Engine Update Options

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

  1. I think I went about the whole process arse about face. Paul did me an engine based on the original gear ratios and also on the basis of me getting hold of my own carbs. After the engine was done, I went for the longer box, which has been great in terms of improving cruising comfort and economy (cruising comfort was the main reason for doing it) but has left big gaps between the ratios. The carbs are also a problem. They are a pair of DCNFs that I picked up cheap. After fitting them, I got the van on a rolling road and asked the guy to set them up. He did the power run, but didn't actually change anything - he said they were OK, but what I had asked him to do was to set them up, not do a quick check. The carbs need sorting and I think that will improve the low speed running, but they are a pig to start when it's really cold and I don't now want to start throwing money at parts and set up labour on something that might now work out in the long term.

    Having run the van for about 5,000 miles on Paul's engine and with the new box, I certainly have a more focussed view of what I need!
     
    paradox likes this.
  2. Apologies for the unfortunate choice of words... it should really have said "why have an engine built...." No criticism intended but the gearbox swap does answer that.
     
  3. A combination of mission creep resulting in deviation from the original project perameters to negative effect and some value engineering resulting in output dictated by price rather than specification... Now where have I heard that before.......?
     
    Owen Snell likes this.
  4. Of course! See what can be done within your budget based on what you already have and build an engine. Increased capacity adds torque, but you can then double (or more) the ultimate power with valves, cam and carbs combo. As power is torque x revs (ish) the further you push the power up the revs the more you will have. The trick is to deny yourself the ultimate power you know can be obtained. But just how much of it do you want to "give back" to get your low end driveable? Personally I felt I had to hang on to a lot of it just for the experience. I have no regrets there, but now based on that experience I'm going to aim my mods at capacity firstly and a small valve size increase to compensate for that. Won't be long to find out anyway, a few weeks.
     
    paradox and Owen Snell like this.
  5. Yes, a rather poorly managed project. BUT, the experience has made me much better informed and I hope to be able to get it right this time. The issue now is to get the job done and finished and not be messing around with it again in the future. Hence the discussion about FI and ECU ignition control.
     
  6. Not so much 'you don't know what you've got till it's gone' as 'you don't know what you don't want till you've got it'.
     
    zed and Dicky like this.
  7. Lol. It is difficult. My last 2 litre motor had a B grind crank standard everything else and a weber on it. It was amazingly efficient on fuel but was a bugger to get rolling from a start. Loads of clutch to get it away! mid range was very fluffy and top end was very low torque wise but it would accelerate albeit slowly off the clock. I persevered for year but it wasn't nice to drive. I now know that if id slapped a pair of dells on it would have been much more tuneable.
     
  8. I am tempted to go with a pair of Dells as everyone likes them, but would be gutted if I spent a grand on carbs and then found that they weren't what I wanted. How are the Dells on cold start? Cold weather is an issue with mine, but that may just be that the vents are too big so there's not enough flow to get the fuel atomised when it's cold.
     
  9. Mine were £200.
     
  10. Not brilliant it has to be said on cold start but that's not so much of an issue with us fair weather drivers. How big are your vents?
     
  11. Im not familiar with DNCFs but surely its just an issue of getting them properly set up. Im guessing your vents are too big and youd be happier if they were smaller..... (Sound familiar @zed!)
     
  12. As we know I did try that, but really they killed the top end rather than improving the low end, though they did make it sound more purposeful at lower rpm.
     
  13. Mine were cheap and I didn't look at the vents, but they are an old design and parts are not that easy to find. The linkage is home brew by LP, who put these on another type 4 engine, which is pretty crap and the throttle action is stiff and I get massive idle speed variation. I bought them from the guy cheap after his RR man advised him to get some new IDFs! Should have paid attention really!

    So it's tempting to get a new setup with a nice linkage and new / reconditioned carbs that all runs properly, at which point the extra dosh to go all out and do a FI setup becomes interesting. No more issues with starting, cold weather etc. as it all gets corrected by the ECU.
     
  14. Yes, when the engine is set up for top end and the carbs for bottom end it's the worst of both options combined.
     
  15. the DNCF`s were used on ferraris
     
  16. Im running a 2056,see the specs in my signature.
    Its done about 3000km and has loosened up nicely,its a steady torquey motor with a very mild cam and slightly ported.
    I am very happy with the conversion,it cruises effortlessly at 110kmh but the only problem is the intake roar annoys me,this winter im going to try to build a central airbox using a panel filter to make it quieter.
     
    Owen Snell likes this.
  17. Bargain .....
     
    zed likes this.
  18. I just had this conversation with @Paul Weeding with reference to FI systems. I assume most builders use the twin Weber pattern throttle bodies because they are readily available and easy to fit, but a modern system with an air box and a single throttle would be just as good and a lot quieter. Running on a drive by wire system would be great too, get rid of the long cable.
     
  19. CB Performance do injected manifolds, so that's one part of the problem sorted. Where to get a plenum and rive by wire throttle kit?
     
  20. The thing with advanced fuel injection systems is that when they dont work its hard to fix them on the road,this is unfortunate because they are so precise.
    I am happy with the carbs except for the induction roar.
    I know that they make central airbox kits for type iv motors with Webers but they are too expensive.
    This winter my brother and I are going to have a go at making a fiberglass box.
     

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