Rav4 3VZ V6 Conversion

1998 Rav4 - 3vz V6 conversion

This Blog is a write up on converting my 1998' Rav 4 with 3s-fe engine to 3vz-fe in the hope that someone will find some useful info, or be inspired to convert their own rav. The blog will be posted in sections from top to bottom - as a build thread from start to finish. Each time I complete a stage of the project I'll add a post to the bottom until it is finished.

First up a bit of history why I decided on the 3vz conversion. I've been looking around for a donor engine to put in my Rav4 as the 3s engine was smoking at startup & I was considering replacing the engine with a rebuilt 5s, 3s, 1mz or 3vz. The cost of a rebuilt engine was about the same for all of the engines, so it really came down to whether it was worth the extra effort to get a V6 into the engine bay.

The 5s was clearly the best option as it was the simplest to install & would get the extra capacity & torque, and would drop straight in re-using all of the existing 3s manifold, ecu etc. essentially just dropping in the long block engine would have been easy.

The 1mz-fe was what I was really keeping an eye out for as the mountain of power from this engine with only a couple extra Kg weight over the 3s installation would have been awesome. Installing the 1mz would have been the most complex. Finding a manual transmission 1MZ camry or getting a front cut / engine with wiring loom, then rebuilding it would have been the most expensive option as well. Either that or buying an already rebuilt 1MZ then sourcing all of the parts for the conversion would be a mammoth task.

Finally the 3vz with it's forged crank, steel block & forced induction potential is what really what pushed me in that direction. The extra weight (25kg) over the 1mz was a bit of a downside and the fact that I found out later the 3vz has head gasket problems with the stock head gaskets.

I had been keeping an eye out for 92' - 02' Camry's for wrecking as a donor car was the best option, and a 95' V6 camry vienta turned up for less than $600. As a bonus it had a manual transmission (E53) so the ECU & Flywheel issues were not a problem. Later after testing the engine, I found out that it had a leaking head gasket, so a rebuild was inevitable.

Much of this conversion process is valid for the 1MZ-FE and if you can find a manual donor car with the E153 Transmission, you'll be in the best position for a conversion where you could possibly get away with not rebuilding the engine and getting a decent life out of it.

Posted by ST: 9th May 2013

E53 to AWD Transmission Conversion

The Rav 3s engine with it's E250F gearbox (AWD) is excellent for a 4cyl 2L engine, but my concern with this conversion was that the V6 would be doing those same revs at road speed, and when starting off in the Rav's dreadful low 1st gear would become annoying pretty quick. Below the gear ratio's for the Rav E250F & Camry E53;

Rav4 E250F

1st - 3.833
2nd - 1.913
3rd - 1.258
4th - 0.918
5th - 0.775
Final - 4.933
Example Speed 110km/h at 3100rpm in 5th gear

Camry E53

1st - 3.538
2nd - 2.045
3rd - 1.333
4th - 1.028
5th - 0.820
Final - 3.625
Example Speed 110km/h at 2400rpm in 5th gear

After a LOT of reasearch, I found that there were a lot of similarities between all of the toyota E & S manual transaxle families. Both of mine were E series so I was even more confident that there may be the possiblity to swap parts between them. Ultimately I wanted to have the AWD diff out of the Rav 4 put into the camry gearbox, which is exactly what I've ended up doing!

Research

Although I couldn't find a diagrammatic version of the rav AWD Manual transaxle & transfer case, I could find an E153 from the AWD 3s-gte celica.

Camry 3vz E53 Transaxle

3s-gte E153 Transaxle & Transfer Case

You can see that the E153 AWD trans - like the E250F - has a front differential, & centre differential inside the differential case, then it has 3 shafts inside eachother going through to the transfer case. the centre shaft goes through to the right hand side to the front right wheel. The shaft around that goes to a ring gear which drives a pinion driving to the rear diff at the bottom of the image. The final outside shaft is connected to the outside of the front/centre diff case & has a locking hub which locks the 2nd & 3rd shaft together which is the centre diff lock. You'll see all of this in images in later posts. The E53 transmission only has a single differential, however the differential case is the same as the E250F (and E153 presumably).

Transaxles; From the information I've found from various places regarding Camry, Rav, MR2 & Celica Manual transaxles I've deduced the following;

S51 from Camry 2.2L & E250F Rav - Weakest gearboxes.
S53/E53 - I think they are pretty much the same gearbox with different ratios

The E53 has a longer centre section & heavier gears than the S51/E250F.

E153 - Even heavier version of the E53 used in the GT4 Celica AWD.

What I've ended up doing is swapping the ring gear off of the front/centre E250F differential & putting the camry ring gear onto it. then installing the E250F diff into the camry transaxle. I like the fact that the gearing will be the same as driving the camry & also the gears are a lot heavier than the standard rav trans.

Posted by ST: 9th May 2013

Dissasembling the E250F & E53 Transaxles #1

Transaxle Comparisons

Below are a couple pictures of the E53 & E250F Transaxles.

You can see from the last image with the E53 on left that the centre section of the gearbox is 40mm longer than the Rav's E250F trans. Fortunately the bolt holes for all of the mounting points are in exactly the same location from the clutch end (left on last picture), so that all mounts will bolt on & fit up to the Rav perfectly. This means that the E53 gearbox will be 40mm longer, so may have to modify the cover in the wheel well for this which is no big deal. You'll also notice the black 5th gear cover at the right end is pressed steel plate on the E250 while the E53 has cast aluminium which is a lot thicker.

Transfer Box

Left to right; E53 Cover plate, E53 Cover plate removed, E250F Transfer box removed,
The E250F has 2 additional Studs for the Transfer box which might be able to be removed & installed on the E53 Trans.

Dissasembling 5th Gear

You can see the difference in gear size between 5th gears. Left is E53, right E250F. The 5th gears are interchangeable between gearboxes because they are the same height, spline etc... so if I so desired I'd be able to have the 0.775:1 5th instead of 0.82:1, but would loose the strength of having a stronger gear. There is the possibility of putting the 0.731:1 5th gear from the E153, however that paired with a final drive ratio of 3.625:1 would mean I'd be sitting on 2100rpm at 110kph, which is a little low, even for such a big engine in the rav. I'm keeping the 0.82 gearing in the E53.

Posted by ST: 10th May 2013

Dissasembling the E250F & E53 Transaxles #2

Main Case Dissasembly

Here are a couple pics disassembling the central transmission.

Since all of toyota's transaxles are all pretty much the same, you can use the S51, E250F, E53 or E153 or other similar workshop manuals to help dismantle everything. The Rav4's E250F manual was pretty hopeless, having short explanations for what to do, and hard to follow part/bolt names. I ended up using the S51 manual for all of the torque specs as I was just guessing what bolt was what from the Rav's manual. All of the torque settings are the same between these transaxles.

Differentials

Left is a pic of the Camry & right is the Rav Diff.

The Camry has a separate row of bolts on the inside to hold the diff internally together, but the rav only has the bolts around the ring gear. This means that when you undo the bolts on the ring gear, the whole diff comes apart... Shown below.

You can see in these pics that there are indeed 2 diffs inside one enclosure. It's a very clever setup for such a small differential. The left is with the ring gear still attached & right is after I've pressed it off. You will need an actual press to get the ring gear off as it's held on quite tight. You can keep the diff together by installing service bolts, there's 4 positions behind the ring gear near the nylon speedo gear where you can put these.

Here are the ring gears compared... the teeth on the smaller E53 trans are beefier & fewer, and diameter is less by about 10mm which you'd expect going from 4.9:1 to 3.6:1.

Here is the ring gear installed on the AWD Rav Diff. The Manual suggests boiling the ring gear in water to fit it on which is what I did, but only got the water up to about 80deg C & the gear dropped straight on. I was told to run an oxy over the ring gear before reading the manual, but boiling some water & dropping the ring gear in seemed to me to be the better option.

Now we need to remove the taper bearings from both the diff & trans cases of both, and swap them over. This is because you should always keep the bearing sets together. I'd suggest at this point that it'd be a good idea to get a new set of bearings, however I kept the same ones because I couldn't figure out how to press the bearings off of the rav diff. You'll need to remove the outer oil seal, then remove the oil baffle (the blue thing) before you can press the bearing halves out. Pressing the bearings out is a very tricky procedure, and you'll need the right tools (75mm bearing puller - which you will need back at the start to pull the 5th gear anyway). I swapped the oil baffle from the E250F to the E53, and you will need to use a E250F oil seal to fit the Rav CV shafts as the camry has different size. Since the cases are physically the same, the oil seal fits perfect.

Posted by ST: 10th May 2013

E53 Transaxle Reassembly

Here are a couple pics of the jig I made to hold the diff while torquing the bolts on the diff. The bolt holes I'm using are the service bolt's around the back of the diff. The service manual suggests clamping the ring gear in a vice while tightening these bolts, but since there were some holes there I thought a jig would be the better option.

Now we're ready to re-assemble the trans. First up the diff installing as per the E250 Manual, you need to install the differential & output shaft & measure the side bearing preload, & the output shaft preload. You will need to assemble the transmission without the FIPG and test the torque that it takes to start turning the diff, then the output shaft. Mine were close enough to being in spec to not worry about changing the shims. The shim for the differential side bearing is hard to change as you need to use the bearing puller to press out the bearing halve on the oil baffle/oil seal side.

Next up remove the case halve & remove the output shaft. Install the input & output shaft together as they won't go in separately. In goes the reverse idler gear & rocker arm, the three selector shafts & selectors.

Case halve goes on with the FIPG gasket. You need to either use the genuine Toyota Red FIPG which is about $40 for the tube or a FIPG that is suitable for use with gear oil. The standard off the shelf stuff, even the high temp red/copper will eventually fail as it's not suitable for use with gear oil. It needs to be specifically for differentials or manual gearboxes. I used the toyota red FIPG.

AWD Transfer Box

Now there's the problem of installing the bolt studs. The genuine bolt studs are M12x1.25 68mm long. Unfortunately they were not available here in AUS, so I've ended up getting 1m of high tensile threaded rod and making my own studs. The problem is that they were not zinc plated, so would rust & be pretty hard to get off next time so I got some "cold galv" & painted them. I'll also paint them after installing just to make sure it's not going to rust. Left is the original stud in the E250F Trans, Right are the new high tensile threaded rod studs. I cut them with a hacksaw - which took a very long time - as I didn't want heat de-grading the tensile strength of the stud using a friction saw. This may not be necessary but thought I'd take the precaution.

Next is sliding the transfer case into place & doing up the bolts

Posted by ST: 27th May 2013

Additional Pics Differentials;

Left E250 (Rav), right E53 (Camry)

E53 Dissasembled;

E53 inside gearbox;

The rest of the images are on the previous post "Dissasembling the E250F & E53 Transaxles #2"

Updated by ST: 19th Sept 2016

3VZ-FE Top End Rebuild

Engine Removal

Now onto the V6. Removal of the engine from the donor car took me about 8 hours. Disconnecting everything and labelling everything then using a hoist to lower the engine and engine subframe (suspension crossmember & engine mounts) out of the bottom of the car.

I ran the engine when it was in the car and it used a bit of water while running for 1/2 hour, and there wasn't any water leaking anywhere so i suspected head gaskets. After research on the net, these engines are known to have head gasket issues around 200,000k's so decided on a top end rebuild.

Dissasembly

First up took heaps of pictures of the engine at all angles so that when I re-assembled, I could refer to the images to figure out where everything went. Here's a heap of images of dissasembly.

The heads were pulled and the block cleaned mating face cleaned off with razor & finished with 800grit wet/dry sandpaper with a flat edge. The heads were sent off to a local head machining shop and found out that one of the heads was corroded to a point where it could not be repaired where it mates with the intake manifold. 2 second hand heads later I arrived with 2 fully reconditioned heads for less than $500. then onto re-assembly.

All up the top end rebuild kit + head rebuild cost me less than $1k

Posted on 19.06.2014