Exhaust gas leak. Suspect manifold

[Telf 224 2 Cars]

Hi all.

 

After about 1000 miles since rebuild I've had a constant problem with fumes and a general smell of petrol/exhaust when the windows of the car are open. I noticed yesterday that the engine had developed a ticking noise under load so I thought 'ah ha!' maybe I have a manifold issue. I've stripped the manifold off and found a few issues as can be seen in the pics attached.

1. The left most port appears to be corroded- and the gasket has burn/wear marks .

 

2. There appears to be a crack on the right centre port.

 

3. The exhaust deposits are quite white .

 

So I presume this is the cause of the noise but is it repairable or scrap? Thoughts please.

 

 

Many thanks

 

Paul

[Telf 224 2 Cars]

[DamirGTI 342]

Heat erodes the manifold ends creating "craters" on the edges and pitting on the mating surface , pretty common these days .

 

Two options here , good second hand manifold or get this one fixed by machinist ... the mating surface can be resurfaced-skimmed , it's a little bit tricky to fix it centre prior to skimming but it can be done , also that crack needs welding up asap till it spreads further .

 

Also seems like you need new downpipe mesh ring and buy new exhaust fixing kit (includes bolts nuts washers springs and some do the mesh ring as well) .. as if the current fixing springs are squashed/sagged you'll never get proper seal around the mesh ring .

 

Now , if you can get good second hand manifold for say 20-30 quid i'd go for that rather than fixing this one , as me thinks you'll pay much more for machining and welding work over there in UK .

 

D

[Telf 224 2 Cars]

I was wondering if the manifolds are still available actually. I think circa 2015 you could still get them?

[Telf 224 2 Cars]

I think the part number is 034194

[DamirGTI 342]

https://www.pieces-de-rechange-classic.com/205/180068-collecteur-ech.html

 

 

D

[Telf 224 2 Cars]

So I've dug out two I had in storage. One appears to have a crack in the same place.. the second seems ok

[Telf 224 2 Cars]

I think on balance I'll risk fitting this and see if it survives the shock of being heated after who knows how many years!

[DamirGTI 342]

Check also between 1-st and 2-nd joint , its the most common place for them to crack there :

 

 

 

.. good practice is to re-torque the manifold nuts few times occasional , as some have tendency to "loosen off" after the heating-cooling cycle .

 

D

[DamirGTI 342]

.. prep the surface well , if there any pitting on the mating surface where the gaskets go can use some high temp. copper sealant or exhaust paste (put some on the gasket , both sides) to be safe .

 

 

D

[Telf 224 2 Cars]

manifold replaced, all new seals and gaskets fitted, i used Loctite 5990 silicone copper gasket maker/sealant on the manifold surfaces to seal and potential issues.

 

The ticking noise has gone and the fumes so far seem to have gone too.

[Telf 224 2 Cars]

Well that was short lived . Smells bad again today. So ive taken out the sparks to see if it's over fueling. It seems not as they are very white? 

 

I took a pic of all 4 sparks.

 

I also noticed the cam cover seemed to be leaking so I stripped cleaned and sealed it up. Alot of oil under the seal( see pics)

 

I've put it all back together and it still smells horrendous. I'm at a loss. 

 

It's been set up again by emerald and they have checked emissions which are within MOT limits.

 

Other than the fact it's on a emerald system the engine is standard. The only real change is no AFM it's just got a straight inlet through the air filter . The car is running essentially on 4 sensors , water temp, air temp, crank sensor and the throttle pot. I have. map sensor wired in but it's disabled. Emerald say it's not required. I'm wondering if the fuel smell is overfuel at idle or something ?

 

Does anybody else run a 8v with this setup?

[DamirGTI 342]

Does the engine consume any oil ? since it's freshly rebuilt ..

 

Oil additives (from modern synthetic oil especially) when burnt make some of the weirdest/nasty exhaust smells i have ever encountered on a car .. doesn't smell on unburnt petrol , nor particularly "oily" either , really hard to describe but smells - so bad that you must walk away asap ! especially if working on a car inside the garage with the engine running . And there's usually no visible smoke at the tailpipe but with the smell present , also especially with synthetic , until it's beyond middle well worn out engine then it starts to be visible smoky at the tailpipe .

 

Dunno how old are those plugs , but looks like the engine perhaps runs a little bit lean (bit hard to read the plugs nowadays with unleaded fuel) , do you have someone to lend you an WB lambda sensor to check/measure the AFR ?

 

Incorrect AFR , incorrect ignition and/or cam timing can all cause incomplete combustion hence bad exhaust smell .. also worn out engine/bottom end .

 

 

D

[Telf 224 2 Cars]

Damir,

 

It doesn't burn oil but has been leaking. The loss on the dip stick is minimal.  Using semi synthetic 10w-40 atm. The plugs are 1000miles old.

 

In terms of engine wear it's completely rebuilt , it's producing good power and there's no real odd noises etc.

 

I presumed the Air flow ratio was set/measured at emerald during the setup procedure.

 

I noticed yesterday it's popping at the exhaust is that a timing issue?

[Thijs_Rallye 87 4 Cars]

What is it that you smell? Fuel, oil, oil vapours or any combination of the three?

 

How are your breather hoses connected, closed circuit or does it vent to the atmosphere?

[Telf 224 2 Cars]

The hoses are set as standard apart from the the hose from the 90 degree bend on the air inlet- that's been blanked and the hose on the bottom of the inlet manifold. Also blanked . I dont have a SAD fitted so the are both blanked. See pics

 

The smell is exhaust/fuel vapour I think. 

[Telf 224 2 Cars]

So after the comment about the breather system I went and tightened up all the hose clips and I've noticed the cam cover breather appears to be 'sweating' oil. It's a silicon hose from Baker BM . Should that be happening?!

[DamirGTI 342]

What kind of air flow/mass sensing is on this emerald system ? if it's not AFM (vane AFM) , MAF (hot wire or film type) , MAP (internal within the ECU or external) - how does the system measure/calculate air flow ?!

 

Also , does it have lambda sensor ?

 

 

D

[SRDT 175]

Just TPS vs RPM and a bit of AFR I guess.

Bosch did that on some single point Mono-Motronic but other than that it's mostly a racecar thing.

[jackherer 543]

Yes it's running TPS vs RPM (alpha-N), no AFR though, it doesn't have an o2 sensor, it was mapped with Emerald's wideband sensor in the tailpipe.

 

As Paul said we presented it to Emerald for mapping with a MAP sensor fitted and working but they didn't use it. Which we didn't realise after our first visit there...

 

Paul, as it doesn't seem to happen all the time I wonder if you have an intermittently loose connection to a sensor or ground perhaps?

 

You can connect a laptop to the Emerald and datalog various values while you drive, if you have it logging and it starts to smell/overfuel take a look at the graphs for any values that have suddenly changed or look noisy.

[jackherer 543]

6 hours ago, Telf said:

the cam cover breather appears to be 'sweating' oil. It's a silicon hose from Baker BM . Should that be happening?!

No, silicone oil breather hoses should have a flouro inner liner to stop oil damaging the silicone itself. Can you see the inner layer when you take the hose off? Has it been damaged at all? I've seen them get torn or pushed back into the silicone hose before but that was Spoox hoses, not BakerBM ones.

[SRDT 175]

2 hours ago, jackherer said:

Yes it's running TPS vs RPM (alpha-N), no AFR though

 

It can be fine for a race car but probably a bit basic for a road car.

[jackherer 543]

It works fine on my 205 with the same type of ECU!

 

That has an XU9J4 with individual throttle bodies so alpha-N made sense for that.

[Telf 224 2 Cars]

Kieran it seems to be a constant thing. Certainly there's a issue I think at low rpm or when you come off the throttle. 

[Telf 224 2 Cars]

I'm a bit ignorant about the whole electronic ECU setup so what difference will the Map sensor being active make? Does it need an O2 sensor etc?