Itinerant Air-Cooled

Hey sg...

It's coming from around the exhaust port..no pictures. Far from my bus right now.

Definite leak around the copper gasket. Confirmed when looking at the header as well after removal and replacement. Widened the through holes, tapped the header with a rubber mallet as I torqued to help seat...annealed....copper sealant...nothing working.

No matter how I torque that #1 header it just is not making a complete seal. I wouldn't be surprised if this darn Dansk is warped in some fashion already...I'm about to drop $375 on an OE NOS header....

If it's verboten to double up on the copper gaskets I'm going to try the OE header...I can't run it with a leak like this.

:)

Just this past weekend Jake Raby was telling me has soldered two gaskets together and used them as one unit to make a good seal. He also said that often the flange for bolting to the head is too close to the end of the riser so it can't pull up tight enough to seal. Grinding down the flange a bit allows it to seal.

These are 72-74 replacement boxes? I would pull them off and look very closely how they are mating then figure how to tweak them to seal. Don't tighten them all the way when testing because the copper rings can't be resused when you do that. If you just bolt them up easily you can see the high and low spots then adjust accordingly. Once they are heated per RAtwell they do get softer and crush. It makes a huge difference. I used an infared gun as well as a color chart to know their temps when I did mine.

Great ideas guys! Thank you VERY much!

I'll post results.

Curt

Update: doubled up on copper gasket on #1 and refit exhaust manifold. Sounds perfect. Long road test to follow!

It appears the LITTLE that was sanded off to level at the machine shop was all it took to cause the flanges to bottom out by a thousandth....didn't confirm until the gasket trick.

More to follow..

Road test confirms gasket trick worked! Sounds great...next to attack the "no descending rpm" during shifting. Decel valve?

Curtp07 wrote: ↑

Sat Aug 26, 2017 8:24 pm

Road test confirms gasket trick worked! Sounds great...next to attack the "no descending rpm" during shifting. Decel valve?

Remove vacuum line to decel valve and plug it. Test drive. Report back.
Colin

That's the culprit...soaking in carb cleaner now. Cleaned it up...18psi to open the diaphragm...

So, the decel valve works great now. No more RPM hanging...

Next up, the brakes. New check valve, all new vac hoses to the check valve.

Symptoms: sometimes the brakes feel "mushy"...just doesn't seem like full stopping power.

All the brake hardware is new. Going to re bleed first. Replacing brake switches as well to diagnose the "brake warning light on...off when brakes pressed" that we tried so hard to fix last visit.

Update soon..any comments please chime in :)

Curtp07 wrote: ↑

Wed Sep 06, 2017 9:10 am

So, the decel valve works great now. No more RPM hanging...

Next up, the brakes. New check valve, all new vac hoses to the check valve.

Symptoms: sometimes the brakes feel "mushy"...just doesn't seem like full stopping power.

All the brake hardware is new. Going to re bleed first. Replacing brake switches as well to diagnose the "brake warning light on...off when brakes pressed" that we tried so hard to fix last visit.

Update soon..any comments please chime in :)

Do a Brake Forum post as you wade in. That was vexing. Please do not bother with Euromax brake switches should you need to replace any.
Colin

Curtp07 wrote: ↑

Wed Sep 06, 2017 9:10 am

So, the decel valve works great now. No more RPM hanging...

Thanks for reporting back! It's satisfying to read a diagnostic-resolution exchange with so few posts. Hell, compared to some other forums, it's satisfying to read that anybody actually answers relevant questions anymore.

Robbie