F12s to get Jake Brake
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EXCLUSIVE
• By the middle of next year Volvo F12 truck operators will be able to fit their tractive units with the legendary Jake Brake.
The Jacobs Vehicle Equipment Company has developed a new version of the popular secondary engine brake, designated the 122, specifically for the 12litre Volvo engine. It is claimed to provide up to 160kW (215hp) of retarding power at 2,100rpm, and up to 187kW (250hp) when used in combination with the F12's exhaust brake.
Mike Spencer of Jake Brake EC, Jacob's UK importer, says the 122 engine compression brake has been approved by Volvo for retrofit and will be offered on TD120, TD121 and TD122 versions of the popular 12-litre engine.
Volvo and Jacobs are now discussing making the Jake Brake an on-line option. Initially the UK will have a "very, very limited release from January 1992", says Spencer, "with full availability from 1 April".
The move "marks the first example of an expanding trend towards US style engines in European heavy duty truck markets", says Jacobs in America. Test trucks with the 122 Jake Brake have already been evaluated in the US, and on the Continent by Jacob's French distributor EBS, which displayed it at the Paris Show in October.
The 122 retarder weighs ar ound 30kg and fits on the cylinder head. It works by converting the engine into a compressor, popping the exhaust valve just before the piston reaches top dead centre to stop the normal ignition phase. The forward motion of the truck then forces the piston back down on the next corn pression stroke.
The Jake Brake has three stages — high, low, and off — controlled by a switch on the dash. It is operated via switches mounted on the throttle and clutch pedal. Spencer describes the 122 model as "a combination brake" which is best used together with the existing F12 exhaust brake.
ln addition to the new retarder for Volvo, Jacobs has also developed a Jake Brake for Mitsubishi truck engines.
Some UK hauliers already run the Jake Brake on Cummins 10 and 14-litre engines and with the Caterpillar 3306B and 3406B diesels in Foden trucks.