New Zealand Datsun Club

James whipped me up a cad drawing for the backing plate to try, looks like it's going to work pretty well! I'll get some 8mm or 10mm ali and make up a new plate off the drawing. I'll have to see what kind of clearance I've got, I've thought about getting another spacer made about 10mm wide of the outside of the drawing to space the top of the plenum out a bit to give it a bit more internal volume.

Measured up the differences between the turbo and non turbo oil pumps as I couldn't find any real solid info around, the non turbo gear is approx. 6mm smaller in diameter from my rough measurements. Also I don't think the non turbo pump had the two roll pins to locate the oil pump backing plate, the turbo pump shown is from a late model intercooled DR30.



Started work on the plenum backing plate, I'm going to helicoil all the outside bolts and run nylocks on the inside studs. If you need some ali plate etc I would highly recommend Little Metals, the piece I bought cost $20 which I thought was pretty damn good.

Holey shit yes, plenum came out very legit!

Yeah man, it's going to look awesome once it's finished. The plate I bought was an offcut and is slightly too big so needs about 10mm cut off the bottom and about 7mm off one side but so far it's looking pretty good.

Drilled the rest of the holes and helicoiled all the outside ones, came up really good apart from the bottom left one being about 2mm out which is my fault as I was rushing to finish it, will probably just slot the hole in the plenum top. I'm trying to figure out a way of putting a nice bellmouth around each of the holes, when I talked to Racefab he was doing it with a wood router which seems like the way.

yip wood router will work really well, take your time though if you want to keep all your fingers intact, I have a router here, happy to give you a hand, you will need to supply the router bit, as mine are new and alloy wont do them many favours, second hand tool shop may be able to supply one, ideally get the half inch shaft as it will flex less.

2 doors wrote:yip wood router will work really well, take your time though if you want to keep all your fingers intact, I have a router here, happy to give you a hand, you will need to supply the router bit, as mine are new and alloy wont do them many favours, second hand tool shop may be able to supply one, ideally get the half inch shaft as it will flex less.

I've been having a bit more of a look and I don't think there is enough meat around the holes to make it worth while using a router, there's only about 6mm between the hole and the edge of the holes for the studs, and using a router bit with a bearing wouldn't work as the plate isn't deep enough so I'd have to have it bolted to the throttle bodies which would mean the studs are in the way unless I remove 4 of the studs at a time. I'll figure out a way of a bit of a chamfer on them, we used to have a small bevelling machine at work.

I used the big bevelling machine today to put a bevel on the back of the plate to hopefully clear the fuel rail, haven't had a chance to check it again on the throttle bodies yet. It worked okay, I've never used it on ali before and you're supposed to have a bit of plate at each end to lead in and lead out on but I didn't so it's a little uneven, I'll clean it up with a file and it should look pretty good.

Sounds like you have a pretty sweet assortment of tools at your work. This might be a dumb question, but is there any reason you couldn't/shouldn't just use super short Weber style ram tubes for your bellmouths?

broke wrote:Sounds like you have a pretty sweet assortment of tools at your work. This might be a dumb question, but is there any reason you couldn't/shouldn't just use super short Weber style ram tubes for your bellmouths?

The firewall end of the plenum is maybe only 40mm tall on the inside so there wouldn't be enough room for them, I did think about it as I've got a set of them already but they are way too tall.

I can see a solution to your problems with the router, but it would take to long to explain with my one finger typing, swing by and ill show you how it can be done.