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View Full Version : Crack in valley next to injector


onetrackmac
01-25-2016, 12:38 AM
Recently trying to remove injector #1 using a threaded puller I cracked the aluminum around the passenger side of the injector. Nothing is seeping out as of yet, but I haven't gotten the injector out either and havent tried starting the motor. Is there water or oil pathways under that side if the shell? Is this something I can leave alone, should I JB Weld it, or is it much worse? Any insight someone can offer is much appreciated.

lindenengineering
01-25-2016, 12:42 AM
Splashed oil from valve gear operation.
The holes is sealed underside by a pear shaped rubber gasket.
If it doesn't leak then leave it alone or put a blob of JB on it if it makes you feel any better.
Dennis

misterbond10
01-25-2016, 12:46 AM
not sure if this is a good idea or not but those HPS-2000 alumiweld sticks are supposed to be the bees knees.

Aqua Puttana
01-25-2016, 01:14 AM
... Any insight someone can offer is much appreciated.
The bad news.

The oil under that cover gets splashed around alot. In my experience any crack needs to be sealed or it will fill the injector gallery until it flows out the weep hose.

The good news.

As Dennis suggested, JB Weld is a righteous repair. :thumbup:

Read about it here.

...

I ordered an injector puller to be shipped. While I waited I sprayed PB Blaster and another penetrating oil about twice daily at the base of #2. Rather than wait patiently as I should have, I tried hammering #2 with a ground square end chisel, wedging the puller for tension, and levering it with a bar. Nothing worked to free the injector, but I did mess it up pretty good.

As it turns out, hammering on the injector with the squared off chisel was not a smart move. I ended up with an oil seeping crack in one corner of #2 injector valley. The good news is that so far scraping the area clean, wiping with acetone, and then sealing the valley with JB Weld seems to have worked. Doktor A commented that the aluminum head cover is as fragile as an egg shell. There are many thin areas in the casting. The pull bolt injector removal tool is designed to stay close to the injector where the casting is stronger.
...

I got pretty discouraged with #2 being stuck as badly as it was. Interestingly that position didn't suffer seal leakage, but the stuff must have worked over to it. Cracking the aluminum head cover was a real bonehead move. It either happened when the chisel slipped one time, or from just too much hitting of the injector body while trying to loosen it. Most of that was when I was waiting for the puller to come from Eurpoarts. I should have had more patience and just waited.

...
If the injector doesn't come out you can re-install the hold down claw with the old bolt just snug, soak penetrating oil and still drive it. That said, having new extra hold down bolts and seals is a very good idea in case you need to remove and re-install any injector(s).

...

A picture is here.

http://sprinter-source.com/forum/showthread.php?p=137488#post137488

The thread is here.

Remove Pull Replace Install Change T1N Fuel Injector
http://sprinter-source.com/forum/showthread.php?t=16068

As long as you get everything clean the JB Weld repair will work without question. I didn't check the date/miles of my repair, but I am now at 294,000+ miles as of today.

Good luck. vic

312d
01-25-2016, 04:45 AM
i do not know what JBweld is, i assume it is some kind of magic 2 parts epoxy glue, well i dont have it here so i cannot speak for it, but certainly i would weld the crack with some aluminium specialist welder, i send to repair a cracked oil pan with TIG, and i can say that after the repair i never thought of it anynore, that good was the welding, and it was cheap indeed, cost me around 50 USD oil pan handed, versus the 800 usd for the new oil pan.

Aqua Puttana
01-25-2016, 03:34 PM
i do not know what JBweld is, i assume it is some kind of magic 2 parts epoxy glue, ...
That's exactly what it is.

The formulation has really good bonding strength and fairly high temperature tolerance. I have used it for many repairs on many different metals and plastics. It has great resistance to fuels, oils, brake fluid, and many other liquids.

J-B WELD can withstand a constant temperature of 500 F (260 C), and the maximum temperature threshold is approximately 600 F (316 C) for 10 minutes. J-B WELD can also be used inside a microwave oven, exposed to microwave radiation instead of infrared radiation (heat)
http://www.jbweld.com/pages/faqs

It is perfect for repairing the damage mentioned in this thread. With proper surface prep and allowing proper cure time the repair will be 100% and last as long as the aluminum cover.

I was once a bit skeptical of some of the epoxies and adhesives for repairs. Step into the 21st century and become a believer. :cheers: Epoxies aren't magic, but they do have their place for many repairs.

vic

MercedesGenIn
01-25-2016, 09:28 PM
Hi there,

I can only describe the rocker cover material to be similar to a 'cheap easter egg'. It reacts exactly the same as a hard tap of the finger on the chocolate shell. If it does crack its most likely that it has cracked 'around' the pressure point and not just in a 'line'. If the fragment falls in at some point after a few hot and cold cycles further down the line then you may have an issue on your hands. This is especially important to consider when replacing the injector cover which totally hides the problem from view and occasional monitoring. If its anything other than a very minor crack you may have to bite the bullet and replace it as there is a great deal of vibration and heat variation on that spot of the engine. I would prep the area by a light spindle grind or burr to give the epoxy a good keying surface. I am all for avoiding unnecessary work but this would be on my list of 'be absolutely sure' it was intrinsic before deciding to leave well alone. Only you can decide that when you get the injector out and can really closely inspect the area.

Here is a photograph of a piece that has broken out in the above described fashion and fallen in (2nd pic down in the text) http://www.mercedes.gen.in/WP35/mercedes-diesel-injector-advice-sprinter-others/
All the best
Steve

MillionMileSprinter
01-25-2016, 09:52 PM
Mac, here's what I would do if I were you: First, make a 1/4" steel plate insert to go around the injector and cover the cracked area so when you try to pull the injector again, the pressure is spread out over more surface area. Then I would work on getting the injector out. You may be able to get the injector back together. If so, do it and get the engine good and hot. Only tighten the hold down bolt a bit, so the engine compression has the opportunity to push that sucker out. If it doesn't loosen on its own, quickly remove the hold down bolt, claw, fuel line and top of the injector. Get the steel plate in there and try the puller with the engine hot. I like to have a can of aerosol keyboard duster on hand. Turn it upside down and out comes freezing cold spray. Spray that injector down good to hopefully make it contract enough to loosen it.
If that won't work, or you can't get the injector back together, I would try using the puller while the engine is running. I did a write up on running your engine on 4 cylinders. Search for that and see if you can get some ideas. Good luck and keep the forum posted on your progress!

MercedesGenIn
01-25-2016, 10:31 PM
You can identify the places that are designed to be pulled against on the cover in the video below: Anywhere else is pretty much a no-no on the rocker cover unless you have a large spider type puller that rests outside of the cover area.

https://youtu.be/Htgz-AMmZMo?t=1m48s



Steve

Aqua Puttana
01-26-2016, 12:10 AM
Hi there,

I can only describe the rocker cover material to be similar to a 'cheap easter egg'. It reacts exactly the same as a hard tap of the finger on the chocolate shell. If it does crack its most likely that it has cracked 'around' the pressure point and not just in a 'line'. If the fragment falls in at some point after a few hot and cold cycles further down the line then you may have an issue on your hands. This is especially important to consider when replacing the injector cover which totally hides the problem from view and occasional monitoring. If its anything other than a very minor crack you may have to bite the bullet and replace it as there is a great deal of vibration and heat variation on that spot of the engine. I would prep the area by a light spindle grind or burr to give the epoxy a good keying surface. I am all for avoiding unnecessary work but this would be on my list of 'be absolutely sure' it was intrinsic before deciding to leave well alone. Only you can decide that when you get the injector out and can really closely inspect the area.

Here is a photograph of a piece that has broken out in the above described fashion and fallen in (2nd pic down in the text) http://www.mercedes.gen.in/WP35/mercedes-diesel-injector-advice-sprinter-others/
All the best
Steve
Steve,
Good information.

My problem was a crack. All the pieces were there.

I will say that as long as the pieces are intact enough to be coated then the JB Weld will tie things together well enough that nothing will come apart and fall in. For an injector cover repair grinding to rough up the surface isn't that critical. There isn't much stress on an "eggshell" cover. Properly cleaning the oily surfaces does help to achieve good bonding. For some repairs I have used sections of metal, aluminum screen, fabric mesh, etc. to add strength when needed.

All situations are different, but a bit of common sense applied to the JB Weld repair can go a long way to end up with a long lasting solution.

vic