Datsun Roadster Forum-311s.org

Hey Guys -
Looking for insight on 1) brake master cylinder and 2) fuel pump options.


1) My race car is set up with Wilwood front calipers, vented discs, Wilwood proportioning valve, stock drums out back.

My master cylinder looks like a 7/8" 510 Master, mounted on an angle - which aside from looking goofy, seems to have a history of leaking out onto the frame rail below, as judged by the absence of paint.

I have looked at Tilton and Wilwood and read a bunch about both. Wondering whether the master cylinder is limited by SVRA or similar organizations, and if so - that would mean going back to a roadster master.


2) My car is set up with a Mikuni 44 (type 4) and has a regulator under hood, and a surge tank and fuel cell at the back. The surge tank is currently disconnected and I intend to replumb all of it to the back of the bulkhead wall in the trunk as it is currently underneath. Without spending a ridiculous amount of money, what makes sense?

a) keep the surge tank and replumb with a pump either side - in which case, what size pumps and do I wire them together and have a fuel shutoff wired in as well?

b) remove surge tank and use a single pump?

The fuel cell has a bladder and foam inside.

I expect the car will just be used to run vintage races and the occasional auto x etc...

Other options or insights?

Thanks!

dw

Here are a couple of pics...

Looks like someone was getting creative to clear the hood?
Linda

Nope. To clear the fuel banjo on the Mikunis...

I had same issue with my solexes. I went this route, the hole is bigger than a Nissan master, so I built an aluminum plate to move the master over a bit and avoid blasting a bigger hole in the firewall

https://www.summitracing.com/parts/wil- ... isc-brakes

this one is 7/8 using 4 piston dynalites up front with drums out back. Same unit is availabale in a 1 inch bore also

Thanks for this! Did you remote mount the reservoirs?
My firewall has a piece of 1/4” plate welded over original anyhow, so a larger hole would be no dig deal... I am running 7/8” right now so think I would stick with that...

csp54 wrote: Sat Mar 03, 2018 12:02 am I had same issue with my solexes. I went this route, the hole is bigger than a Nissan master, so I built an aluminum plate to move the master over a bit and avoid blasting a bigger hole in the firewall

https://www.summitracing.com/parts/wil- ... isc-brakes

this one is 7/8 using 4 piston dynalites up front with drums out back. Same unit is availabale in a 1 inch bore also

I did not have to remote the res, the front JUST cleared my hood (68) by less than 1MM. but I did move it down just a bit. if you dont build the spacer but just cut a hole it will probably give you more room. Willwood has pretty accurate dimensional drawing. I did trim a small amount from the bottom of the reservoir for a bit more clearance.

Thanks again. Very helpful. There is a local shop here with a pretty good selection. I will try to swing by Monday and see what it looks like. How fiddly was it to find the right fittings?

csp54 wrote: Sat Mar 03, 2018 9:19 pm I did not have to remote the res, the front JUST cleared my hood (68) by less than 1MM. but I did move it down just a bit. if you dont build the spacer but just cut a hole it will probably give you more room. Willwood has pretty accurate dimensional drawing. I did trim a small amount from the bottom of the reservoir for a bit more clearance.

Measure twice cut once, did have to fab push rod. The Wilwood stuff was much heavier than the stock, so some fiddling there, brake lines of course.master throw it very close to Datsun in length, but I did drill a new hole in pedal bar because of how i mounted(with spacer)

Thanks a lot for the feedback CSP. I haven't made it to look at the Wilwood yet and may have rounded up an easy roadster master option locally... I am tempted to rebuild a stock one in the interest of immediacy...

That master cylinder is a creative and bad solution. I have no issues with the master clearing my carbs. I have a 510 master cylinder, and type 5 solexes. No there isn't a lot of space, but I've never had contact issues with anything there. I think the bigger issue is that the reservoirs for the 510 are taller than the roadster ones. They were trying to clear the hood I think. My solution, rotate the master back to where it should be, that should fix the leaking fluid, make sure you have the correct brake lines, and have them routed correctly. Check to make sure you have the correct reservoirs for the master. Lastly, adjust the banjo, or get the correct banjo bolt for the carb.

Will

Stupid question - I was just muddling through my tickle trunk and found these...

Can I swap over the tops and just run with the top mounts?

Without taking them apart, I don't see any obvious obstacles but I don't really know my way around...

I don't know why you would want to. Just rotate the master cylinder. Here is my setup. It will be close, but it fits just fine.



Will

Yea I was going to ask you why you didnt just get a left hand feed carb or cover....

But then again if this is a race car, suggest you switch to dual master w/bias bar.

Respectfully, that 7/8" master probably isn't helping your stopping distance...

Just a thought//

Hey Will -

Thanks for the insights. Unfortunately, the 510 master definitely conflicts - possibly in part because there is a piece of 1/4" plate welded to the firewall, which I am sure was also an effort at reinforcement.

JT -

Thank you for weighing in. When Will mentioned the correct banjo bolts, I went digging through my stash, because it occurred to me that the conflict might be a result of the aftermarket AN banjos (although several others have noted the same issue with the 510 master). I didn't find any extra banjos, but I did realize I have two sets of the other style covers. So, hence my question. I will swap the covers over.

I am remiss to mess with the brakes too much as the car was very competitive when last campaigned - winning the 2005 ICSCC EIP Championship - it does run Wilwood front calipers, Brembo vented rotors and has a brake proportioning valve in the cockpit and Green Stuff Shoes out back.

Mainly, right now, I want to get the car to a baseline where it will run and drive so that I can figure out where to go from here...

Someone should put in the tech wiki the point about overcoming the fuel inlet conflict with the 510 master - as there are several references to same - by swapping the covers on the carbs! Thanks for the reassurance that this will work JT! I will take a couple before and after pics and share them in a new post once I get it done... might be a couple of days as I am also in the midst of prepping for paint...