L28 Transmission Swap Options

[thehelix112]

Whittie,

 

http://www.ozdat.com/forum/viewtopic.php?f=8&t=6393 Is a sans-pics tutorial I wrote a few years ago re the SR box onto L. Its incredibly simple. Will take you less than an afternoon. It also includes part numbers for the bearings required (the hardest bit for me when I was doing it).

 

I used a S14 SR20DET box that I got for $500, so I can't correctly say if the gearboxes are different between DE and DET. I'd pop over to nissansilvia.com (and probably regret it) and have a search for differences. I seem to recall d0ritf0 guys swapping in SR20DE boxes when they break theirs due to the likelihood of them being in being less abused.

 

Also have a look here: http://www.ozdat.com/forum/viewtopic.php?f=8&t=6340 . Despite me not knowing what gears are what (whoopsy), the figures are accurate, and its clear that the C box's gears are significantly larger.

 

Have you wacked one of those thermo sticky things on the side to see how hot the box is getting under racing conditions? Maybe a thicker/different gearbox oil as has been suggested, or a transmission cooler, is in order.

 

Also, why was your engine builder dictating the oil you run in your gearbox when you have a gearbox guy? Sounds like a cop-out on his part to me.

 

Dave

[Whittie]

Hey Dave,

 

I've come across your tutorial in a few places (here and NZ forum??) and have it in my bookmarks. Pics is the only real thing that is missing from yours, it was very useful otherwise.

 

Ive got an s13 SR20DET box for $150. Was going to go s14 or rb20 but the only ones i could find locally were $600+. The s13 and s14 boxes are identicle ratios. Only thing they might be is the s14 might be a later revision box witht the even larger gears and dual syncro 3rd.

 

The engine builder is our mechanic. He does pre/post race servicing and just put the wrond oil in the box. The gearbox guy is the local zed expert and wrecker and he changes syncros and rebuilds the boxes.

[thehelix112]

SR20DET for $150.. can't go far wrong there!

 

Hopefully that'll be the end of your gearbox woes.

 

Look forward to pics.

 

Dave

[Whittie]

Yeah it seems like a reasonable price. That and i reasoned with myself that i'm not breaking boxes from harsh use or excessive power, just old components, so $500 saving on the box is $500 in my pocket with any luck... Or just somewhere else on the car A mate of mine used to have silvia's and thats all he sold his box for so it was the number i had in mind when i was haggling with a few guys. I also managed to pick up a New In Box nismo shifter for $250. Kinda had to buy the shifter as well to get the guy to part with the box, but I wanted a short shifter anyways and i've heard really good things about this model.

 

All in all, it's going very smoothly at the moment. However, Murphy is never far away with these things, so time will tell

 

Only thing i did differant to your build was to enlarge the countershaft hole to fit the larger C box bearing. I figured that if i was going to do it, i might as well do it properly and that i might as well use the proper countershaft bearing. It's a $250 job to get the hole enlargened though so i'm not yet sure if it's worth it, but the zed guy and myself decided jointly that it would probably be better and potentially cause less issues to use the larger bearing. He mentioned bearing strength and gear movement as his main issue with using the smaller one. Looks like you've not had any problems with yours though, so maybe a bit of overkill to bother with switching the bearing over.

[thehelix112]

My car is also a long-term member of Team Axle Stands, so don't judge anything by it.

 

I think its a toss-up between casing strength, or bearing strength. The B casing wasn't with ridges to support the countershaft bearing hole being that large. I think if you compared two of them you'll find that you've basically machined out the lip on the inner side which gives the hole some amount of strength. Thats being said, chances you'll have an issue I'd think are pretty small. But its easier to replace a bearing than it is to replace a bell housing IMHO.

 

Hope Murphy stays away for you.

 

Dave

[Whittie]

Well, It's only been a year since I said I would post up this tutorial with pics and learnings....

 

The original word document is 31 pages long and 3500 words so hopefully you can all struggle through it and not give up. It is long but I have included everything that I thought was relevant and then some, including plenty of photos.

 

I would have liked to have posted it as a text post with pictures but I think the post would just have been too big and would have made it unreadable, so I have just attached the original document. I have instead just posted the full res pics on photobucket because I shrunk the ones in the word doc right down to keep the file size small enough for everyone to enjoy.

http://smg.photobucket.com/albums/v621/Tommo560/Datsun%20260Z/FS5W71C%20Gearbox%20Install/

 

I also attached the FS5W71C gearbox manual as I thought it was particularly useful when I was stripping an rebuilding the gearbox. It is the gearbox chapter from the official Nissan Repair Manual. I do not believe sharing one chapter is a breach of copyright (1 chapter or 10% of the publication is the limit) but if it is then let me know and I'll remove it. I just found it posted on the internet in the first place.

 

Please enjoy and let me know what you think of the document. Hopefully it can be of some use to someone and save them the 3 gearboxes and 2 bell-housings it took me to get this right!!!!

 

Please feel free to re-use anything you like in the document, print it out and share it around. Of course, a mention of thanks is always appreciated!

How to Install A Late Model FS5W71C Gearbox Onto An L Series Engine - small.doc

FS5W71C Transmission Manual.pdf

Edited July 15, 2010 by Whittie