The '3 Amigos' WILL NOT seal!?!? NOW FIXED!!!!

[1ZZ-FE]

Banging my head against a brick wall here guys! Since having the entire exhaust off to do other jobs including pre cat removal, I'm having a ridiculous rise in blood pressure as I cannot seem to get to simple mating faces to seal! With 12 years aircraft maintenance experience, replacing gaskets, torquing nuts/bolts/unions is a daily activity. How on earth I'm getting this wrong defies belief.

Gaskets and studs/nuts are new. Torqued to the settings found on another thread, starting in the middle, following it up with the outer nuts progressively and equidistantly. It leaks. Add 90 degree turn. Still leaks. Remove, 2 further new gaskets assembled with a 'sensor safe' assembly paste. Had an assistant hold the main cat pipe in such a way that the two flanges are square and flush. Yep, still leaks! I had considered it could be the new flexi joints that had been welded in but use of my trusty aircraft high temp leak detector fluid (it bubbles where there is a leak) shows these are indeed sealed.

I've now ordered £25 worth of gaskets from Toyota rather than use the local motor factors incase there is a fitment issue? I'm gonna start again, from the manifold gasket down. Are there any useful pointers from anyone who has had trouble in the past?

Kind regards,
Jim

[Joesson]

I cannot claim your practical experience however when I de catted the OE manifold I had no problems with the new (Toyota) gaskets sealing.
My guess is that it is a problem with the gaskets you are using or possibly an incorrect torque figure, although having only a very long torque wrench I did not use it on the 3 Amigo's.
The Toyota gaskets, 2 off x 174108 are a crush type.
Hope to hear all is well when you try the new (Toyota) gaskets.

[spit]

+1 on Toyota gaskets. My only experience of non-T mani-cat gaskets has been with those that come with the cheapo stainless aftermarket manifold. They are notoriously pants, beaten only by the head-manifold gasket that comes with the kit which is double-pants!

The seal face is the indented ring around the exhaust hole and not on the flange itself, so thats the bit to concentrate on for cleanliness. Hopefully the MrT offerings will work OK. I've only had one poor experience with them. That was when working with 'tinkered' manis and cat pipes, where the recess was far too deep. Doubled-up gaskets solved that one.

Occasionally, the 'bulb' on the studs can impede the full travel of the cat flange onto them. Again, thats something I've only seen with aftermarket stuff and it sounds as though you're already happy that the flanges come together OK.

An outside possibility could be that you have an alignment issue on the mating surfaces due to distortion where the flexis have been welded on, although the flange is pretty chunky so thats something to park further down the list of possibles. The MrT crush gasket will take up some of the minor imperfections.

Oh, and make sure its an exhaust leak you're getting and not a draught from the flywheel. Some folk get confused by that - I'm sure you won't.

[mrzwei]

An outside possibility could be that you have an alignment issue on the mating surfaces due to distortion where the flexis have been welded on, although the flange is pretty chunky so thats something to park further down the list of possibles. The MrT crush gasket will take up some of the minor imperfections.

I had this problem, it was important to torque up the manifold block gasket first and then the three amigos before the lower block bracket fixings. I ended up having to use a nut and bolt on one because of an alignment issue. That was with a 'made in China' cheapo though.

[1ZZ-FE]

Oddly, I had not considered a draught from the flywheel, but it's certainly an exhaust leak. Under partial load it's pretty much inaudible. Anything past half pedal depression and you get that 'rapid tick' of a tiny exhaust leak.

I'm not sure it's a flexi alignment issue - I disconnected the cat pipe from the back box and had a colleague hold the pipe where I wanted to get the flanges nice and flush.

A good point about the blank portion of the stud - I'll inspect those upon removal when I get my Mr T gaskets.

It's reassuring to hear other folk have had issues with aftermarket gaskets. For what is worth, I don't think the crush washers are thick enough as when the flanges at pushed together by hand, the gap between the two is virtually nil, implying the tightening of the stud nuts is there purely to retain the cat pipe and not to compress the gaskets to form the required seal.

Great advice guys, thank you.

Jim

[Anonymous]

I had some motor factor seals and they weren't as thick as the toyota crush seals as you say. I ended up ordering from CTP on here and the crush seals were much thicker. Mine went together without and leaks (so far) so I suppose the issues you are seeing are due to poor quality pattern parts

[1ZZ-FE]

£51 on genuine Toyota gaskets (manifold and downpipe x2), studs and nuts, correctly torqued......im STILL getting the 'rapid tic', such you would get from a leaking manifold. Only heard under load/deep throttle depressions. If it was a tiny hole, i'd expect it to improve as it got warm but it doesn't! Had the leak detector solution on it again.....no leaks.

Really, really, really stuck. Short of replacing the entire exhaust system......suggestions?

Regards,
Jim

[tomaky]

When i got my latest car it had the pre cats removed i noticed a tick noise compared to the last car which had the precats in is this possibly the answer?

[1ZZ-FE]

Seriously?  Wow, I'd never had  thought something like that would cause a tick!?!? But as you've had direct experience of both, and co-incidentally mine is de-pre catted,  that could be the reason. I'd been wondering whether to buy an aftermarket manifold for a while now which would surely eliminate the tick?

Any other decatted members wish to  share their experience?

Thanks mate.
Jim

[Alex Knight]

It's not blown flexis is it?

Mine went and it was hard to pinpoint the blow.

Quite a common fault as these cars age.

[1ZZ-FE]

Flexis are brand new, though it has crossed my mind there's a possibility of a pinhole in one of the welds. Again, leak detector solution was used but still no sign of a leak?!

[vincenzo]

If there is an exhaust leak then you would have found it with the leak detector solution, assuming you've gone over the whole lot? Definitely no leaks from a tiny crack or rust somewhere?

Take a recording of the sound and upload it somewhere.

[tomaky]

You can hear the raspyish ticking, under load for examplew if in too high of a gear you would definitely hear it.

[1ZZ-FE]

Yeah, drive along at 30mph in 4th, a decent press on the accelerator and the tick is heard getting quicker as the engine rpm rises?

[tomaky]

Aii thats the one.

ALways been there Matt said it wasnt leaking and its been MOT'd recently no bothers, i always have and still belive its because the pre-cat chamber is not empty.

[1ZZ-FE]

Just got back from a local garage who bunged a smoke generator up the exhaust tail pipe. Not a single whiff of smoke from anywhere.

Must be a weird side effect of emptying the pre cat chambers. Great excuse for a stainless manifold!

[tomaky]

its not the worst noise in the world to be honest, but it make sense as the sound waves not have a chamber to bounce around, im in the process of decatting the main cat chamber so going to see how that affects the sound.

[1ZZ-FE]

Perhaps not, but I hate noises/rattles/squeaks  that I know shouldn't be there!

[bobbybsings]

Does it go away after ten minutes or so. I have a tick on mine but it goes after a while and I believe it is one of the hydraulic tappets that is not getting oil quick enough. When the oil warms up and starts to get round quicker it goes away.

[1ZZ-FE]

No, it's constant mate. I'm sure someone will be along to correct me if I'm wrong, but these engines have solid lifters/tappets.

Regards,
Jim

[Wabbitkilla]

Solid lifters is correct. Still they do wear and you can check the clearances.

[bobbybsings]

Just shows you that when searching for information read the bloody thing correctly. I mis read a post on tappet noise and thought they were hydraulic tappets. I have since re-read the post and now have no idea what's causing my ticking noise. I think I was happier when I thought it was the tappets:)

[1ZZ-FE]

I should know over the next day or two when I fit my new manifold....I'll report back.

[Anonymous]

I have noticed mine is a bit noisier with the precats removed. Like the ticky/tappy noise these engines have, but a little louder. Maybe it is a side effect.

[1ZZ-FE]

Manifold has arrived at last. Should have that on tomorrow so we'll know for sure.

Regards,
Jim