How close did I come to burning it down?

[adamr]

So another day in my Porsche Saga, for those who have been following my progress.
I started the car today to let it idle for a bit, while i put tools away from yesterdays work etc, and I see the motor stops smoking, great finally got all the oil out, then about 5 mins later I see new smoke coming out of engine bay. I go to lean over and put my hands on fenders and just before I put them down, I see the paint bubbling up! I ran and cut the car off, and grabbed the fire extinguisher thinking its on! The muffler that runs from drivers to passenger side had gotten so hot that the whole rear end from wheel wells to bumper all the paint has bubbled up. The tail lamps are slightly warped from the heat.
I heard some backfires in the exhaust system before this happened.

I dont know if there was a fire in the Cat or in muffler from the excess oil pooling and it finally lit up?
Or is the fuel system sending too much fuel into the cylinders and it being blown into exhaust and re-ignited?

[tharbert]

Wow! How long was it idling? It sounds as if you have a partially blocked cat or some restiction in the exhaust.

[schumicat]

agree with the other guy that cat or muffler could be blocked up. may have mice or something that were living in there and are now fried.

[gshase]

Oil soaked muffler or cat.

[kyle242gt]

Cats will also get seriously hot if you have a misfire or other over-rich condition.

Scary stuff!

[tirwin]

Yikes! Terrible news!

BUT you can and will recover. Obviously you will this forum to be a great resource for help and advice.

Keep us posted!

[adamr]

The car was running for about 10 mins

The exhaust gas feels really hot when it is running. I will take the ir gun and see if I can find the culprit.
any suggestion?

[T77911S]

too lean??

there was a guy on the BMW forum that said his exhaust was glowing from the being too hot. hi was running lean.

could be timing too. at idle, timing set too retarded could make it run hot too.
i wonder what the engine temp was???

after swapping motors, and some modification to make it work, in my volvo 960, the same thing kinda happened to me. it was running fine for half an hour, turned my back for a few minutes and it over heated and blew the head gasket.

[Pazuzu]

Do not start your car again.

If 10 minutes of idling in the driveway was enough to melt paint, then your exhaust system is full of oil from when you overfilled it. There should be no way that 10 minutes at idle could charge the system that much.

Remove your exhaust and clear it out. The cat is clogged and might be ruined (I don't know how sturdy the Porsche cats are, but the ceramic honeycomb design that I've worked with would be destroyed after that). Depending in emissions requirements where you live on the Island, you might consider a cat bypass.

It's probably time to pull the engine and do your clutch like you wanted to do. That will give you some freedom to pull the exhaust and properly clean/replace it. You'll also get the chance to properly sort out the dozens of things you've come across (vacuum issues, clutch cable wrapped up in your throttle line, etc).

[adamr]

That is what i was thinking Mike. I know the engines running pretty well, so i have a good baseline to start from. There are no emissions tests here, so i plan on removing the cat. I bought a Bentley manual and the 101 911 projects book to familiarize myself before I get down and dirty with it.

Id just like to clarify I wasn't the one who over-filled it, was the P.O. I bought the car with out running, and only did it that because I paid less that the Fuchs wheels are worth. Its been fun going through all the silly things that were overlooked by the last two PO because they couldn't be bothered with it. The most recent PO didn't want to change the plugs because they were too difficult to get to, nor change the fuel filter.

[Reiver]

Agree that the cat is probably toast if soaked in oil. I don't run a cat on my '83 (not required on collector cars in Az). A bypass works well on SC's as the lower cam profile/timing are not much affected by the cat loss (its back pressure is figured into the air/fuel/timing mix). You will need to fatten up/change your air/fuel mix to a 2.5/3.0 using an exhaust analyzer. You'll gain about 7 HP at top end.

[DanielDudley]

First of all, don't idle your car in the driveway. It does not cool very well if it isn't moving air. Make sure you are running on all six cylinders. cats get really hot when you are dumping raw fuel into them.

If you don't need the cat in your state, now would be the time to retire it. I can't really imagine that sort of heat coming from any other source. Let us know what you find.

[Justin@Athens]

Don't forget all those old exhaust parts are worth good money at the scap yard!

[adamr]

So I pulled the exhaust down, rather cut it down, and found the muffler must be partially collapsed inside, hear allot of rusty stuff moving around in there, so that would explain why it got so hot.

Can I cause any harm by running around the subdivision with just no muffler and cat, just HEs?

Adam

[andyt11]

Originally Posted by Justin@Athens

Don't forget all those old exhaust parts are worth good money at the scap yard!

what kind of scrap yard?! Like scrap scrap or salvage? I will be retiring mine soon, everything from HE to cat and muffler.

[adamr]

So almost 1100 views and no opinion on running with no cat and muffler??

[tharbert]

You are dumping exhaust under the car rather than behind it. It might smell a bit and I certainly wouldn't be in the car that way for too long: CO. There are many here that track these cars with very little in the way of exhaust.

[Reiver]

Why not just cut the flange off of the old cat and weld a straight pipe to it until you get a proper system (I'd still run the 02 sensor...weld a proper sized bolt over a drilled hole)....then you'll not have to worry about gassing yourself.

[Reiver]

just looked at my old cat. Sawzall your cat about 1" past the 02 bung and then weld a pipe to that, it's not exactly round so a plate should be cut out then the pipe welded to it. Would be very easy to knock out. Then you have the proper 2 in hook up, 02 bung, and one out.

[adamr]

I have no O2 sensor on the car, its a euro sc, did they come on them or PO did an O2 sensor delete.

I cut it with sawsall, and plan on putting temp pipe til I figure out which muffler I will use.
thanks for replies