What is Laycock overdrive?
What is Laycock overdrive?
At the press of a button or flip of a switch (depending on the car) in the cockpit, the overdrive would engage and lower the engine speed relative to the driveshaft, markedly improving fuel economy. …
How does a Laycock overdrive work?
Laycock Overdrive A and D Type cone clutch, which was operated by hydraulic pressure. Pressurized oil is fed to the positions when the solenoid lifts a lever and raises the control and ball valves. Laycock Overdrive J Type. This raises the pressure in the circuit and forces the operating pistons down their bores.
How does overdrive work?
An overdrive consists of an electrically or hydraulically operated epicyclic gear train bolted behind the transmission unit. It can either couple the input driveshaft directly to the output shaft (or propeller shaft) (1:1), or increase the output speed so that it turns faster than the input shaft (1:1 + n).
What is a Laycock?
Laycock is an English surname, likely originating from the placename Lacock, in Wiltshire (which is pronounced Laycock) or Laycock in West Yorkshire. According to the 1990 United States Census, Laycock is the 22,119th most common surname.
How does a Laycock type a overdrive unit work?
Brief description of the unit: The Laycock O/D has a number of working components including a pair of hydraulically operated pistons which move after the driver selects O/D. These move a cone clutch attached on splines to a sun gear, to stall them both onto a brake ring attached to the O/D body. This running surface on the cone clutch is
Can a Laycock overdrive be replaced on a Volvo?
That wasn’t such an issue—the tank needed to be replaced, anyway. The Laycock overdrive is common on older Volvos. These are often listed on ebay—without the front drive shaft.
Where is the annulus on a Laycock overdrive?
In the Laycock overdrive unit, the annulus was mounted on the output shaft of the unit and drove the propeller shaft and the planet carrier was splined on to the output shaft of the main gearbox. The sun gear was mounted on a sleeve which slid over the gearbox output shaft and splined to the sun gear was a cone clutch.
What kind of transmission did a Laycock J have?
Laycock J-Type Control System. The solenoid for this overdrive unit had only one winding which drew about 2 amps and the solenoid plunger acted directly on the control valve. When the transmission was in direct drive, oil was pumped past the crowns of the operating pistons to a relief valve.
What kind of cars can a Laycock overdrive be fitted to?
As all-in-one 5-speeds with integrated overdrive became de rigeur, the Laycock Overdrive faded from the scene. Until the late ’80s, the Laycock Overdrive was fitted to a wide variety of cars, not just Volvos: Jaguars, MGs, Austin Healeys, Alpines and Triumphs, among others, were available with the unit.
Is the Laycock solenoid an overdrive unit?
The solenoid in particular could be finicky on higher mileage cars, and frequently the overdrive unit had its own fill and drain plug separate from the “main” transmission, requiring a unique maintenance interval. As all-in-one 5-speeds with integrated overdrive became de rigeur, the Laycock Overdrive faded from the scene.
In the Laycock overdrive unit, the annulus was mounted on the output shaft of the unit and drove the propeller shaft and the planet carrier was splined on to the output shaft of the main gearbox. The sun gear was mounted on a sleeve which slid over the gearbox output shaft and splined to the sun gear was a cone clutch.
How big is a Laycock Model J overdrive?
I began a search that led to a Laycock model J overdrive, about the size and shape of a small watermelon. It fit nicely in mid-frame. I installed two drive shafts, one from the to transmission to the overdrive, the second from the overdrive to the rear end.
