SUPERTECH bronze inlet valve guides Subaru BRZ Toyota GT86 FA20 4U-GSE

The Subaru and Toyota engines concerned

These guides fit the cylinder heads of the 2.0 litre flat-four sold as the FA20 by Subaru (FA20D, FA20E and FA20F versions) and as the 4U-GSE by Toyota. It powers the Subaru BRZ, WRX, Forester XT, Levorg, Outback and Legacy, and the Toyota GT86.

The inlet guides in this set carry SUPERTECH reference GDE-TFRS55-I-8: 5.5 mm bore, 10.05 mm outside diameter, 41.3 mm length. The lot of 8 matches the eight inlet guides of the engine; the exhaust guides have a page of their own. Subaru lists the original guide as 13212-AA231 on the FA20F.

SUPERTECH inlet valve guides for Subaru and Toyota FA20

On a flat engine each head carries its guides right beside the inlet valves: they keep the stem true, drain part of its heat into the head alloy and give the stem seal its seat. Once worn they let the stem play; oil drawn in by inlet vacuum then runs into the chamber, which shows up as blue smoke, more frequent top-ups and a drop in compression.

SUPERTECH chose manganese bronze for these guides. The maker states that it carries heat away noticeably faster than the sintered metal fitted at the factory, and they are normally paired with reinforced valves. The lot of 8 covers exactly the inlet side of the engine.

Valve guide technical specifications

Valve guide installation

Technical guide

For the inlet, reinforced valves also appear in the catalogue:

Our brand

For more than thirty years in Silicon Valley, SUPERTECH has made valves, springs, titanium retainers and racing guides, calculated with finite element analysis and then validated with engine builders.

Manganese bronze

This bronze is copper-based, with zinc, aluminium, iron and manganese added. It stands up well to rubbing and to corrosive surroundings, and you find it in bearings and bushes under heavy load, hence its use as a valve guide. Its hardness holds up under heat.

When valve guides must be replaced

• Oil level dropping with no leak, blue smoke when cold
• Reinforced inlet valves for a high-mileage head
• Boxer prepared for track days or a turbo conversion
• Heads removed and rebuilt

Vehicle compatibility

OEM reference (inlet valve guide): 13212-AA231 (Subaru FA20F)

Remember the exhaust guides and the valve stem seals

New guides call for new stem seals: with the head off, take the chance to change both.