As I'm now chasing a set of rods for the black 2+2 TT, I've got a couple of questions. Is there any difference between the stock NA and TT rods? Are the crank journals or bearing sizes different different? Has anyone used NA rods in a TT motor? A line on some cheap rods and bearings would also be helpful
Here are all the differences that one should know about http://www.twinturbo.net/net/viewmsg.aspx?forum=main&msg_id=699268 As for cheap rods. Depends what you expecting from your engine to archive 300 or 1000HP? China cheap $20 a pop H beam rod could be as good as any brand name rod but you don't have any guaranties that advertised high tensile steel was used. (they will most likely require wait balancing) Supplied China "rod bolt kits" I wouldn't recommend using... However H beam design is much stronger than stock design, but again if your goal is high HP output you would go with something that offers some assurance. "Most likely that no company will accept the warranty on the rod that fail and cost of the replacement parts" but yeah... Fat wrist pins if going big HP. And yeah get a set of good quality bearings.
Wrist pins are different sizes. TT rods are good up to around 400rwkw, especially if case hardened (ie shot peened). I've got some new clevite and ACL race bearings that I don't need anymore. Both standard size, shoot me a pm if that's what you need I'm happy to let them go for less than I paid.
Re: NA & TT Connecting Rods Q - "Is there any difference between the stock NA and TT rods?" A - No. Q - "Has anyone used NA rods in a TT motor?" A - Nissan Part No. 12100-30P00 connecting rods are used in NA & TT engines. Q - "Are the crank journals or bearing sizes different?" A - Nissan Part No. 12200-30P80 crankshafts are used in NA & TT engines "A line on some cheap rods and bearings would also be helpful." The bearing sizes are determined by the size of the crankshaft journals. The journal sizes will be determined by how much wear is present & how much material is removed to obtain an as new surface. Therefore, you can't get the bearings until after you have the crankshaft ground. Unless you are using a brand new crankshaft.
Thanks, will spend some time checking out the link. Not looking for big power from this engine, only needs to make 350-400rwhp at most and be reliable. Not chasing aftermarket rods, just getting some learning on the factory stuff and what it's capable of. How much difference? Are we talking 200rwkw drop in usefulness or small enough it won't matter for shit on a mid 300rwhp engine? Once I have the engine out and tolerances measured I'll definitely be in touch re those bearings, cheers. Fully aware of all of the above, I'm hoping the wear is minimal meaning I can use stock size bearings or close to it. Seeing as I will be chasing more rods, where can I find the rod measurements so I can compare to make sure the rods I put back in are within spec, correct and not setting me up for further failure?
Just double checked; OD of the wrist pins is same TT/NA so won't affect rod selection. The TT pins have a thicker wall and smaller ID.
"Seeing as I will be chasing more rods, where can I find the rod measurements so I can compare to make sure the rods I put back in are within spec, correct and not setting me up for further failure?" There is a stack of information available in Nissan FAST relating to crankshafts, conrods & bearings. It could also be available in the Nissan Factory Service Manual.
When design the engine one should over build the engine so that in theory engine can support maximum power of the components that are added, and that that point is far from marginal space. Depending on the turbos and injectors you choose, you will most likely have more power alienable then 400rwhp mark. From the machinist that I use and, he have seen it all: "350-400kw on the crank is the maximum they can take". Once you start to wind down on that boost, stock rods are first to bend. So little investment on aftermarket rods aren't all that bad in the long run
I'm aiming for 350-400hp, not kilowatts. Having built a car or two in my time I know if you let the Nissan out you introduce a whole lot of unknown. Unless I can get aftermarket pistons and rods for 8 bucks, it's not happening. It's not needed, it's pointless extra expense and will ensure the car stays off the road even longer, if not indefinitely. That's not happening, I need the garage space back to build other cars.
It is not top end power but LOW END TORQUE that will bend rods. Ash (ashspec) bent rods in his VG powered mazda on STOCK turbos due to making 600+ ft/lb of torque at 4500-ish rpm. There are also cars making 750rwhp on a dynojet with stock motors, simply due to the fact that the engine is not making a massive amount of torque at low RPM with a laggy turbo/turbos. Keep the timing conservative at peak torque and it'll take plenty of power.
Awesome. Sent Dave a message because he had some spare around the corner from my place but I think he's camping at your place at the moment working on the silver rig? If I have to drive out and nab a set of rods I'll transport your engine to Niall as payment PM me your number and we'll sort something out.
Too easy mate, I think I have access to 5 spare engines, 1 is a TT. That one we pulled the cams from is still as we left it, you can take it away if its easier to do the teardown in your own time and space
