The Discovery is having a new cam and chain at the same time as the LPG conversion. I'm probably also going to fit magnecors and an A&R amp, but that isn't my query here.
What cam should I fit? Warren reckons 'stay standard', but then he's an old stick in the mud. RPI reckon the Piper cam is a good swap. The cost difference isn't big enough to be a factor. As I'm swapping it anyway I'm tempted by the promise of smoother idle and a bit more oomph, but am I just overcomplicating matters?
Hi Tim. I was wondering why you had decided to go with an LPG conversion now, in thew light of the recent decision to raise the 'duty' on LPG in stages, until it will apparently be similar to petrol? I converted my
110csw to LPG about 2 years ago,so have recouped the cost already, but am unsure of your intended mileage, so I just thought I'd ask.`Mark
all ifs buts and maybes, but put simply I got the kit for £250, so it is worth it if only for the etended range and cleaner running,
Cleaner and greener I can understand :0) Seems (earlier post?) the Govmt have missed the idea of older or larger engines becoming more environmentally friendly this way as well. I'm still thinking of getting wing tanks installed, so I can reclaim the lost loadspace, or maybe even a torroidal combo plus wing tanks for range. Where are you having yours fitted?
`Mark
under the sills, or at WGB Autos, depending on what you were asking !!! :-)
On or around Mon, 26 Jan 2004 21:43:07 +0000, Tim Hobbs enlightened us thusly:
depends what's in there already.
The 3.9 standard cam is almost-identical to the original Rover V8 style cam as fitted to early RRs, but 2 degrees earlier, and is reckoned to be a good one to go for, has the advantage of being cheap. In particular, the injection 3.5 is different, presumably for a reason.
If you're looking for an upgraded cam, then you're after one that allows it to be tuned for more torque, rather than more power, or more specifically, you don't want a lot more power at the expense of low-mid-revs torque. In other words, you don't want anything too extreme.
these are what HBOL has for standard cam specs - timings are in degrees before/after top/bottom dead centre, I suspect they're all 9.9mm lift
engine valve inlet exhaust dates lift open close durn. open close durn. c/r etc.
3528cc 8.5:1 -74 ) 8.25:1 74-79} 9.9mm 30BT 75AB 285 68BB 37AT 285 8.13:1 79- )9.35:1 carb -89 36BT 64AB 280 74BB 26AT 280
9.35:1 inj. -90) 24BT 52AB 256 62BB 14AT 256 8.13:1 inj. -90)3947cc
9.35:1 inj. 90-) 32BT 73AB 285 70BB 35AT 285 8.13:1 inj. 90-)can't find any info for the 4.2, other than that the valve lift appears the same.
You don't say what engine you have or exactly what cam RIP are offering you. I had bad experiences with that particular company and cams, they basically sold me a cam telling me it was exactly what I needed when it turned out to be incompatible with the current induction setup or gearbox. Hence my mis-spelling!! Unless you want to put the vehicle to a different use than originally intended, then Warren is right. Fit a std cam which you know will fit straight in and do what it says on the tin. There is considerable mileage however in junking the std timing gears in favour of a vernier adjustable one and setting up the cam timing with a proper degree wheel, I've found the machined keyways on replacement std cams to be anything up to 5 degrees out! That's a lot of wasted bhp or economy. Set it up right and it'll work fine. Badger.
Hi Badger,
It's a bog-standard 3.9 EFi from 1995. It's got 135,000 miles behind it, so presumably is ready for a bit of TLC. It runs well enough, but had a bit of lumpiness and generally doesn't feel as willing as it did
45,000 miles ago when I bought it.Vehicle use isn't going to change - mostly road work (especially once it has underslung LPG tanks), mixed 50/50 between town and motorway mileage. Power is not the objective - I'm a lazy sod and any extra torque to cut out a few gearchanges is welcome.
I'm hearing a lot of bad things about RPi here... But whenever I've dealt with them before they have seemed quite efficient and knowledgeable, though certainly not cheap.
Anyone suggest a source for the vernier timing kits that isn't RPi?
On or around Tue, 27 Jan 2004 10:37:28 +0000, Tim Hobbs enlightened us thusly:
Real Steel? they do a lot of V8 stuff. found 'em good for parts, though only standard ones in my case.
ads in LROI among no doubt others.
Not surprised. At that mileage, the cam'll be devoid of a few lumps......
Talk to Holly, very knowledgeable guy. Ignore Chris or suffer financially.
Easily sourced from most of the rally type suppliers Kent Cams or Piper Cams do one which suits the std timing chain so saving a little dosh. Cam timing is so very important to set up accurately. Don't be fooled into all the hype that your cam chain will wear out within a few thousand miles unless you spend a lot of money on a double roller conversion, it just isn't true - unless it's a competition engine or one which spends most of it's working life at high rpm's. You could fit a mild road cam, but it'll probably knock out the gas metering a bit (don't know what gas system you have, my experience is with AEB Leonardo systems) and if it's an auto, you may find it stalls when selecting D or R. If auto, stay well clear of the piper 270 or 270/110 cams as it will stall. I think RIP do a cam called Optimax that's tailored to work with auto's? Whatever aftermarket cam you go for though, be aware that your ignition advance curve is optimised for the std cam and the advance will be incorrect at certain rpm/load combinations with any aftermarket one.
Badger.
3.9V8 powered LPG110 BMW 523 not yet converted - ouch! B.H.Engineering. Rover V8 engine builders.MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.