Wide range of Compression between cylinders, is it bad?

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jared0
Posts: 2
Joined: Sat Aug 24, 2019 7:50 pm

Wide range of Compression between cylinders, is it bad?

Post by jared0 »

Engine is a rebuilt type IV 2.0, dual Weber IDF 40s, with 2000 miles on it. That's all I really know for sure.

Mechanic told me:

"Cylinder compression
1, 140
2, 160
3, 172
4, 158.
Leak down on cylinder 1 is 68 over 85% and the leakage was about a 50/50 split between the rings (coming out the oil fill tube) and the exhaust. Causes a dead skip at idle and picks up at higher rpm. I tried swapping around spark plugs and ignition Leeds. I don't believe spark is the problem. And the competition is a little low but should run. Cleaned idle jet for that cylinder and no change"

It seems those numbers are above the expected range. And obviously we prefer the numbers to be the same. But could I safely drive from Vermont to Pennsylvania? If I take it easy and make a 2 day trip?
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Clatter
Posts: 2056
Joined: Sun Apr 28, 2002 1:01 am

Re: Wide range of Compression between cylinders, is it bad?

Post by Clatter »

As long as the valve adjustment isn’t moving around why not run it?
Perhaps it wasn’t tuned well early in life?
Get a wideband on it to tune it well and maybe some hard running will get it broken in..
Speedier than a Fasting Bullet!

Beginners' how-to Type 4 build thread ---> http://shoptalkforums.com/viewtopic.php?f=1&t=145853
jared0
Posts: 2
Joined: Sat Aug 24, 2019 7:50 pm

Re: Wide range of Compression between cylinders, is it bad?

Post by jared0 »

Also, one other thing I know. It has hydraulic lifters. Sorry I forgot that.

Clatter: that's where I'm leaning towards, I've definitely driven longer with worse. I think just keep an eye on my CHT and take it easy on the mountains. Mechanic seems more concerned, but he's an aircraft/motorcycle mechanic by trade. So maybe he's more exacting than us VDub wrenchers.
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