ISF exshaut manifold

[BTCC_ Racer]

Hi all,

I was hoping someone could help me.

Can someone confirm if the manifold flange which connects to the engine is supposed to be loose and not connected to the pipes?

Im on my way to the garage so pic will follow shortly.

 

Thanks

[BTCC_ Racer]

Pic added, is this normal? The flange moves but there is no holes, otherside is coming off.

[4969_LXS]

Hi @BTCC_ Racer. They should be attached. That's the infamous manifold failure. The garage might be able to reweld them together as the cheapest option.

[hockeyedwards]

Known problem as mentioned above, could be worth a go on the 'ol welder, I think a few people have replaced them with PPE ones as I'd imagine OEM might be a smidge hard to come by and maybe ££.

[Charliecloud]

I don't think that's the 'infamous' failure - which refers to the manifold cracking. Unless you have any cracks then that looks how it should be.

I don't know this from personal experience, just looking online, I have seen lots of stock exhausts looking like that.

@Womble72 changed his a while back, I'm sure he will be able to put you on the right path.

[BTCC_ Racer]

From what it looks like that part of the flange is supposed to have movement. However the other manifold is far worse:

I’m going to see if this can be welded up. On my way to the welder. 

 

[4969_LXS]

After looking at the images again, I agree with @Charliecloud, the first pictures don't look cracked, try and wiggle the flange on the other two cylinders of that same manifold, if it's loose then it should be that way.

The second set of images of the manifold looks like mine when it cracked, cracks on the last cylinder where all the gases meet, mine was the drivers side manifold that cracked.

apologies for the wrong information, I've only ever seen when the flange is loose it's broken.

[BTCC_ Racer]

16 minutes ago, 4969_LXS said:

After looking at the images again, I agree with @Charliecloud, the first pictures don't look cracked, try and wiggle the flange on the other two cylinders of that same manifold, if it's loose then it should be that way.

The second set of images of the manifold looks like mine when it cracked, cracks on the last cylinder where all the gases meet, mine was the drivers side manifold that cracked.

apologies for the wrong information, I've only ever seen when the flange is loose it's broken.

Your spot on. The flange easily wiggles up and seals correctly - that’s the first pic passenger side.

Anyhow the driverssides just been welded. The garage is going to file it down and make it smooth as possible.

 

 

[Womble72]

Flanges are supposed to be loose, the welded branches are where the design flaw is, there is no flexibility on the welded ones, from memory I think the flange/weld are arse about face which is the design flaw, the stress on the welds is the issue, I had mine changed as the only real answer is to tig weld and a pyramid style of about 3 layers, the labour is the biggest expense hence why I changed mine over to the GSF ones, the branches are bigger/bigger bore and the design has been rectified…… mine went at 49k and has never been tracked and only the odd spirited drive……. I think they rectified the design when things were updated during the ISF build….. BUT they are about £800-ish a side from lexus.

[BTCC_ Racer]

Your correct as there is no movement on the welded ones they let go over time. If the manifold fails again GSF ones for sure. I'll keep an eye out!

On a separate note is the brake fluid a Dot 4 or Dot 5.1 Im getting different answers even from Lexus.

 

Thanks

[Womble72]

52 minutes ago, BTCC_ Racer said:

Your correct as there is no movement on the welded ones they let go over time. If the manifold fails again GSF ones for sure. I'll keep an eye out!

On a separate note is the brake fluid a Dot 4 or Dot 5.1 Im getting different answers even from Lexus.

 

Thanks

If u go GSF Lexus will not fit them, they’re funny about ISF - GSF parts and what goes with what, u will also need the heat shields are they have different locating holes, not sure about brake fluid mine has always been serviced by my local specialist 

[BTCC_ Racer]

Little update, the weld sorted out the engine ticking noise! Alongside this, I had all the fluids doing including the gearbox and diff oils. Also had the Radiator changed. Drives like new!

[C.B]

Who did the manifold work? Just in case my manifold ever goes since you are local be good to have someone who has done it before.

[BTCC_ Racer]

20 hours ago, C.B said:

Who did the manifold work? Just in case my manifold ever goes since you are local be good to have someone who has done it before.

Local garage to me near Manchester, he works on alot of Toyota's, 50 years experience, his yard was full of toyotas and Lexus. He had't taken of a manifold of a ISF before but undertook the challenge without a problem, however I had to wait alot longer than he originally quoted, partly due to him catching covid and he's very slow at work but fussy about getting it right which he did. Taking the manifold off which was a pain, he had to lower the subframe a little to gain sufficient access so quite labour intensive. I then got a local exhaust specialist to carry out the weld as they carry out exhaust and manifold repairs all day. 

I viewed a lower miler lexus before buying mine and that also had a ticking noise on cold start, alot of people think its normal or a timing chain noise, however it's the manifold. Its really a factory fault and lexus should have sorted this out, the amount of mess it makes around your heat shields with the carbon is really something else and not forgetting your engines not 100% optimal.

[NothernDan]

Yep, @Twellsie and me have the same issue (tick, tick, tick) on cold start. Looking at either GSF replacements or (if we can get a set of old headers to use as a template) we can look at getting some UK made catless versions name up. Import costs on PPE versions are the killer.

 

I don't suppose @Womble72 has his old headers laying about or if anyone knows the part numbers for the gsf versions and the various other parts required for thr job (heatshields etc) as mentioned above?

[4969_LXS]

Hi Dan, there was a thread about some UK made manifolds that might be useful for you, I've put a full stop comment on to bring it onto the 1st page. @YN57OCK had some manifolds made and fitted to his car. I believe STG performance undertook the work.

@YN57OCK would you be able to provide any more details about it ?