SUPERTECH bronze valve guides Ford Mazda 2.5 L5-VE BGDA BGDC

The Ford and Mazda engines concerned

This set fits the 16-valve head of the four-cylinder 2.5 litre sold as the MZR L5-VE by Mazda and as the Duratec by Ford. It is found in the Mazda 3 (BL), Mazda 5, Mazda 6 (GH) and CX-7, and in the Ford Transit Connect (S7GA, S7GB) and the hybrid Kuga III (BGDA, BGDC).

SUPERTECH reference GDE-DUR16 covers inlet and exhaust alike: 5.5 mm bore, 11.055 mm outside diameter, 39 mm length. A lot holds 8 guides; the set combines two of them, which gives the 16 guides of the head.

SUPERTECH valve guides for Ford and Mazda 2.5

Seated in the head casting, the guide channels each valve stem toward its seat and takes up part of its heat; the stem seal also locates on it. Once the bore ovalises, the stem floats, the valve returns badly and oil finds its way into the chamber: more oil used, bluish smoke, compression that crumbles.

SUPERTECH turns this kit in manganese bronze, a metal built on copper. The maker says it lets heat out far more freely than the sintered guides from the production line. It most often goes in with reinforced valves. A lot of 8 fills one row of valves, hence the two lots in the kit.

Valve guide technical specifications

Valve guide installation

Technical guide

Reinforced valves are also in our catalogue for the exhaust side:

Our brand

Founded in California, SUPERTECH has designed valve train parts for racing for roughly thirty years: valves, springs, retainers, guides. Each novelty is first calculated on computer, then inspected by ultrasound, radiography and laser, and finally tried on engines belonging to experienced builders.

Manganese bronze

Copper leads, with aluminium, iron, manganese and a little zinc added: this bronze is hard, wears slowly under friction and shrugs off corrosion. It turns up in heavily loaded bearings, hence its appeal for guiding a valve stem.

When valve guides must be replaced

• Oil vanishing with no visible leak, blue smoke when cold
• Reinforced valves meant for an already tired head
• Engine built for competition, head due to be refreshed
• Valve train reworked from top to bottom

Vehicle compatibility

Remember the valve stem seals

Changing the guides is the right moment to fit new valve stem seals as well: they stop the oil running down the stem toward the combustion chamber.