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> Leaking exhaust at head..., multiple copper gaskets / more muscle on those exhaust nuts
Jax914
post Oct 8 2007, 09:57 AM
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Okay,

I'm looking for some ideas....

I have a 1971 1.7 - stock heat exchangers, manta exhaust.

I've replaced the copper gaskets between the heat exchanger and the head, applied what I think is way too much torque to the exhaust nuts and can't get it to stop leaking. I removed the exchanger and made sure the top of the flange is level and smooth. When I start it up and crawl under, I can feel the leak.

My thoughts are to try running two gaskets?!?

Anyone else have similar problems?

TIA,

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jk76.914
post Oct 9 2007, 05:54 PM
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Be careful on the torque. I'd say 18 ft-lbs is on the high side. It's OK for M8 steel threads in the steel nut, but the other end is steel threads in aluminum, and any torque you apply to the nut pulls on the aluminum threads in the head with the same force. M8 x 1.25 in aluminum is only good for 14 ft-lbs. I think the late VW T2 spec is 14 ft-lbs. And it's low enough that you'd better use a torque wrench or you'll overshoot.

I printed this chart out and keep it in my tool box.....

http://dodgeram.org/tech/specs/bolts/M_bolts.html

Sorry if it's "Dodgeram". It's the clearest chart I've found.

If you go to an 9mm/8mm step stud, in clean and full aluminum threads, you're probably good for the full 18 ft-lbs.

Ever wonder why the 1.8L had 9/8 step studs? Or why they bothered with 8/7mm studs for the rocker pedestals? The larger aluminum threads can then match the strength of the steel on steel at the other end....

Just my engineering opinion. Your actual experience may differ.
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