Tech:Engine/K Series/Blocks

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All K Motors are watercooled inline 30-degree slant 4-cylinders, have overhead valves with pushrods, and are driven by a single or double row timing chain. Ranging from 1.0 to 1.8L made from 1966 to present, they appear in Corolla RWD (KE series), Publica and Starlet RWD (KP series), and various Toyota Vans. Currently still in production in the TownAce SBV (7K) and Toyota Industrial forklifts (4K).

Models up to 4K have points-style distributors, some 4K, and all later motors have an electronic distributor, of which there is an external ignitor dizzy on 4Ks and internal ignitor model on 5/7K. There is one common manifold stud design across all Ks, however sumps can vary depending on vehicle application

4K onwards have a 10mm higher deck height than 3K and earlier. All Ks have an aluminium alloy head, the 1K, 3K and 4K combustion center is in the head, while 5K and 7K perform combustion in the cylnder bore (called a heron-type combustion chamber). 1K-5K heads are interchangeable (disregarding the resulting compression), however 7K head bolt pattern is different to all the others, in that it has 3 more bolt positions neaar the pushrods

Dished piston 4Ks did exist, in the 4K-U and 4K-E variants, each having different piston dish capacity. Most 5Ks are dished, but there are some 5k's with flat top pistons, these engines also can have solid lifters,however aftermarket flat-top pistons do exist.

The diaphragm-type fuel pump is mounted on the side of the block and actuated by a lobe on the camshaft. The injected 4K-E has a different rocker cover than the others due to intake plenum design. Oil filter is Toyota Genuine Parts 15601-33021 (Ryco Z68). The small oil filter from 4A engine (part no?) also fits, as does a large Ford Z9 filter.

K-5K blocks have the same bellhousing studs and engine mount points, so you can drop a 5K in place of your 1K without a problem. 7K Blocks are wider than the others, and while the gearbox pattern is the same, there can be issues with Engine mounts. 3K stock mounts have been used with success, but the sump requires modification to clear the crossmember.

Automatic cars have a different engine backing plate than the manuals, but all gearboxes bolt up to all engine blocks.

The Gregories says this more eloquently than I can:

The five bearing crankshaft and flywheel are dynamically balanced and crankshaft end play is controlled at the centre main journal by thrust washers which are separate from the main bearings. The main big end bearings are replaceable steel backed shells. The cam ground alloy pistons are equipped with two compression rings and one oil control ring. The fully floating gudgeon pin is offset towards the camshaft side of the engine and is secured by circlips at both ends. Connecting rods are H section forged steel. The camshaft is chain driven and supported in four precision type bearings. The aluminium alloy cylinder head is designed with wedge shaped combustion chambers to allow efficient heat distribution. These wedge type chambers, together with independant inlet and outlet ports, provide smooth performance during all operating conditions. The lubrication system is a forced feed, full flow filtering type. The trochoid gear type oil pump is driven through the distributor shaft from the camshaft. The oil filter is a spin-on throw away type.

Note: The Build a Tough K Motor article mentions the better quality pistons, but as per rob83ke70's experience, they can't be swapped to a 4k as they will foul with the crank. Link to Thread.--Philbey 12:32, 22 February 2009 (EST)


Engine Year Displacement BHP Torque (lb-ft) Bore (mm)
Stroke (mm)
CR Notes
K 66-69 1077 [email protected] [email protected] 75 61 9:1  
K-B 68-69 1077 [email protected] [email protected] 75 61 10:1 sprinter twincarb
2K 69-88 993 [email protected] [email protected] 72 61 9:1  
3K 69-77 1166 [email protected] [email protected] 75 66 9:1  
3K-B 69-75 1166 [email protected] [email protected] 75 66 10:1 sprinter twincarb
3K-D 69-77 1166 [email protected] [email protected] 75 66 10:1 dual carb
3K-H 74-79 1166 [email protected]   75 66 9:1  
3K-C 77-79 1166 [email protected]   75 66 8.5:1 Californian emissions
4K 78-89+ 1290     75 73    
4K 80-81 1290 [email protected]   75 73 9:1  
4K-U 82 1290 [email protected] [email protected] 75 73 9:1 Japanese emissions
4K 82-84 1290 [email protected] [email protected] 75 73 9.4:1  
4K-C 81-82 1290 [email protected] [email protected] 75 73 9:1 Californian emissions
4K-E 82-84 1290 [email protected] [email protected] 75 73 9.5:1 Fuel Injection
5K 83-89 1496 [email protected] [email protected] 80.5 73 9.3:1  
7K 98 1781 [email protected] [email protected] 80.5 87.5 9:1  

Please note that these are intended to be FACTORY quoted BHP and torque figures.

Article by Superjamie

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