Head Gasket Replacement - Tips/Tricks?

[rlearp]

I am joyfully (not really) disassembling and re-assembling my 907 motor for the purpose of re-freshing it and making sure it'll run decently for my Jensen Healey IT car.

Of course I'll be having to put a head gasket on this thing when I re-assemble and was wondering if there are any tricks to this? This sleeved wet liner engine concept is a little different from everything else I've done and don't want to screw it up.

I assume the gasket needs to be sealed to the liners. If so, with some standard hi-temp and good quality gasket making material do the job?

Thanks for any help from you fellows who have done it before.

Ron

[Esprit2]

Ron,
There are two types of cylinder head gaskets available. The original 907 gasket was a steel/asbestos lamination and it's torqued down using the specs in the manual. In order to better contain the pressures in the 910 turbo engine, Lotus switched to a composite gasket made by Goetze. For that you use a torque-angle meter and a different set of specs... I've pasted them onto the end of this message.

The original cylinder head studs were replaced in production by an upgraded version. For high compression ratios and/or sustained high speed/ full throttle running (IT ?) it's best to switch to the newer studs. The originals are prone to stretching under sustained high cylinder pressures and can lead to blown head gaskets.

For regular track use, I strongly suggest the upgraded studs and the composite cylinder head gasket.

Check the liner nip... the distance the top of the liners protrudes above the perimeter of the block. There's a spec nip range. Then within that range, all four liners must be consistent. If not perfect, then the center liners should be slightly more proud than the end liners.

No sealant is used at the top of the liners. They seal dry and any applied sealant will be counter productive.

The steel laminant gasket must have sealant applied around the outside perimeter where it contacts the cylinder block... sealing the water jacket. Top and bottom, and completely encircle the oil feed passage. The manual specifies Wellseal. Similar period sealants would be Loctite 504/ 524 or Permatex Aviation Form-a-Gasket (stuff in the 4oz bottle with brush applicator cap... don't use the stuff in the little tubes). A more modern sealant would be Loctite 515/ 518/ 574, Permatex Anaerobic Gasket Maker (Loctite 518 private label) or Permabond A136.

The 910 turbo composite gasket is install dry. No sealants anywhere.

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Fitting Instructions for Goetze Cylinder Head Gasket B912E7029Z.

When fitting the Goetze type (grey/brown) cylinder head gasket on any Lotus 900 series engine, use the following tightening procedure and notes:

** Check that the cylinder liner nip is within specification (see Service Notes Technical Data).

** Use the latest type cylinder head studs (B907E0224Z) identified by a dimple machined in the top end. Tighten into the block (with oiled threads) to 37 - 41 Nm (27 - 30 lbf-ft).

** Fit the head gasket DRY .

** Fit cylinder head and washers before oiling the head stud threads and fitting the nuts. Tighten the nuts using a torque/angle gauge, in a sequence from the center outwards, in the following steps:

1) 20 Nm (15 lbf-ft) initial draw down.
2) +75 Degrees
3) +40 Degrees
4) Wait 5-plus minutes
5) +20 Degrees

Good luck,
Tim Engel
Lotus Owners Oftha North