free hit
counters
GavinT's Content - The Lotus Forums - Lotus Community Partner #ForTheOwners Jump to content


GavinT

Full Forum Member (FFM)
  • Posts

    1,320
  • Joined

  • Last visited

Everything posted by GavinT

  1. This is a great video on how to trouble shoot the Bosch CIS injection system. Esprit Turbo HCI 1986 - 1987 and 1988 Stevens USA. Although the engine in the video is from a 70’s Porsche 911, the injection system is the same. You just need to check your workshop manual for the Lotus spec’s.
  2. This transaxle also has pretty badly worn primary shaft splines and really needs a rebuild. Not something I’ve budgeted for. Good job it’s a spare.
  3. Happy Christmas all you Lotus lovers !
  4. Visually I can’t see any damage. This box is an unknown to me and was purchased as a spare. Not witnessed it in action. Told it work fine but you know how that goes.
  5. Taking the bellhousing off the gearbox to do the circlip upgrade. Checking things over I’m presented with is. Not too far away from totally failure. I have no idea what could have caused this type of wear but somebody has been in there before and the bearings are not original. The spacer rings and collar were inserted out of order when I removed the output shaft housing.
  6. Lotus Service bulletin 1993/07 TITLE: Introduction of revised cylinder block, head & gasket REASON: Quality improvement. The cylinder block and cylinder head of the Lotus 910/920 engine have been re-cast and upgraded in respect to stiffness, lightness, cooling efficiency and dimensional control. In addition, a new type of cylinder head gasket has an increased tolerance to severe thermo-cycling, and improved durability. ACTION: The new components have been introduced on engine serial number: 28096 (last 5 digits of engine number) - January 1993. With the exception of the block deck height and various core and blanking plugs, the new block and head share all functional dimensions with the old type, and when service stocks of the older components are exhausted, the new parts will replace them. New heads may be fitted to old blocks and vice versa, but the new head gasket should be used in both cases. The new block and head may be readily identified by cast Lotus logos on the front and rear faces of the cylinder head and at the top right hand rear of the block. Cylinder Head Gasket The steel and asbestos laminated gasket, B907EO026Z (Coopers - silver incolour) has been replaced by a reinforced fibre-composite gasket A912E7029Z (Goetze - grey/brown in colour) This uses a built-in silicone sealing bead around the periphery and a Viton seal around the oil feed hole. The compressed thickness of the new gasket is approx. 0.5 mm (0.020") greater than the old gasket and the deck face and liner seats of the new cylinder block have been lowered by a corresponding amount. Service Replacement i) New engines must be fitted only with the new type gasket. Fitment of an old type gasket to these engines may result in piston foul and/or detonation due to the raised compression. ii) When stocks of the old gaskets are exhausted, old engines should be fitted with the now gasket, which will also replace the 'extra laminate' thicker gaskets (A911E1292, B911E1292) used on some low compression 912 N.A. engines. Note that the extra thickness of the Goetze gasket will result in a slight reduction in compression ratio (typically about - 0.5 numerically) when used on old engines. This may be advantageous to fuel octane tolerance, especially if the head face has been machined to correct distortion or erosion. Goetze Gasket Fitting Procedure There are two points to note when fitting the new type gasket to new or old type engines: a) New engines must be fitted only with the new type gasket. b) The cylinder head nut tightening procedure has been amended and requires the use of an angle gauge. A Sykes Pickavant tool under Lotus Part No. TOOOT1235 will be despatched and invoiced to all dealers shortly. Use the latest type cylinder head studs (B907E0224Z) identified by the dimple machined in the top end. Tighten into the block (with oiled threads) to 37 - 41 Nm (27 - 30 lbs.ft). Fit head gasket (dry) and cylinder head. Fit washers, oil head stud threads and fit nuts. Using the existing tightening sequence (from the centre outwards; see Service Notes EB.7), Tighten the head nuts in the following stages: i) 20 Nm (15 lbs.ft). ii) + 75 degrees iii) + 40 degrees iv) Wait 5 minutes v) + 20 degrees Cylinder Liner Adhesive The sealant used between the base of the cylinder liners and the block (formerly Hylomar) has been changed to Loctite 572 adhesive/sealant (A912E7030V) in order to reduce fretting and noise; improve sealing durability; reduce the risk of liner disturbance with the cylinder head removed. The use of Loctite 572 has been introduced together with the new block and head castings, but may be used on all Lotus 900 series engines. Loctite 572 Application Procedure: Thoroughly clean the liner spigot and seat, and the corres­ponding areas in the block. Dry fit the liners and check that there is a nominal clearance between the top ends of the liners. Check the stand-out of the liners above the block deck face (liner 'nip') which is unchanged at: - 0.03 mm to + 0.05 mm (- 0.001 to + 0.002 in); Maximum variation between adjacent liners: 0.03 mm (0.001 in) Apply a small bead of Loctite around the seating face of the liner. Apply a thin smear of Loctite around the outside of the liner spigot. Apply a thin smear of Loctite around the top edge of the liner spigot bore in the block. Slide the liners into the block and fit the cylinder head within 4 hours to ensure that the liners are seated correctly before the adhesive cures. If this procedure is used on an “old” engine, apply a red paint mark for reference to the cylinder block at the end of the engine number stamping. Note that when assembled as above, the liners will subsequently require the use of a liner puller tool (TOOOT0012A - existing part of the dealer special tool kit) in order to extract a liner from the block. The improved security of the liners also means that if care is taken, there is no necessity to reseal the liners in the normal course of cylinder head removal/refit Cylinder head layout and orientation Lotus Esprit cylinder head tightening sequence Summary Vehicle manufacturers specify torque values for certain fasteners such as cylinder head studs and nuts. This is to make sure that fasteners are not over-tightened or under-tightened. The torque wrench is used to apply a specified amount of torque to a fastener. The torque angle gauge is used to make sure there is equal tightness across all fasteners on a particular component.
  7. I was under the impression that when you install the Geotze gasket you must upgrade to the newer head studs or the ARP ones. Reason being, the. Goetze gasket requires a greater clamping force over the old metal gasket. The old studs are not up to the task. Tim Engle…. the current Goetze composite gasket requires high-strength cyl head studs, and the nuts are tightened with a torque angle meter, not a torque wrench. Using the old torque wrench spec won't get the head tight enough for the new composite gasket. Use a Torque Angle Meter (initial set with a Torque Wrench) Initial Load = 14.7 Lb-Ft / 2.0 Kg-m / 20 N-m (torque wrench) Then, using a Torque Angle Meter. Tighten an additional 75 in one step, then. Tighten an additional 40. Wait 5 minutes, and then. Tighten an additional 20
  8. Update….The issue with 0.030+ bearings is availability. The lower shells are the problem. Getting OEM quality is the next issue. SJ offer alloy 2 ply which I was advised not to installed. I emailed all the usual suppliers. LotusBits and PNM didn’t respond. SWLC didn’t have any options. Garry Kemp could offer OEM grooved lower bearings but they are not suitable for a turbo esprit. JAE are out and their supplier is not doing another run anytime soon. The winner was QED. They have both OEM and aftermarket bearings. Aftermarket in 0.030 lower bearings, but their aftermarket bearings are tri metal and are OEM spec. Ultimately I had a stroke of good luck and scored an extremely lightly used 910 crank that is still standard from JAE. Shout out to Tim Engle, Garry Kemp, Dave(Changes) and Mike Sekinger for all their advice, extremely grateful for their time.
  9. Reached out to Garry Kemp. He has original OEM .030 bearings available but they are all grooved. He didn’t express concern about taking it down to .030 under. Tim Engle also didn’t express too much concern about taking it down to .030. But added it would be beneficial to have the crank journals nitrided. His main issue was that the crank has gone as far is it can go. So any future need for crank work would result in a new crank.
  10. Gents, unbelievably frustrated with this one. Machinist messed up #1 main journal and cut it down to .025 under, was meant to go .020 under. +30 mains are available from some of the vendors but is it a good idea to go this deep?. Machine shop will correct the situation, I just need to determine the correct course of action. options: 1. Cut to 30 under 2. journal repair and cut to 20 under 2. Replace crank This is on my 1988 910HC Turbo. Thanks all.
  11. I’ll do a plastigage clearance check with the .010 bearings and see where we are at.
  12. Thanks Ian. JAE supplies Deves rings which I know Garry is not a fan off. Once I know which piston/liner combination I’ll be using I think I will get the rings from him.
  13. @Chillidoggy i just looked at the id numbers on the liners JAE set me and they appear to Westwood liners. That assumes that no other manufacture is using the same Part# LT1932, which is on the spigot. Ian, I have read your rebuild thread but can’t remember if you reused your Mahle pistons?
  14. Hello Steve, appreciate your thoughts. Things are progressing ‘slowly’. I was hoping to have the car back on the road by now but unfortunately it’s been a bit of the old one step forward, three steps back. I hate to say it but the engines been out for 18 months now. Almost there with the components assembled ready for the build. Liner and piston choice is really my last pieces of the puzzle.
  15. What is the benefit in switching to iron liners? With my engine apart, now would be the time to make the switch to iron but if the Nikisal liners are still ok it seems silly not to reuse them. I did order a set from JAE but having googled around I’m finding that Nikasil is better than iron. Been reading the Porsche and the Ferrari forums. I really want to do my engine build with the right components, so if switching to iron is preferred over reusing in spec Nikisal liners I will. This also opens the door to reusing the in spec Mahle pistons. If you go for the iron liners should you also change to CP Carrillo pistons to? Which is the piston manufacture that JAE sells.
  16. Appreciate your input Michael. Maybe @CHANGES also.
  17. Oversized, +.020. Or as the parts manual reads -.020 My crank was ground by the previous owner but the machine shop went too far. They over cut it by .0013. So under the advice of my machine shop they are going take off .008 to get me to the .020 spec. I hate to do it but they are worried about low oil pressure with a +.010 bearing and a +.0113 journal. Both sets of bearings are engraved .020 on the back surface, the none holed has a manufactures icon whereas the holed ones just has what could be a serial number. They also have different color finishes, one being dark grey and the other being much lighter. Not sure if the different finishes is a factor as I see PNM offers bearing sets with different color finished bearings.
  18. I received a set of main bearings from one of the US vendors. The bearings with the holes are from one manufacture, whilst the none holed bearings are from another. Shouldn’t bearing sets be from the same manufacturer to insure proper alignment?
  19. Yes, out of the 1988 manual. The range is large and the manual doesn’t differentiate between N.A. and turbo engines. I would follow the manual but the Deves rings appear nothing like the Lotus rings. So rate of expansion is probably totally different. Deves list two recommended ranges: min 0.010-0.018 & max 0.010-0.028, these are generic and not specific to Lotus and nor do they differentiate between N.A. or Turbo application. My machine shop / builder is advising to use the larger range because of the extra heat generated by the turbo. I’ll call Deves later today and ask.
  20. New Deves rings on Mahle HC pistons, Nikasil liners, 910 HC Turbo. Anyone know if the gap is the same as the Lotus rings per the manual, .010 - .023. If so, is it better to go far a wider gap with an HC Turbo to allow for greater expansion?. Recommendations on gap size?. Thanks.
×
×
  • Create New...