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Guys,
In searching around for a 240Z to race next year, I see some referances to a 'double pinned' transmission. Can someone explain this? Is it the shift forks?
That brings me to another question, are there any other mods that can be, or need to be done for a 240 transmission? Are there 'pro' shops that do rebuild such as Rebello and the like? What is the ballpark for a tranny rebuild? How often do they need rebuilding?
Thanks,
Jeff
Double pinning the shift forks and selector rods help prevent over aggresive people from breaking them. I rebuild these gear boxes all the time for my ITS customers. Rebuild prices will vary depending on whats needed and the level of prep desired.
Joe Harlan
TopTech Motorsports
P.S. What area are you from?
As Joe said it's replacing the single layer roll pins on the shift forks with a double pin (pin within a pin, available from Nissan Comp, will last a good while) or a double roll (single piece of material rolled up twice, won't last) like the later stock 5 speed pins. We actually use a piece of solid 4mm bolt stock swaged into the holes (will last forever). Even non-ham-fists break the stock ones, it's only a matter of time. Other than the roll pins and synchro's (which will last at least as long as the 3rd gear teeth) they hold up pretty well for all starting out with 200,000 miles fresh out of the junkyard. We have rung the teeth off the innards once or twice in 10+ years, but roll pins and synchro's are the only "rebuilding" we do.
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katman
I use the pin within a pin method and run safety wire through the innner pin. There is still some flex this way. I'm too heavy handed to go the solid pin route. A solid pin will 'allow' you to break something more expensive if you aren't carefull. The 240 transmission is an easy rebuild. Buy one from a junkyard, take it apart and see how it works. If you are going to race a 240z, get used to taking things apart.
I've done both the double pin and the solid pin, never broken either one but it sure dosen't hurt to be prepped for it. I have see trannys with syncros so worn that you had to strong arm it into gear. With healthy syncros you should not have any problems. The best thing I have found to do is run Redline MTL. I was replacing syncros every off season until I found this out. I haven't even had to open my tranny since I started using MTL, 3 seasons worth. May open it this winter just to check, but it still is working fine.
Thanks for the info guys. Just what I needed.
Joe, I am in Austin, TX.
Thanks!
Jeff