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?Waldo?
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Joined: February 22, 2006
Posts: 9752
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 Posted: Fri Apr 16, 2021 11:50 am Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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| MarkWard wrote: |
| The diesel piston top is very thick. The valves move square to the piston, so if there was “kissing” it’s probably fine. |
I don't agree with that. Yes, the pistons will be fine, but the valve stems are 7mm unlike the earlier VW diesels with 8mm stems which are considerably more tolerant of contact. If the later 7mm valves contact the pistons, even if they seal afterward, the contact weakens the stem and they have a tendency to pop the heads off a couple/few thousand miles later. When the head pops off a valve the damage is catastrophic, always ruining the head and piston, and often ruining the block also. I would not run it without doing my due diligence to know that valves did not contact pistons and replacing any that did. |
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MarkWard
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Joined: February 09, 2005
Posts: 17124
Location: Retired South Florida
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| Posted: Fri Apr 16, 2021 12:05 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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Plenty of time to pull the engine apart.
| Quote: |
| M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
I’d be trying to pinpoint the original problem. Getting the engine running again would be a place to start and determining what is wrong.
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daltonhawk
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Joined: August 20, 2019
Posts: 84
Location: OR
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| Posted: Fri Apr 16, 2021 1:27 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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I guess for lack of a better theory, either the cam sprocket turned or the timing belt jumped a tooth? I’m not sure how to conclusively determine which.
Given the copper showing on the lifters should I consider just putting on a rebuilt head? Is there a preferred source for a head?
I’ve swapped a head before but never rebuilt one. I suppose I could learn but I do want to go camping soon. |
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daltonhawk
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Joined: August 20, 2019
Posts: 84
Location: OR
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| Posted: Fri Apr 16, 2021 2:35 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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| ?Waldo? wrote: |
| I have a borescope that will fit into the injector holes on a TDI head. It is useful for checking for valve contact. |
Do you have a link? Would a cheap thing like this work?
https://www.amazon.com/Actron-CP7669-Video-Inspect...&psc=1 |
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Steve M.
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Joined: July 30, 2013
Posts: 6829
Location: Fort Lauderdale, Fl.
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| Posted: Fri Apr 16, 2021 2:40 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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I have a Depstech borescope/endoscope that has been working well and often for the past year. WiFi connect to the smartphone allows it to take photos
https://www.amazon.com/s?k=depstech+wireless+endos...-doa-p_2_8
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daltonhawk
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Posts: 84
Location: OR
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| Posted: Fri Apr 16, 2021 2:59 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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| The ability to take photos and post them here would probably be good since I’m not sure I’ll know what I’m looking at. Does anyone have a picture of the witness marks I’m looking for? |
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?Waldo?
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Joined: February 22, 2006
Posts: 9752
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| Posted: Fri Apr 16, 2021 3:07 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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| MarkWard wrote: |
Plenty of time to pull the engine apart.
| Quote: |
| M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
I’d be trying to pinpoint the original problem. Getting the engine running again would be a place to start and determining what is wrong. |
As part of "getting it running" I would investigate and find out if the pistons hit the valves. If they did, then replacing the affected valves would be step #1 of getting it running because getting it running prior to knowing if valves have been hit is the opposite of progress. I mentioned a very quick way to see if pistons hit valves. Use a borescope. It takes 5 minutes to pull the injectors and another 5 to inspect the piston crowns for any marks from valve contact.
I don't have a link. I got mine more than a decade ago prior to the smart phone borescopes. The one you linked says it is 9mm. That is unlikely to fit through the injector hole. The one I have is 5.5mm and the center hole of the copper injector washer is 7.5mm. |
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?Waldo?
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Joined: February 22, 2006
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| Posted: Fri Apr 16, 2021 3:34 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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| daltonhawk wrote: |
| Does anyone have a picture of the witness marks I’m looking for? |
Now that you have corrected the valve timing, one of the reasons it would be prudent to look at the piston tops prior to running it is because if the valves contacted the pistons and the contact was light, it will be much easier to see the marks if the engine does not run fresh carbon over everything. It is also possible for there to have been valve contact in the past that was corrected with replaced valves. Old marks might be present and indistinguishable from fresh ones if you run it prior to checking.
I don't have a decent pic, but if fresh, the valve mark will be more shiny that the surrounding carbon on the piston crown. If present, they will be within the valve cutouts in the piston crown. |
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RolandD
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Joined: January 15, 2017
Posts: 247
Location: Menomonee Falls, Wis
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| Posted: Fri Apr 16, 2021 6:22 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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I would not pull the engine. If the TDI uses hydraulic lifter like the 1.9 IDI, you can check for interference without removing the head... Remove the cam and remove each lifter, checking for an imprint of the valve stem in the little thimble it pushes on. I lost a brand new belt in 20 miles when the idler froze on my IDI engine. I pulled the head but did not have to. The valve stems punched clean thru the thimbles. I could have just replaced the lifters.
Roland |
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?Waldo?
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| Posted: Fri Apr 16, 2021 9:19 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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| If any valves are hit hard enough to damage a lifter, they should most certainly be replaced. Simply replacing lifters is folly. Inserting a borescope into the injector hole and looking at the piston crown is easier than pulling the cam and lifters and is more likely to let you know if valves were hit especially if the contact was not very hard. |
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daltonhawk
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Location: OR
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| Posted: Fri Apr 16, 2021 9:41 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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I’m going out of town for a week but I plan to have a 5.5mm scope and timing parts, seals etc waiting for me when I get back.
With the piston at BDC hopefully there will be plenty of room to look around. The hardest part will probably be getting my crusty injectors out and cleaned up but I suppose that’s a good thing to do anyway. |
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?Waldo?
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Joined: February 22, 2006
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| Posted: Fri Apr 16, 2021 11:13 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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| I have a slide hammer that I made a small adapter for. The adapter is a coupling nut that threads onto the slide hammer welded to a nut that threads onto the injector when the metal line is removed. That slide hammer quickly removes even the most crusted injectors that are glued in by carbon. |
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ALIKA T3
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Location: Honolulu,Hawaii and France
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ZsZ
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Joined: December 11, 2010
Posts: 1645
Location: Budapest Hungary, Europe
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| Posted: Sat Apr 17, 2021 12:42 am Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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| ALIKA T3 wrote: |
M14x1.5 for the injector side. Same as the wheel hardware, hint hint  |
A wheel nut amd a wheel bolt and you have something to tap/grab
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1.9 MTdi 2wd Multivan (ex Caravelle)
Van since 2006, engine since 2008 |
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daltonhawk
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Joined: August 20, 2019
Posts: 84
Location: OR
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| Posted: Tue Apr 27, 2021 12:39 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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Thanks for the help with the injector removal. I bought a m14x1.5 nut and welded an adapter. 3/4 of the injectors come out pretty quickly with the only trick being avoiding hitting the cabinet with the slide hammer. The pilot injector refuses to come out however. I banged on it until the weld on my adapter broke, welded it stronger, and then banged on it until I got tired. It’s soaking with degreaser right now so maybe it will come out later.
I got the depstech and took some pictures of the other 3 pistons. I don’t see any signs of contact. What do you think?
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?Waldo?
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| Posted: Tue Apr 27, 2021 1:05 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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The pistons DEFINITELY hit valves and recently!
That shinier circle in one valve cutout of each piston shows distinct piston/valve contact. If they are each exhaust or each intake valves, then it was certainly a fault with cam timing.
The head should be pulled and each valve that got hit should be replaced as step 1. |
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daltonhawk
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Posts: 84
Location: OR
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| Posted: Tue Apr 27, 2021 1:19 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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| Ahh ok. I was thinking intake valve area was just cleaner than exhaust but maybe that doesn’t really make sense. I’m also not 100% sure which valve is which in the photos but I think the shiny side is consistent. I guess I’ll go pull the engine and then the head. At least I can stop stressing about injector crud that might have fallen in. |
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?Waldo?
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| Posted: Tue Apr 27, 2021 1:34 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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| ?Waldo? wrote: |
| I don't have a decent pic, but if fresh, the valve mark will be more shiny than the surrounding carbon on the piston crown. If present, they will be within the valve cutouts in the piston crown. |
These are the valve imprints in the pistons:
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?Waldo?
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Joined: February 22, 2006
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| Posted: Tue Apr 27, 2021 1:37 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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The exhaust valves are to the outside of the head. As you look down on the head, from left to right the valves are E-I-E-I-I-E-I-E. If you look at the manifolds the ports of the intake or exhaust line up with their respective valves. Probably all four exhaust valves hit due to the cam timing slipping.
At this point, the head should be removed and those valves replaced, so you will have ample opportunity for a more intimate view. |
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MarkWard
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Location: Retired South Florida
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| Posted: Tue Apr 27, 2021 2:22 pm Post subject: Re: M-TDI Vanagon Suddenly Blowing Huge Clouds of White smoke |
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If you pull the head, take this piece of advice. Put a dial indicator on number 1 or 4 piston. Rotate the engine to TDC and make your own flywheel TDC mark using the dial indicator. This way you are 100% sure your crank is at TDC when you set the cam and pump timing.
I can’t account for why the engine was running fine till it started blowing white smoke. As I stated earlier once the engine timing is set correctly, it’s set. Something changed.
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