TR250, 5, 6 Solid copper head gasket nominally 0.8mm thick (depending on material availability, the gasket may be slightly thicker or thinner). our gaskets come with fitting instructions to show how to adjust the shape of the gasket to ideally suit the dimensions of the head and how to anneal the gasket before use. These gaskets are renewable once re-annealed.

Available in nominal thicknesses of 0.8, 1.0 and 1.5mm, various thicknesses allow for alteration to compression ratio especially where too much material has been removed from the head in the past. Suitable for all engines of standard bore upwards. These gaskets come with fitting instructions as they need to be annealed before use and can be reused after annealing. Care must be taken when fitting these gaskets to ensure a gas tight seal. Yamabond is recommended for normal applications and Wills rings for high performance applications.

We are often asked if it is acceptable to skim xxxx thousands of an inch or xxxx mm of a cylinder head when another (usually longer duration) cam is installed.
This approach to head skimming, whilst in principle is correct (to increase compression ratio with a longer duration cam), by simply shaving off a number or thou is not the correct way to go about it as there are other factors to consider such as gasket thickness, combustion chamber size and piston diameter.
What you should be doing is: -
1. Measure deck height (height of pistons below the face of the block)
2. Measure piston diameter
3. Measure head volume (usually done with a piece of Perspex set over the head with grease to act as a sealant with two small holes, one to introduce measured quantities of paraffin and the other to let air out)
4. Measure gasket thickness. The special head gaskets we supply made of solid copper can be shaped to match the combustion chamber. This would be 1-1.5mm thick usually if the head is likely to be skimmed. In some cases the head is already too thin in which case we have various sizes up to 2.5mm thick.
5. Choose a suitable compression ration as advised by your cam supplier (likely to be 9.75-10:1 for a fast road cam, up to 10.5:1 for a sprint or rally cam and up to 11.5:1 for a race cam)

You will need, and we can supply

Copper head gasket which can be fashioned to suit the head shape.
Heldite sealant
Suitable push rods
Other gaskets

Once you have done this you can expect the engine to run badly until it is properly tuned on a rolling road to ensure the engine's ignition and carburation settings are correct throughout the rev and power range. Depending on where you are in the world that might prove easy or difficult. For those customers within reach of RevingtonTR in Somerset we can offer this tuning service as we have an 800hp rolling road in our workshops.

This part is listed on the following page of the website, where further information and background reading may be found.

Engine, Transmission, wheels/Tyres and Heating/Cooling » SPECIAL HEAD GASKETS