M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke

[daltonhawk]

That makes sense. I checked the timing the first time because I didn’t know what the previous owner had done (it was pretty far off) and the second time because I was trying to figure out what changed (it seemed still close to where I set it). Once I’m happy with how it’s running, I won’t plan to touch it until I do the belt next time. (Which might be a several years or never depending on how many road trips we do). The chassis has 150k miles in 40 years so it’s been on a pace for a new belt every 20 years.

[daltonhawk]

Well the results of the compression test are a disappointingly low 220,240,200, 220 PSI. This is on a cold engine that hasn't be run in six months. I'm fairly confident in my method but it is a new gauge tool.

[?Waldo?]

What tool are you using? Post a link.

[daltonhawk]

Here's the tester: https://www.amazon.com/gp/product/B0787FYB42/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

[MarkWard]

Probably best to keep moving forward and see if you can get it running. With those numbers its definitely going to need working glow plugs. Not much you can do about the compression at this point. If its that low, without at minimum valve job, and bead hone with new piston rings. So, best to move forward. If you can get it to run, the compression may improve.
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[?Waldo?]

Considering the relatively close results you got, I would tend to suspect that the test kit is junk but it could also be an issue that affects all 4 cylinders. As far as issues that affect all four cylinders, what is happening with your intake and exhaust? It needs to be clear all the way to the cylinders and any blockage will result in blowing smoke and poor compression.

There is a LOT of crap out there as far as diesel compression testers go. In order to get an accurate reading, the adapter needs to closely mimic the volume of the item it is replacing (injector or glow plug) and it needs a check valve in the tip of the adapter. Many crap testers move the check valve to the end of the hose. That can drastically increase the unswept volume and significantly lower the reading. The gauge also needs to be accurate.

In the past I purchased a couple crap diesel compression tester kits and they were entirely not worth having. I have had a high quality IDI compression tester but was lacking a decent quality TDI tester until recently. I purchased this kit in order to be able to test either one with the same tester.

https://www.tooldiscounter.com/product/cta-diesel-...XhEALw_wcB

The adapters closely mimic the volume of the injector or glow plug they replace and they correctly have the check valve in the tip of the tester. I have compared test results between the prior IDI tester I used and this one and the results were the same. Here is some additional info I posted on another forum regarding this test kit:

[daltonhawk]

That’s a nice kit. I wish I would have bought that instead. Maybe I still will.

I was wondering about the lack of the glow plug tip effecting the readings. I was thinking of trying the tester on one of my Kubota engines that run well to see how the reading compares to spec. Of course if it takes a different adapter, it won’t quite compare to the VW.

Considering that the engine ran generally well before, I probably shouldn’t jump to rebuilding it based on a questionable tester, though the thought has crossed my mind.

[MarkWard]

If you can't get it running, you may need to rebuild the engine. I'd work on getting it running. Did someone accidentally fill it with gasoline by chance? Waldi knows a lot more about these engines than I, but in a nut shell. Its the engine or the pump or both. They are pretty basic setups.
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[daltonhawk]

Im not aware of gas in the engine since I’ve owned it. Now I’m trying to remember the last fill up but it’s been six months.

I did just remember a slight flaw in my procedure - I only removed one glow plug at a time. Maybe taking them all out would have made a difference in the reading? It was cranking reasonably fast I think.

[MarkWard]

My wife accidentally added gas to her rabbit diesel. It wasn't her fault really. The pump had diesel on one side and high test on the other. Both fuels were the identical price. She went in and told the attendant pump 3. She never made it home. Fortunately in those days, the pumps could handle that. The new engines won't.
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[daltonhawk]

My wife did do the last fill up but she’s confident it wasn’t gas. 15 years ago an attendant put half a tank of gas in my 99 Jetta before I caught it. I filled it the rest of the way with diesel and just ran it. It sounded off but survived it.

Tonight while I’m trying to decide what to do I decided to take the crank sprocket off to see if that could be the problem. There is a small amount of play but it looks alright so that’s probably not the problem. It is pretty oily in there so I should probably replace the crank seal nd it looks like the intermediate shaft might be leaking a little too.

When I lined everything up before i removed the timing belt I noticed that the cam was quite a ways off from the mark I made on the flywheel.

I decided to put it back together (temporarily with the old sprocket bolt) to recheck everything. I put the belt back on and used a clear tube from a glow plug hole to a jar of water to re-check TDC. I found that it matched the mark I’d made using a dial gauge before. The clear tube method worked really well - very sensitive to small degrees of rotation. I also noticed that after reassembly the cam was perfectly timed. Perhaps it had skipped a tooth before and I put back one tooth different? I’m tempted to put on a new timing belt and see if it runs.

How dire do these lifters look?

[MarkWard]

The oil on the front of the engine is likely coming down from the intermediate shaft seal and the O ring in the seal retainer.
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[daltonhawk]

Well I was curious how the cam timing might effect the compression so I repeated the test on cylinder 1 and it’s up to 320 from 220!

So I think this might confirm the issue. But how did it get off? Belt doesn’t look bad. I thought it was a little loose but not crazy. I had never messed with the belt tension or cam timing before, just the injection timing, but at that time I thought the cam matched measured TDC. But obviously something changed since then to make it stop running.

[valvecovergasket]

having a nice clean surface for the cam pulley to sit, and making sure thats torqued properly is a good start.

that picture definitely looked quite off though! id go through and confirm torques on all your pullies especially the cam, and the tensioner.


id probably do all the front seals now that ive got the crank pulley off. reseal that front main carrier plate, the crank seal, and the intermediate seal and oring also. not much work, theyre cheap, and it looks like lots of stuff has been leaking up there
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MegaSquirt resource - SpitfireEFI.com

gone, but not forgotten: '83 tdi westy - swap thread

[MarkWard]

The cam shaft has an unused key way machined if I recall, but depends on the taper to secure it not a key. I believe the design was that if some how interference happened between the valves and the pistons, it would slip. The torque on the cam bolt for the 1.6 was 33 foot pounds, it probably is similar to the 1.9.
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[?Waldo?]

When the cam sprocket is off be sure to clean the sprocket and taper on the cam with brake cleaner in order to ensure that there is no oil residue.

[daltonhawk]

Given the amount it was off would you guys be concerned about valve contact?

I don’t see any damage to the lifters other than normal wear and they seem centered but I’m not sure I know what to look for.

[daltonhawk]

So I think my plan is still to pull the engine. By the time I do all the seals, the water pump and the thermostat, I’ll probably have saved most of the time it takes to pull the engine and I’ll have the benefit of finding out why the TDC mark on the flywheel comes around about 15 degrees before measured TDC.

[?Waldo?]

I have a borescope that will fit into the injector holes on a TDI head. It is useful for checking for valve contact.

[MarkWard]

The diesel piston top is very thick. The valves move square to the piston, so if there was “kissing” it’s probably fine.
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