My 4.6 V8 Rebuild Thread

[101 Ron]

Just to confuse things...........the 101 has no wiring in place for EFI and no ECU etc.
Fitting the extra wiring is more difficult in a 101 than a standard engine bay especially if you are using a half 24volt/12 volt system.
My simple answer would be
use the standard carburettors.
Every thing will be bolt up as standard.
I would
add broad band sensor in the exhaust to allow fuel mixture to be known.
Rejetting of carburettors is not that hard and can be done at home and without too much trouble if the engines fuel mixtures are known via exhaust sensor.
Yes the 4.6 will not most likely run as hard as it could with a EFI system, but it will use proven standard set up and components and the 4.6 with carburettors will still be more than enough power for a 101.
Rejetting of a CD Stromberg is simple with only one jet and a needle to worry about.
The needle can be accessed on the 101 without pulling the carburettor off the manifold.
We know the 4.6 will run and drive with standard 3.5 carburettor jetting without trouble, so rejetting to get good performance can be done when time is advalible at home with little cost except for time.

[discojools]

Will be watching this thread with interest.. Am about to 4.6 fitted to my 82 classic using the original Strombergs.

Jools

[Davo]

Will be watching this thread with interest.. Am about to 4.6 fitted to my 82 classic using the original Strombergs.

Jools

Someone here had that done but went to a specialist with a dyno and Stromberg/SU experience. They put the needles on a lathe to get them just right. .0001" can make a difference with those things.

[101 Ron]

You take the piston out of the carby.........4 screws and then remove the needle from the diaphragm/piston assembly which is another 1 or 2 small clamping screws.
place needle into a chuck of a drill clamped in a vice and tighten up.
Run drill and spin needle.
Run 600 or 1200 wet and dry sand paper around needle and slowly thin out needle where required to richen the mixture.
Top of needle is low speed running and middle to end of needle is 1/2 to 3/4 speed running.
Full power /top speed tends to be the size of the main jet its self......wouldn't touch it unless reducing the size of the very end of the needle doesn't work.
the above is why I say a mixture sensor in the exhaust is needed as to get a idea of what is needed to do with the needles.
Ron

[Davo]

You take the piston out of the carby.........4 screws and then remove the needle from the diaphragm/piston assembly which is another 1 or 2 small clamping screws.
place needle into a chuck of a drill clamped in a vice and tighten up.
Run drill and spin needle.
Run 600 or 1200 wet and dry sand paper around needle and slowly thin out needle where required to richen the mixture.
Top of needle is low speed running and middle to end of needle is 1/2 to 3/4 speed running.
Full power /top speed tends to be the size of the main jet its self......wouldn't touch it unless reducing the size of the very end of the needle doesn't work.
the above is why I say a mixture sensor in the exhaust is needed as to get a idea of what is needed to do with the needles.
Ron

That's more my style! Mixture sensors are pretty common these days and that's the way I'd do it.

[Collins]

If you are looking for a simple ignition system you could simply use a 8 cylinder EDIS system, ie the control unit plus coil packs. It will run your engine & provide adequate spark for use with LPG.
The standard system runs at the default setting of 10 degrees BTDC.



I obtained a quote from DIY Autotune about a year ago for a fully assembled MS3 - sequential ignition & all of the necessary cables etc of approx US $1010, with additional cost of approx US $510 for wide band O2 sensors (2)
This system will run utilising the standard Thor sensors with the addition of a MAP sensor

[101RRS]

If you are looking for a simple ignition system you could simply use a 8 cylinder EDIS system, ie the control unit plus coil packs. It will run your engine & provide adequate spark for use with LPG.
The standard system runs at the default setting of 10 degrees BTDC.



I obtained a quote from DIY Autotune about a year ago for a fully assembled MS3 - sequential ignition & all of the necessary cables etc of approx US $1010, with additional cost of approx US $510 for wide band O2 sensors (2)
This system will run utilising the standard Thor sensors with the addition of a MAP sensor

Thanks - while I know how edis works I hadn't thought about using it by itself on default mode so that I can get the engine running and the cam run in - I can use these later with a MS system and not have to buy a Magajolt to fire the ignition. As well these components can then be used in the final system. I will just need to see if the default Edis stays at 10 BTDC across the rev range or has advancing advance over the rev range.

The Brits are dead set again MS3 and want to change the sequential injection to bank injection and use MS1 but DIY Autotune have confirmed that MS3 is virtually made for the Thor and have 2 channel ignition control so when later I go back to LPG I will have a petrol ignition map and a LPG ignition map. My current dual fuel system is good at static 10 BTDC for both fuels.

Thanks for the EDIS tip.

Cheers

Garry

[Collins]

The EDIS ignition advance does not vary from 10 degrees BTDC at all. It is the default setting. Variation is only possible via signal processing using an electronic device such as a Megajolt or Megasquirt
Both of these have the capacity for different ignition mapping. Ie, 2 maps, one to suit petrol & another to suit LPG
The wiring requirement to run a rudimentary EDIS set up is very simple.

[chazza]

If you haven't seen the latest post on the other forum Garry, it may make your decision easier

I think you will find that changing the Thor to bank-injection, is the best way to go and MS 1 will do that, unless you want to run a stepper-motor in which case MS2 will do the job,

Cheers Charlie

[pibby]

gary - you've not doubt said it in this thread though it's up to 248 replies, but what was the reason for wanting to use Thor?

i put the thor intake on mine which you know is possible so must be something else you are chasing?

my next step was to use MS to put on knock sensors, think i used MS2 from memory. it could do duel maps. but then life gets in the way.