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Refurbishing A 1993 Diablo Engine and Clutch

Removing the engine from a Diablo is quite a complex task. This is already written up once on this web site. See here.  However everybody has a slightly different way of doing it. This write-up is really a series of photographs and comments that first appeared over on the Lamborghini-talk Forum web site. See here. I have combined the many forum entries into one series of photographs with some added comments of my own. The well known Lamborghini-Talk member "madlyhs" (Hussein Almadly) resides in Kuwait and has given me permission to add the photographs here.  You should contact him directly at if you have further questions.

Below is a series of blow by blow accounts of progress illustrated with a series of photographs.  The car is a 1993 Diablo. 

Please note currently, (Oct 2007), this is still a work in progress. I will add more photographs as Hussein's work progresses.  Also there are a lot of photographs on this page so please allow time for them to download from the server.

Lets get started....

First remove the engine cover and surround the outside of the car with padding/blankets to prevent damage to the paint.  Remove the engine air inlet ducts and muffler.  All hose and electrical connections to the engine. Not shown here, but the gear shift leaver assembly from the car's interior also needs to be removed. This is described in more detail here

Fig 1. Remove engine cover, rear spoiler and air intake ducts Fig 2. Remove muffler
Fig 3.  Disconnect water and oil hose connections   Fig 4. Lifting engine out of car
Engine out of car    Engine out of car 
Fig 5 Engine out of car. Front view.   Fig 6. Engine out of car. Side view.
Engine on Floor    Valve manafold cover 
Fig 7. Engine on floor ready for disassembly.   Fig 8. Top view of engine with fuel intake manifold removed.
    Timing chain 1
Fig 9. Cam cover removed.    Fig 10. Timing chains

Removed all the timing chains, gears and chain guides after marking TDC (figs 11,12) . You can see that there is some wearing on the left side chain guide but interestingly it is not where the chain sits! Is this due to heat??  Sadly all the pistons (except one) had clearance issues.
This project now grows into a major job!
 Timing Chain removal    Timing chains 3
Fig 11.  Remove timing chain cog wheels    Fig 12. Remove timing chain 
 Timing chains 4    Cylinders exposed
 Fig 13. Timing cog wheels removed    Fig 14. View of cylinders
before clean    After Clean 
Fig 15. Before cleaning engine parts   Fig 16. After cleaning engine parts
Fig 17. Crankshaft diagram.   Fig 18.   Inspect Thrust bearings.
Fig 19. Installing crankshaft    

The liners above (Figs 14),  had to be removed from the engine as they also had clearance issue. It appears the engine over heated few times resulting in damage. Upon opening the engine it was found out that the engine was opened before and whoever worked on the engine installed the Thrust bearing (the one towards the flywheel) the wrong way see Diagram in figure 17.
Whoever was doing this probably was following the manual diagram which by the way is WRONG.  This mistake resulted in the scraping the Thrust bearing and it also scraped the crank which resulted in a clearance issue. This made the in and out crank movement out of its limit range (0.04-0.09); Due to this the crank was scraping the cylinder block as you can see from the picture (fig 18).

The machine shop smoothed the crank surface but that resulted in further clearance issues for crank in and out movement. The Machine shop wanted to weld on the crank and smooth the surface again to solve this problem but we opted to use the old Thrust bearing as shim for a new stock Thrust bearing from Lamborghini. (They do not supply Over Sized Thrust bearings for this engine!).  The trick worked fine and now we have 0.06 clearances which is within the limit.

The liners had to be removed from the engine as they also had clearance issues as well. The machine shop said the engine over heated a few times resulting in damage.
Fig 20. Custom cylinder liners   Fig 21. Custom pistons

Madlyhs said he could not use the same cylinder liners but he honned the cylinder block for new liners he had custom made. He sent two piston's (one from each bank) and one liners with the technical spec and drawings to Steve at and they made for him a set of High Performance Custom Pistons and Liners for $5000 which is $2320 less than the Lamborghini OEM parts.
Fig 22. Insert Liners into block   Fig 23. Tap liners gently into final position

Sliding the liners is easy.  First apply lubrication oil on the outer surface of the liner and the O ring.  The liner will slide in but a rubber hummer is still required to make it go all the way down.
Fig 24. All Liners now in block.   Fig 25. New pistons ready to go
Fig 26. Slide each piston into liner   Fig 27. Attach piston connecting arm to crankshaft.
Fig 28. All pistons attached to crankshaft.   Fig 29.  Ready to applied high temp silicon gasket and installed the crank case lower mounting.
Fig 30. Applied silicon gasket on the differential base so that we can install the oil cover.   Fig 31. Apply cover.
Fig 32. Apply silicon gasket to lower crank case mount   Fig 33. Side view of assembly

Next we will replace valve seals and grind valve openings for a better seal. All 48 of them!
Fig 34.  Next valves were removed and new seals inserted   Fig 35.  Used a valve spring compressor tool to remove the tappet lock cone in order to remove the valve springs.
Fig 36.   Fig 37.
Fig 38. The head was found to be slightly warped.
A common problem with engine overheating. It was refaced in a machine shop so it has a exact flat surface.
Fig 38. Using grinding paste each valve is then reseated in the head.   Fig 39. Madlyhs found out that the valve seals from a BMW V12 engine are exactly the same in shape, size, color, and material as that from Lamborghini. The complete set (48 pieces) cost $50 ONLY a saving of $1390.

For Reassembly, M
adlyhs then placed the lower washers followed by the springs and the upper washers. With the valve spring compressor tool he compressed each spring in order to install the tappet lock cone.  We then used lubricating oil and placed the tappet & shim for each valve position on its original place. With this the head is now ready to be installed on the cylinder block.
Fig 39.  The valve seals are inserted   Fig 40.
Fig 41.  Head before valve replacement   Fig 42.  Head after valve replacement
Fig 43. It was realized that there was no way to install the engine oil pump/water pump housing with the oil sump/Diff installed first.
Sadly there was no other option but to remove the Oil Sump/Diff first in order to install the timing /housing.
  Fig 44. Sump removed.
Fig 45. Install lower timing chains   Fig 46. Now cam chains
Fig 47. New and old chain guides   Fig 48. Cam chains with chain guides installed.
Fig 49. re-install the oil sump/Diff.  Had to remove the old silicon gasket before applying a new silicon gasket to complete the installation.
  Fig 50. Cam chains cover installed
Fig 51.  Head gasket   Fig 52. Flywheel installed.

Next install the head gasket and then the heads.  Used a torque wrench as the head needed to be tighten first 70 NM, then 90 NM, and final torque 110NM. Also installed the flywheel in preparation to set up the timing.
Fig 53.   Fig 54.

This is the most critical part of the job and needed to be done accurately and according to the work shop manual...We confirmed that piston 1 was in TDC and we placed the cams for the left side head first.  Then installed the chain tensioner and positioned the cam so that the reference marks on the Cam and the Cap Coincided.  This part took a while to get it spot on as it is difficult once the chain is installed. Moreover the cam position will move slightly once you install Cap on the Cam and tighten it. After making sure both Cams reference marks and Cap coincide.  Then placed all the other Caps according to their position and secured them. 

Note, before we disassembled the engine we positioned piston 1 in TDC , and we marked the cams and phase sensors positions. Obviously we made sure that rotor arm coincide with piston 1 on the distributor body during reassembly.
Fig 55 Install com rods   Fig 56 Adjust to TDC
Fig 57. Tighten chain guide.   Fig 58. Finish cam supports 
Fig 59. Install cam covers    Fig 60 Install plug guides 
Fig 61. Install end gaskets    Fig 62. Install pulse generator 
Refurbishing A 1993 Diablo Engine and Clutch (Continued - Second Page)
Repairing the Clutch    
See this section for pictures about repairing the clutch in this car.    
Checking Out Rear Differential    
While no problems were anticipated. It is always a good idea to check out the rear differential when the engine is out of the car. This process is described here.















































































This page was last modified on 03/12/2014

This page was last modified on 09/06/2014