3T GTE Tech

[YelloRolla]

question - when engine was rebuilt i couldn't source new sprockets.

I'm worried that they've died and that's why my timing chain died / came off.

Are new sprockets available anywhere? Like toyota Japan?

And i remember a dude on here replaced the timing setup with a $500 setup from USA, just wondered they fit it and how it performs etc?

Replacement sprockets are available from Kameari - these are new ones with extra knock pin holes to allow different cam timing.

Sorry to hear about you engine, I wouldn't worry about trying to predict where the the failur has occurred, just check it as you pull it down and diagnose it with an open mind.

Please let me know if I can assist with the rebuild.

jason

[steeko]

Thanks for the reply yellow rolla, my car has a 10,000km guarantee but I think it's still my fault for not replacing the sprockets. But wont truly know till we've pulled it apart.

are these the sprockets you're talking of? one is 13hole adjustable, the other is infinitely adjustable:

http://www.kameariusa.com/2TG_Campulley.php

[YelloRolla]

Either or would be nice.

I have never seen the sprockets in these engines to be excessively worn. It is my personal bet that they got something wrong.

[3jcelica]

Steeko,

As YelloRolla says something has gone wrong, something has fallen into the timing chain cover area and been caught in the chain if the sprockets are dead. I have never seen a sprocket fail catastrophically because of wear.


After numerous playing around with my oil pump, pulling the sump off six times with the engine in the car, blowing the seals out of two oil filters, and blowing up two mechanical gauges. I ran the car last year with oil pressure peaking off the gauge, had to run a 2t pump with the pressure relief hole ported to ~14mm almost the same size as the oil outlet feed.

Observing my oil pressure it would act ok until about 3000rpm but would just rocket off the scale, so I figured I am still not getting any relief.

The whole time I have been using the same upper body section, the one that I ported the crap out of. Each of the six times I changed something I cleaned the pressure relief valve in carby cleaner and blew out with compressed air.

When my engine was rebuilt six months ago we noticed the pressure relief spring had previously been cut must of been 12 years ago before I bought the engine. So someone had experienced this problem in the past.

I bought a brand new 2t mellings replacement oil pump (which did not fit due to the lower section being in compatabilte with my sump) and even used the pressure relief valve and piston from this in my old ported housing without joy.

Getting sick of having so much pressure with oil seeping out all the banjo fittings and oil pump shaft near the head, seeping out the oil filter seal etc decided to put the ugly looking mellings pump body in with new pressure relief piston and spring (the mellings pump is cast iron and the original is alloy). At the same time bolted in the original 3tgte pump shaft and gears for higher flow into the mellings upper body. Hey presto 30psi cold idle (5w30 oil) and 65 -70 psi max pressure when cold. Damn am I happy.

So after all my theory, the problem is the bore on the pressure relief valve wears due to the alloy body and steel piston after many years and results in a stuck relief piston. Putting in a new body fixes the problem.

A long write up I know, but only explains half of what I have been through but gee I am happy.

Roger

[steeko]

Thanks for the info.. Only thing we didn't replace on my engine was sprockets and tensioner

[3sgte]

Finally got me a 3T-GTE!

It came with a complete car:


I need to fix the engine before I put it on the road.

The engine doesn't look to have ever been mucked with.
It hasn't run in about 3-4 years.
I bought it knowing that the engine was bad.

I did a compression test tonight,
the readings were:
1: 8kgf/cm2 (113 psi)
2: 8kgf/cm2 (113 psi)
3: 8kgf/cm2 (113 psi)
4: 0kgf/cm2 (0 psi)

My buddy has a little penlight/microscope borescope kind of thing, and we pulled the plugs and took a few pictures in #4 cylinder:




I have never looked through one of these before, and I can't really make out whether that is just carbon on the piston, or whether it is detonation damage.

I will be pulling the engine, I just wondered if anyone had any thoughts.

[TheToyman75]

Mike,

The most common type of Piston Failure in a 3T-GTE is breaking of the ringlands. You wont be able to see this until the piston is removed from the bore.

Then you will probably find something like this:


Those curved bits of casting to the right of the piston are bits of the ring lands that have cracked off. The rings lands being the bits of casting between the rings which you can still see on the piston.

That was Number 4 too from memory

[TheToyman75]

Thanks for the info.. Only thing we didn't replace on my engine was sprockets and tensioner

Steeko,

I would bet running for President at the next AGM naked on the cause of your problem not being the sprockets. Tensioner maybe, but not the sprokets.

Do you have any images of the damage ?. And when you do pull it apart pay very close attention to looking for any loose bits inside the sump or timing cover. Anything that could have been bouncing around in there,

[3sgte]

Toyman75,

Thanks.
Right now I am trying to figure out whether to get a used engine for parts, or just strip this one down.

I have seen a bunch of 3sgte pistons with busted lands, and in these the fire also melted away a chunk of the piston.
I am totally not looking for massive hp, so a repair with used parts sounds fine to me.

Edit:
Is there a common trigger/cause for ring land failure I should be looking out for on a bog-stock motor?

[TheToyman75]

Mike,

The factory pistons are a cast item and are not very forgiving to detonation.

If your going to pull the engine down anyway then a set of new pistons and rings would be a worth investment. You can get a set of forged pistons for these things (including rings) for less than $1000 so regardless of the power you think you might be chasing i would recommend fitting them.

Fitting a second hand piston is an option but not one I would entertain for an engine I was keeping.

[steeko]

Mech had a look, busted chain and bent valves so far. Builder is bewildered at failure and yes tensioner and sprockets are fine. Mech has guaranteed work and will fix it all, but we first gotta find out why it failed.

[Spectre]

For anyone here looking for a 3TGTE package, I've got a complete running 200hp setup that is currently in a TA22

http://www.toymods.org.au/forums/showthread.php?t=65445

[steeko]

works out timing chain guide had a bolt come loose which killed the chain. Isnt there a lower chain guide too? And can u buy new ones?

[3jcelica]

steeko,

Good news that the mechanic is going to fix it, it did sound like something got caught down there.

there is a lower guide and a lower tensionser. Yes I belive you can buy both of these new, and they are the same as 2tc/3tc parts. Upper guide and slipper are hard to find new or second hand, tensioner is avaliable, but can be rebuilt.

Hope you are back up and running shortly.

Roger

[turbotoy]

Is it just me or am I seeing a pattern in #4 failures? Any input?