Vanagon 1.6TD: low compression and oil use

[dr. no]

On this last trip around the state I had the occasion to tweak the pump fueling and so forth and confirmed what I have been fearing: I have less power, more oil consumption, worse mileage and harder starting. The mileage I might have attributed to the switch from Vanco 8s to Haka snow tires, but this seems to be a package of issues. Also, it seems to be making more of a exhaust "blatt" than before.

So I dragged out the compression tester:
275
175
175
275

I'll get the leak-down tester on tomorrow...nerving up for pulling the head at least. There does seem to be more crankcase pressure at the valvecover (leaks) than the bottom end (no real blowby at dipstick or oil filler--which is on the oilpan); I'm hoping not to have to mess with rings or bearings.

Bets? Valves, valve seals, and/or rings?

(This is a JX-code engine, native to German Vanagons, 1.6, solid lifter, K14 turbo, mounted at 50*)

[TylerDurden]

I'd wager there are about 250,000 miles on the clock and the rings are gone.

Impressive to see it running fairly well with such low compression.
- How cold has it gotten, and still started (or not)?
- Have you set the timing by ear (aka hillbilly Hagar)?

[dr. no]

Started at 20*F, takes some cranking, though. It's been colder but I haven't tried it lately.

Timing set ~0.98 by clock, dammit I bought the tools so I'm gonna use 'em. (But very close to where it "sounded best".
AFAIK the valves have never been reset.

[Fatmobile]

So that's what the timing is set to now,
or how it was set before the last trip?
You might recheck the timing sometimes it slips/skips.
Usually the injection pump skips but sometimes the cam slips,.. not sure how much it could move to mess with compresssion and still run.

[dr. no]

I will look at timing when I take off the valve cover later, but I've had it a tooth off before: it runs horribly...as is it starts and idles normally with no compression so I think I've got all the easy adjustments in the right ballpark.

[dr. no]

Started my leakdown test, but my adapter (Horbor Freight compression tester to leakdown tester) leaked more than the engine, so it was hard to tell anything. One prominent finding: the engine wants to turn A LOT MORE than I expected. Flinging the wrench off the nut on the crank was not in any of the descriptions of doing this test that I read. I'll try later with lower pressure.

[TylerDurden]

Hey, if all yer body parts are intact (or same as before), life is good.

Zero damage on the vehicle is a bonus.

[Quantum-man]

With the blow-by , and those compression figures, almost certainly compression rings thinned out, so will be the oil scraper, so a degree of oil in main chamber. valves probably intact, but likely stem seals hard and leaky.
With thin rings [radially speaking], they will be more prone to sticking in the piston grooves, and making life worse.

My engine was in a similar position some 4 years ago. Merely re-ringing and minor bore treatment could be sufficient.

[Fatmobile]

Started my leakdown test, but my adapter (Horbor Freight compression tester to leakdown tester) leaked more than the engine, so it was hard to tell anything. One prominent finding: the engine wants to turn A LOT MORE than I expected. Flinging the wrench off the nut on the crank was not in any of the descriptions of doing this test that I read. I'll try later with lower pressure.

Hmm so you are saying you tried to turn the engine by hand and the wrench went flying.
Ooor you mistakenly left it on the crank bolt and turned the starter?

You are using the starter to do a compression test right?

Sometimes compression gauges are off, leaking and/or have a large area inside which basically makes the compression area bigger.

Put that socket, extentions and breaker bar on the crank bolt again and feel the compression.
Turn clockwise. If you feel like letting off pressure will cause the wrench to move backward, compression is about 375 or better. GOOD
Turns hard but compression won't be able to push it back if you let off under 350. Still pretty good might start down to 20F.
300 to 325 moves pretty easy. Summertime engine.

[dr. no]

No, I had the compressor set at 95psi for the LEAK-DOWN test, that much pressure makes the engine turn, not far but quickly. I thought higher pressure would make the leaks more noticeable.
Tried again with lower pressure (~20pi) later and got 35% on #3 and 4 (and then it was dark and time to make dinner). I could not feel anything out of the tailpipe, intake or oil filler, and the gloves I put on those did not inflate (my own innovation). The only place I heard any air movement was in the valve area. I will need to find the pressure that lets me hear the leak AND hold the engine still.

[dr. no]

OK:
35% leak all around, I could only hear leaks from the oil drain in the head. So it looks like re-ringing time.

Also, the valve clearances were all very consistent: 0.005 and 0.015. Just not quite up to spec, but not bad... Overall pretty consistent, cylinder to cylinder.

(This was from a leak-down test)

[dr. no]

Head's off, I expected cracks between valves, but the prechambers look pretty beat and there's more pitting than would make me happy. In order, 1-4 with closeups of the prechambers:









The valves do have some play to them.

and here are the pistons (1-4):





Besides valve kiss, those appear (and feel, you can catch a fingernail) to be cracks across the top. I think the rings are probably fine. They're probably holding the piston heads together! More work tomorrow pulling the pistons.

Does the head look salvageable? New prechambers?