welding a cracked IP - PeachParts Mercedes-Benz Forum

erubin · #1 10-02-2004, 08:09 PM

The picture shows the idle screw with a chunk of the injector pump's cast aluminum case. There is now an approximately 1/2" gaping hole into the IP's internals. The idle screw (and hence the hole) is in the real case of the IP. That is the case without all the injection lines. Now i know the case can be welded once i get the pump off and the hole cleaned, but are there internals such as seals, orings, ball bearings, etc that would be damaged by the heat generated from the welding. If yes, can the internals be removed before welding without needing specialty IP rebuilding and measuring equipment. At the very least I should seperate the front case from the rear case. BTW, a rebuilt IP is too expensive for the budget and a used one is too risky. I believe this IP is fine except for the hole.

I thought about using JB weld but there is stress on this part from the trottle hitting the idle screw. Furetheremore getting epoxy in the crack will make it much more difficult to weld the aluminum because of contamination.

Wasuchi · #2 10-02-2004, 08:32 PM

I would look on ebay and try to find a used one, should be pretty cheap.

leathermang · #3 10-02-2004, 09:03 PM

I agree with Wasuchi....
but if you want to convince yourself with a good try... then go to one of the machinist companies like Bass Tools in Houston.... and try some of that epoxy stuff which they say is machinable..... and really strong....
but I think you would be much better off checking Ebay and getting one there... I have seen them go for $45-85 regularly in the last couple of years.... just make sure the numbers are correct....

whunter · #4 10-02-2004, 09:08 PM

Quote:

Originally Posted by erubin

Now i know the case can be welded once i get the pump off and the hole cleaned.

It can not be welded.

A used injection pump is a better risk.

If you remove the internals, it will need recalibration on a stand.

.

leathermang · #5 10-02-2004, 09:12 PM

But it just can't be used as an injection pump after that.... might as well weld up the five holes on the top..... LOL

Wasuchi · #6 10-02-2004, 09:21 PM

That machineable epoxy stuff might work, it's really tough. I would just be worried about how long it will hold up to heat, vibration, oil, Diesel.... whatever else might be around. You can bet that it would fail at the worst possible time!

Even if you did take everything out to weld it the case would likely warp from the heat and be unusable.

Brian Carlton · #7 10-02-2004, 09:42 PM

who would love to weld it. It may not work as a suitable injection pump after he gets done with it, but, he would love to weld it.

He lives in "central Texas" about 20 miles east of Austin, if you are interested.

leathermang · #8 10-02-2004, 10:09 PM

I could weld a stand on the bottom.... cover it with leather suitable for desktop use .... and the five holes in the top could be used to hold five pens..

erubin · #9 10-02-2004, 10:15 PM

Since welding appears out of the question I guess it's worth trying epoxy. JB weld is real strong but it does require a real clean surface. I'll have to make sure that no brake cleaner gets into the IP. There will be some stress on the part cause the throttle linkage will rest against idle bolt with spring tension and then transfer some bending force to the case. Using medium (blue) locktite on the bolt will eliminate having to lock the idle bolt down with the jam nut. Tightening down the jam nut would break the epoxy. Maybe I should think of a creative way to set and fix the idle without using the IP mounted idle screw. That way the hole could be patched with epoxy and it would not also have to hold the idle bolt.

I have not run the car with the hole. What is in there? Oil or diesel? Will it come pouring out if the epoxy failed and the hole opend up?

The idle will have to be set once and for all. It's at 750 now. The engine had some big problems including a destroyed precombustion chamber and faulty injectors which are now repaired and for a week was running OK. The engine still vibrates a little too much even with a new rack bolt and two new injectors. The rack bolt seems to have no effect on the vibration at idle even after returning to idle after reving.

leathermang · #10 10-02-2004, 10:28 PM

Anything you use will require a really clean surface.... don't skimp on that part if you are going to try this....
And just like concrete patching .... it would be good to undercut as many surfaces as you can.... while this stuff seems chemical... the bond you will have will actually be Physical.... so best to plan that way....
See if you can get Bass Tool in Houston to send you a paper catalog... they have some of these things displayed well in there....

But remember, we are suggesting you get a used one .....

jbaj007 · #11 10-02-2004, 10:47 PM

erubin,
If you are doing this yourself, I'm nearby to you and I have a spare used IP that should work on your engine. Email me off list and we'll work out where you can "borrrow" it, try it and if it works out, just replace it with another good used spare one from ebay or a wreckers. If it doesn't work out just return it.

kmaysob · #12 02-25-2006, 11:44 PM

Quote:

Originally Posted by erubin

The picture shows the idle screw with a chunk of the injector pump's cast aluminum case. There is now an approximately 1/2" gaping hole into the IP's internals. The idle screw (and hence the hole) is in the real case of the IP. That is the case without all the injection lines. Now i know the case can be welded once i get the pump off and the hole cleaned, but are there internals such as seals, orings, ball bearings, etc that would be damaged by the heat generated from the welding. If yes, can the internals be removed before welding without needing specialty IP rebuilding and measuring equipment. At the very least I should seperate the front case from the rear case. BTW, a rebuilt IP is too expensive for the budget and a used one is too risky. I believe this IP is fine except for the hole.

I thought about using JB weld but there is stress on this part from the trottle hitting the idle screw. Furetheremore getting epoxy in the crack will make it much more difficult to weld the aluminum because of contamination.

gonna be near az anytime soon? 20 bucks but it doest have a shutoff valve or alda

erubin · #13 02-26-2006, 04:50 AM

Thanks for the IP offer. For now it's holding. If that changes will explore replacemnt. The epoxy is not stressed by the idle screw since the epoxy only seals the case. The idle screw is held in place with a fabricated heavy gage sheetmetal bracket that is mounted to a nearby bolt as described in an earlier part of this post.