Help please

Tranquil · Thursday at 09:53

Hi,
I purchased a Lightweight 3.5 V8 auto (my youngest son has an arm injury and can only drive an auto)) but due to then moving house and undergoing a complete referb on the property it's been sitting in a field since then.
Now in a position to start refurbing. Loads to do but one item is a hole in what appears to be a heater control but I cannot find anything on RR or LR diagrams that look similar. Anyone got any ideas as to where it came from?

kermit_rr · Thursday at 10:06

i didnt know the 3.5 fitted in a lightweight!! I bet thats a fun drive!
no idea on the unit but assume its a flow valve to regulate cabin temperature? where do all the pipes go, it looks a little over complicated

marjon · Thursday at 12:49

Looks like a temp/pressure sensitive flow valve.
IE when the main thermostat is not open all the water pump activity pushes it through the heater and the relief line back to rad.
When the main stat opens the pressure will drop/Temp rises and so the majority of the flow is directed to the heater.

That is a pure guess without knowing how its plumbed in.
I belive some 3.5s didnt have a bypass for when the thermostat was closed so it was needed.

But of course I could be talking a load of rubbish

.

Nice project though will watch for the project thread.

J

Tranquil · Thursday at 13:07

Discovered on another forum that its a bypass valve from a London taxi, used in loads of kit cars and conversions as it's a simple option.
It's a 3.5 Efi with RR auto box .
Yep, fun going forwards but not so much fun stopping. Series single leading shoe 10" brakes are not up to the job. Replacing fronts with twin leading 11" which apparently makes a big difference. Fingers crossed?

Tranquil · Thursday at 13:10

Valve below

norseman · Thursday at 22:50

Interesting project.

I owned a Lightweight years ago, a (now) rare 2A & remember it was a different driving experience to a standard 88/109, examples of which I've also owned & I didn't really take to it .. but that's just me.

Good luck with the progress.

Tranquil · 2025-02-21T09:04:22+0000

Hi,
It's a bit of a blast from the past for me. I drove them back in the day, primarily in Cyprus in 74/75 as UN, post invasion.
Although not an Auto or with a 3.5 under the bonnet.

Help please

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