X-members, 5-speed, L18 and L20

[Robert Palmonari]

Hi all, My first 1600 had an L18 in it with a single Dellorto (45 I think) carby and a standard 4-speed gearbox. The guy that sold it to me knew nothing about the motor but I could tell straightaway that it had at least a lumpy cam. That was 10 years ago and I paid $1200 for the complete car. Soon afterwards I put on twin SU carbies from a 180B SSS and dropped in a five-speed gearbox from 240K. It growled and it flew.  Without researching it (the Internet wasn't really happening much then) I came up with a fairly simple system to modify the gearbox mounts. It seemed that the gearbox wanted to sit 25 mm further away from the body than the standard 4-speed. So my solution was to cut some rectangular 25 mm thick steel spacer blocks, and countersink holes in it for bolts to go into the ORIGINAL CROSSMEMBER MOUNTING HOLES. Anyone that has pulled up their 1600 carpet will have seen the reinforced floor area where the gearbox bracket mounts. Sure, you can drill new holes but I prefer not to whenever possible, and the holes already have captive nuts. So after doing this step I had two steel blocks bolted to the underside. I think I still had to reverse the original 4-speed cross-member, re-attach it to the new 240K 5-speed, then push the gearbox hard up against my spacer blocks and trace the outlines of the bracket holes against them. Then I removed the blocks, and drilled and tapped some (10 mm I think) threads into the spacers. Sounds like a lot more trouble than re-drilling some mounting holes but the bodyshell remains untouched. Also I think from memory the tailshaft universal at the gearbox end stays a lot straighter than fitting the 5-speed 25mm higher (without the spacers- hence drivetrain loss). The offset between the new holes and the original holes is greater than the 10 mm reported by other Ozdat listers. If anyone is interested, I have recently removed the gearbox and spacers from one of my 1600s and could supply a sketch of the spacer dimensions. Removing the L18 when it died and replacing it with a stock L20, I found no modifications were required to the spacer blocks, although the gearbox bracket seemed a just little bit harder to install, perhaps due to slightly larger block height. BTW, the lumpy SU-fed L18 was a fantastic performer and on a few occasions I got a bit carried away and spun it out to 8500rpm!! It would be screaming at this point of course, and eventually it blew a head gasket (another casualty of my "angry young man" phase) :o( . I still have the motor, and one day I will pull the head and check out what made it go so well. The L20 stocker I replaced it with was supposedly a "high output black motor" but disappointing compared to the L18. So now I have an L16 (working), L18 (seized) and L20 (working) just sitting around doing nothing. Anyone got any ideas what are the best combination of parts to build the ultimate L-series frankenstein motor using these donors? One of my ideas is to build up a L18 powered SSS PRC rally car with these parts, so I can make use of WA's ball-bearing gravel bush tracks. Just call me Mr. Sideways. Any tips would be appreciated.   Cheers all   Rob 3 x '72 Datsun 1600s --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/membersozdat@datascribe.com.au/ ---------------------------------------------------------------------