+2 Dual circuit master options

[The Veg]

Regarding the Girling unit, I've got a further curiosity. I've found that that MC was made in both 11/16" (.7") and in 3/4", both with the same casting number (64676597). Dave Bean sells rebuild kits for both. Ken at Bean said he thought that the 3/4" MC would be better than the 11/16" for a non-servo Plus 2 application when I inquired. What do the experienced hands in this forum think?

[joe7]

The Veg, That is correct same casting number different bore size. I currently have the 3/4 bore.

[mbell]

I also spoke to some one at dave bean while order a few engine bits. They have a Chinese made small master available, side exit around $200 with hardware. Also have lots of rebuilt 0.875 units as used with the servos on +2.

In the end I've ordered the spitfire unit, should be delivered this week. Currently running a 5/8 single master. That I think it's probably a little small. Will see what the 11/16 is like

[Davidb]

Mbell: I too bought a Spitfire m/c but have not yet figured out how to get the brake pipes to fit to the l/h side on a l/h drive Elan. What are your thoughts?

[mbell]

Mbell: I too bought a Spitfire m/c but have not yet figured out how to get the brake pipes to fit to the l/h side on a l/h drive Elan. What are your thoughts?

I have a +2 so can't really advise as the +2 has completely different peddle box setup. I guess at using Banjo bolts or modding the fiberglass as your options...

[Davidb]

I think it would require both banjo bolts and modifications to the fiberglass. I my get one of the Datsun units instead.

[mbell]

If I had an elan that's the way I'd go.

Attempted to fit the spitfire unit today, at ~7 3/8" long it won't fit with the pedal box fitted to the car. Thinking it might not fit at all at not much more than 7 1/2" clearance total and depends on height it goes at. Front port access may also be in tight side, may or may not just clear pedal box side.

Need to see how much effort I want to spend trying to get it to fit...

[mbell]

Well I removed removed the pedal box at the weekend. The spitfire master fits length ways, and the front connection clears the pedal box ok. However on my RHD the rear port is in the very corner of the engine bay and there no space to make a connection. So it's a no go! Would be fine for a LHD car thou.

At this point I think I am just going to fit a new brake line and re-fit the single circuit master. Seem that a master needs to be no more that 7" and have the exits on top or right to work which I think I am going to struggle to find quickly.

[berni29]

Hi

I know that adding to old threads is not good forum etiquette, but I think the following photo of the dual circuit master cylinder in my newly acquired car might be useful. The car was previously raced.

There is another thread on this matter here. Also from Oct 2016

viewtopic.php?f=42&t=38002&hilit=datsun&start=30



Berni

[mbell]

I know that adding to old threads is not good forum etiquette

I personally think its better to put the information in one thread than have lots of small separate threads with key information spread around them!

Yes that looks like a custom setup to get dual masters. Which is interesting but probably a little further than most want to go here.

[The Veg]

That allows for tuning the proportion of force between front and rear circuits, but is totally un-necessary for road use. That said, if it works and is fairly trouble-free, I'd just leave it until it breaks.

[berni29]

Hi

Do you think its for front rear bias? I thought it would be criss cross. I will have to ask the PO.

Thank you for pointing that out!

Berni

[mbell]

Its front/rear bias. Very common/standard thing to do with race cars.

[nmauduit]

Its front/rear bias. Very common/standard thing to do with race cars.

I would have thought the purpose was a safety precaution (2 separate circuits)...

for just front/rear bias braking power adjustement, if playing with pad material is not sufficient, one can use a proportionning valve to achieve that very purpose. I don't suppose racing rules applying to a Plus2 in the US would prevent using a proportionning valve, or does it ?

[mbell]

I am not sure on the exact reason or regulations. I guess it gives more fine control and consistency, while meeting the required regs.