Popping exhaust fix

stevef · stevef's Garage

Whats the best way to fix a leaking exhaust manifold while the engine is still in the car. I have a 2.0L with webers and a sport conversion muffler. The engine has been in the car for about 2 years. Only about 4000 miles and has been popping for the last 250 miles. I don't want to end up with sheared off exhaust studs and have to remove the engine. I'm making the assumption the mainifold is leaking as I've re-adjusted the valves, checked timing and mixture. Any ideas?

makaio · 12-21-2003, 06:20 PM

If it's leaking at the flanges, then the only proper way is to remove them and put in new gaskets.

stevef · stevef's Garage

Should I be able to hear it leaking if the leak is the cause of the popping or could it be so small to be drowned out by the noise of the engine

RoninLB · 12-22-2003, 04:06 AM

maybe try a hose placed to your ear and probe around to determine the exact place of the leak.. have you checked your head studs ?

911nut · 911nut's Garage

Steve, my test pipe to muffler connection leaked after installation. I loosened up the joint, took my oxy-acetlene torch and heated up the side of the test pipe that was in the direction that I wanted it to move. Got it cherry red, took the torch off and immediately sprayed it with water. This induced distortion moved the test pipe just enough so that everything sealed up nice.

stevef · stevef's Garage

Ronin. Thats a good point, I haven't checked the head studs. What would you suggest would be the check. Should I be taking the covers off to re-torque the heads.

RoninLB · 12-22-2003, 08:49 AM

Quote:

Originally posted by stevef
Ronin. Thats a good point, I haven't checked the head studs. What would you suggest would be the check. Should I be taking the covers off to re-torque the heads.

Exactly what I would do after the hose act.
Remove valve covers. 4 studs per cylinder.

I WOULD NOT loosen stud nuts before retorquing. I would set max torque, then twist.

I like 911nut's method of custom decking.

Martin Sellers · 12-22-2003, 09:01 AM

Steve,

I've got a 70 and went through the same syndrome. If the exhaust note gets louder than normal when you mash the throttle
one or more of the jugs/heads may be loose. It sounds like there is no baffleing in the muffler. ........

I had to retorque the heads and the engine sounds fine now. Provided your studs aren't broken or stretched I'd retorque the head and see

Good luck

RoninLB · 12-22-2003, 09:21 AM

Quote:

Originally posted by Martin Sellers
I had to retorque the heads and the engine sounds fine now. Provided your studs aren't broken or stretched I'd retorque the head and see

IF the nuts need respond to the retorque it may be a sign that the case threads are weakening.. just my opnion.. thus another check after another 1,000 miles

stevef · stevef's Garage

Martin, yeah, you are right, the muffler is modified to remove the inner baffles so I've never been able to really hear a change in engine sound due to anything else but the muffler.

Ronin, I never did recheck the torque after I ran the motor for a while. I've only just done the first valve clearance check. Maybe an ommision on my behalf.

Wonder if my wife will put up with me doing this on Thursday. I think I don't have to go to work that day.
Thanks

RoninLB · 12-22-2003, 01:19 PM

Quote:

Originally posted by stevef
Ronin, I never did recheck the torque after I ran the motor for a while. I've only just done the first valve clearance check. Maybe an ommision on my behalf.

check it with engine Cold.

Martin Sellers · 12-22-2003, 03:56 PM

Steve,

It's probably a good idea not to drive the car until you torque the heads so you don't burn a hole in the head/barrel gaskets.

Whe I had my problems the hex nuts that hold the head had actually come loose from two flanges and were flopping around in the channel

If this is indeed your problem you'll need to replace the washers that have probably exited the scene.

I'm always amazed that these engines still run even with missing parts!

Good luck

Martin Sellers
Fallbrook, Ca

stevef · stevef's Garage

I haven't been driving it recently anyway since the road salters have been out. I just changed the oil last week for the winter storage. I know I've seen posts that talk about taking the valve covers off with oil still in the motor. Is that possible by jacking the car up one side at a time. How much mess will I get into without dropping the oil.

makaio · 12-23-2003, 05:49 AM

Like you suggested, you can jack it up one side at a time with minimal leaking. Then just replace whatever might have leaked out & the valve cover gaskets.

Martin Sellers · 12-23-2003, 07:34 AM

Steve,

Dittos on what makaio says.......just keep the paper towels handy.

When you get into it I'd like to know if the barrel nuts are still on.

I hadn't retorqued my heads since a rebuild many miles ago and didn't realize that it was required................DUH!

Anyway ,Otto, who is a regular on this board says that he re-torques at every major service to 27 ft/lb

Good luck,

Martin

Fallbrook, Ca

Superman · 12-23-2003, 07:37 AM

I agree that these should be retorqued after a rebuild. After a rebuild, you're changing oil at, like, 500 miles or something. Drive until the oil is hot, drain, sleep, wake up and adjust the valves, retorque the barrel nuts, replace gaskets, covers and oil. After a couple of retorques, the nuts will stay stable.

stevef · stevef's Garage

Thanks guys, I'll let you know what I find and pick up this thread again