=jon= Posted September 8, 2015 Share Posted September 8, 2015 Hi All, After a 1000 mile road trip across france in the 110, I've realised that possibly a 3.5 v8 hasn't got quite enough go to keep me happy.... Here's what I have at the moment: 3.5 v8. Refreshed by the previous owner a fair few thousand miles back with a duplex timing chain and new cam - specs unknown but it was recommended for LPG usage. Currently megasquirted, fuel injected with Thor heads and a single point LPG conversion. ZF Autobox, 1.4 transfer box, 255 85 MT's. Engine sounds pretty sweet, runs well but doesn't have a lot of oomph. Show it a long hill (eg. M40 towards Wycombe, A34 across the Ridgeway) and it'll start dropping speed from 70ish until it gets to the point that the box will kick down and then it'll hold it's speed at about 50mph. It's the same on LPG as Petrol... I've not got as far as sticking a compression tester on it, but it sounds decent - I think it's just a case of lots of mass in a 110, lots of air resistance and not enough power! I have a complete spare 3.5 bottom end which has been honed and has a few bits on it (such as a duplex timing chain). What would the recommendation be? Rebuild the 3.5, as a healthy 3.5 should hold a 110 at motorway speeds whatever the hill? Source some 3.9 pistons, rebore the 3.5 to 3.9 and get a bit of extra go (but still have a v belt engine, not serp) Source a 4.6, and do the job properly? Will a standard HP22 autobox need upgrading to cope with this though, Ashcroft seems to suggest a larger torque converter and internals are recommended, but not sure if this is totally necessary.. Advice from the experts much appreciated Quote Link to comment Share on other sites More sharing options...
Tanuki Posted September 8, 2015 Share Posted September 8, 2015 There's no replacement for displacement. And in a daily-driver I'd be wanting to use the newest engine/transmission-design available to make spares-support issues less (original-RV8 parts are not exactly off-the-shelf anywhere these days). Is your LPG a proper closed-loop-controlled, throttle-body-injection setup or one of the crude vapouriser/venturi/mixer things? By their design, venturi systems restrict airflow - sometimes by 15% or more at wide-open-throttle. And the venturi restricts upper-rev-range airflow when running on petrol too.... Quote Link to comment Share on other sites More sharing options...
=jon= Posted September 8, 2015 Author Share Posted September 8, 2015 It's a mixer just before the throttle inlet, with a closed loop controller... I may try taking it off and seeing if it makes much difference - I recently disconnected the snorkel which made a surprising amount of difference... It's not really a daily driver, more of a weekend toy - but it's big enough to fit all the stuff for camping trips, weekends away etc hence the trip across France. On a side note, if you see a French landy driver on the roads they tend to go mental - flashing and waving etc... Guess they are a much rarer sight over there!! Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 8, 2015 Share Posted September 8, 2015 As stated above. Size matters! But then it's like everything else, how deep do your pockets go just now? You can make a 4.6 out of a 3.9 block surprisingly cheaply. Or there are plenty of old P38 RR's about being broken.. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted September 8, 2015 Share Posted September 8, 2015 I'd say you have the gearing right, but perhaps not the power levels. I ran the same boxes and tyres as you in a 90, but behind a 3.9 with similar sounding LPG setup. Lots of oomph for illegal speeds, and hills weren't a problem. I now have another 3.9 with LPG in my current 110 - same tyres and trf ratio, but manual box this time. Hills are not a problem. Get yourself some more cubes - a 3.9 should be fine, but a 4.6 even more so ? Quote Link to comment Share on other sites More sharing options...
=jon= Posted September 8, 2015 Author Share Posted September 8, 2015 Is there that much difference between a 3.5 and a 3.9? On the flat, it'll cruise at 80ish (speedo is pretty accurate according the GPS), but show it a hill and it'll drop right back... Pain in the arse for the french autoroutes! If I went with a bigger engine I'd prob drill the manifold for 'proper' LPG injection as I realise the cooker ring thing isn't the best solution... Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 8, 2015 Share Posted September 8, 2015 I'd try it without the cooker ring for a while, see how you cope, cheap solutions first Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 8, 2015 Share Posted September 8, 2015 Can't comment on difference between 3.5 and 3.9, but I can say there is quite a difference between the 3.9 and 4.6. I had the opportunity of driving both flavours (both in a defender) and that's what inspired me to build the 4.6. It was awesome. Mind you it was slightly breathed on compared to the 3.9 but nothing too hard core. Just a cam If memory serves.. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 8, 2015 Share Posted September 8, 2015 3.5 - 3.9 is anything between 90 and 35BHP difference, though for injection probably around 40BHP over the 150ish, you will notice it, but if I were doing the whole hog I would probably look for a 4.6, though my 4.0 is a lovely free revving item and has a good smudge over 200BHP Quote Link to comment Share on other sites More sharing options...
=jon= Posted September 8, 2015 Author Share Posted September 8, 2015 I'd try it without the cooker ring for a while, see how you cope, cheap solutions first Cheap apart from my wallet will empty much much quicker... My only worry with the 4.6 is the auto box - is it going to require internal upgrades to the 4HP22, which is where the big bills are gonna start!! Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 8, 2015 Share Posted September 8, 2015 Nah I reckon the gearbox would take it.. Aren't the autos supposed to be a bit over engineered anyways? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 8, 2015 Share Posted September 8, 2015 Yep, HP22 would be fine if in good fettle, the Ashcroft stuff is more for competition/heavy use. Quote Link to comment Share on other sites More sharing options...
=jon= Posted September 8, 2015 Author Share Posted September 8, 2015 Cool... I was guessing that Ashcroft have to cover themselves for every eventuality - like you say for heavy off road use... Time to keep an eye out for a decent 4.6 I guess then!! Quote Link to comment Share on other sites More sharing options...
mickeyw Posted September 8, 2015 Share Posted September 8, 2015 It is possible to drive a V8 in an exhilarating fashion, but still manage some mechanical sympathy Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 8, 2015 Share Posted September 8, 2015 http://www.ebay.co.uk/itm/Range-rover-p38-4-6-thor-breaking-all-parts-wheel-nut-/251701962820?hash=item3a9a9b2844 For the win... Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 8, 2015 Share Posted September 8, 2015 http://www.ebay.co.uk/itm/Rover-V8-4-6-Complete-Engine-Range-Rover-Landrover-TR8-or-Project-Car-/271978813735?hash=item3f53335927 Might be worth a punt also Edit: Let me know if your not interested as I might have it to build something special one day if I can get a bargain.. Quote Link to comment Share on other sites More sharing options...
Disco-Ron Posted September 8, 2015 Share Posted September 8, 2015 Jon...... slightly off topic but can I ask how you find the gearing. ... I have a 3.9 auto in my 90 but with the 1.2 transfer box. .. it locks up at just over 50.... but it feels like I'm always on the gas trying to get there. .. have been considering a 1.4 box as I think it would help. .. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 8, 2015 Share Posted September 8, 2015 Yes, 1.4 much better Quote Link to comment Share on other sites More sharing options...
Disco-Ron Posted September 8, 2015 Share Posted September 8, 2015 I have two 1.4's sat in the garage. .. but lack the enthusiasm to take it apart again. ... Quote Link to comment Share on other sites More sharing options...
mickeyw Posted September 8, 2015 Share Posted September 8, 2015 Jon...... slightly off topic but can I ask how you find the gearing. ... I have a 3.9 auto in my 90 but with the 1.2 transfer box. .. it locks up at just over 50.... but it feels like I'm always on the gas trying to get there. .. have been considering a 1.4 box as I think it would help. .. Tyre size may influence this decision, but with 265/75R16, and later 255/85R16 I found my 3.9 auto horrible to drive with a 1.2:1. Long hills were a struggle and needed a manual down shift, or flooring to make it kick down. I found on rural roads it never had a chance to lock up in top. Changing ratio to 1.4:1 totally transformed the drive. Quote Link to comment Share on other sites More sharing options...
Disco-Ron Posted September 8, 2015 Share Posted September 8, 2015 Thanks mickey..... I'm on 235/85's..... and based on that post alone I'll be swapping to the 1.4.... I find hills a bore.... and whilst I'll end up using more revs I suspect that the end result will be a nicer drive... also toying with the optimax chip to make it run better. .. it goes really well but figure I might as well get the best out of what I have. ... Quote Link to comment Share on other sites More sharing options...
=jon= Posted September 8, 2015 Author Share Posted September 8, 2015 I had a 1.2 box previously, and as you said, it would seem to run out of puff when it locked up just over 50mph.. With a 1.4 it's a lot perkier, it's happier on the flats but still struggles on steep hills... Quote Link to comment Share on other sites More sharing options...
=jon= Posted September 8, 2015 Author Share Posted September 8, 2015 Rather than a chip I'd suggest megasquirt BTW - prob a similar cost to an off the shelf chip and a lot more potential Quote Link to comment Share on other sites More sharing options...
Disco-Ron Posted September 9, 2015 Share Posted September 9, 2015 If I was going to continue to add mods to it then I would consider ms...... However the only thing that will happen when needed is a rebuild. .. thankfully I think its a while away from that yet.. Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 9, 2015 Share Posted September 9, 2015 Deciding to add MS will be one of the best mods you could do. But it will hike the cost of the build up somewhat. The cost of the MS system was twice what it cost me to build the engine... Oh and can you reply to my previous post and let me know if your going to bid on the engine I linked to. Quote Link to comment Share on other sites More sharing options...
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