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I'm converting an ex ambulance Rover V8 powered LDV van to LPG, it has twin dashpot type carbs but I'm not sure if they're SU's or something else. I've had mixers on shelf to suit SU's as fitted on some Rover V8's for years... they might fit this but I'm asking in case they don't as it could save me a bit of time when I start the job if mixers on shelf don't suit and I need to order other mixers - Mixers for dashpot type carbs are not circular they bolt directly on so need to match the bolt pattern and flow area. Day off work today, just had the van dropped off and took the pics.

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Quaife LSD on this van... And on the floor seen through the window to the left of the sticker Romano reducers I removed from this P38 https://www.lpgforum.co.uk/viewtopic.php?f=27&t=14509&sid=7a71dc88de8366acee8e5d1015589dcc

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The LDV has only done 26000 miles in it's 21 years but the engine smells a bit blow-by breathy and exhaust smells rich so I'm half expecting a few complications, running rich on petrol won't affect running on LPG but blowby and crankcase ventilation issues can. The engine has a bit of a tick, if it's had so little use wonder if rust ever formed in cylinders and damaged rings, no smoke though. The van is high roof, automatic, carries a cooker and camper gear, canoos etc on the massive full length roof cage and owners reckon it gets 14mpg which I'd think seems about right.

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Don't forget everyone is away.

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OldShep56 wrote:

Don't forget everyone is away.

Ah thanks, P38 meet?

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Standard Rover so SU HIF, probably HIF 6 or HIF 44. Possibly the front drillings are different but the usual gaskets are universal with redundant holes.

Sorry can't be more help but the only SU's I've had serious dealings with over the last 20 odd years are the ones on my rotary engined Norton Commander and they are, ahem, weird.

Clive

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Lpgc wrote:

OldShep56 wrote:

Don't forget everyone is away.

Ah thanks, P38 meet?

Yes - the radius arms post ( https://rangerovers.pub/topic/1254?page=5 ) gives details, but there is an early meet up this weekend at Marty's would be the general theme of whats going on.

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Yup, that's right, back in the hotel now. But I'll confirm, SU HIF series carbs, The engine smelling of blowby could suggest sticking oil control rings, Try dumping some ATF down the bores while you've got it sitting there.

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Thanks all for replies and advice. Hope the meet went well.

I believe the mixers I have are for SU's used on RV8s...so hopefully they'll be correct, will find out tomorrow.
Even if correct I may not yet use them as they'll space the carb to air filter pipes away from the air filter and there might be a better way that doesn't involve extending one or both of those pipes back to the air filter.

What make were other dashpot type carbs used on V8s in Landrover models then? I remember buying those I have on shelf years ago when I presumed carbs on an RV8 were SU's but found out they were a different make when the Land/Rangerover I was converting arrived.

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I thought they only ever fitted SUs but someone may have swapped them for Strombergs which are the only other dashpot style carb I know of.

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Must be SUs on this one, the mixers I had on shelf fit.

The mixers are only 10mm thick but that's thick enough to make the studs from the carbs too short, may be able to unscrew studs slightly or fit longer studs. The none metric studs have a course thread into the alloy carbs and finer thread for the nuts, if I need to extend them could either make all M8 (involving slightly widening holes in angled pieces and mixers, possibly re-tapping carb holes M8 or maybe using a nut at the rear of carbs) or see if the bolts supplier has set screws and matching nuts in the course thread. But I think I've gone the M8 route before, couldn't re-tap the carbs M8 and there was little space for a nut at the rear of carbs.

Measuring up for and ordering the tank is the next priority though.

Taken some pics of these plate mixers on the carbs, will post up when less busy.

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Gilbertd wrote:

I thought they only ever fitted SUs but someone may have swapped them for Strombergs which are the only other dashpot style carb I know of.

Just had a shufti at the James Taylor bible on the Rover V8 and was surprised to discover that Strombergs were a much more common fitment than SU from 1973 to 1989. I guess cheap'n nasty copy has its attractions!

Anyway that ambulance is something of an oddball. Quaife diff suggests it should be a Metropolitan Police Rapid Intervention Personnel carrier mini-bus. Apparently Met Police were the lead customer for the V8 version of the Sherpa aka Freight Rover V8. Ambulances were probably most common. A Quaife diff seems overkill there. Especially at Quaife prices!. Engine is basically the ordinary SDI one as used from 1977-1981 and in the TR8 in "Saudi-tune". 8 to1 compression ratio, 132 bp and 186 ft lb of torque, couple more ft lb and 3 bhp less than the Rover installation. OE carbs were Stromberg 175CD-(SET?). I imagine its now wearing SU HIF 44 to Land Rover One Ten and Ninety 1986-90 settings. Whether it also gets 134 bhp and 187 ft lb is anyones guess.

Allegedly these V8 Sherpa things can exceed 90 mph even when fully loaded. Yikes! Seems to be pushing the envelope a bit given the close relationship between Sherpa chassis design and that of the old J series Transit competitor. Short legs and narrower body of the J made a lot of sense for local tradesman guy. But they also somewhat channel the old Austin A30 tendencies to falling over in abject terror when confronted by a corner at anything approaching normal motorised vehicle velocities. Which doesn't seem a good basis for something that quick!

Plenty of varieties of CD carbs made over the years. Mostly licence made versions of the cheapy crappy Zenith Stromberg copy. OK (ish) when new but putting rubber diaphragm flexibility into the carburation characteristics mix is not a good idea when things get old. Especially so with the dashpot-less, air damped Bing version beloved of BMW Motorcyles. Which I shouldn't really grumble about having made a fair bit of beer money over the years from knowing how to set up the orrible things so they stayed set up.

Clive

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I too think the Quaife LSD overkill Clive, especially with the twin wheels on the back.

Some pics and a bit of a write up / questions :-)

SU mixer

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I went to the specialist bolts supplier I use in Doncaster (Bapps) but they didn't have any longer studs in stock (apparently they would usually be able to supply 5/16ths UNF thread studs but not at this time). They did have that thread in bolts but the threads were only an inch up the bolt then a straight shank... I did try cutting the heads off said bolts and dieing the other end to M8 but that didn't work... So I tapped the carb holes M8 and made some M8 studs then fitted an M8 nut at the other side of carbs just in case (can't put a tack where a nail's been)...

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Mixers fitted

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Inside view of the dizzy, bit of oxide / corrosion in there, I scraped most of it off. The rotor arm looks newer than the dizzy cap but had a bit of wear on the anticlockwise edge - I could have found out from firing order but just as easy to ask you lot - which way does the dizzy spin? Cleaned up the rotor arm too.

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Spent most of today under this vehicle finishing off the rear end and main gas pipe feed but done a bit in the engine bay too, mostly just fitting the mixers, finding which pipes are fuel feed/return / breathers, etc.

Seems to miss on one cylinder at idle, not quite so bad as was now that I've cleaned the dizzy etc but still very prominent. A loud ticking from the engine which I now think is valve gear related (due to frequency vs rpm), perhaps the miss and tick are related?

When the engine is idling I can completely cover the carbs with hands but feel no vacuum on my hands even when I blank off breather pipes - what's going on with that (where is the engine getting it's air? How come the carbs supply fuel when there seems to be no airflow through them or at least not from main air intake?

I don't hold much hope for good results on LPG due to the hand vac test and also because I put a film of spit across the 12mm gas pipe feeds to mixers with the engine running and it didn't even pull the spit down the pipes.... so much for 'signal' on the 12mm pipes! But I haven't got as far as that yet.

Carbs have a fuel return pipe but seem to be fed from a conventional mechanical fuel pump (wide diameter feed, narrow diameter return) so looks like I'll be fitting a conventional carb fuel shut-off solenoid rather than cutting power to an electric pump.

I watched this engine run last night in the dark, no sparks from HT leads etc. Runs better with a bit of choke even when warm but that could be the choke holding throttle open a bit. Hell of a rock on the engine with the misfire, very soft engine mounts.

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Just tying this thread off...

Pics of finished engine bay

Engine / mixers etc
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Reducer
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And tying off for a second time... It's been a while since the owner got back in touch to say that it's all running really well, he took it to his mate's garage who fitted new ignition bits (leads / plugs / cap / rotor / condenser) that I advised (I did offer but told him I didn't mind if he wanted to use his mate). I originally told him to come back for a check of calibration after having the ign bits changed but he said it's running so well he doesn't see the point, it's saving him over 50% on fuel bills and running great now.

Crazy but only a limited proportion of installers will fit a mixer system these days. Some of the (fill in the blank) lot tell potential customers it is impossible to convert carb vehicles lol!