LT Texan

I bought some of these off ebay years ago and had problems getting them installed. And I gave up.

I have the engine out in order to replace the cam tower gaskets, so I thought best time to give it another try.

The first problem I had was that the bolt holes would not line up. I solved that by re-drilling the guide holes on the inside of the outside runners. I used a 3/8" bit and it just gave enough clearance for them to fit. The manifold's inside diameter at the head is quite a bit larger than the '86 Euro S head's exhaust port (I ditched the stock heads when I rebuilt the engine a couple years ago), so I figure no problem there.



The next thing was to bolt everything up to see how it fits. (Yes there is a wide band oxygen sensor fitting downstream of the cat and yes I am going to bash the cat material out and yes my car is exempt from emissions.)



I understood that a spacer is required for the right hand side manifold to downpipe. And that is exactly what I saw, albeit, with an offset.



The gap between the manifold and the downpipe flange is 32mm.



But the thing that concerns me is that the manifold is outboard about 12mm from the downpipe.





Is this the same experience others have had?

I always understood this was a simple swap with a spacer. I don't want to fail twice and put those boat anchor cast iron jobs back on!!!!

Imo000

Heat up the first bend on the Y pipe and re alight it.

Landseer

Thanks for this post. I needed to know that dimension!!!!.
Exactly the topic Jadz and I discussed this weekend.
He was recounting doing this back in about 99 or 00.

Am doing similar.
Cut the flanges off a scrap 84 cat yesterday.
They, opposing each other, with a little wire welding and a sliver of pipe, will become my spacer.

I, too, had to overdrill those holes. Used 27/64. Took about 90 seconds.

LT Texan

man, I want a welder.

Just paid Meineke $100 to weld up the test pipe fittings on the manifolds and to weld on the fitting for the O2 sensor.

SMTCapeCod

Elongate the holes...I purchased a pre-fabbed spacer from the folks in Utah. Heat relief to aid alignment is a good idea. Still bummed that someone else scored the Euro front muffler from 928 intl during half-off..I was looking for one of those for years (despite the drawbacks..)

'86 Euro head..any flow data/cam profiles that go with that on-hand?

soupcan

I might have one, go a part # or pic so I can confirm?

Lizard928

I have done this on another car.

Yes your dimensions are correct. So a simple spacer will not work.

I cut the pipe, and had a spare old cat to steal a chunk of the same pipe. I then TIG welded that short chunk of pipe into place.

IcemanG17

I also did this on the 928 Estate....I found it easier to cut the pipe and extend it vs making a flange adaptor...since straight pipe is much easier to cut-weld and add in

toofast928

I have an X pipe FS with the right extension already welded in. Bolts right up to the 16V. PM me if interested.
Tony

hacker-pschorr

Looks good to me.

I had to elongate the two front most holes & Todd made me a spacer out of a solid piece of stainless. Overkill yes, but quick and easy for him to bore a hole for the exhaust & add three small ones for the bolts.

I purchased a nice SS Y off an 85/86 from 928 Intl, fit like a glove.

Landseer

Might be the better way, especially for Dan.
In my case, was trying to not alter the cat.
Wanted to be able to cycle that piece across other cars as needed...

UncleMaz

This is a very timely thread as I am expecting a set of 85-86 manifolds directly. Lots of good advice here. Thanks.

LT Texan

Sorry, no. Just bone stock euro S heads and cam.

LT Texan

I'm thinking insert two pieces of pipe.

One to the left section to move the flange outward, then

Second below the flange to meet the manifold.

sharknoob

You may not like the sound if you gut the cat.