Compression Ratio Is the Decision

Everything else on this page follows from one number, and getting it wrong is the most expensive mistake in an engine build.

  • 7.8:1 forged (+.040") — for serious boost. Low compression gives you the detonation margin that lets a turbo or high-boost supercharger make real power safely.
  • 10.0:1 forged, in +.020" and +.040" — the sensible performance compression for a strong naturally aspirated engine or a mild low-boost build.
  • 12.5:1 forged (+.040") — race compression. Requires race fuel and a naturally aspirated combination.

Fitting high compression pistons and then adding boost is how engines get destroyed. Decide which one you are building before you order.

The class-legal one

The 12.5:1 destroked to 2.5L set exists for a specific reason: short course off-road classes that cap displacement at 2.5 litres. They carry valve reliefs for 2.5mm oversized valves and an anti-friction coating. If you are not racing to that rule, you do not want these.

Street pistons

For a rebuild rather than a race build, the Street Performer sets come complete with rings in STD, +.020", +.030" and +.040". Matching Hastings ring sets are available separately in the same oversizes.

All of our forged pistons now ship with gas nitride rings as standard — originally developed for boost, and useful on any engine because the material seals at a thinner cross-section, which reduces friction. See the Turbo page for the full explanation.

Connecting Rods — Two Different Answers

Both are chromoly and both are a large step up from the factory rod. They are built differently and suit different budgets.

Crossbeam rods are custom made and suit anything from stock-style to high-torque long-rod engines. They come fully balanced with bronze pin bushings and ARP rod bolts. This is the best chromoly rod we offer.

Spool H-beam rods are a two-piece chromoly forging in 4340 steel — high carbon, and considerably better than the low-carbon 51-series steel used in cheaper rods — with ARP 2000 fasteners as standard.

The honest guidance: a healthy factory rod is good to a surprisingly high power level on this engine. Upgrade rods when you are adding serious boost or serious rpm, not as a default.

Crankshaft

The new OEM Toyota crankshaft (13411-75901) is a genuine forged replacement. If yours is damaged or has been ground past a usable size, a new crank is often cheaper than the alternative once machining and undersize bearings are counted.

Bearings — Coated or Not?

The range covers stock rebuilds through to race:

  • Standard main, rod and thrust sets for a normal rebuild, plus 0.25mm and 0.50mm undersizes for a ground crank.
  • Coated sets — the coating survives the moments when oil film is marginal, which is exactly when a bearing gets hurt. Worth it on any engine that will see boost, high rpm or steep angles.
  • Clevite 77 rod bearings and Safety Auto sets for different budgets.

Measure your crank before ordering. Undersize bearings on a standard crank, or standard bearings on a ground one, will destroy the engine on the first start.

Studs and Fasteners

The Pro main stud set clamps the main caps more evenly than the factory bolts and does not drag the block threads while torquing. It belongs in any engine seeing boost or high rpm.

For a stock rebuild, OEM main bolts and OEM rod bolts are correct. Both are replace-on-assembly parts — do not reuse them.

Also here: street rod bushings, the crankshaft key set and brass freeze plugs, which are a sensible upgrade over steel while the block is bare.

Harmonic Balancer — and the Leak It Causes

The elastomer in the factory balancer deteriorates with age, which costs performance and lets vibration through to the crank. The OE replacement balancer is the fix.

If you have a persistent oil leak at the balancer, stop replacing the seal. The usual cause is a groove worn into the balancer's seal surface by the old seal, and a new seal riding in that groove leaks immediately.

The Seal Saver is a repair sleeve that presses onto the balancer to give the seal a fresh smooth surface to ride on. There is an equivalent Seal Saver for the rear main, and the OEM front seal and balancer bolt are also here.

Build Combinations That Work

  • Stock rebuild — Street Performer pistons and rings, standard bearings, OEM bolts. Start at Rebuild Kits.
  • Naturally aspirated performance — 10.0:1 forged, coated bearings, main studs, factory rods.
  • Supercharged or turbo, serious — 7.8:1 forged, coated bearings, main studs, upgraded rods, and a matched valve train.
  • Race, naturally aspirated — 12.5:1, Crossbeam rods, race fuel.

Specifying a bottom end? Tell us the power target, the fuel and what the truck does and we will put the combination together with you.

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