My header arrived today but there was no donut gasket with it, so i thought i'll just get one from any exhaust place. I measured the collector to get an exact size and found that its oval in shape. Its exactly 2.5" OD in one direction and 2.6" OD in the opposite direction I have never seen this before in a collector. I have emailed the guy who i bought it off and he said he'll try and get me one but it would be monday before he could talk to his supplier in japan. I really wanted to fit this tomorrow and wondered if it would be possible to shave 1/8" of both inner sides of a 2.5" donut to widen it? What are they usually made from...from memory theyre pretty soft and so this shouldnt be too big a task if i take my time and test fit it every so often to ensure i dont take too much off??? Any help or advice galdly welcome. Heres some pics>>>

2.5" OD


2.6" OD (sorry about crap focus)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mugenracer &raquo;</TD></TR><TR><TD CLASS="quote">I really wanted to fit this tomorrow and wondered if it would be possible to shave 1/8" of both inner sides of a 2.5" donut to widen it? What are they usually made from...from memory theyre pretty soft and so this shouldnt be too big a task if i take my time and test fit it every so often to ensure i dont take too much off??? Any help or advice galdly welcome.</TD></TR></TABLE>

I have no idea why the collector would be oval shaped (and whether it's intentionally designed that way or simply a manufacturing defect), but you shouldn't have a problem removing some material from the donut gasket in order to get it to fit. The gasket is constructed from a relatively soft graphite material with metal reinforcement. As you said, just test fit it occasionally, take your time, and you should be fine.

 

That's strange. Even if the donut will fit, the question is whether it will leak at the cat flange side.
The donut should be 65 mm.

The primary tubes looks kinda narrow...

 

Have you tried fitting a gasket yet?

Eventhough it is out of round, the gasket is somewhat flexible and should press around it I'd assume.

I was told to use the S2k donut for my JDM DC (2.5"), perhaps you can mosey on down to the stealership and perform a "test fit"

 

I say bent and should be replaced at their cost.

 

its likely to leak unless you find an oval donut.. sounds like defectife collector. send it back

 

I dont see how it would leak...if i get a normal round gasket and shave the inside of it on two sides so that the inner circumference is oval, then the outer shape is still going to be round and will fit perfectly into the cat inlet flange.


Modified by mugenracer at 11:36 PM 3/11/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mugenracer &raquo;</TD></TR><TR><TD CLASS="quote">I dont see how it would leak...if i get a normal round gasket and shave the inside of it on two sides so that the inner circumference is oval, then the outer shape is still going to be round and will fit perfectly into the cat inlet flange. </TD></TR></TABLE>

I agree. I don't understand why others would state that they feel it will leak. Personally, I don't think you will have any issues with modifying a standard 2.5" donut to fit.

 

I have just been taking a look at it again...i do now think that its a defect. Its only slightly out of shape and the most i would have to shave of the inside of a donut gasket is 1/16th inch on both sides so its pretty small...and as i said above the gasket will still be round. I'll buy two gaskets tomorrow and have a go at shaving one to fit. (couldnt be bothered with all the hassle of sending it back to the seller in the Uk and him having to ship it off to japan again...its not that big a problem)

 

Problem solved...i bought a 2.5" donut gasket today expecting to have to shave it slightly but due to the soft nature of them it fitted straight on without any problem. There is a little gap of 1/6th of an inch either side but its on tight and so should seal perfectly in the cat flange. The gasket cost me just $5 for one made by Bosal intended for a Peugeot 506/7!