Fixing tii injectors

[JsnPpp]

Very nice work!

 

Jason

[jimk]

7 hours ago, dlacey said:

Agree: 'good' injectors have the flat suface of the pintle clearly proud of the faceplate, i have some other more worn ones where they are at the same level - the pintle resting deeper inside the injector...these are really end-of-life... not every injector can be saved.

Given the above wear observation and the fact that the injector parts are virtually irreplaceable this product seems appropriate.  Ethanol fuels make the situation worse.

https://www.amsoil.com/p/upper-cylinder-lubricant-ucl/#pills-home_0/?=36101

[irdave]

8x12 shims are easy. Readily available in 0.1, 0.15, 0.2 mm. Probably thicker as well. About $1.50 each. Very flat, very precise. 

[BarrettN]

Well, I finally played around with this - first try with my worst condition injector. The spray pattern was very much improved (I used 400 & 800 grit compound). I have access to a nice lighted stereoscopic Leica microscope, with the magnification maxed out you can see EVERYTHING - very helpful if you at all have a chance of using one. I could see where there were still a few pits on the backside of the pintle, but stopped where I was to put it back together to test. HUGE improvement in spray pattern, and the opening pressure went up a little bit. (380 psi, with a small drip before opening). I'll do a few more and also work this one some more to see if working it enough to get out the pitting drops (and how much) the opening pressure. I need to find a source for the internal washer, I'll probably see if I can play with some shims as well. 

[dlacey]

All,

Thanks to AliExpress I finally got some hardened flat washers... The size we need is 5mm ID, 12mm OD...the ones are got are 1mm thick.

Fitting those as described in the diagram above, & fitting the original (soft) sealing washer on-top allows the injector to be reassembled & seal fine...The assembly is now 1mm taller, but this doesnt matter. This recovers the spring tension caused by wearing of the peg, the peg is often worn about 0.5mm deep...likely the pintle equally worn...so by raising the peg 1mm its back how Bosch intended.

 

My pop-test results show badly worn injectors that were opening at 180-220PSI are now 'recovered' to 400-500PSI  ...thats in the range of the original spec. Success!

 

Now i need to road test these injectors and see if they stay good...I am confident they will be fine..only risk is accelerated wear of the new washer...lets see.

Edited July 21, 2020 by dlacey

[BMW 1600-2]

@dlacey - How did your injectors with the shims perform?  I’m going through 2 sets to see if I can get them back up to spec pressure with a good spray pattern. I am very interested in how well this worked out for you!

[dlacey]

Still running good on my daily driver orange tii, probably got 10Kmiles on them so far. i will remove them and check for both wear of the new washer and the performance of the injectors...maybe later this year.

[BarrettN]

I'd love if we could find a place that would be willing to do a limited production run of new springs - I really think that would be the best way to address the issue.

[BMW 1600-2]

I will check with these guys - katyspring.com - they are local and pretty capable - 

[dlacey]

I am working on getting complete new nozzle assemblies made by a diesel injector company.. i dunno yet if it will work out or make any economic sense. The idea would be that the nozzle includes all the parts except the blue body & green check valve in the schematic earlier in this thread... a 'drop-in' solution to rejuvenate injectors. Lets see....