Low compression - has been sitting

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deschutestrout
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Low compression - has been sitting

Post by deschutestrout » Tue Jun 28, 2016 7:20 am

Hey gang. '78 Westy 2l FI. My Westy has been sitting for nearly a year (I know, shame on me) ... I'd starter her quite regularly during this period though....

Took her on a short trip this weekend and she progressively ran worse. Got home and was starting a full tune up and decided to check compression. #3 topped out at 30, the others between 90 and 100.

Is there anything I should try to boost/restore compression on #3? Thanks!
"You're not always obligated to paint an outhouse." Ruckman 2011

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asiab3
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Re: Low compression - has been sitting

Post by asiab3 » Tue Jun 28, 2016 10:52 am

Hi there,

I'm going to ASSUME your '78 bus has hydraulic lifters. Did you get any clattering at startup? How about a 30+ mile drive with clean oil to ensure the lifters have pumped up, followed by a valve adjustment. If I don't have a valve adjustment on recent memory, I don't even get the compression tester out.

Starting regularly during storage periods won't help the lifter situation since idling without a long/hot/hard run won't burn the moisture and condensation out of the oil.

Did your "full tune up" include valves?

Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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SlowLane
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Re: Low compression - has been sitting

Post by SlowLane » Tue Jun 28, 2016 1:25 pm

Worst case is you may have dropped a valve seat on #3, but it seems unlikely. You may be able to peer down the #3 spark plug hole and see if a valve is being blocked open by a dislodged seat. In this scenario the compression would be 0, though, so probably not the case.

More likely that the valve stems on #3 have varnish crudding them up, causing them to stick and prevent the valve from seating fully.

Try one of the popular snake-oil formulations like Marvel Mystery Oil or Seafoam to clean out your engine and see if it frees things up. Short-term only. Be prepared to do a couple of sacrificial oil changes with inexpensive oil before you commit to some good stuff for long-term.

Best of luck.
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

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