Inlet Manifold

[sadgoth]

been reading on the forums a lot about 3rd gen Inlet Manifold Gaskets bing paper and quite fragile. Is this also the case with 2nd gens as my TII has the same symptoms (smell of petrol under boost & slightly lumpy idle). My original guess was the Inlet Manifold Gasket, how easy is it to change on a TII and where can I get one? Spoke to Rotechnics and they said it is a long joba nd normally costs £400+ mostly man hours  If anyone has done this on a 2nd gen HELP! cheers,

Mark

[Fish]

Mark, it is a long job that is also a pig to do (on an FD). There are cheaper places than RoTechniks that could do this for you.

Fish

[oldrotary]

Mark, did you ever resolve this as I have similar symptoms and also think it likely that I have a manifold leak? I have replaced some split/leaking vacuum/control lines, which resolved boost control and oscilating idle problems, but am left with this slight petrol smell only under boost.
Regards John

[sadgoth]

erm, yes i did, but not in the way you\'d think! I threw a tip in the FC and had the engine rebuilt! The leaking manifold problem then vanished!

[Prof]

Mark, did you ever resolve this as I have similar symptoms and also think it likely that I have a manifold leak? I have replaced some split/leaking vacuum/control lines, which resolved boost control and oscilating idle problems, but am left with this slight petrol smell only under boost.
Regards John

I\'ve had that problem a couple of times.  The engine was eating gaskets when I had the HKS induction kit fitted.  Appeared to be connected to overboosting issue I had, but the test for this was to spray some degreaser or other solvent near the intake manifold - if the engine revs increase, then you have a leaky gasket, as it\'s sucking in air and making for a slightly rough idle and erratic boost.

[oldrotary]

Thanks Mark and Prof. This does sound like my problem. When I bought my T2 earlier this year one of the faults was that the turbo boost control line had split and burst off the wastegate connection thus causing an over boost problem. So possibly the gasket suffered at this time. Prof can you remember the material and thickness used in the manifold gasket? I will try the solvent spray test before dismantling.
John

[Prof]

From what I saw of it, it was a hardened paper/cardboard gasket - like the old paxolin stuff - but way thinner - about 0.5mm at a guess.  It cracked both times near one of the bolt holes - right to the outer edge from the secondary (outer) runners.
 
In the end Rotechniks smoothed the block and the manifold, then scored them to allow more bite into the gasket.  Seems to have done the trick, although several other things were done at the same time (change of ECU for one with mapping past the fuel cut, and mapping for air intake and exhaust), only using 98 RON or higher, thicker plug leads (Magnecor).

[oldrotary]

Is it possible to remove the inlet manifold without removing the turbo? The Haynes manual seems to indicate that it is not necessary to remove the Turbo, whilst the factory manual seems to indicate that it is necessary to first remove the Turbo.
John

[Prof]

you have to take the intercooler off if you still have a top mount, but I can\'t see why the turbo would have to come off - should be able to get a spanner on the end of the bolts - but it\'s probably tight.

[oldrotary]

Thanks Prof. I tried the spray test tonight using my wife\'s hairspray with a propane/butane propellent, but it did not effect the tickover. It\'s difficult to get near the flange itself, did it work for you?
John

[antnicuk]

i never had a problem with the gasget even with minimul material around the ports as i had enlarged them so much. I was running up to 1.2 bar.  I always smear a thin smear of good silicone on both surfaces and i think this helped.

[Prof]

Thanks Prof. I tried the spray test tonight using my wife\'s hairspray with a propane/butane propellent, but it did not effect the tickover. It\'s difficult to get near the flange itself, did it work for you?
John

It was Rotechniks that put me onto this trick - he demonstrated on mine when I had the cracked gasket.  Mr crack was on the front rotor ports - so was easy to get to with a can and attached \'straw\'.  If it\'s on the back it will be a bit more difficult to reach I guess.  The theory is that under idle the engine has vacuum so will suck air in through the crack - spraying hydrocarbons near the hole will cause them to be sucked in and give a rise in RPM as more \'fuel\' is introduced.
 
SAFETY:
 
And before anyone says fire....           ....You need to reach either the ingition temperature of the material or have an ignition source like fire or spark.  A hot engine will just cause the stuff to evaporate.  However, this should therefore be done in a well vented room.

[oldrotary]

I decided to take off the throttle and dynamic chamber to see if all the inlet manifold bolts were accessible with these items removed. However after removing the intercooler and the relevant bolts I found that the joint between the inlet manifold and dynamic chamber was holding the parts together. This made me think that if this joint was bonding well with the mating surfaces then the probability was that the manifold joint was also bonding well, making the possibility of an inlet manifold joint leak less likely especially as it passed Prof\'s spray test and antnicuk\'s comments. I therefore decided to do a pressure test. I bolted the dynamic chamber and throttle back on tight and blocked the line from the intercooler with an old spray can top. I then connected an air line (I am lucky enough to have an air compressor) to the brake servo connection on the dynamic chamber and applied pressure. I could not find any leaks around the manifold but did find another vacuum line that had blown off. This was the lower of the three lines behind the throttle. I put this back on tight and removed the airline/blank and refitted back to standard. Tickover seemed better and on a test drive "No Smell Of Petrol". So thanks for the advice and it looks as if I have saved myself a lot of unnecessary work.
John

[Prof]

Nice one - those old spray can lids do come in useful! :Thumbs-up