[T2] cyl 3 compression = 0, what can I do to fix without removing the engine.

[John Anderson]

Although I'd certainly optimistically go with John, et al.  I will be realistic.
 
It is #3, you have no compression, you have hydraulic lifters so it would take a (relatively) incredible change to affect valve seating.  This isn't going to end up well.  It is still always #1 or #3, and usually 3, even in Vanagons, least air cause forward cylinder and on the oil cooler side.  Sure, first things first, pop the valve cover, pull the rocker arms off (the 2 hold down bolts.)  Lay a straightedge across the valve tips.  You are likely going to find #3 exhaust (the forward most valve tip) to be sticking 1/16" or more out past the others.  If they do line up, by all means, replace the rockers (torque wrench please) then follow the type2.com site suggestions on adjusting worn hydraulics (my 15 year old suggestions are just as good today, but I'd only go 1-1.5 turns past contact now days) then test again.  If still low compression, sure squirt some oil down the plug and try again.
 
Chances however if the engine was fine weeks or months ago, and nobody has screwed with the valves, then the problem is you've had a seat fall, and it is now being held "open" so no compression.  If nobody has F'd with anything, this boils down to a mechanical failure, and it is going to be a fallen seat, or a head that has loosened WAY up (I'd think you'd hear it phsst, phsst, phsst) or lesser chance failed rings/ovalled liner, again as #3 gets hotter.  Totally flattened cam might be possible in todays low zinc oil world, I haven't seen that yet but the T4 cam does sure wear badly, and no compression sure happens now days with 350 Chevy flat tappets, more than 20 years ago.  Any way that engine is coming out after 1-2 hours of testing unless you get crazy lucky, as long as it isn't an iatrogenic (someone felt the need to F with the hydraulic lifter adjustment) problem.
 
On a positive note.
 
The T4/091 combo in a Vanagon is a JOY to pull.  15 years ago I could have one out, 1 person by myself, hand tools only, on a dirt floor if I had a sheet of 1/2" plywood, in 90 minutes, 50-60 minutes if I had air tools, as long as the CV bolts didn't give trouble, which if you clean them anally and hammer the triple square 5-10 times before loosening each, will mostly be the case.  On a stick, pull the engine/tranny as a unit, on an autobox you can pull just the engine perhaps a smidge faster.  You need good hand tools, the triple square for the CV's, a good full size floor jack, an about 18" of 2x10 to balance under the sump, and just under the bellhousing.  The balance point is just a smidge back (engine side) of the engine/tranny junction.
 
Look at the valves, adjust em, squirt some oil, but be prepared to pull it.  No way I'd do it in car, it is easier (sort of) to do in a Vanagon than a bay, but you will blow way more time than just pulling it out.  As I was surfing for T1 heads on samba last week, I noted several good deals on what might be reasonable square port Vanagon heads, might still be there, might not, but 5 hours of time and under $200 for a used head that looked perfect and I touched up the seats (by hand, just lap em in) would make good sense to me.  Likely end up no worse than the condition of the other side on the cheap.
 
John
 
 

________________________________
 From: Christophe Guilbert <cguilbert at picasso.ucsf.edu>
To: Type 2 List <type2 at type2.com> 
Sent: Friday, October 4, 2013 8:10 AM
Subject: [T2] cyl 3 compression = 0, what can I do to fix without removing the engine.
  

Hi ,

For those who followed my saga, all my rough idle problem was due to a 
faulty cylinder 3 which compression was ... 0 (10 PSI to be exact).

What kind of work I can do while the engine  is still in to diagnose and 
eventually fix the problem ?

THanks for any help