Marrow's '79 280zx

djz · Post by **djz** » Fri Aug 22, 2014 10:07 am

Changing to an RB25 will also require a huge investment in wiring and a computer if you don't stick with the factory one.

Excluding the initial investment of buying the RB25 I would say you would be looking at a similar dollar figure either way but with the RB25 having more potential (in my opinion) than the L28 and a better selection of aftermarket parts.

The RB25 wouldn't really provide an easier solution to a manual conversion, if you are using the big RB25DET box it doesn't fit in the tunnel without cutting the mounting ears off so you have to make custom mounts.

waidez · Post by **waidez** » Fri Aug 22, 2014 12:37 pm

Hi Marrow. You got parts from me. The auto box was purchased from me by previous owner. Let me now if you need anything else mate. Cheers, Waide

marrow · Post by **marrow** » Fri Aug 22, 2014 3:33 pm

djz wrote:Changing to an RB25 will also require a huge investment in wiring and a computer if you don't stick with the factory one.

Excluding the initial investment of buying the RB25 I would say you would be looking at a similar dollar figure either way but with the RB25 having more potential (in my opinion) than the L28 and a better selection of aftermarket parts.

The RB25 wouldn't really provide an easier solution to a manual conversion, if you are using the big RB25DET box it doesn't fit in the tunnel without cutting the mounting ears off so you have to make custom mounts.

Wiring yes, but I've seen a few rb25 frontends that come complete with loom and ecu. I'll probably look at getting a link or megasquirt anyway, because MS seems pretty interesting.
Is there a better solution for gearboxes then? because trying to find a stock l28 5 speed box would be hard (not to mention old)

djz · Post by **djz** » Fri Aug 22, 2014 4:57 pm

L series gearboxes are still out there, I sold one a few weeks ago. The other option if you are sticking with the L series is to use an L series bellhousing on the front of an later RB/CA/SR gearbox, but those are getting harder to find is good condition as well.

Andy · Post by **Andy** » Fri Aug 22, 2014 6:14 pm

djz wrote: later RB/CA/SR gearbox, but those are getting harder to find is good condition as well.

Yup thats your option, good for 400hp some say. It's the box that is usually described on trademe as RB20DET and will both fit in the tunnel and straight onto your RB. (note most boxes on TM described as RB20DET are not!! Be careful)

marrow · Post by **marrow** » Fri Aug 22, 2014 6:29 pm

Andy wrote:
djz wrote: later RB/CA/SR gearbox, but those are getting harder to find is good condition as well.

Yup thats your option, good for 400hp some say. It's the box that is usually described on trademe as RB20DET and will both fit in the tunnel and straight onto your RB. (note most boxes on TM described as RB20DET are not!! Be careful)

So I could use an rb20/sr20 box for a simpler conversion if I get the l series bellhousing, or if I go the rb25det route, to get the rb20 box?
I enquired with a parts importer about getting an RB25 and box, and they asked if I wanted an RB20 box or an RB26DETT box for it.
this is good to know.

Andy · Post by **Andy** » Fri Aug 22, 2014 8:48 pm

Correct on both counts

L series engine use L series bellhousing modified for RB20de or RB20det box

RB engine use RB20de or RB20det box without modification

The lighter weight RB boxes are almost the same weight and dimensions as an L series box.

I looked at using the big box on our race car, was put off it by wiser people, and very happy with the RB20det box, have only broken a fifth gear once.

No point carrying extra weight around if you dont have to.

We drive Japanese vehicles because they are efficient designs, no point over engineering stuff, thats for the hot rodders and muscle car guys

Greensheep · Post by **Greensheep** » Fri Aug 22, 2014 9:42 pm

I guess the question all comes back to how much hp you want and how fast you want to go
The gear box will give you fun either way and at the risk of upsetting the Auto fans out there, maybe a bit more performance as well, the L28 is a rock and will rev bog standard to 7000 and come back for more, give it a cam grind for peanuts and have a bit more fun, you wont wear it out or break it, then think about the RB
I do agree the std hp from the L28 wasn't earth shattering, but if you are restoring the interior, you may want under the bonnet to look original, unless you are building a sleeper

marrow · Post by **marrow** » Fri Aug 22, 2014 10:26 pm

Greensheep wrote:unless you are building a sleeper

Pretty much... although I don't know if you can rightly call z cars sleepers, they already *look* fast, but stock, not a lot of fun. I don't have the budget for a true sleeper, but I'd love to combine classic jdm styling with modern tech under the hood.
My specimen isn't really restoration material, but if I do an engine swap I'll probably keep the l28 in case I want to put it back in down the line (wouldn't want to kill any more of these endangered species).

marrow · Post by **marrow** » Thu Oct 09, 2014 1:48 pm

Been pretty busy with it, working through the interior/exterior while I collect parts for the conversion.

Had my flywheel machined, new m/s cylinders, new clutch kit this week.

Does anybody have any wisdom on pulling the pedalbox out? I've taken out the dash, and as far as I can see I've removed the 4-5 nuts that should hold it on to the chassis/firewall.. but it doesn't seem to be coming out.
Should I be taking the pedals off before taking the box out? or just disconnecting the brake cylinder?

djz · Post by **djz** » Thu Oct 09, 2014 7:01 pm

From memory it's bolted near the steering column too, they are quite a pain to get in and out.

marrow · Post by **marrow** » Thu Oct 09, 2014 9:06 pm

Ok, cheers I'll have another look. Otherwise got a mate coming in the weekend if it takes me that long.
Also I know i'll have to disconnect the brake master cylinder, but how about the accelerator/throttle 'pushrod'. There are no bolts to disconnect on it, so do you just need to pop off those little white plastic ball joints to remove the pedal?

(A pain that I can't disconnect all my wiring, because the alarm system has been hardwired, so to get it out of the way i'd need to cut and rejoin it. )

djz · Post by **djz** » Thu Oct 09, 2014 9:14 pm

Yup just pop the ball off, hopefully it hasn't gone brittle, sometimes they can crack.

waidez · Post by **waidez** » Thu Oct 09, 2014 10:00 pm

Remember I'm not far away if you need a hand.

marrow · Post by **marrow** » Thu Oct 09, 2014 11:01 pm

heh, yes that did occur to me. I might flick you a pm if I can't unstick myself in the next few days