Exhaust Leak?

[ruckman101]

So Bertha Bus's engine is out. New exhaust recently installed, but sure seems like I have a leak. Sounds like, and engine lopes a bit. Lately my starts have been odd, like it gets too much gas initially and dies.

Yet I see no obvious exhaust leaks, other than a minor one at the clamp into the muffler for the resonator pipe. And oil. From the blow-out tube on the oil-fill neck? Valve cover? And my thermostat seems to have gone south.

The plan was to wrestle the exhaust system into a more relaxed fit, but without spotting any obvious exhaust leaks, I'm loathe to do that. As the engine is out, I thought I would again check the torque on my heads, as the last two times they had loosened, especially the 3/4 side.

Puzzled. I'll get some photos up at some point today.


neal

[ruckman101]

Here's some photos.



I have no idea why the bolt holes aren't lining up. But I seem to have exhaust leaks at all three clamps.



Blasting right into the heater box. Are the metal exteriors suppose to be snug, or solid to the exhaust pipe that runs through them? Mine sure aren't. Gaping holes around the pipe at entrance and exit.

And oil all over the place.





The nuts holding down the fuel pump were pretty lax. And my tin under the thermostat that went bad was drenched, a drop hanging from the and the end of the breather tube.

Could this be the cause? Blowing oil out the breather tube?



And then there's my exhaust leaks. JB Weld? More high temp gasket goo?


neal

[hambone]

I tighten the clamps until the bolts bend a little. Also, it helps to mock-up the exhaust loosely and then tighten slowly all around so things snug up uniform-like.
You sure your oil cooler isn't leaking? BTW I like to glue down VC gaskets with Permatex in a tube, forgot the #. Seems like to not do so is asking for trouble.

[ruckman101]

Oil cooler is dry. Absolutely no leaks there. I have the fan shroud and most of the tin off to get to the top bolts of the heads for a torque check. Problem side was still a problem, more than 15 lbs, but less than 23 on the 3/4 side bottom bolts. The top was fine, the other side was fine. At least I can check them again without pulling the engine.

So I know a sagging valve cover gasket isn't a rarity, but does that result in oil spraying out the breather tube? Between that and seepage from under the fuel pump could explain the oil issues.

Will definitely reef on the exhaust clamps. My inclination is still to after that clean things up and goober on some kind of re-enforcement, RTV, JB Weld, something. Exhaust fumes in the cabin heat isn't going to fly.


neal

[Amskeptic]

Oil cooler is dry. Absolutely no leaks there. I have the fan shroud and most of the tin off to get to the top bolts of the heads for a torque check. Problem side was still a problem, more than 15 lbs, but less than 23 on the 3/4 side bottom bolts. The top was fine, the other side was fine. At least I can check them again without pulling the engine.

So I know a sagging valve cover gasket isn't a rarity, but does that result in oil spraying out the breather tube? Between that and seepage from under the fuel pump could explain the oil issues.

Will definitely reef on the exhaust clamps. My inclination is still to after that clean things up and goober on some kind of re-enforcement, RTV, JB Weld, something. Exhaust fumes in the cabin heat isn't going to fly.


neal

I had the same problem with Chloe's damper pipe mount not lining up. It is a lousy damper pipe, poorly bent at the exit from the muffler, and Dansk or whoever makes the damper pipe needs to be notified that they are making a round pipe oval at the muffler outlet bend, and we all are getting brain-damaged by exhaust in the heat.

What I did, was to bend the muffler tab a bit, and install the damper tab underneath instead of above. I tapped a socket into the pipe to make it more round so the gasket would not be so prone to leaking. It is holding so far. The exhaust leaks I have had to chase down have been deeply annoying. Exhaust is too important for shoddy parts. I will not install those stupid mushed wire mesh gaskets without first slathering them artistically with ultra-copper rtv. They too are now holding, but you *have* to set up a date to re-tighten the exhaust clamps in a couple of days after assembly, then again in a couple of weeks. Do not overtighten (we don't bend bolts, Hammie). they are supposed to be barely 7 ft/lbs.

I do not understand why your heads are losing torque.

Oil blowing out the breather where? Is your breather stock, with the draft tube and the little rubber cap at the bottom? Does your air filter have the weighted flap? Is the oil sender and distributor d- profile seal certifiably OK?

Valve cover gasket droop leak there is such a no-no for an engine without an oil filter. Do you normally put a good coating of grease on the valve cover before laying in the gasket and coating it with another layer of grease? me and John Muir have been doing it that way since you were a pup! and have not had issues.
Colin

[ruckman101]

Initially my oil sender weeped. Tightened it more than I was comfortable with out of concerns of cracking case. Finally teflon taped the threads and it hasn't been an issue since, and isn't in there near so uncomfortably tight as before.

Apparently I wasn't "liberal" enough with the ultra-copper rtv, along with just slamming it on there, no efforts to assess and correct out of round issues. Damper pipe out came off the old muffler, used and gifted to me. and new muffler of German manufacture. Perhaps attention should have been paid to cleaning metals before assembly, but that is so persnickety anal I didn't. Currently the stress of a poor fit seems to be on the intake manifold. On installation, I put it on last, all loose, snugged, but not tightened, and couldn't get a nut on the intake at the heads, backed things off and got the intakes down before snugging it into compliance. And in the process of taking it off, that stress was still there, but the seals looked good.

Rubber cap at the bottom of the breather tube? Never seen one. Such a beast exists? The preponderance of oil was indeed directly under the breather tube. Dripping wet. But all at the bottom. You'll notice the thermostat was dry. Nothing seeping down from heads or pushrod tubes.

Is there an alternative to "stupid mushed wire mesh gaskets"?

Valve cover gaskets were due for a change, and you'll be appalled, but I've always used a very conservative careful bead of blue rtf on the cover to seat the gasket, and dry to the heads. Now when you suggest grease, axle grease? Old habits have been known to change.

Air filter does have weighted flap that has been refurbished in terms of extraction, clean, grease, re-install at engine build. I even got the tube sucking warm air off the heads into the air cleaner that I have never had until the last two engines I've built.


neal

[Bleyseng]

I have always put Permatex #2 on the valve covers and then stuck the gasket on and let it dry so it's glued on. I found one of those rubber caps that go on the end of the breather tube (AirheadParts) but it comes without the slit at the mouth so check that if you get one. All the little details to bring these engines back to stock is a lot of fun.

[Amskeptic]

Now when you suggest grease, axle grease?

Any ol' grease, the more fibrous the better.

Air filter does have weighted flap that has been refurbished in terms of extraction, clean, grease, re-install at engine build.

You know what that weighted flap does?

It makes the engine have to suck a little to get fresh air. Guess where it gets its air from before it overpowers the flap? That's right, the crankcase. Pretty trick PCV valve, except that it is a NCV valve.
We don't want too much suck (like Ted Cruz) because it will bring in contamination (like Ted Cruz) and grind up the works with abrasion (like Ted Cruz), but we do want a little to help your engine not blow oily vapor all over . . .
Colin

[ruckman101]

So with a sagging valve cover gasket, would provide the crankcase with an abundance of fresh air, and no suck at all, so blowing oily vapor all over, well, at least out the breather tube with no rubber cap.

neal

[ruckman101]

Well, engine's back in. Oil was pretty shot so was warming it up to drop it, back at the engine, and noticed I hadn't clamped down my distributor cap. Yikes! Shut 'er down and clamped 'er down. No issues.

Took Colin's advice on the valve cover gasket, axle grease both sides, and passenger side streams oil. Looked like it was seated properly, so now waiting for things to cool off to give it a look. New thermostat seems to be working.


neal

[ruckman101]

My bad. Valve cover wasn't fully seated properly.


neal

[asiab3]

Is there an alternative to "stupid mushed wire mesh gaskets"?

Unbeknownst to many, the damper pipe and heat exchanger pipe donuts are different sizes. Also, the old style ones here seem to work better on my Earnst stock (except for the fitment quality) exhaust.

I think the damper pipe is 32mm, while the larger ones are 35mm. The earlier bug engines used all 32mm's.

http://www.thesamba.com/vw/classifieds/ ... ?id=986061

I found some of these in the 35mm T1 bus variety, but I can't find an active seller with them right now. Keep looking and maybe you'll get lucky.

Robbie