Fitting 4.6V8 inlet manifold on 3.5V8

[Pim]

NOTE: might have posted it in the wrong section of the forum, but having trouble moving it.

Hi all,

My name is Pim, almost 38 years old, father of 2 and proud owner of a RRC Vogue 3.5EFI 4-door from 1986. Having it since almost 3 years and now is the time to upgrade it a bit.

After some work on the chassis, floors, wheels, tyres, suspension I am now in the phase of fitting a complete MS1 kit from Nige.

I received the whole kit from Nige as well as an 4.6 inlet manifold which is replacing the 3.5 inlet manifold.

Having removed the old inlet manifold I noticed some differences and am now a bit confused on how to connect al the hoses onto the 4.6 inlet manifold.

Nige advised me to set up an account and ask you guys for some assistance/guidance, so here I am.

I am mostly a bit confused about the coolant hoses which go into the bulkhead (3.5 inlet has 4 connections. 2 at the front, 2 at the back while the 4.6 has 2 connections, 1 at the front and 1 at the back).

Added also some pictures to illustrate it.

Thanks!

Pim

 

 

IMG_0524.HEIC IMG_0525.HEIC IMG_0501.HEIC

Edited April 7, 2023 by Pim

[Hybrid_From_Hell]

I think many members are going to have issues as the attachments are a weird format ?

 

 

 

[Retroanaconda]

[smallfry]

Hope this helps.

[smallfry]

Your old 3.5 bypass (purple) goes into the back of the water pump, which I think will still work.

The old 3.5 heater return goes to the metal pipe that runs underneath the manifold, then is joined by short rubber hose to the back of the water pump, OR a stub on the bottom hose connection, depending on what year. This does not exist on the 4.6 manifold, so you will either have to fix the metal pipe to the 4.6 manifold, or run a hose right through.

I assume you are going to use the old style thermostat in the manifold ?

I find it hard to believe the seller of the kit does not know how to do this.

 

[garrycol]

8 hours ago, smallfry said:

I find it hard to believe the seller of the kit does not know how to do this.

 

He does and sells all the bits to convert the new thermostat system to the old system - works well too.

[Hybrid_From_Hell]

I’ve just had a serious operation 1st of 2 and am a bit out of it recouping 2nd op 22nd and told 4 weeks minimum recovery doing nothing 

 

asked Pim to ask in here 😐

 

nige

[Stellaghost]

2 minutes ago, Hybrid_From_Hell said:

I’ve just had a serious operation 1st of 2 and am a bit out of it recouping 2nd op 22nd and told 4 weeks minimum recovery doing nothing 

 

asked Pim to ask in here 😐

 

nige

Get well soon

Regards Stephen

[Gazzar]

2 hours ago, Hybrid_From_Hell said:

I’ve just had a serious operation 1st of 2 and am a bit out of it recouping 2nd op 22nd and told 4 weeks minimum recovery doing nothing 

 

asked Pim to ask in here 😐

 

nige

Hope you are better soon, was worried about you.

[Pistonsquirter]

Hello,

as it happens I am converting the other way round; 3.5 (carbs) manifold on a 4.6..

the 4.6 uses an external thermostat per the image from smallfry, this external stat receives heater return and pump bypass.

your 3.5 efi managed this from ports on the manifold. 
so you’ll need to tee the heater return into the bottom rad pipe, and route bypass as mentioned above.

heater flow is fed from front of manifold (red pipe item 10 in above diagram)

though I must say I am tempted by the ‘cows udder’ external stat as a retrofit for a number of reasons;

1. different opening temp options to choose from 

2. full bypass shutoff 

3. It seems to annoy people 

4.etc

 

beers!

HH

[FridgeFreezer]

My build thread has many details & piccies in it:

But the short version is...

Pull the stat elbow off your old 3.5 manifold and bolt it to the 4.6, the stat will fit straight in there too - I recommend drilling an extra ~5mm bleed hole near the top of the stat as with the re-routed (3.5 style) plumbing the 4.6 can heat up faster than the stat can open from cold, causing a slightly alarming spike on the gauge before it settles down.

 

Easier option might be to just swap the better injectors over from the 4.6 and the plenum if you want to be bling and leave the rest as it's either identical or doesn't really make a difference / can be ignored.

[Pistonsquirter]

Cheers FF.

I am typing a post on it at the moment if you might have a ganders!

[smallfry]

On 4/11/2023 at 1:09 PM, FridgeFreezer said:

 

 

On 4/11/2023 at 1:09 PM, FridgeFreezer said:

Easier option might be to just swap the better injectors over from the 4.6 and the plenum if you want to be bling and leave the rest as it's either identical or doesn't really make a difference / can be ignored.

Fridge ..... Just out of interest and clarity, assume you mean the GEMS injectors ? Do you know if the green Thor injectors can be fitted to a Hotwire manifold ??

[FridgeFreezer]

11 hours ago, smallfry said:

Fridge ..... Just out of interest and clarity, assume you mean the GEMS injectors ? Do you know if the green Thor injectors can be fitted to a Hotwire manifold ??

I don't know about Thor ones as they are different (whereas ERR722 were fitted on everything from 3.9 to 4.6) but the lower inlet manifold is the same casting so it's likely the injectors & fuel rail would swap. The Thor rail is returnless and the injectors need slightly higher pressure but I don't know if you could swap the older GEMS/hotwire fuel rail on to them - my guess would be it's worth a look as the Bosch injector style is a pretty widely used one.

To be clear: The injectors & fuel rail from the one on the left will swap onto the one on the right:

On 4/7/2023 at 5:32 PM, Retroanaconda said:

 

 

[Escape]

Yes, the Bosch injectors can be fitted to the older manifold. Quentin is running the MS 4.6 in his Classic like that. He did fit the later fuel pump as well to make sure there is sufficient fuel pressure (3.5 bar instead of 2.5 bar IIRC). And some modifications to the fuel rail were needed.