blz6662 Posted August 29, 2013 Share Posted August 29, 2013 Hi Guys, not posted for a bit due to work on disco. Anyway to the point. I have done a serious amount of rebuild on my 87 (EA chassis) 3.5i manual rangie and ready to decide what to do about the engine upgrade. I have a complete 4.2 engine, hot wire etc still in donor car at the moment BUT slipped liner and needs top-hatting and maybe push to 4.6 litre. Thoughts please chaps on easiest/best way forward if I get the 4.2 sorted by someone like Turner Engineering. Whats best with the efi? keep/adapt the original flapper system (sort ecu map) or fit complete hotwire from donor. If so what's needed please. cheers in advance Quote Link to comment Share on other sites More sharing options...
duncmc Posted August 29, 2013 Share Posted August 29, 2013 With mine, I am thinking to just look for a 4.6 with slipped liners. And use that as a base to rebuild a 4.6 with my 3.9 EFI and front end a bit like Task has done on his CSK. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 29, 2013 Share Posted August 29, 2013 Rebuilding to 4.6 is neither cheap or easy I'm afraid... new crank, with specially machined journals to fit the smaller crank bearings, at least that's how I remember it Hotwire over Flapper any day, rebuild the 4.2 with liners and off you go Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted August 29, 2013 Share Posted August 29, 2013 Rebuilding to 4.6 is neither cheap or easy I'm afraid... new crank, with specially machined journals to fit the smaller crank bearings, at least that's how I remember it Hotwire over Flapper any day, rebuild the 4.2 with liners and off you go +1 on that ! Quote Link to comment Share on other sites More sharing options...
Ash.Witty Posted August 29, 2013 Share Posted August 29, 2013 Gutted that the 4.2 has slipped liners, although you could slip the crank into a good 3.9 block and retain the 4.2L capacity for not too much expense, just means buying another engine. I had a 4.2 in my 110, lovely free revving engine with plenty of power, you could do a budget build as well. If the 3.9 is in good conditions eg. Pistons/bores, you could hone the block, fit the 4.2 crank and con rods and have the pistons pocketed for the valves and fit a good camshaft. The reason for above is the 4.2 runs about 9.2:1 comp ratio, the 3.9 and 4.2 have different gudgeon pin heights and by fitting the 3.9 pistons with valve relief cuts will raise the compression ratio to roughly 10.5:1 so the engine should make 240+ bop with a nice set of headers on Quote Link to comment Share on other sites More sharing options...
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