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Pete-B

Member

• Apr 19, 2017

• #1

I'm planning to move the SU carbs from my 3.5 to the interim 3.9 which I'm rebuilding (I know the arguments for keeping EFI but for now I'd like to stick with carbs). The only problem that I can see at the moment is connecting the heater matrix pipe to the water pump (the pipe which runs between the inlet manifold and the carb mounts).

On the older style front cover there is an outlet on the back of the water pump that has a short hose connecting to the heater matrix pipe. On the later interim front cover there is no rear outlet on the water pump.

How have others done it? Is there a specific radiator hose available which would allow it to be connect to that?

Thanks.

 

RobV8Defender

Active Member

• Apr 20, 2017

• #2

Hi Pete, I have a 3.9 but with an Edelbrook carb - happy to take a pic of my setup if that helps.

I didn't have any success with the carbs from my SU 3.5 carbs on the 3.9 - I didn't get much benefit from the bigger engine. Engine was transformed by putting the Edelbrook carbs on it.

 

RobV8Defender

Active Member

• Apr 20, 2017

• #3

Hi there, remembered I am away for the weekend so may not be able to get photos to you as promised. So have quickly taken some in the dark - let me know if you want any more, happy to do so on Tuesday.

 

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cooltide

sheep fancier

• Apr 21, 2017

• #4

The 3.9 heater matrix is fed and returned from 2 metal hoses passing over the o/s rocker cover. Cant remember the exact plumbing. You might get the info you need from Google images unless someone posts a pic of a standard hotwire efi rrc disco setup

 

cooltide

sheep fancier

• Apr 21, 2017

• #5

 

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Pete-B

Member

• Apr 21, 2017

• #6

Rob - thanks for the photos. It looks like you've got the earlier front cover with the rear outlet for the heater. Incidentally, did you change the needles when you tried SUs on the 3.9 or did you stick with the originals?

Cooltide - thanks for the photo as well. What do the hoses from the two metal pipes connect to by the radiator?

 

cooltide

sheep fancier

• Apr 21, 2017

• #7

That's the but I'm unsure of
IIRC one of them tees into bottom rad hose, but it is a
vague memory.
Someone will come along with the answer. I think @Saint.V8 or @lorri789 might have a rrc stood nearby

 

discool

Well-Known Member

• Apr 21, 2017

• #8

The 'serp' 3.9 as fitted to D1s picks up the heater matrix feed from the o/s front of the inlet manifold, the return is to the radiators bottom hose.
both hoses use a short length of steel pipe, the return pipe is just to drop down to the bottom hose between the head, block and alternator, the feed pipe is just a right angle elbow before it connects to the manifold.

 

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Pete-B

Member

• Apr 24, 2017

• #9

Thanks Discool. It was the return feed that I wasn't sure of. I'll need to find the part number for the radiator hose.

 

RobV8Defender

Active Member

• Apr 28, 2017

• #10

Hi Pete - I left the original needles, so quite possibly that contributed greatly to the underperformance.