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Old 12-02-2018, 11:50 AM   #225
Washmitt Meister
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Weekend update. Got an opportunity to spend a few hours on the car this weekend. Now I've been experiencing a minor version of something similar to what people describe as the 3k rpm exhaust buzz. Initially I thought it was a loose heat shield, however as I'd removed, refurbed and refitted all the heat shields I was pretty certain it wasn't that.

Basically I concluded that think this is the issue:

The manifold bottom end is double walled and when the insulation between the two walls breaks down you get this resonance issue which makes the rattle. A quick google search suggests this is pretty common issue, certainly across the UKDM, EUDM and USDM cars. Not sure if the JDM cars manifolds have that same double wall construction.

So, first up heat shield off. Looked in pretty decent condition on the car but now it's you can see that the bottom edge is pretty rotten and there's also a decent crack in it.

IMG_20180210_114102 by PoobahUK, on Flickr

Searching for a replacement on Ebay suggests these cracks are reasonably common and as they're UKDM specific, so is corrosion which could make getting a decent condition replacement a bit of a mission, especially as 'shock-horror' it appears Honda have discontinued them. Nevertheless I'll keep my look out for a decent one that's not priced like it's made from unicorn hair.

So, now off with the manifold. All came off nice and easy. It helped that the cat/manifold had been split for the underfloor refurb but everything else came apart nicely.

IMG_20180210_113721 by PoobahUK, on Flickr

IMG_20180210_113702 by PoobahUK, on Flickr

So, once off the car I had a good look over the manifold. All looked good apart from one of the nuts (there are three) which hold the top and bottom halves together. This is the nut facing the front of the car and clearly 20 years and 70k miles has taken its toll. I actually had to check the parts diagrams to make sure that it was meant to be a nut!

IMG_20180210_114259 by PoobahUK, on Flickr

In my younger days I've have been tempted to sort the resonance issue out and just put the manifold back on the car but my OCD can't leave a fastener like that these days so I decided I was going to have to split the manifold and renew the studs and nuts joining the two together. As predicted, the two good nuts came out nice and easily, the third problem 'nut' took some persuading with the grinder. Came apart in the end though.

IMG_20180211_153429 by PoobahUK, on Flickr

IMG_20180211_153434 by PoobahUK, on Flickr

Now I've just got the struggle of getting the old exhaust stud out of the top part. Currently soaking in Plusgas and awaiting a date with my mole grips and some heat.

Next up, some of you will remember that I previously mentioned about the sump on my car being a bit scabby. Picture below of said scabby sump.

IMG_20180210_121222 by PoobahUK, on Flickr

Set about getting the replacement unit ready to go on. A quick buzz over to remove any surface corrosion and then a few coats of high temp satin black engine enamel. All ready to be fitted once I get a new OEM sump gasket.

IMG_20180211_164635 by PoobahUK, on Flickr

Finally I drained the coolant and removed the radiator. I'd noticed previously that the fins weren't in a particularly good shape so had already bought a replacement ready to go in. Old rad below and a comparison against the new one.

IMG_20180210_155221 by PoobahUK, on Flickr

IMG_20180210_155216 by PoobahUK, on Flickr

IMG_20180210_155750 by PoobahUK, on Flickr

Just need to mount the fan unit onto the new one and then I'll get it all put back together one the manifold is sorted and back in the car.
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