Engine Update Options

Discussion in 'Modified Shizzle' started by Owen Snell, Aug 22, 2015.

  1. Before I bother Paul, a bit of TLB input may be useful. It's time to do a bit more engine work on the van, but how far to go?

    I've got 1911 cc with quite a hot cam, ported heads and twin 40 DCNFs. This is connected to a longer ratio box so cruising at 65 is a reasonably comfortable experience.

    What I like: nice revive engine with plenty of power. Pulls a loaded van well, but you need to keep the revs up.

    What I don't like: below 3,000 revs, torque drops off fast. Below 2,000 revs there nothing - no torque and no throttle response.

    Reasons for the problems: The longer ratio box has big gaps between gears, so it's sometimes a struggle to bridge the gap when the torque curve is so steep. The fuelling on the DCNFs isn't great, not helping with low rev response. The cam fitted is probably a bit 'sporty' to drag such long ratios in a van.

    The cam is probably fairly easy to sort, but what route to take for fuelling and ignition? I'm reluctant to throw money at the DCNF set up as I'm not sure it will ever be perfect.

    So, new carbs or FI? 123 distributor or crank fired set up? I'm tending towards a mappable ignition so it can be set up to run better at low revs as well, but is FI going too far or will a nice new pair of carbs do the job?
     
  2. Torque, they say, is as near as damn it directly related to engine size.
     
    Owen Snell and paradox like this.
  3. More capacity and less cam would suit a bus better
     
  4. Or more stroke and less cam.
    Pure funking grunt.
     
    paradox and Owen Snell like this.
  5. I was going to edit and add the more capacity option. 2056 cc would be all extra stroke, so more grunt from the capacity as well as better low speed cylinder filling from the longer stroke. Set up the ignition right and it should run much better at low speeds. With this option, does FI really bring much to the party compared to a quality carb setup?
     
  6. Stick with the carbs but maybe come down in vent size to increase intake air speed

    You can always sell the carbs on at a later date if you decide you want fi

    Large capacity with smallish inlet and mild cam = lots of low down torque
    Perfect for a big heavy bus
     
    Lasty likes this.
  7. Ive just seen you have ported heads
    It depends on how much port work paul has done
    If paul has ported them with the current cam in mind they may be too large if your going to use a milder cam
    Paul will let you know im sure and could also advise on what milder cam to use
     
  8. Seems a lot of effort just to be able to cruise at 65 ? My 1700 will do that and more with the twin dells ..
    Its common in the states to go smaller cc and add a turbo ..which kinda makes since as most modern cars are going smaller cc with either twin turbo or turbo /SC to eek more torque and Bhp out ..FI is always going to be better so is crank fire ignition ..or swop for a pair of Dells ..reckoned to be the best carbs out there
     
  9. All that though adds extra complexity though

    I agree on the dells as they have more progression drillings than the webers so perform better on light to part throttle
     
  10. i just wish i knew what the hell you lot are talking about o_Oo_O
     
    cunny44 and Pickles like this.
  11. You have the same scenario I had. I sold my engine.
    I think to get torque out of your ported (41mm?) heads you will need more capacity. I keep saying that don't I. :) A 2L crank, std cam and bigger B&P's perhaps. I'll let you know in a few weeks... :D
     
    paradox likes this.
  12. Fuel injection kits can be bought off the shelf , as im sure tubo kits can , along with crank fire ignition kits ..all tried and tested ...I do love my dells though
     
  13. The thing is, unless you're on a motorway/dual carriageway you'll be going slower. If the engine is just waking up at 65 you're not getting the good out of it.
     
  14. Dont worry it makes your head hurt thinking about it too much
     
    Skid66 likes this.
  15. I was thinking more of roadside repairs
    The aircooled engine in its original form is perfect for working on in a field
    Once we try and make it more modern we start adding complexity

    We can keep the engine old school and agricultural in build but still give it more power

    It all depends on the bus owner and what they want at the end of the day:)
     
    Lasty likes this.
  16. I am starting to think that the future is scooby shaped.

    I can buy a new*, reconditioned* t1 engine for a few hundred quid and it will be a winky liability or I can pay someone a millionty pounds to rebuild my original motor.
    Thinks Laurie Petit, thinks bull frog.
    Or I can get an eager young chap to shove a scooby into the noisy cupboard.
    Then I'll be able to cruise at eighty and get forty to the galleon....

    I need more whine.
     
  17. One things for sure campervan living isnt cheap anymore
     
  18. it can be if you don't want to be messing about with everything........i'd love a better, quicker bus but just as happy to tootle around at 60/65.
     
    paradox, Lasty and zed like this.
  19. It will cruise at a lot faster than 65 and gets up steep hill at speed, as long as you don't let the revs drop off. I've probably got more power than I need, but not enough torque.
     
  20. In it's original guise, on the 1700 box it would've been fine... But swapping the box out has given you what I found when I swapped the cam on my 2270... more power, but higher in the rev range, so the 2l gear stack all of a sudden has a load of holes in it, so you have to run the engine right up in each gear, so you're not off cam when you change into the next gear..

    So more CC, slightly different cam, and you'll be flying along again :thumbsup: You could even get away with a milder cam in your current set-up... It's all above moving the power band down the rev range.... Currently you've got 281° duration, and .475ins lift... If we reduced that to .435ins of lift, then the valves would be open for a shorter period of time, so the power curve would be lower in the rev range..

    Heads are ported 1800s, so 41x34... Inlets are mildly ported, with all of the casting marks removed... Exhaust is de-bossed with full length guides, so it will flow a hell of a lot better than a stock head
     
    zed likes this.

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