Carb intake manifold on 3.9 earlier efi

danbm · Post by **danbm** » Sat Apr 14, 2007 11:16 pm

Today i ripped out the efi to mount a 4brl Carter carb on my 3.9. The carb and the inlet manifold was taken off a Rover P6. Unfortunately this wasn't a direct fit. The coolant system is the main issue.

Whilst the P6 water pump has two hose outlets, the 3.9 has only one. Same thing with the intake manifold. The P6 has two hose connections and has also blocked two interior channels.

Does all 3.5s have the water system wich i experienced on the P6?
I'm thinking of buying a new manifold from Summit Racing, but i'm afraid of buying the wrong kind. Does anyone know where and what to buy?

I'm also buying a new carb. Should i go for the 500 or 600cfm? Does it matter wich one i choose?

Cheers,

Post by **katanaman** » Sat Apr 14, 2007 11:21 pm

3.9 should have 2 connections they are just in a different place. The difference is between the 2wd a 4wd pumps and front covers.

Get the 500 the 600 is too big.

dnb · Post by **dnb** » Sat Apr 14, 2007 11:27 pm

I found a vacuum secondary Holley carb in a friend's garage when I was helping him clear up. IIRC it was 500 CFM.

I think he could be persuaded to part with it since I've almost convinced him that VEMS is the way to go for his Rangie.

danbm · Post by **danbm** » Sat Apr 14, 2007 11:45 pm

had a look at it now...
Can only see one outlet from the pump.
I think it goes like this:
from pump -> heater -> manifold -> air intake heater -> and then straight back to the radiator... though the hoses to and from the air intake heater is much thinner.

The P6 manifold had a outlet in the back, the efi had not...
I'll give it some thought to see what i can come up with...

dnb · Post by **dnb** » Sun Apr 15, 2007 12:12 am

On my TVR manifold (should be the same as a 3.9) the front 2 water channels are blocked amd it doesn't use the thottle heater at all.

I don't have the water pump to hand to have a look at it...

danbm · Post by **danbm** » Sun Apr 15, 2007 12:18 am

yeah, dnb
you're right. They're blocked on the 3.9 as well...
just noticed

And after having a visual on the waterpump , i can confirm a second connection.
Although it's blocked. Is this just to be drilled out - without damaging anything?

danbm · Post by **danbm** » Sun Apr 15, 2007 8:52 pm

Is there someone that has done this before and can confirm that this is the way to go?
(To drill the second pipe on water pump on a 3.9 efi to fit a carb manifold...)

ChrisJC · Post by **ChrisJC** » Mon Apr 16, 2007 7:06 am

I drilled the 2nd water pump pipe from a 3.5EFi front cover to fit a P6 manifold.

Chris.

danbm · Post by **danbm** » Mon Apr 16, 2007 7:23 am

Cheers, mate!
I better get on with it...

jrv8 · Post by **jrv8** » Mon Apr 16, 2007 7:38 am

Hi,
You don't need to drill it out, it's only blocked with a small core plug, and it will tap out quite easily.
Jim

danbm · Post by **danbm** » Mon Apr 16, 2007 7:44 am

even better

Will i manage to get at it from the outside, or is opening the pump a must?

jrv8 · Post by **jrv8** » Mon Apr 16, 2007 11:33 am

Hi
It's easier with the pump off , as you can hammer it out and no swarf will end up in the pump but you could try drilling a small hole and screwing a self tapper into it. You mey be able to pull it out with a claw hammer.

Jim

danbm · Post by **danbm** » Mon Apr 16, 2007 7:38 pm

The self tapper worked perfectly!
Just had to bang it loose from the corrosion first!

Btw: which way does the water circulate?
From the pump, thru the manifold, heater and then back to pump?
The manifold front is connected to the left tap on the w. pump.