datsun book about it and went to double check it. The piston was installed the wrong way from the old motor. Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 5, 2012 Share Posted February 5, 2012 That would do it! Quote Link to comment Share on other sites More sharing options...
akeboshi Posted February 6, 2012 Author Share Posted February 6, 2012 ... I was worried about running those pistons anyways, this gives me a excuse to get some new turbo pistons. Parts dinosaur has a set with rings for under $200.00 What a steal. Quote Link to comment Share on other sites More sharing options...
josh817 Posted February 7, 2012 Share Posted February 7, 2012 (edited) Oh boy... I don't remember any particular direction on mine either. Meh, car isn't running, but did run like a champ for 3 years (lost spark), I guess I will pull it and play around.... I remember notches on my KA pistons but I can't remember for the life of me about the rods... Can you quote his statement from the book? I don't have mine with me... I figure it's something like the oiler hole faces a certain side? Knowing me I probably ground off all remnants of it. :[ I feel like a hipster doofus now. Edited February 7, 2012 by josh817 Quote Link to comment Share on other sites More sharing options...
akeboshi Posted February 8, 2012 Author Share Posted February 8, 2012 @ josh817 No problem, This is straight out of the how to rebuild your nissan datsun OHC engine book by Tom Monroe, Use the notch or arrow on the piston dome, rod number and oil squirt hole in the rod as reference for positioning the piston and rod. the notch or arrow must point toward the front of the engine block; number to the left and squirt hole to the right. I ended up ordering some new turbo ITM pistons/rings from the parts dinosaur guy for 202 dollars shipped! They should be here tomorrow. Quote Link to comment Share on other sites More sharing options...
josh817 Posted February 8, 2012 Share Posted February 8, 2012 Boy wouldn't that be unfortunate if it was all correct to begin with. I'd be PISSED lol Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 8, 2012 Share Posted February 8, 2012 The rods being backwards is a thrust loading thing, as well as how it lubricates as mentioned. Quote Link to comment Share on other sites More sharing options...
NewZed Posted February 8, 2012 Share Posted February 8, 2012 There's a drawing in the FSM of the rod and piston assembly with the oil hole and notch shown. Also some Notes describing the same. Page EM-22 of the 1976 FSM, probably close in the others. A little late here, but good for future reference. Quote Link to comment Share on other sites More sharing options...
josh817 Posted February 9, 2012 Share Posted February 9, 2012 Tony, I was rereading through here and you note the notch on the piston, which I understand, have seen, and made them face the front. Now the question is, could the pistons and rods be paired only one way? Could the pin press in the correct way, flip the rod around, and still press in? If so, I suppose you best have a machine shop that doesn't do V8 stuff and says "oh yahhhh we do that all the time" I had one of my fathers customers stand over my should while I was building my motor, telling me about his domestic motors and how he builds 700HP monsters. Then I remember, this is the same guy that bored a block .030" over, used the old std pistons with .030" over rings, and accidentally left a towel in the oil sump somehow so when he started it up he didn't have any oil pressure. A very bright person indeed. Quote Link to comment Share on other sites More sharing options...
kaito Posted February 9, 2012 Share Posted February 9, 2012 OK, so I have the new pistons, I have a few questions, how do I check for rod straightness, and how do i press the old pistons ou without damaging the piston or bending the rod? Quote Link to comment Share on other sites More sharing options...
josh817 Posted February 10, 2012 Share Posted February 10, 2012 If you put them in yourself, I would take them out the same way. If not, probably best to send to the machine shop. If I were to do it: -find a drift or a deep socket that is obviously slightly smaller than the pin so you don't press the socket into the piston -brace piston on a solid support, preferably with a few rags over the support so you don't have metal on metal. Don't brace the piston on the skirt walls! Brace up at the top of the piston where its a solid piece; above the pin! -hold the big end with your hand -start jacking the press -it should slide through with little effort. There shouldn't be a point where the press starts getting tough to pump, and then the pin pops out a little, and repeat. If that happens, you're probably fouling something. This happened to us when we had an old TR3 piston rusted in the sleeve. My dad just wanted the sleeve so we put it in the press and started applying pressure on the top of the piston. It's a 12ton press and it got to the point where we had to get a cheater bar over the pump so we could get more leverage. After heating with a torch and applying some PB Blaster, all of a sudden BANG, louder than a gun shot, it popped loose but only a little. It would pop, you would get a few pumps in, and then it would get stuck again. Repeated this several times until it came out and it was very nerve racking... applying 12 tons of pressure to a piston stuck in a sleeve. I was worried the sleeve would break and send pieces into me... Finally got the piston out, cleaned off the sleeve; yup, big'ol crack going from the bottom, and circling around. almost made it's way back to the bottom, and if it had, I bet it would have gone flying. So, don't let it build pressure. The pin may be hard for you or I to push out by hand but a press should do it with ease and never get into a bind. Do this. You won't bend a rod and yes, you will be able to hold the big end. It won't want to angle down with tremendous force since you are trying to support it as close to the pin as possible: Quote Link to comment Share on other sites More sharing options...
Noddle Posted February 10, 2012 Share Posted February 10, 2012 (edited) If you put them in yourself, I would take them out the same way. If not, probably best to send to the machine shop. If I were to do it: -find a drift or a deep socket that is obviously slightly smaller than the pin so you don't press the socket into the piston -brace piston on a solid support, preferably with a few rags over the support so you don't have metal on metal. Don't brace the piston on the skirt walls! Brace up at the top of the piston where its a solid piece; above the pin! -hold the big end with your hand -start jacking the press -it should slide through with little effort. There shouldn't be a point where the press starts getting tough to pump, and then the pin pops out a little, and repeat. If that happens, you're probably fouling something. This happened to us when we had an old TR3 piston rusted in the sleeve. My dad just wanted the sleeve so we put it in the press and started applying pressure on the top of the piston. It's a 12ton press and it got to the point where we had to get a cheater bar over the pump so we could get more leverage. After heating with a torch and applying some PB Blaster, all of a sudden BANG, louder than a gun shot, it popped loose but only a little. It would pop, you would get a few pumps in, and then it would get stuck again. Repeated this several times until it came out and it was very nerve racking... applying 12 tons of pressure to a piston stuck in a sleeve. I was worried the sleeve would break and send pieces into me... Finally got the piston out, cleaned off the sleeve; yup, big'ol crack going from the bottom, and circling around. almost made it's way back to the bottom, and if it had, I bet it would have gone flying. So, don't let it build pressure. The pin may be hard for you or I to push out by hand but a press should do it with ease and never get into a bind. Do this. You won't bend a rod and yes, you will be able to hold the big end. It won't want to angle down with tremendous force since you are trying to support it as close to the pin as possible: mmm, not sure about the area you suggest to support the piston, from memory, you place a tube on the side of the piston, near the pin, on the flat area, and press the pin into this, like my picture if it's a floating pin setup, then you could take it out by hand, otherwise you will need to press it Nigel Edited February 10, 2012 by Noddle Quote Link to comment Share on other sites More sharing options...
NewZed Posted February 10, 2012 Share Posted February 10, 2012 (edited) Here's a picture, just for fun. Not trying to be an FSM fanatic, but it's all right there to be seen, I can't help myself. It's like two thousand words worth of this thread. Edited February 10, 2012 by NewZed Quote Link to comment Share on other sites More sharing options...
nash542001 Posted February 10, 2012 Share Posted February 10, 2012 What about when you order custom pistons and rods that have no arrows or marks on the piston and no oil hole on the rods. The fore mentioned rods are Pauter rods and look symmetrical. The pistons are JE forged. Quote Link to comment Share on other sites More sharing options...
NewZed Posted February 10, 2012 Share Posted February 10, 2012 If you don't have oil holes on the rod ends, you'll be better off to find out before you install them. The holes serve an important purpose. And you'll still need to know how to orient the piston. I'm just having some fun. Like watching someone look for their glasses when they're perched on the top of their head. Laughs for everyone. Quote Link to comment Share on other sites More sharing options...
josh817 Posted February 11, 2012 Share Posted February 11, 2012 mmm, not sure about the area you suggest to support the piston, from memory, you place a tube on the side of the piston, near the pin, on the flat area, and press the pin into this, like my picture if it's a floating pin setup, then you could take it out by hand, otherwise you will need to press it Nigel Very true! I just try to avoid the skirts like lava. Broken one before. Still have that set of 5 240z flat top pistons with slight valve relief, by the way, for those 4 cylinder people. Quote Link to comment Share on other sites More sharing options...
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