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4.6 RV8 rebuilt again!
Posted: Tue Mar 10, 2009 8:08 am
by ChrisJC
I've finished rebuilding the 4.6V8 in my Landie. Major improvements are:
- 4.0l pistons
- 2" SU carbs
- EDIS8 distributorless ignition
- GEMS front cover
Some pics of the highlights are here:
http://www.cowdery.org.uk/v8rebuild-08.php
The Landie is now driveable, however now I need to get the fuelling
fairly close on both LPG & Petrol, and get the ignition map right. Then
hopefully it's a trip to Wilshers rolling road to get it spot on.
Oh yes, there'll be a few bugs to iron out, hopefully nothing too
major..........
Enjoy!
Posted: Tue Mar 10, 2009 9:03 am
by RoverP6B
G'day Chris,
That is a very interesting engine!..
The aircleaner box is the same type as I have on my 4.6 too,..nice large 3" inlet, lets in more than enough air. What airfilters are you running?
Are they P6 elbows? If so,..what are the brass pipes coming off them?
I understand that the P6 elbows offer the largest cross sectional area for air flow.
Can I ask,.with a gems from cover and no distributor,..how does the EDIS8 ignition system work?
When I was researching before going ahead with the 4.6, your site was one that I visited often. Excellent indeed.
Ron.
Posted: Tue Mar 10, 2009 10:37 am
by ChrisJC
Hi Ron,
The airbox is from an SD1 with Strombergs, and the elbows are Rover P6B. I used P6B elbows because the bore is larger, which was necessary for the LPG mixers which sit inside each one. They are fed by the brass inlets. There is a breather on one side as well as all air into the engine is supposed to pass through the mixers. For this reason the normal breather inlets on the carbs are blanked off.
At the moment, there's standard SD1 paper air filters fitted. You can't use anything much better as the LPG mixers need a pressure drop to work effectively.
The EDIS8 / MegaJolt Lite Jr combination is very simple and popular. In a nutshell:
The EDIS8 takes its trigger from the crankshaft sensor and drives four double ended igntion coils with a static 10degBTDC timing. This is it's 'limp home' mode.
It also generates a square wave output which is synchronised to the crankshaft position.
The MegaJolt takes this square wave, and feeds it back to the EDIS8 with a variable phase offset (or pulse width, I can't remember) to instruct the EDIS8 to alter the timing. The MegaJolt makes this calculation based on its internal map depending on MAP and engine speed. The MegaJolt can be connected to a laptop to adjust the parameters in real time.
Chris.