bigsyke

Both of my civics EJ8-2 and EJ8-4 (d16y8s) have 4-2-1's, 2.25" DNX midpipes to a WS2 and Magnaflow chambered muffler.

Both were running some thick felpro type aluminum grated generic exhaust manifold head gasket. It was the layered type with the aluminum plating with some kind of gasket material on the inside.

They were both also running a NAPA donut collector gasket.

Also I was using the OEM collector spring setup.

The generic manifold gasket wouldve seemed to work, however with several tests, I found it disrupted flow by somehow allowing air to enter, and excape at certain pin hole locations where there wasnt a 100% seal around cylinders 4 and 2. Both cars were torqued to 27lbs in 10lb increments, starting with the center of the 9 nuts. Still with the New gaskets and proper tightening it would leak at 4k+rpms. This leak would disrupt the O2 readings very slightly, and limit throttle response.

The NAPA collector gasket somehow was a few mm's off, and would have a sliver type leak at accelleration, or turning. Ive had the exhausts off the cars many times and always replaced the gaskets.

I finally was sick of turbo sounding leaks, so I went to majestichonda. Got 2x nippon leakless manifold gaskets, and the collector gaskets. #3



and the collectors are #20



From majestic, these were cheaper than napa!

I then wanted something better for the springs holding together the Cat and collector, so I hit ace hardware. I got 4 m8 longer stainless bolts, with 4 stainless fenderwashers to hold the springs. 4 m8 stainless nuts and 4 steel spacers that were just big enough to slip over the stainless bolts, resembling the design of the OEM setup, but would close a little tighter, and the bolts were a little longer, ill try and get pics up. (i only suggest this if you have stiffer engine mounts, since the engines weakest point durring any kind of acceleration is the collector area, and with less flex you could warp the flages)-however for keeping leaks away, i HIGHLY suggest MM inserts anyways, less flex, less leaking.

All I can say is amazing. When I mash on the gas, no more leaking sound and throttle response has improved, more than I thought was possible. The OEM manifold gasket is a 1 time use, so you need to replace it when you remove the manifold, same with the collector gaskets. IMO it is VERY easy to get leaks in your exhaust, and you wouldnt ever know about it. The OEM gaskets are a perfect seal, just make sure you clean off ALL of the carbon off the mating surfaces.


Moral of the story is; I dont suggest reusing your old gaskets when you do any kind of exhaust work. Go OEM, I put on new gaskets just for an overhaul and its night and day difference.


Modified by bigsyke at 1:20 PM 3/22/2008