Silencer refurbished, re-installed and back to nominal performance

GBS did a good job on the silencer.

Keith confirmed over the phone they could sort it out so I took it up last weekend, had a chat with Richard, handed over the offending item and meandered back through Lincolnshire. 

Got to have a wander around my namesake City - Lincoln, it's Cathedral and medieval quarter.

The refurbished silencer was back on my doorstep by Wednesday!

The silencer rear end cap had been removed, interior pipe re-worked, wadding re-packed, re-assembled and cleaned into the bargain.

Re installed on the car today: new exhaust gasket, manifold, lambda probe re-installed and then the silencer. This time no exhaust jointing compound - 1. because it was so hard to part last time 2. the old tube of the stuff had gone off.

I replaced the rear bracket padding - the old pad was made from fuel pipe offcut which must have lasted 10k miles now - a little worse for wear but seems to work so replaced it with the same thing.

Quick run to my parents - around 70 mile round trip to test.
Everything back as it should be - engine and exhaust sounds & no rattle at any rev range, power or idling.

15100 miles on the clock - lets see how long she stays like it this time.

Running repairs - Silencer

The silencer has developed a nasty rattle around 2,000-2,300rpm, and on overrun, first noticed it on the Barcelona run last year.

Finally got to the point where I have had enough and it needs to be resolved permanently.

Spot the missing item from the left hand side of my Zero:

The manifold had to come off too - there was just no budging the manifold/silencer joint on the car, or even off the car.

After lots of advice from the RhoCar club on possibly approaches - '2b cruising'  helped out. Application of two pairs of hands, rubber mallets, gravity, heat and brute force did the trick - silencer now separated from the manifold and no damage done.

Next step is to return the silencer to the supplier to see what they can do.

Silencer bracket - padding

Since the build I had used exhaust wrap around the tailpipe to cushion it & the silencer against the rear bracket.

I have stock GBS silencer with Cat and the bracketry.

Heat wrap generally lasted about 500 miles or so before looking like the left of this picture - its not so much heat damage as the silencer needing to move and wearing through it.

I selected two materials for an oven test to gas mark 8/220ºc (while my wife was out :) ). Rubber windscreen surround & an off-cut of silicone cooling system pipe.

The windscreen rubber bubbled and perished within about 30 seconds, the silicone pipe didn't seem to mind at all even after 5-10 minutes and maintained its rubber properties; some question over its abrasion proof properties though.

However...

After some chat online, Paul recommended using an off-cut of fuel pipe.

I tried this for the run out to Castle Combe this weekend, approx. 300 miles round trip of mixed driving.

Looks like a contender, the picture is after 300 miles - mostly abrasion marks either side and some evidence of heat getting to it - but still in good condition - certainly better than using exhaust wrap; so this stays on until I find something better.

I just cut the length to sit over the bracket itself, over the top is the normal spring clip.

Update - Added a short length of exhaust wrap over the top, under the spring too, just stops excessive rattle when driving.

Noise - testing the sound levels

Al Milton kindly offered to come round and help test the noise levels, he had access to a noise level meter.

After a couple of runs today with Al's help it looks like I'm anywhere between 92dBA and 99dBA - depending on the revs; So the wire wool in the silencer is definitely doing its job.  Thank you Al for giving up your Sunday morning!

David S kindly shared the outputs from his recent Dyno run - David has an identical engine, intake, exhaust & silencer setup to me. David's Zero was producing 163bhp @ 6,067rpm before tuning & 168bhp @ 6,182rpm after.

I'm hoping I can use this information to persuade IVA I put the wrong values on the application form (165bhp @ 6,500rpm advised by GBS). I already discussed changing the rpm on the form & they will do so provided I can come up with some evidence. If I can get a lower max power RPM on the form the noise text will also be run at a lower rev range (0.75 x max power RPM) & get me a little breathing room on the noise levels.

Good support from my fellow RHOCaR club members -  Thank you!

Silencing the silencer

A little real work; longer days are back with the clocks changing but its still pretty cold in the garage;

I took another look at the silencer & the wire wool down the pipe approach - my first prototype was promising but needed some way to secure it - concept demonstrated in this picture - a wire from the bottom of the can out through the tailpipe which could be secured to the wire wool cage. The challenge was not knowing the internal design of the GBS silencer & knowing there would be a central holed pipe to negotiate:

I drilled through the centre of an existing rivet and managed to feed a short length of steel cable through the hole, through the central silencer pipe and out through the tailpipe.

Test run with my prototype caged wire-wool extended - excellent blueing of the wool after some engine runs, but overall this was just too complex - time for a little simplification:

I decided on a much smaller cage which would simply stop the wool being pushed out - internally the wool bundle is held in the central silencer pipe anyway. This little 2" long cage grabs the end of a 12" long wire wool bundle and follows it into the pipe secured in place with the wire through the bottom drilled out rivet hole:

Cable secured underneath with a self tapping screw:

Just the tip of the wire wool visible in the tailpipe, hopefully its far enough back to let the IVA emissions probe insertion - checking with them they need 3" for the emissions probe so I should be fine:

Finally tidied up with the cover back in place - I also added a strengthening bracket with 2 rivets at its mounting point:

Update - This didn't really work at all - quietened the exhaust ok, but means the emissions are impossible to test because the emissions probe will no longer fit in the exhaust. Ultimately passing the sound part of the IVA was down to making sure the car wasn't near any buildings so no sound reflections.

Prototype exhaust baffle

In the quest to quieten the exhaust 2dbA @ 4875rpm best advice is a baffle. 

The design of the GBS silencer precludes a standard baffle in the tailpipe (it might take one in the inlet pipe), so my first attempt is the wire wool approach. I created a cage from some galvanised mesh - the wire wool loops around the centre section and back on itself which stops it being blown out of the cage:

First attempt - too much wool and my 'baffle' turned into a mini missile as the engine simply pushed it out. Second try I reduced the amount of wool by about 50% (relative to this picture) and everything seemed to stay in place, turning it 90º as it is fed in the tailpipe lets me slide the whole assembly a resonable amount inside:

The next step is to do some measuring to check its actually making a difference & decide how to keep this in the tailpipe - it needs more than just friction, possibly a bolt through the underside? - I need to think that through before making permanent changes:

Promising start though...

Thought - The regulation says I the exhaust can have 'manufacturers drainage holes' so probably hooking one of the cage wires through one of those will do the trick?

Update - I need to confirm how far the lambda testing probe is inserted - it may mean I need to keep the tailpipe completely clear and sort out the baffle on the intake end of the silencer.

Silencer bracket guard

One of my fail points was the rear silencer fixing. GBS haven't had any issues with this and  installed, as I have done, with the hook turned inwards so the 100mm sphere cannot contact any sharp edges. However its the spring itself & the two black lugs on the bracket which my inspector had issue with, I think he was almost disappointed at not being able to get at those corners on the hook & couldn't find any other exerior (or interior) projections :)

I could argue the point, but this one is relatively easily solved with a heat shield style guard. Regulation states any contactable edge must be rolled 180º back on itself - other than that I think I'm ok. I attached it with a jubilee clip to the existing bracket:

My metalwork isn't up to the point where this coould be polished so I've opted for the brushed finish. The guard is 1.5mm aluminium but doesn't touch the exhaust anywhere so heat shouldn't be a problem:

I think the 100mm sphere will only touch the trailing edge, which I hammered back on itself & can't get at the jubilee clip or underneath. The guard sits on & bent around the silencer bracket just where it goes into a 'Y' shape so its locked solidly in place:

I hope thats ticks the box on this issue.

Hindsight - I might fold back the bottom outside edge too - just to make sure

Update - This disappointingly fell off on the first long run due to vibration fatigue. For the second round IVA a much simpler approach - a strip of rubber approx 10cmx2cm cable tied onto the spring.

Silencer & CAT

I bought the GBS silencer with the CAT built in & now I have my two fixed points to work from; the manifold & the rear wheel arch. Offered the silencer in place and marked where the manifold needs to be cut back:

There was just enough room to do this with the dremel extension:

Then a slot in the silencer so the clamp can squeeze it:

... and the GBS bracket which bolts into the floorpan with 3x M10 bolts/nylocs etc. It turned out I couldn't push the silencer onto the manifold with the bracket in place, so it had to come off again.

Silencer fitted - pipe clip & a smear of exhaust paste at the front...

Spring clip with an offcut of exhaust wrap at the rear....

It doesn't sound much quieter on the video - but it is - theres still some oompf there but its a gentler, rounder sound. The video is grainy because it was dark & low light in the garage when I took this:

I ran the engine long enough to get the heating up to temp, also for the first time had hot water through the cabin heater, I also ran the two new GBS maps for power and emissions; I couldn't immediately work out how to use the Lambda sensor - but had open loop readings coming through so its all set to have a play another day.

Everything worked fine except - my leak returned on the low pressure fuel pump - in the same place - the brass fitting on the outlet side of the pump - it will have to wait until I have daylight to fix.

Bonnet exhaust opening

The bonnet opening for the exhaust manifold is next up; 

I cut an cardboard template which lined up with the bonnet catches and sat flush on the chassis tube, then cut the actual hole shape from an A4 sheet of paper - starting small and just cutting until I had the shape I wanted, fixed the paper to the cardboard template and marked up to make sure nothing could move as I transferred the pattern to the bonnet: 

The whole template could then be lined up with the bonnet catches and the shape traced on. I then re-measured about 3-4 times - front catch to front of opening, rear catch to rear, rough height, front of bonnet to opening etc... just to make completely sure I was right before cutting anything:

Once I worked out the floor was the best cutting position, I took the dremel at 25k rpm and a metal cutting disc to it; the sharper corners took some care but really no issues at all:

Back on the car - looks to be right first time - it will have some trim around this edge in due course to keep the IVA man happy:

Looks pretty cool; + now the engine has run a couple of times the manifold has an interesting surface colour from the heat:

I need some cap head bolts as bonnet locators then the bonnet will be completed finished.

Exhaust Gasket

I obtained a new exhaust gasket from Ebay, identical shape to the old one however its constructed from a sandwich of gasket rubber type material with metal cladding - Ford part #1053902

Removed the manifold and ensured the head face & manifold mounting face were clean and flat. The manifold did have one bead of weld on it which I filed off, it also had a very minor bend along its length less than 0.5mm so should be good.

Fitted gasket & manifold and re ran the engine; there was a little smoke at first but then things settled down - I think its fine now:

I ran the engine for a good 10 minutes to get eveything up to temperature; the fan kicked in about 85-90º & as it warmed up I put in some rudimentary IACV values so it will run without the laptop attached.

Minor leak from the water hose take off for the heater - tightened.

The water gauge appears to be reading low, at least different from the ECU.

Addendum, got the fuel gauge working too - it needed another 5 litres of juice in the tank and tap the tank/rock the car to unstick the float - 5 litres is showing 1/8th of a tank right now which is a little low but good enough for now.

All seems fine & ready for someone who knows what they are doing to tune it for me.

Its alive !

Manifold

Last up today; the exhaust manifold - It went back on with the original Ford metal gasket & cap head bolts from GBS (see later post - problems here with the head seal) :

(note to self: that positive battery terminal is just close enough to the edge of the scuttle that if tightening/loosening it with a spanner its very easy to short circuit the battery through the spanner on the bodywork - I think I need a little rubber trim just there to prevent future issues)

First Start

.... Now there is nothing preventing a check of the engine...

Family audience watching from the driveway;

Fire extinguisher handy;

Attached the +ve battery lead;

Ignition on;

Dash lights up, all the dials sweep across their range and back to zero;

Volts showing 12v, No fuel (perhaps theres not enough in the tank to register);

Check the gearbox is in neutral,

Turned over the engine, and instantly fired into life !

Its a good job I'm partially deaf - nice meaty sound & although I only ran it for a few seconds it sounded reasonably smooth :) in fact - what do I know re smooth -  it sounded LOUD :)

Excellent!

BIG GRIN - bl**dy fantastic!

I haven't wired in the IACV so the car wont tick over without a healthy dose of accelerator. My air  intake butterfly valve shuts off all air intake, the intention being to let the ECU control the IACV for tickover.

No leaks anywhere either. (Update 24 hours later, one minor drip from somewhere on the LP fuel circuit)

I need a plan now to finish parts off; if I fit the silencer & sort out the IACV wiring I can run the engine a little longer (without winding up the neighbourhood) and check the ECU, Clocks etc are all working correctly.

Remaining major jobs for IVA

• Silencer
• Steering line up and tighten ball joints and track rods
• Brake fluid
• Boot area, finish spare wheel carrier, boot carpets & boot cover
• Wheel arches all round
• Dashboard fit
• Seats fit

I really should think about sending off the IVA forms; I need a new VIN plate too - my original had 2012 build year on it and one thing and another delayed me a little into 2013.