3S-GTE Fitment to NA Celica


Any 3S-GTE can be fitted to any front wheel drive Celica shell that was originally fitted with a 3S or 5S series engine.    Mounting is identical in each case,  however the plumbing and wiring will vary in each case.

This is not intended as a blow by blow installation procedure.  Hopefully this will give you enough guidance and confidence to go do your own research to find out what goes where.  To complete this type of project you need to have the ability to figure things out for yourself and not rely on others to show you how to do it.  To be blunt,  if you read this and then come back to me with the query "how do I do this conversion", then you don't have the capability to perform this.

So you want to the later engine to your Celica then do you?  Well ST205 GT-Four motors are not overly easy to find,  let alone at a decent price.  Late SW20 Turbo motors are more common but much more is involved in terms of fitment.  ST165 and ST185 engines are now commonplace and reasonably priced. 

A note with buying a used engine,   while earlier 3S-GTE engines may be cheaper than later engines, consider that the later engines come with larger injectors, larger throttle bodies  and many other advantages that can easily offset the price differential, especially if you intend to modify the engine. 

A 3S-GTE motor will almost literally bolt straight into a front wheel drive car,  after all all "S" series blocks share common mounting locations.  The mounts on the gearbox are in the same locations and your older cambelt end mount bolts straight up to the block.

Toyota use (I believe) "S" series front wheel drive manual gearboxes in the Celicas.  All forced induction 3S-GTE engines use the stronger "E" series gearboxes.  How much stronger?  I can't really say,  how long is a piece of string?  Is the "S" series strong enough??  Who knows,  depends how you drive/abuse it.  Are there alternatives?   Yes!

There are people using the E153 transmission from the MR2 Turbo.  The shift levers must be removed and replaced with those from a GT-Four gearbox (possibility others may fit?).  An alternative driveshaft must be sourced.  I believe there is also a Camry V6 manual gearbox used in some markets that may be used.  And no a 4A-GZE "E" series gearbox will not work,  the bellhousing is different.

If you use an air-air intercooler ST185 motor you will need to either modify the bonnet or got front mount air-air.  The ST165 water-air IC will fit under any Celica hood,  I can't comment on the larger ST185RC or ST205 intercoolers.  I've seen photos of cars with plain NA hoods fitted with these engines but I cannot confirm what other changes were made. Note however that the ST185RC and ST205 hoods are actually budged to clear the intercooler.

Radiator and heater hoses are in the same locations so no worries there.  Your existing AC pump will bolt straight up to any engine. You will need to retain the AC system from your original bodyshell, in that all original sensors and plumbing should be used. Power steering pump and even alternator are interchangeable between all GT-Four motors,  however ST185 and ST205 alternators will only fit a ST165 without the cooling shield.  The PS and alternator brackets are common fitment across all models.  '86-'91 70A GT-Four alternators use different size plugs from '91-'99 80A alternators however the plugs are easily swapped as required.

Wiring will be the main issue,  the newer engine wiring will have to be interfaced to the older car harness.  Both wiring diagrams will clearly be needed.  This is where the main complexity of the swap is and good troubleshooting skills are required. Note that a Japanese spec Celica motor has the harness enter the firewall at the distributor end of the rear of the engine,   whereas US spec cars have the harness at the cambelt end of the rear of the motor.   All MR2 engines have the harness at the distributor end of the head however the interface wiring is completely different.  Basically if changing an engine from one body type to another expect a significant amount of rewiring. 

Good luck!


Info gleaned off the net:

1. The alternator bracket/engine hook is different - 2nd gen's wont fit. The alternator itself is the same though.

2. The accessories tensioner (below the alt) is different - 2nd gen won't fit. Then you'll need to cut off the rear support arm to clear the water outlet on the 2nd gen. block.

3. The water outlet / elbow is different - 2nd gens wont fit. There are four outlets on the 2rd gen:

A. water temp sensor
B. water temp sender (for the gauge)
C. cold start injector signal
D. A/C water temp.

There are 2 sensors on the 3rd gen - water temp sensor and water temp sender. You'll need to tap a hole for the A/C temp if you plan on keeping the A/C.

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