Metal Gaskets Need Extra Torque?

[cowie165]

Hi guys

Replaced the front and rear pipe and tightened to the torque setting listed in the manual, being 37-44ftlb.

At idle -> 3,000rpm things are fine.

When actually driving, at 2,000rpm or so it starts making that sound like you have a hole in the exhaust.

Do you need to overtighten when using a metal gasket instead of a cardboard one? I know the existing one was cardboard/gasket paper.

Cheers guys, regardless, I'll be under the car again in the morning and we'll try 60ftlb on those biatch nuts.

[PHATR32]

i think all exhuast gaskets are metal, so therefore you should need to over tighten. did you use some exhaust sealer??

also, were the surfaces clean?

steve

Edited February 2, 2006 by PHATR32

[MANWHORE]

I wouldkn't worry about using a torch wrench to tighten things like exhaust bolts. For that sort of thing, just do it until it's tight using the appropriate spanner.

If it's an aftermarket exhaust, chances are the surfaces are not flush etc.

[soon2b33]

just following the exhaust theme here rather than start a new topic. i get this flutter under boost. t-t-t-t-t which has worsened to a squeel when cold or at fullboost occasionally.

im not losing boost pressure, and it doesnt come on just free revving in neutral so i cant trace the sound. can it be exhaust manifold gasket?

It looks like a pain to do especialy with all the stuff in the way.. anyone done this? and how long did it take

[cowie165]

i think all exhuast gaskets are metal, so therefore you should need to over tighten. did you use some exhaust sealer??

also, were the surfaces clean?

steve

<{POST_SNAPBACK}>

Hi Steve,

No sealer, on advice from the dude at Auto One. Last time I listen to that guy.

Surfaces were not 'spotless', all previous gasket material removed but could have used a good go-over with a Dremel if I had one. Any ideas on cleaning stock dumps whilst fitted to the car?

Cheers dude!

  I wouldkn't worry about using a torch wrench to tighten things like exhaust bolts. For that sort of thing, just do it until it's tight using the appropriate spanner.

If it's an aftermarket exhaust, chances are the surfaces are not flush etc.

Hi Chris,

Aftermarket exhaust, flanges are dissimilar shape I torqued them because I was concerned if they were too loose then gas may escape but if too tight mightn't allow the gasket to seal properly.

I'm hoping my torque wrench has reverse! I dunno if the breaker bar is up to it again. Well, I won't blame the tools, I just hope I've had enough weet-bix to undo the suckers again.

Cheers guys. I'll jack the car tonight, pipes off early tomorrow morning, will report back one way or another.

Thanks for the advice, it's funny how much sense it makes now. Should I be surprised that two flanges that are slightly different and a little bit dirty make a poor seal on a gasket that doesn't have any goo on it?

...just wanted to try that smilie, hehe

[cowie165]

just following the exhaust theme here rather than start a new topic. i get this flutter under boost. t-t-t-t-t which has worsened to a squeel when cold or at fullboost occasionally.

im not losing boost pressure, and it doesnt come on just free revving in neutral so i cant trace the sound. can it be exhaust manifold gasket?

It looks like a pain to do especialy with all the stuff in the way.. anyone done this? and how long did it take

<{POST_SNAPBACK}>

I had that sound when I had my 180SX. It's just the start I'd say. It was the turbo->dump gasket that had deteriorated. It'll slowly become worse until your beautiful car sounds like a Landrover 110 dragging itself up a hill.

The reason you're not losing boost is because the compressor is still spinning and if it hasn't become laggier then I'd argue it is because the exhaust gases are still flowing through the turbine, but then leaking/venting under the bonnet.

My exhaust noise is barely noticeable when revving in neutral, which is why I lowered the car off the stands and allowed myself a contented grin. First time I actually drove it the car made the dreaded noise.

have to go put kids in the bath, back later.

[cowie165]

Here's a few pics whilst we're here.

Before:

Why I took it off (reason 1):

Why I took it off (reason 2):

Rusted Trust v. Used Hitech

Yes, the pink car is my daily driver and the tools are from SuperCheapAuto

and job done. Or so I thought.

[MANWHOR3]

I wouldkn't use exhaust sealer. It just makes it really nasty to take off.

Basically, what 97 gtst said is correct. When installing my exhaust, I found that some of the flanges had the pipe sticking out by a couple mm. That is, when they welded it, they left the bit of pipe sticking through the flange. I just hit that with the grinder, and it sat flush.

If you look at the gasket, it has a sticky goo substance between it, which gets melted and serves the purpose of the sealer anyway.

phat is correct. There is no such thing as a paper exhuast gasket I didn't need to overtorque. I don't even have a torque wrench. I just grabbed down on the 14 mm and did it up.

[cowie165]

Thanks manwhor3. After having tried not using sealant and putting up with that awful sound, I'm happier to seal it and endure the pain of taking much later down the track. That said, I'll make sure I take a closer look at the flanges when I pull it off and check they are all flush.

Ah, my mistake with the paper gaskets, thought I saw them at the auto shop. I'll try again and we'll see what we see!

Thanks for posting, all great points to read.

[markimak]

Nice gunmetal GTR.. that was my first choice when getting one.

i got a real nice genuine NISMO exhast on my GTR. it came with it.. its too quiet and i think restrictive. middle muffler must have "S" bends.. it also sounds like a leak at low rpms.. whats the prices for a nice 3" turbo back.. RRP?

just wondering how much u paid for ur bits cowie165

Edited February 5, 2006 by markimak

[cowie165]

Thanks Mark. Sorry about the slow reply, been busy after work cleaning and refitting that exhaust! You should have seen how much gunk and gasket bits were left. I cant believe I didn't clean it more thoroughly first time around. I ended up using a wire brush mounted in my cordless drill and that did the trick. Test drive <4,000rpm last night seem ok, I'm taking it to work in 15mins so we'll see how we go...

Funny you mention colour, I've always preferred silver if I had found one when I was looking!

For RRP's try nengun or greenline but even better would be to email Zac at Slidewize and use Zac to buy an exhaust through Yahoo Japan. If you ship it via container it isn't too expensive in postage and they usually sell for cheap or at least competitive prices. That's where I'd go if I had to replace an exhaust.

As far as the Hitech in the picture: I purchased it from another SAU member for $500 and he advertised that he paid $2200 new.

My only other advice is to try and make it out to an SAU cruise so that you can hear a few different exhausts and see what you like the sound of, rather than take a guess or be forced to rely upon a retailers opinion.

Cheers!

[markimak]

thanks cowie165

hitech is the exhast u just put on?

i got a feeling my car is clogged.. hehe