I checked my vacuum today, and I wonder if my readings are normal. With the engine thoroughly warm and idling, it reads 18" Hg. The needle vibrates rapidly within a range of I'd guess about 1/4". Maybe once in 10 seconds, it dips down to about 17.5" momentarily. On rapid acceleration it drops momentarily to zero before coming back up to 18. As RPM continues to rise, vacuum rises to about 19 before starting to drop off again (no tach, but I'd guess the peak vacuum occurs around 3000 rpm). It continues to drop to about 17 or 16" by (I'd guess) about 4500 rpm. On rapid deceleration it rises momentarily to about 30" before settling back down to 18".

I teed the gauge into the intake manifold vacuum port. Before testing, I warmed up the engine by driving about 3 miles each way to the barber shop (averaging 40-50 mph, parked probably a half hour before driving home). Outside temperature today is about 50 F. It's possible the engine wasn't completely warm but it was certainly close.

Within the last 6 months, I've set my timing to TDC in accordance with the sticker and set my valve lash to 0.010 intake, 0.020 exhaust with an easy slide fit on the feeler and engine fully warm.

Sounds pretty normal overall to me. Bring the car to the Mason-Dixon Slant 6 drag race and Mopar show on May 14-15 and we can have a 30-60 min conversation about it in person!

Best,

Lou

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Home of Slant6-powered fun machines since 1988

Yes consider this your personal invite to come out and race with us. We'd all love to meet you! Where are you located in Md.?

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

In the meantime, see here: http://secondchancegarage.com/public/186.cfm

Thanks everyone. Reed, I actually meant to post that link and ask if there's anything different or particular to the /6. That link was what motivated me to finally buy a vacuum gauge.

I'm in Annapolis. I'll plan to come to the Mason-Dixon if I can get my car put together by then. I'm about to install a new rear end including leaf springs and rebuild the front end with disc brakes. Since I've never done any of those things before, I expect it will be frustratingly slow. But having a completion date goal might help keep me going.

Nothing really different with the slant form other naturaly aspirated engines. Vacuum is vacuum. You do get a more even and accurate reading if you tap into one of the vacuum nipples on the carb ratherther than the vacuum tree on the #6 intake runner. Using the vacum tree as the source can sometimes cause the needle to jump a bit.