I'm not crazy... 3fe cam gear slipped 10 degrees

[Sand or Foam]

@george_tlc I guess I kind of did, but if the composite gear is such a POS, why don't we see more of them fail?

But you guys do have me rethinking my gear selection. Might have to see if Dan will except returns and get an early all metal F gear.

 

[george_tlc]

I'm sure (grain of salt...) that the composite will last a long time, but look at all the crap you had to do to get to it. If it was steel...

I don't mind some effort to sound suppression, but not inside an engine where major work needs to be done if that rubber/plastic/composite thing decides to s*** itself.

cheers,
george.

 

[Tools R Us]

I get that metal is going to be more durable, but why can't I find other instances of composite gears failing in 3fe's? The only time I did see the cam gear fail was on a rebuilt motor that had a shiny black plastic gear used. And that one lost a whole section of teeth.

I went with a new Toyota composite gear, because I have yet to see any threads on those failing and if this one lasted 200k+, why not stay stock? Not trying to argue, I am just curious as to why everyone seems to always go metal.

Because, well,,, most would prefer to never have to deal with it again, especially with the work, pain required to get to it? Agree it's not an epidemic failure but, yours is not the first, have seen them stripped, teeth worn causing timing drift/power loss, and cracked. The only downside to the solid steel gear is slightly more noise.

IIRC, the ITM 50060 is solid steel, likely offshore, if that matters to you? Rockauto lists it for $26.79.

 

[FJ40Jim]

There is a good quality, made in Japan, solid steel gear set available from Melling.

 

[Juan Ramirez]

Hi guys! Just replaced mine with a metal gear from cruiser parts and it's noisy as hell. Kinda rethinking this. I get that it will last longer but..... Anyone else replace theirs with metal and how long did the noise last? Thanks in advance for the info!

 

[LazyEye]

Yes, the fiber composite gear is a known weakness. Toyota changed from fiber composite (early F) to all metal (mid F) then to a steel outer gear with elastomer ring (late F & all 2F) then back to the composite. It was done to reduce gear whine.
Upgrade to the F solid steel gears for maximum durability and supercharger whine.

so from your statement then is there a good chance that the 92 3F-E has the all metal gear or the steel outer gear with elastomer ring?
i own a 92 fj80, and now after reading this thread i'm feeling a bit paranoid.

 

[christooopher]

If any one cares, the cam is out and I was able to get a better video of what is happening. The composite gear is rotating on the metal center hub. Any thoughts on how this might have happened? In all my searching I can not find anyone else with this issue in a 3fe...


And for future reference, this is where you need to get the truck to pull the cam out with the engine in an 80.

So it’s a big job, that would cost a ton, if ya laid someone to do it?

 

[FJ40Jim]

Yes.

 

[javaman]

Thank you for this post mr "Sand or Foam"

After my newly acquired FJ75RV Troopcarrier suddenly lost all compression I trawled through the internet and took me here.

I am documenting the process to help others with similar issue:

FJ75 3F Timing Gear replacement

Lost all compressions suddenly. Checked and timing was off. 516,000km on the clock. Bought oem fibre gear and cover gasket

forum.ih8mud.com

There is no mention about maintenance interval of these fibre timing gear in toyota shop manual. I didn't even know they were not steel. For sure doesn't last a lifetime and I reckon a scheduled replacement at 300-400K would be a good preventive measure.

 

[javaman]

My gear slipped much more than yours. Let's say... 90 deg!

It was a blessing in disguise as the engine wouldn't run at all (no compression) and did not have the chance to burn valves etc.

I "simply" replaced it and all worked normally now. No bent valves/pushrods etc. phew!

 

[CruiserDM]

@george_tlc I guess I kind of did, but if the composite gear is such a POS, why don't we see more of them fail?

But you guys do have me rethinking my gear selection. Might have to see if Dan will except returns and get an early all metal F gear.

So after all was said and done, nice and steady acceleration? No more power jump around 2500 rpm?

 

[jonheld]

So after all was said and done, nice and steady acceleration? No more power jump around 2500 rpm?

On a 3FE, a power surge around 2100 RPM indicates an issue with the EGR system. From my 3FE tune up document, "The EGR valve and modulator (flying saucers mounted on top left of intake manifold) both have rubber diaphragms inside that become brittle with age and heat. They tend to disintegrate and the resulting particles can clog vacuum lines. A faulty EGR system will yield poor acceleration under 2100 RPM and feel like a turbo kicked in above that range."

 

[CruiserDM]

On a 3FE, a power surge around 2100 RPM indicates an issue with the EGR system. From my 3FE tune up document, "The EGR valve and modulator (flying saucers mounted on top left of intake manifold) both have rubber diaphragms inside that become brittle with age and heat. They tend to disintegrate and the resulting particles can clog vacuum lines. A faulty EGR system will yield poor acceleration under 2100 RPM and feel like a turbo kicked in above that range."

Hey Jon! Your documents are great. I've replaced everything using your tune-up doc (Except for EGR stuff, I just finished my EGR Delete).

It's definitely running better now but still has that power surge in the mid 2k rpm range. I currently have no O2 sensors though, as the previous owner had their cats stolen and the thief chopped off the O2 bung part of the pipes too. There are currently some cheap aftermarket cats installed, but I'm planning on buying these rockauto pipes with bungs to have functioning O2 sensors again:

Could the missing O2 sensors cause this issue? Or do I need to somehow relearn the ECU to the newly installed EGR delete? I'm planning to try a smoke machine to look for vacuum leaks if these pipes don't help.

 

[jonheld]

Hey Jon! Your documents are great. I've replaced everything using your tune-up doc (Except for EGR stuff, I just finished my EGR Delete).

It's definitely running better now but still has that power surge in the mid 2k rpm range. I currently have no O2 sensors though, as the previous owner had their cats stolen and the thief chopped off the O2 bung part of the pipes too. There are currently some cheap aftermarket cats installed, but I'm planning on buying these rockauto pipes with bungs to have functioning O2 sensors again:

Could the missing O2 sensors cause this issue? Or do I need to somehow relearn the ECU to the newly installed EGR delete? I'm planning to try a smoke machine to look for vacuum leaks if these pipes don't help.

For downpipes and cats, I've used these with good success.

6 Cylinder 1991 TOYOTA Catalytic Converters

discountconverter.com

The O2 sensors provide feedback to the ECU for fuel trim. I would definitely replace them.
Anytime you replace a sensor or do any work under the hood (even a simple tune up) I would reset the ECU. This clears out the memory along with any stored error codes and forces it to relearn the sensors. True for both the 3FE and the 1FZ.

 

[CruiserDM]

For downpipes and cats, I've used these with good success.

6 Cylinder 1991 TOYOTA Catalytic Converters

discountconverter.com

The O2 sensors provide feedback to the ECU for fuel trim. I would definitely replace them.
Anytime you replace a sensor or do any work under the hood (even a simple tune up) I would reset the ECU. This clears out the memory along with any stored error codes and forces it to relearn the sensors. True for both the 3FE and the 1FZ.

Is an ECU Reset completed just by pulling the EFI fuse for a few minutes? Thanks for the feedback, will check out those cats.

 

[jonheld]

Is an ECU Reset completed just by pulling the EFI fuse for a few minutes? Thanks for the feedback, will check out those cats.

Exactly. The 15 amp EFI fuse in the relay box on the left fender. Less invasive than pulling battery terminals, but either one will work.

 

[jonheld]

Thanks for the feedback, will check out those cats.

With any aftermarket exhaust parts, make sure you use OEM hardware and gaskets. The ones that come with the "kits" are very inferior. That includes O2 sensor hardware.
Make sure you use high temp anti-seize like Loctite LB 8036 on all studs and hardware.
To further complicate the issue, yotashop.com sells weld in Toyota O2 flanges with hardware, KIT-1098. Comes with the weld in flange, studs, nuts, and gasket for $19.