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Everything posted by rgh0

  1. When the gearboxes were made the bell housing and gearbox casing would have been bolted together and then the 80 mm hole bored. Nominally this bore would have been centred on the split line but it appears there is some ( systematic?) small error in the machine setup used to do this boring so the centreline of the bored hole is moved 7 thou from the split line to the gearbox side. This type of tolerance / error is not uncommon in machinery fabrication which is why it is always wise to check the location of the centre line of bored holes precisely as done, rather than assume the split line is also the centre of the hole cheers Rohan
  2. Most synthetic and mineral base oils actually tend to cause rubber seals to shrink so appropriate rubber swell additives are added as part of the formulation in quality oils to counteract this. "High mileage" engine oils or supplementary lubricant additives have additional swell additives to help counter wear on seals by additional swell to minimise leakage from places like the rear main seal cheers Rohan
  3. I dont believe the Polyol Ester molecular size is significantly different to any other lubrication oils. In any case fluid leakage does not really relate directly to molecular size but more to bulk properties of the fluid such as viscosity. In my experience with MT90 in my S1 esprit at least its leakage rate is similar to other modern synthetic oils. If leakage is a problem then you have something wrong that needs fixing. The common leak point in the Citroen boxes is the gear change shaft. You put up with it normally as its small or you fix it if you really want a totally oil dry rear of your transaxle. The advantages of polyol ester base oil are huge in terms of thermal stability and lubricating properties so even if they did leak a little more they are worth it in my personal opinion but from my experience they dont. i will stick with MT90 cheers Rohan
  4. You could talk to these people - never tried them but looks like what you need cheers Rohan
  5. You can work out the original design valve stem install height as follows if you have a bit of time and some measuring tools. Valve tip must be the following distance from the cam centreline standard cam base circle radius + design clearance ( say 0.010") + follower thickness ( std is 0.220") + standard shim (nominal 0.120") You can then measure cam centreline to spring pocket base buy measuring the cam carrier depth to cam centreline and spring pocket base below cam carrier mounting face You can then calculate how much spring stem tip needs to be above the spring pocket base when setting the valves in the head. If fitting a high lift cam then you may need a smaller cam base circle and longer valve stems and thinner follower to fit in a suitable spring that is 0.060 away from bind at full lift cheers Rohan
  6. The 0.060 inch figure is the usual minimum distance of maximum spring compression from coil bind for any engine. You can push it to be a little less but you must ensure everything else is perfect if you do. cheers Rohan
  7. Looks like someone who did not know what they were doing attempted a number of modifications somewhat unsuccessfully back when the previous owner did engine work in 2016. Looks like they tried to port the engine badly. Fitted valve stem seals badly. Got the timing or something else wrong in the valve setup resulting in the valves hitting the piston tops which was probably also the cause of the extreme bearing wear You are lucky to have picked up the issues and stripped the engine down when you did before a more catastrophic failure. cheers Rohan
  8. I would measure up the followers and carrier for wear. if its all within the factory specs then it does not matter which goes in which location. You need to measure top middle and bottom of the follower and carrier as the follower wears in a barrel shape and the carrier in a hourglass shape. The other issue can be wear on the follower top to cam so check the cam lobes and follower for any signs of wear also. In the end a new set of followers is not that expensive if you find enough wear to give concerns about reassembly in different locations cheers Rohan
  9. It would be great to get a copy. it would inspire me to pull one of my spare heads off the shelf and start measuring it up for the 220 HP 907 engine I want to build for my S1 one day cheers Rohan
  10. Looks like something has failed in the distributor / oil pump assembly allowing the shaft to move forward, Pull it off and investigate cheers Rohan
  11. The thinner followers are typically needed when using high lift cams that have both a smaller base circle to keep the lobe tip radius acceptable but also to enable a longer valve stem and larger valve tip height and long valve spring that can accommodate the higher lift. Of course the thinner follower can also be used to hide bodges with valve seat over cutting or reground cams. I deal with this when building competition twin cams for my Elan and have a design spreadsheet to manage all the variables. One day I will set up a similar design spread sheet for the 9xx engines when I finally get around to building a big engine for my S1 Esprit but so far the original engine keeps working. cheers Rohan
  12. Is this the Rover Forums or Lotus Forums. Personally i never see any Lotus 6 on the roads these days cheers Rohan
  13. Get a copy of the parts manual as that helps to identify what may be missing cheers Rohan
  14. The small thread knobs are probably from the 5 speed Elite / Eclat which used the same gear box and change lever as the 5 speed Elan +2 and had the gear pattern logo cheers Rohan
  15. I understand how the regulator adjustment works to hold the fuel pressure above the carb pressure and that the regulator will "try" to hold a constant fuel discharge pressure relative to atmospheric pressure if the sensor hose is disconnected. As the throttle opening increases and the boost increases the pressure in the carb bowl increases. This means less fuel will be delivered as the back pressure on the float valve increases and the float has to drop to deliver the required fuel. The lower fuel level will lean out the engine leading to loss of power. The fuel regulator is a simple proportional controller and its delivery pressure will increase with increasing fuel back pressure due to increasing carb pressure if the reference pressure line is disconnected There are multiple influences fighting each other here but the end result is a lower fuel level in the carbs and the engine running lean and loosing power. Connect the sensor tube to the plenum and assuming everything else is correct it will work. Unfortunately the odds of everything else being correct are not that great cheers Rohan
  16. with the fuel pressure regulator boost pressure sensor disconnected fuel pressure will increase with boost due to the increased back pressure but it will not stay the required amount ABOVE the boost pressure leading to problems. if this is wrong there may be other major things wrong with the pressurized carb set up that cant easily be seen from your photos. if you dont understand how pressurised carbs with blow through turbo works then find someone who does, as lots of little issues of not properly sealing the carbs and all their connections can give you a problem. cheers Rohan
  17. Just a note of caution. After not driving my S1 Esprit for a few to many months due to Covid lockdowns I finally had a chance to drive it last weekend The car started fine but then immediately started to run on only 2 cylinders so I turned it off to investigate. When I got out there was a large pool of petrol spreading under the engine !!!! Luckily I could push the car away and mop up the petrol without incident Investigations showed that the front Dellorto was flooding with fuel coming out the trumpets soon after the ignition turned on the fuel pump. It was a relatively easy fix by just removing the carb top cover and cleaning the float valve and ensuring everything was moving smoothly. I could see nothing wrong that could have cause the flooding and presume the float valve jammed open due to sitting for too long with the fuel evaporated out of the carb bowls. After the carb fix the car needed new plugs and then ran rough until I filled it will fresh fuel. It bought many smiles to be able to drive it again cheers Rohan
  18. Race tow arrangements on a Lotus with the fibreglass bodies always a challenge ! For my S1 Esprit I use a light steel rod bent in a triangle shape from the two front lower suspension pivots. It sits under the cooling intake moulding on my S1 to provide a centre tow point at the front. At the rear i have used a steel cable from a lower bolt for the lower pivot on the RH side lower suspension link to provide a tow point loop on the end of the cable tied with a wire to the exhaust . If its used and pulled sideways the tie wire will brake and the tow cable move as needed. Never needed on my S1 Esprit but a similar arrangement used more than once on my Elan cheers Rohan
  19. I would try a couple of G clamps with a rubber seal to close of the inlet ports and then apply pressure on the threaded brake line ports with grease or a brake master cylinder. As long as no air trapped in the system no chance of parts flying around but wrap it in a heavy cloth to absorb any flying bits if worried. cheers Rohan
  20. I have the original bolt in my S1. I will take a photo and measure this weekend and post
  21. Nothing wrong with a a VAG R model (I have a couple) but a Lotus starts at that point with its normal road cars and only becomes a "R" when its specifically designed / modified for serious competitive track racing in real life and not just high performance road driving. cheers Rohan
  22. My S4 Elan is best in tight twisty narrow roads My S1 Esprit best on faster more open roads. Both are immense fun to drive cheers Rohan
  23. I have a couple of 2 litre 907 engines from 78 and 79 Esprits and a later 912 2.2 litre from a early 80's front engined car either Excel or Eclat. The basic block castings look the same though there may be some minor machining drilling and tapping difference depending on the original application. The major difference with the 912 block was the beefier ladder bearing carrier and sump casting but the block itself appears to be the same as the earlier 2 litre 907 The earlier 70's rope seal blocks in the Jensen Healys may have been different as Lotus is supposed to have updated the block due to liner reliability problems according to wikipedia ??
  24. Interesting that wheel centres are black on the actual JPS cars . On my JPS style late S1 made just before the JPS cars but with similar colour scheme with these wheels they are white with gold Lotus lettering
  25. cant see the images - photo bucket is useless and most historical images in most posts that use it fail cheers Rohan
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