1HD-T Engine Rebuild Kit - Toyota

Article number: EKTO350 1HD-T Engine Rebulid Kit
Availability: In stock (1)

Engine Rebuild Kit - Toyota 1HDT w/Head Bolts - specify sizes before ordering

Engine Kit prices may be subject to change without notice.

The kit that is in stock has 1993 & later Standard size pistons. The bearing sizes can be selected from the "Kit Contents" selection below with the exception of cam bearings which are only available as Std. at this time.

If you require a different piston size or need a kit, please send a request and I will order them in for you.

Special Order Items - Please carefully read the description below prior to ordering your engine kit by writing a detailed message to RADD Cruisers. 

Engine kits are typically custom prepared for each engine rebuild depending on what parts sizing you need for pistons, bearings and the other parts you need to complete your rebuild.

As availability allows, items may be subbed in or out of the kits if you would like higher performance options for your rebuild and the kit price adjusted accordingly. A common request is for the ACL Race Series bearings to be used instead of the Japanese-made Taiho bearings which are what is supplied with the kit. Taiho is an OEM supplier of engine bearings for Toyota.

--> Performance options are listed at the bottom of this description

Other items are sold as add-ons, you can select other items to place in your shopping cart, or if they do not exist on this eCom site yet please contact us directly.

The process:

The engine rebuilding process typically starts with carefully tearing the engine down and having the parts inspected and measured by your engine machinist against the factory specifications. Once the wear has been determined, the various components can be machined for the correct fitment of new parts according to the available sizes.

Fitment of the head gasket is one of the last things that takes place, and is determined by careful measurement of the piston protrusion at several points for each cylinder across all 6 cylinders. It is important for smooth running that the piston protrusions are identical between bores, or at least very, very close.

Pistons may be "topped" by your machinist to correct for very minor discrepancies in piston protrusions. Discuss this with your engine machinist, otherwise you're going to have get your rods adjusted for operating length through resizing the big end bearing.

Pre topped piston sets may be ordered for your kit at additional cost; these piston sets are pre-topped 0.15mm in compression height to correct for block decking that may cause interference when even the thickest head gasket is used.

Early vs Late pistons 

There should be some discussion about early vs late 1HD-T pistons and the connecting rod bearing problem.

For the 1993 model year (starts 08/1992), the 1HD-T received pistons that had design changes to the dimensions of the combustion chamber. The overall volume of the combustion chamber remained unchanged, however the physical dimensions are quite different and the bowl is somewhat larger in diameter and correspondingly shallower.

Research into the con rod bearing problem has pointed to oil cavitation occurring at certain RPM ranges due to engine harmonics causing premature bearing failure. I feel that it is worthwhile that anyone who is rebuilding their 1HD-T consider upgrading their pistons to the later design as this may reduce the magnitude of the problem. It is critical, however, when this is done the appropriate injector washers are also used as these correct the injector nozzle height in the combustion chamber for the later piston design.

I do not have objective, well-researched information about early vs later engines and how the con rod bearings hold out, however my subjective response is that there appears to be a reduction in the con rod bearing problem with the later piston design.

Some engine tuners have also speculated that they feel engines using the later piston design may produce slightly more power and less smoke.

Kit Contents:

  • Piston Set (6) w/pins
  • Piston Ring, Set (6)
  • Rod Bearing, set (6) (Std., 0.25, 0.50. 0.75mm)
  • Main Bearings, set (Std., 0.25, 0.50. 0.75mm)
  • Thrust Bearings, set (Std. only)
  • Cam Bearings, set (Std., 0.25)
  • Piston Pin Bushings, semi-finished
  • Head Gasket, Gr. 5 is supplied unless you specify - see Factory Service Manual (grades: 1, 3, 5)
  • Engine Gasket Set (no head gasket) - has injector washers
  • Head Bolt Set (26 pcs)
  • 49203S Liquid Gasket, 85gr tube
  • MSMI0001.00 Fitment Pack - contains bore wipes, assembly lubricant, rod bolt protectors and other small items
  • ES-TOY40R1 Specification Sheet for you engine rebuild


Other parts to Consider (not included in kit & available at additional cost):


Performance Options (all special order items, and availability dependent):

ARP 2000 Head Stud Kits (26 studs)
There are two options for using ARP head studs; while the 1/2" studs are stronger, the 11mm items require no additional machine work to fit and are by far the most popular way to go.
• Drop-in fit 11mm - direct fit replacement for the stock TTY head bolts. Typically 40% greater head clamping force over the stock head bolts.
• Machine in fit 1/2" UNC Stud Kit (requires drilling & tapping the block, increasing the diameter of the bolt holes in the head).

Performance Piston Sets - available in Std. 0.50mm & 1.00mm
Pistons are available in "Performance" versions by request that are pre-topped and have anodized and ceramic coated crowns, along with teflon/moly coated skirts. These pistons are also strutted and have Alfin inserts in the top ring grooves.

Gapless Piston Ring Sets - available in Std. 0.50mm & 1.00mm
Improves performance and efficiency, and reduces boost pressure induced blowby.
Total Seal Gapless second ring

High Performance Head Gasket by Cometic available in Grade 3, 5 & Grade 7.
The Gr. 7 gasket is a special item for times when there is too much piston protrusion (0.726 - 0.825 mm) in your 1HDT rebuild.

ACL Race Series Connecting Rod Bearings (6B8396H)
• Available in Undersizes: Std., 0.025mm, 0.25mm, Oversize 0.025mm

ACL Race Series Main Bearings (7M8397H)
• Available in Undersizes: Std., 0.025mm, 0.25mm, Oversizes 0.025mm
• ACL Race series bearings are also available in sizes that permit for extra oil clearance of -0.025mm in both con rod and main bearings. These are known as the HX Series, and are special order items.

Forged Billet Connecting Rod Sets
High performance Chromoly forged connecting rods (available in later 2022)

Stainless Steel Frost/Core Plug Kit (PKETO330A)
31 piece all stainless steel plug kit

Oil Filter Cooler Adapter
to run an external oil cooler

Head Saver Shim
0.25mm gasket shim to correct for excessive piston protrusion beyond what the Gr. 5 gasket will permit. Typically this is used when there has been additional material removed from the deck of the block beyond the factory tolerance.

Front Timing Gear Inner Case assembly with oil pump installed

Front Timing Gear Outer Case assembly when wear is evident at the injection pump support & drive gear bearing

Over-length oil pressure relief valve (corrects for worn valves and bores which can generate oil pressure spikes)

Performance Intake and Exhaust Valve Sets

Performance Valve Spring Sets

Heavy Duty Hi-FLow Cooling Fan & Clutch
Testing indicates an average 4-8C drop in engine operating temperature, and a corresponding improvement in AC condenser cooling. Some testing has shown greater than 8C drops in temperature, depending on engine configuration. Available with either a 32mm or 42.5mm long adapter spacer.

Electric Water Pump conversion kit
Allows the use of an external electric water pump
An electric radiator fan must also be fitted

This product description is being actively updated as new information becomes available - November 2022



2022 11 15

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