Thread: Considering LPG on my 4.6 GEMS

Ron, where in the intake manifold did they install the injector outlets? Trying to figure out how much of the manifold has coolant around it and where it is solid Alloy...

Originally Posted by daljames

Ron, where in the intake manifold did they install the injector outlets? Trying to figure out how much of the manifold has coolant around it and where it is solid Alloy...

Injector nozzles should be drilled adjacent to the petrol injectors. No water jackets here.

Adjacent, as in behind (closer to the plenum)? or next to (same position re plenum just lower)?

Originally Posted by daljames

Adjacent, as in behind (closer to the plenum)? or next to (same position re plenum just lower)?

Adjacent as in next to, beside etc.. The petrol injector sits in a little pocket, and usually I drill the gas injector nipple into the angle between the runner and the manifold face, as close as you can to the petrol injector while making sure the gas hose fits on without fouling the fuel rail. It is after all only a 6mm nipple and hose, the injector is remote mounted.



Sadly I haven't got a close-up of the injector nozzle but this pic gives you the idea of the remote injectors and rubber hoses which go wherever you need them to go.

Here's a pic I found on the 'Net some years ago:

Perfect Ron, you're a legend.

Hi Bee Utey,
Does it matter if the LPG hoses are different lengths from the LPG injector to the LPG injector nipple?

Originally Posted by black betty

Hi Bee Utey,
Does it matter if the LPG hoses are different lengths from the LPG injector to the LPG injector nipple?

Moderate length differences (say from 150 to 200mm) don't affect the flow rate much as the jets at the injectors are usually much smaller than the hose ID. Most engines monitor mixture in 2 banks, so you don't want too much variation in flow. You could of course use a bigger jet if you were forced to use a 50mm hose and a 300mm one. I don't recall I had much problem keeping the hoses similar in length. That is why I used the injectors in pairs, then the nozzles for each pair of cylinders are aimed towards each other and follow the same path. In general I work out how long the longest hose has to be, make all of them the same, refit the manifold plenum, and trim a bit off (if I have to) for best fit.

So I don't it exactly as P38arovers pic shows, I drill about 25mm closer to the heads and aim the pairs of injector nozzles together. The nozzles in the pic aim at the fuel rails so will be sharply bent right at the nozzles.