technical questions RE: PRV V6's
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  1. #1
    Tadpole
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    Default technical questions RE: PRV V6's

    Hello all - 1st time poster on this site, but I've been lurking for a while, and like the technical knowledge and attitude displayed here.

    I'm looking for some info on the PVR V6's to help me with a current project re-powering a 4x4. Parameters are pretty simple - looking to build up an engine of 3 liters or less to run on PROPANE. basic gasoline components would work fine for stress, and heat levels, but for the motor I have in mind I need to either get the compression up in the 11:1-13:1 range, or build up a durable, high boost turbo system to accomplish the same sort of cylinder pressures. (propane fuel within my 'range' is 110-130 octane)

    from reading other posts, I gather the Volvo (oddfire), and Eagle Premier (split crank) versions are equally durable, and both have been turbo'd successfully with gasoline. due to space constraints, a straight 6 is not an option, and while small, the vehicle in question weighs ~3500 lbs, and regularly tows a 2500lb trailer for extended periods, so a high pressure turbo 4 is likely to end up causing me a lot of greif ( doubly so on hot climate runs) on my tech q's:
    1) arguments for/against either block configuration when used with propane?
    2) how hard would it be to get one of these motors up into my target compression range? ( I'd prefer to run without a turbo if possible - this is a functional, hard core 'trek' 4x4, and I've several of the people I run with have been stranded by blown turbos)
    3) are there any ignition limitations on either setup? ( the propane fuel is mechanical, and due to the nature of the terrain I traverse, I perfer to run with as little electronics on the engine as possible)

    I realise its a bit of an odd post, but this is for real, and I'd appreciate any constructive input on the feasibility of the project. My technical level is quite high, and I'm noted for doing custom work with mercedes diesels, but they're too long for this application: dont be afraid to suggest complicated setups, or elaborate machining.

    also: I'm not sure how to post pics on here, but I have 1st hand photos, and experience with the system I'd like to run, and will gladly forward to anyone needing more info.

    TIA (thanks in advance)

    chris aka wanderer4x4

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    Last edited by Alan S; 30th November 2005 at 10:37 PM.

  2. #2
    Tadpole
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    Default no takers for advice?

    OK, I've had a couple of private emails on my first post, but no one wants to go public <shrug>

    anyway, I've been pursuing whats available to me in canada, and gone to take a look at the local variants. the only 2 versions of the V6 I have easy access to locally are the 2849cc volvo, and the 3 Liter Eagle Premier ( sorry, dont know the version numbers)

    basically boils down to the fact that given its availability here, the narrow oilpan, and available rwd manual transmissions a volvo is ideal for my application ( its an old Landy, BTW). Having said that, the volvo isnt perfect, the distributor location is terrible for my needs, and while repair parts are easy to get, aftermarket performance parts are almost non-existant. I've gone through the back posts on here, and even so, a few very direct technical quesions arise:

    1) can 3L eagle heads (later style split crank engine) be used in a Volvo B28 (oddfire engine) if you change the cams over? Obviously, some sort of distributor drive would be needed, but I'm a fabricator by trade, so that doesnt worry me too much - I'm more concerned with headbolt locations, coolant passages, timing gear, bore spacing, tappet types, etc. can it be done, and whats involved?

    2) as regards the V6 bellhousings, ALL of the V6's I've been able to find are automatics. Can I use a Volvo 4 cylinder bellhousing and flywheel (eg: B21, or B23) on the B28 V6, or is it a unique piece? My volvo manual tells me that the transmissions, and starter are the same, so those bases are already covered.

    3) regarding turbos - I cant easilly get higher compression pistons, Euro cams, or other goodies here, so against my likes, I'm going to have to use a turbo to make it run nicely. I THINK I've figured out where to fit the turbo into my engine compartment so it wont give me grief, but there's absolutely no space for an intercooler ( and it wouldnt get much in the way of airflow at the speeds I off-road either) Will these engines handle a lower boost setup without an intercooler? I can handle having less peak HP, and having boost come on slower - this isnt a race truck - but given the weights I listed (6000lbs + combined truck & trailer), I do need decent, sustained torque.

    feedback would be greatly appeciated - I've sourced an '85 760 GLE here(complete car) thats rusty from the climate, but in excellent shape mechanically. the sooner I find out whether / not it will meet my needs, the more likely I'm actually going to be able to get it.

    TIA
    Chris aka wanderer4x4

  3. #3
    1000+ Posts alan moore's Avatar
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    Renault Alpine GTAs are available in single turbo form. The turbo is mounted at the rear of the engine above the bell housing. They are a even fire 2.5L PRV engine.

    I am currently building a 3L version using a late Volvo 760 B280F motor to get the 10mm longer stroke crank, but using the Renault heads with the larger Volvo cams and valves. I am using Renault Alpine A610 pistons and sleeves to take the bore another 2mm to 93mm. My comp ratio will be 8.6, and I expect to run around 12lb of boost.

    Surely the std 9.5 to 1 Volvo would be high enough with a turbo even with the higher octane propane. I believe that the Renault and Peugeot motors have better ports in the head than the Volvo B280F. The distributor on the evenfire engine is mounted on the fan end of the engine on the end of the camshaft and is quite compact being around 3 1/2" from the end of the head with the terminals at right angles. The oddfire engine has the distributor up through the inlet manifold toward the rear.
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  4. #4
    Tadpole
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    Default culture shock !

    LOL - while I know what they are, a 'Renault Alpine' is about as exotic here as a Lotus S4 BiTurbo: aside from maybe one or two private imports, they just dont exist.

    Sounds like there's might be more than just a model name change between the continents giving me greif though! the 'standard' compression on the oddfire V6 Volvo's here is 8.3-8.8:1, which isnt great for non-turbo propane ( but is about dead on for the turbo setup I'm contemplating). Even the later, evenfire 3.0 in the eagle premier is only ~9.5:1, which will run acceptably, but would hardly be getting the full advantage from propane. I regularly run in areas that reach 7000-10,000 ft above sea level. thus compression, or a decent turbo setup are mandatory.

    your info on the interchangeability of the heads is greatly appreciated: thanks. If anyone knows about what manual bellhousing can be used, (IE: can a B23E flywheel and bellhouing be used on a B28 V6) thats the one vital piece I still need to find out.

    TIA
    chris

  5. #5
    1000+ Posts alan moore's Avatar
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    As the B23 is a true Volvo engine I would doubt very much that its' flywheel would fit the B28(oddfire) or B280(evenfire) PRV. The Alpine V6 Turbo is fairly rare in these parts as well, as I believe there are only 6 or so registered in Australia. The Alpines of course are all manual but use a transaxle which would not suit your purpose.

    3L atmo versions of the PRV are available in the Peugeot 605 and Citroen XM, all auto and rare here. A friend has a single cam 24Valve version PRV (Rare from a 605) in a Pug 504 Cabriolet with a manual gearbox, but I don't know who he killed for the Pug 604 (I Think) manual gearbox for this conversion. 604s were all autos here.

    The turbo motor from the Renault 25 V6 Turbo is the same as the Alpine and quite cheap from England. Whole good cars are sold for 500 pounds over there so I expect an engine should not be too pricey.

    There were two of these engines in Brisbane, but my friend and myself have already snavelled them.
    '56 Renault 4CV (16TS Power)
    '62 Renault Dauphine Gordini
    '82 Renault Fuego GTX
    '89 Renault Alpine GTA V6 Turbo
    '02 and '03 Renault Clios 1.4L
    '13 Renault Megane RS265 Trophee+

  6. #6
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    Can you not plane the heads or deck the block and possibly run dome top pistons ? to achieve the desired compression .
    There must be something available over there aftermarket (GM maybe ?) that share similar bore/rod size that you could machine to fit .
    It would aleveate having to run turbo'd if you'd prefer not too , as for running without an intercooler there's always water injection, if metered correctly (boost referenced) even on long trecks you shouldnt have any issues with running out .

    Cheers
    Dale.
    No substitute for C.I. ....except boost

    1973 R17 TL - R18 turbo repowered .
    1989 R25 Monaco v6.

  7. #7
    Tadpole
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    Default issues

    'swishy', my issues with turbos arent absolute - I do a lot of heavy trail work, in areas with no bridges: cold water, and hot turbos are a bad combination. That said, I think I'd have space for a rear mounted turbo, up high, in the valley (in the 'V' between the heads) In that location, the turbo is fairly well protected, and would most likely be ok. The bonuses of a turbo for me iare in high altitude operation, the high power to weight ratio, and the relatively stock core engine.

    conversely, custom rods, pistons, and / or heads become an issue if I ever break down in say, mexico, or Panama ( and yes, I DO run that far) It becomes an exercise in whats going to be available, maintainable, and repairable by me, in multiple locations. With that in mind, worst case with a properly designed turbo system is that a blown turbo just needs an oil line crimping, and you can run on, albeit at lower power. custom high compression pistons, or heads are kind of hard to 'work around' if something happens.

    as it sits right now, I've passed up on the 760 I'd been looking at. Until I resolve the manual bellhousing issue, everything else is a moot point: if the engine is internally balanced, I can probably build a simple adapter plate and fit any transmission to it - I'm hoping this is the case, based on the fact that John Lane is apparently running a racing transmission in his setup, but have been unable to confirm it in my Volvo manuals.

    chris aka wanderer4x4

  8. #8
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    The same could be said for the turbo engine if you have piston/head issues even with the stock configuration ,
    mouting the turbo up there is probably not a good idea either as

    1. heat rises , so you end up with the inlet charge getting immersed in a nice superheated area (being that the turbo and plumbing is likely going to restrict air flow across the top of the engine) , which without a intercooler isnt a nice senario.

    2. are you going to have enough clearance ?, judging by v8 landies I have seen there isnt likely to be enough room to mount a turbo in the valley and still accomodate the plumbing within the constraints of the bay , bear in mind the PRV6 is not much smaller than the average v8 height wise (if not higher in alot of cases)and have decent sized heads .

    imho if you are doing such tripping you need to keep the turbo/s as wide as possible to provide decent airflow across all surfaces, and I'd imagine regardless of wether you have performanced enhanced the internals, parts for such an engine are going to be hard to source regardless in those areas .I personally would tend to er on the side of a solidly built NA engine even if due to the simple reduction in heat as this also affects your oil . and less to physically go wrong .

    Be interesting to see how the landie went with the 6 though , keep us posted if you do continue .

    Cheers
    Dale.
    No substitute for C.I. ....except boost

    1973 R17 TL - R18 turbo repowered .
    1989 R25 Monaco v6.

  9. #9
    1000+ Posts alan moore's Avatar
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    Swishy, you can't plane the heads without planing the manifold as the V gets smaller. This is done on V8s but in the case of the PRV V6 the inlet manifold is sealed by O rings and starts to create problems with sealing and port alignment. Then of course planing can introduce cam timing and timing chain tensioning. The B280 already has domed pistons.

    The PRV evenfire (B280)at least, is internally balanced to answer that question. Don't know about the oddfire but I would expect it to be the same.
    '56 Renault 4CV (16TS Power)
    '62 Renault Dauphine Gordini
    '82 Renault Fuego GTX
    '89 Renault Alpine GTA V6 Turbo
    '02 and '03 Renault Clios 1.4L
    '13 Renault Megane RS265 Trophee+

  10. #10
    farmerdave
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    Yes, the odd fire version is internally balanced.

    Regarding pistons, there were 8.2, 8.65 and 9.2:1 pistons fitted to the 2664cc versions, the dome heights are 0.2, 1.80 and 1.96 mm respectively- a set pistons from forged blanks (lots of US companies do these) would allow you to get the desired CR for Propane- and they are more or less indestructible.

    Farmerdave

  11. #11
    Budding Architect ???? pugrambo's Avatar
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    you can shave the heads to a certain degree before needing to worry about the inlet manifold not sealing or needing attention

    but you will need to machine the timing cover as well when the heads are done

    the chain tension will be ok but you will need to take into account that you will have less travel on the tensioner

    depending on what heads you use the CR will vary
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  12. #12
    Tadpole
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    Default thanks to all

    farmer dave - thank you for the direct, concise response to both the balance, and compression issues. knowing its internally balanced, a manual tranny becomes more or less a non-issue. I've seen references to the 2.7 l volvo version, but havent been able to locate one.

    swishy - (and others) yes, the 6 will fit easilly. My Rover is a long way from stock, and due to the HD off-road suspension, I have more room under the engine than is normal. For balance purposes, I deliberately sit the drivetrain lower than stock. Heat soak shouldnt be too bad, actually - either way I build it, plans call for a custom intake manifold with MPI propane. If I can get the volvo distributor relocated , there will be several inches space, and a set of heat sheilds, between the intake plumbing, and the block. I've also got several rolls of ceramic exhaust wrap to go around the exhausts, turbo, and downpipe to further reduce temps.

    I'll keep you guys posted as I progress.

    thanks again to all
    chris aka wandere4x4

  13. #13
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    Quote Originally Posted by alan moore
    Swishy, you can't plane the heads without planing the manifold as the V gets smaller. This is done on V8s but in the case of the PRV V6 the inlet manifold is sealed by O rings and starts to create problems with sealing and port alignment. Then of course planing can introduce cam timing and timing chain tensioning. The B280 already has domed pistons.

    The PRV evenfire (B280)at least, is internally balanced to answer that question. Don't know about the oddfire but I would expect it to be the same.
    Ah yeap , I had done such on a v8 didnt relise the PRV inlet was o-ring sealed.

    Cheers
    Dale.
    No substitute for C.I. ....except boost

    1973 R17 TL - R18 turbo repowered .
    1989 R25 Monaco v6.

  14. #14
    Tadpole pulse69's Avatar
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    Quote Originally Posted by wanderer4x4
    3) regarding turbos - I cant easilly get higher compression pistons, Euro cams, or other goodies here, so against my likes, I'm going to have to use a turbo to make it run nicely. I THINK I've figured out where to fit the turbo into my engine compartment so it wont give me grief, but there's absolutely no space for an intercooler ( and it wouldnt get much in the way of airflow at the speeds I off-road either) Will these engines handle a lower boost setup without an intercooler? I can handle having less peak HP, and having boost come on slower - this isnt a race truck - but given the weights I listed (6000lbs + combined truck & trailer), I do need decent, sustained torque.

    feedback would be greatly appeciated - I've sourced an '85 760 GLE here(complete car) thats rusty from the climate, but in excellent shape mechanically. the sooner I find out whether / not it will meet my needs, the more likely I'm actually going to be able to get it.

    TIA
    Chris aka wanderer4x4
    If you are worried about an air to air intercooler due to the slow speeds you drive at when off road have you thought of a water to air intercooler? They can take a lot more heat soak than air to air versions. I think they were found on Subaru Liberty turbos and Toyota Celica turbos...

  15. #15
    Tadpole
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    Default intercoolers

    I'd wondered about air to water coolers, but I'm not sold on the idea due to the added complexity of the plumbing. The more I've been digging into this, and thinking it through, the less likely I think low speed would be an issue anyway - not that the 'airflow would be different from my first assessment, but it tends to be low throttle, using gears, and torque, so boost, and 'waste' heat would be quite low. Its is also why I wonder just how badly I'll need ANY intercooler - this rig is going to use dual 4 speed transmissions, plus a 4wd transfer case. Getting mondo HP out of the motor isnt necessary, so much as smooth even power at varying revs, ambient temperatures, and altitudes.

    I dont recall seeing a 'Liberty' model here, BTW - but the Subaru's I have seen 1st hand all looked like they used an air-to-air cooler, right on top of the motor. There were older 'Subaru Loyale' wagons, the smaller ( hatchback) sized 3, and 5 door 'Justy' models, and the uber sport SVX. More recently the Imprezza, Legacy ( incl Outback), Forester, WRX, and the new Tribecca B9.

    thanks
    chris aka wanderer4x4

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