free hit
Drawfiler's Content - The Lotus Forums Jump to content


Basic Account
  • Content Count

  • Joined

  • Last visited

Posts posted by Drawfiler

  1. I  usually take off the air box and have a look and feel the inside of the trumpet with my finger. If the pump  is on you can usually see the fuel working it's way down the trumpet.

    all this is from bittter experience, my engine just wouldn't slow down so I fiddled with the lever stop screw then  it wouldnt tick over. After trying all sorts of things I bought the better needles and had an instant cure.

  2. When you check for leaks, have a look at the 'O' ring seals between the carbs and the adapter plate and the plate and manifold. If there is a leak here you can get your symptoms. The other think to check is to be certain that the carbs are not flooding, turn on ign and look into the trumpets if there is flooding they will be wet with fuel.

  3. The manual says 12 degrees for Dellorto carbs on contact breaker in a 25d4 distributor but 1975 and onward engines call for 16 degrees BTDC rising to 34 at 4000 rpm, 1976 spec is no vacuum static 7 degrees  still 7 at 1000 rpm. however the book also says that you set 25 degrees BTDC at 3000 to 4000 rpm which will give an idle of 7-11 degrees because of distributor tolerances, I assume this is with  Lumenition. The chart on p 15 of the manual says 24-26 at 3000 with electronic ignition so perhaps I go for that.


  4. What ignition timing are you guys running at? I have a 2.2 litre 900 engine running on a Powerspark non vacuum distributor with their solid state unit and a new coil. I have set up cam timing dead right and belt tension correct, I am running at 20 degrees advance at 1000 RPM.

    I would like to see what others are doing.


  5. I would check the pressure at the carb end of the pipe work as that deals with the slight height difference from the pump to the carb. I bought a somple low pressure gauge off eBay and made a  temporary connection at the carb input and went from there. 

    I would add that the correct SU pump will deliver the correct pressure so I would check the needle valve in the float chamber. The standard needle is all brass but there is a version with a plastic type seal ring round it, I had flooding trouble and despite all new parts and the correct pressure, I still had leaks, changing the needle fixied it instantly.


  6. Once again I have had to sort out a leaking exhaust cam cover and I have come up with a couple of ideas to help.

    To make things easier I took the wheels off and with the car on axle stands put a trolley jack under the sump and took off the engine mounts and so could move the engine slightly toward the off side so I could get at the cover easier.

    I made up some lengths of m6 allthread slightly longer than the cover bolts, by screwing them into the holes in the cam carriers, the gasket can be coated in sealant and slid down the allthread into position, the allthread an be unscrewed and replaced with the bolts. 

    I found that the top row of studs is all you need to keep everything in place.


    • Like 1

  7. I think you need to begin with fuel flow, take the connection off the carbs and check volume of fuel pumped against time by using a stop watch and measuring jug. Also check the carbs for muck in the float chambers.

    if the flow from the pump is poor, check the filters, some are built into the pump, some in the fuel line. The breather problem can be checked by running the car without the fillercap on.

    if all this is ok, then suspect the coil.


  8. I had a conversation with Mike Taylor at Lotusbits about this, he showed me some 2.2 bodies and pointed out some special drillings in the carb body casting. As he had a lot of interest in 2.2 carbs he set about developing jets and venturies to convert 2l carbs to the same spec. The parts when bought new were quite expensive so I am wondering if it is all worth doing.


  9. I have rebuilt my 2 litre engine as a 2.2 Litre using the original 2 litre carbs. There is much more low down torque and the driving experience is much better. My question is this, is there a dramatic further improvement by swapping the carbs. I could try and buy a pair of 2.2 carbs and rebuild them or fit all the jets, venturies and so on to mine, either way this is expensive, so is it worth it?


  10. I rather foolishly forgot to replace the fuel pipe when the engine was out of my Eclat so I am wondering if it is possible to thread a length of copper tube from one end to save a lot of dismantling. I am confident that I can fabricate any fittings needed and was considering using either 8 or 10 mm.

    I have asked this before but had no response from anyone doing a similar job.

    thanks Peter

  11. The raise to 2.2l is worth considering, you will need a crank, pistons and other bits. You will have to buy (or your rebuilder will) all the other parts irrespective of capacity, the 2litre carbs work ok on 2.2 engines. 

    You could consider buying a used 2.2l from Lotusbits and rebuild that so saving you original for posterity and the slight extra cost of the used engine is only a small percentage of the total cost.. the 2.2 had some developments that Lotus incorporated over time so you benefit from those.

  12. Thanks Mike.

    My testing has been with the car stationary, the car gets up to 'fan' temperature , i.e. Just over 90 degrees on the gauge and the fans come on,. Quite quickly they go off again, when things settle down, they run for no more than half the time, the fuse holder gets hot while this is going on but only at one end. I have cleaned the holder as best I can with wire wool contact cleaner etc. The fans turn freely and the water pump is in good order, it was rebuilt by Lotusbits recently and checked when refitted to my rebuilt block.

    My next experiment is to to solder a wire to each side of the fuse holder and run these wires to a separate new fuse holder and try that.


  13. I am running at just to the right of centre on the gauge in the recent hot weather. The fans come on and off when standing idle and at a fast tick over,I think this is OK.

    The problem is with the contact between the fuse and the holder but I have cleaned and polished the surface but still the holder (the actual brass spring clip) is hot to the touch when the fans have been running a while.

    I think that I will explore a separate fuse arrangement for the fan supply, I am pretty happy that the fan motors are not drawing to much current as the fuse doesn't blow.

  • Create New...