col Posted May 21, 2013 Share Posted May 21, 2013 Hi, I read that you can fit the RB flywheel to the L series. So I bought one. Measured it up and the clutch fingers will be closer to the box but I can fix that with the bearing. The bolts line up and clamped thickness is the same, so it bolts on. Teeth dia and number is the same. Now my question. The crank hub is 80mm and the rb flywheel is machined to 81mm and clearance . Have people been just relying on the bolts to centre it? My bolts put in finger tight will still allow the flywheel to move sideways the .5mm Thanks for any info. I cut .5mm sheet and bent it into a ring, this centralises and feels tight. So I may get a ring machined up, but I'd like to know what others have done, Especially if it has been on their car and had no problems. Quote Link to comment Share on other sites More sharing options...
PMC raceengines Posted May 21, 2013 Share Posted May 21, 2013 There is 6mm offset .your starter will not engage propely Quote Link to comment Share on other sites More sharing options...
col Posted May 21, 2013 Author Share Posted May 21, 2013 Do you mean the forward-aft placement of the teeth? Quote Link to comment Share on other sites More sharing options...
frank280zx Posted May 21, 2013 Share Posted May 21, 2013 I have seen that solved by machining the starter housing.. I think i have a pictures somewhere Quote Link to comment Share on other sites More sharing options...
col Posted May 21, 2013 Author Share Posted May 21, 2013 I just re measured, a bit dark and with a torch but I think it's right. The teeth offset is within 1mm and teeth width is the same. This is going on a L20B but I have measured the 280 moror and it's the same. I have used the starters on L18, 260,280 and L20b engines with no problems. Gearboxes are the same. Am I missing something? Quote Link to comment Share on other sites More sharing options...
PMC raceengines Posted May 21, 2013 Share Posted May 21, 2013 The flywheel is now 6mm away from the stock position , the rb crank is shorter than the a L motor crank by 6mm so the off set in the flywheel is made to sit 6mm away to make up for it , why not run a stock flywheel , saves heeps off problems Quote Link to comment Share on other sites More sharing options...
col Posted May 21, 2013 Author Share Posted May 21, 2013 The stock one is only 200mm and it's more expensive to get a good clutch over here. The rb one is 240mm and parts are available and cheap. I use the car for rally so I'm hard on it, burned the clutch and looked for something better. Holfords made a 6 puck ceramic for $165 that I was told was good for a na rb30 so should be good on my L20b. I suppose there is a chance I measured wrong, I put a straight edge accross the back- (engine side) of the flywheel. Measured to the edge of the teeth and to the surface that mates the crank then compared the difference. It's dark and I read it with a torch but I think I got it right. I'll check again tomorow in the light. There was only less than 1mm diference and the teeth the same. Quote Link to comment Share on other sites More sharing options...
PMC raceengines Posted May 21, 2013 Share Posted May 21, 2013 I build cranks and flywheels for both , you can trust me on this one , fit a good clutch on the right flywheel and you wont have to do it again for a long time Quote Link to comment Share on other sites More sharing options...
frank280zx Posted May 21, 2013 Share Posted May 21, 2013 Agreed.. people here do it due to the simple fact of availability Quote Link to comment Share on other sites More sharing options...
Xnke Posted May 21, 2013 Share Posted May 21, 2013 I guess the RB25det flywheel on my car doesn't fit either... I didn't have to do anything at all regarding the starter, but I had to machine a shim ring to take up the 1mm difference in crank diameter. Quote Link to comment Share on other sites More sharing options...
col Posted May 21, 2013 Author Share Posted May 21, 2013 If I could have got an L6 240mm or even the 225mm I would have . My spare sixes are auto and the rb flywheels are readly available local. I'll finish this, one way or the other so at least people can get the facts. Too much info on the web, some good some missleading. I read that others have just bolted them on , that's possible but without locating properly I think they will have problems. I'll get it fitted up and post the success-failure, can go back to the 200mm if necessary. Still if anyone has done it I'd like to hear from you. Quote Link to comment Share on other sites More sharing options...
col Posted May 21, 2013 Author Share Posted May 21, 2013 Thanks Heaps!! Quote Link to comment Share on other sites More sharing options...
PMC raceengines Posted May 21, 2013 Share Posted May 21, 2013 Just because you can bolt it on dont make it right , yes people do it , but its not the right way to do it , if you check the ring gear and starter you will find it damaged after a short time , and then you need a difrent thrust , just do it right there is heaps off clutches out there that will live in your L20 Quote Link to comment Share on other sites More sharing options...
col Posted May 22, 2013 Author Share Posted May 22, 2013 I re- measured the offset of the teeth. From the measurment I took there is a difference of 1.1mm. Teeth are the same, dia and pitch same, width same . I suppose the 1.1mm could cause a problem but I don't think the throw on the starters will give issues with that. I would see more problems if the teeth and dia were different. Xnke, How long have you been running this flywheel and do you see hear any starter issues? Quote Link to comment Share on other sites More sharing options...
djz Posted May 22, 2013 Share Posted May 22, 2013 I ran an RB30 flywheel on an L28 for about 5 years with no problems, that was running it with no shim around the spigot either, just located on the bolts. That was using a late S130 reduction gear starter. Neither the starter or the ring gear showed any signs of damage. Quote Link to comment Share on other sites More sharing options...
col Posted May 22, 2013 Author Share Posted May 22, 2013 Waiting on the machine shop for the ring, will post how it goes when I get it all up and running, fingers crossed. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted May 22, 2013 Share Posted May 22, 2013 PMC, Are you saying that the RB flywheel is offset so to add 6mm on the crank side? So one, could simply mill or lathe out the center backside of the flywheel to adjust assuming there is enough thickness as well as correct the centering ring for an L-series at the same time? Or would you run into a pressure plate height issue that way? I have seen the center hub alignment ring on the RB when I was searching clutch options for an Lseries turbo build. But there is also the dowl pin if I remember correctly in the RB crank. I have a ton of RB flywheels around here. I might have an L-series around here as well to check against and see what your describing. Id have to check this against the 300zxTT stuff too as that is our clutch option here(US) for RB25. Quote Link to comment Share on other sites More sharing options...
PMC raceengines Posted May 22, 2013 Share Posted May 22, 2013 I just dont know why you would want to , there is 4 brands off L flywheels hear with any size clutch you want , and there the same price as a RB one , just use the right part and you dont need to mod any part , or play with throw of the clutch , makes no sence to me sorry , Quote Link to comment Share on other sites More sharing options...
Xnke Posted May 23, 2013 Share Posted May 23, 2013 Cost. It is actually cheaper to buy a 14lb chrome-moly forged steel flywheel, than it is to get the purpose-built aluminum L-series flywheel. I don't care for aluminum flywheels, I'd rather have steel, so that's the route I went. Also, the RB25DET flywheels are drilled for the 240mm clutch cover, but many don't have the groove machined in the face where the disk fits, so the 250mm heavier pressure plate 350Z clutch will fit. The larger disk diameter is not ideal, but the much increased torque (400ft-lbs+) for the *very* minimal (barely noticable) increase in pedal effort is nice in a daily-driven car that is expected to make 325+ft-lbs, and at times may have a slim-legged driver. Fidanza 11lb aluminum flywheel + 400ft-lb clutch = around 650$ 14lb forged steel RB flywheel + LuK stock replacement 350Z clutch = 294$ + an hour to machine a shim. Quote Link to comment Share on other sites More sharing options...
col Posted May 23, 2013 Author Share Posted May 23, 2013 The only problem I see is having a ring machined, that's easy-cheap. Then the next problem is getting the right throw out bearing as the rb clutch forks are closer to the gearbox. Ray, as to my measurments the teeth are only 1.1mm different offset, In a 30 year old starter I think there could be more than that in just wear from the thrust. Just looking at the starters I have that work fine, the thrust of the gear has worn the end of the bush and the shaft to bush dia is worn too. I don't think 1mm will give trouble, Still could be wrong though. PMC, Ok I agree if a good clutch for my purposes is available, you may be right and it's just me wasting time but I'm yet to find one to compare. How much can you get one for and where from? Quote Link to comment Share on other sites More sharing options...
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