what solvent to soak injectors in?
 

What solvent should i use to soak the fuel injectors in for my CIS 79 930 engine?

Wanted to let them soak inside a jar while I rebuild the engine.
Which is the best solvent to use on these that wont damage anything?

Fred

Fred,

With all due respect, soaking CIS injectors in anything is simply a placebo and will not clean them.

You need to find someone with the special Bosch CIS test/clean fixture that will clean them as best as possible as well as check their patterns and opening pressures. Most high-mileage ones should be replaced as they don't always clean up successfully.

And there relatively cheap

Turbo CIS injectors are not cheap. Currently $134.25 a piece from Pelican for the correct ones for Fred's '79.

I pickled mine in Seafoam while my engine was being rebuilt. Not to clean them, per se, but at least to keep any fuel residue from varnishing up in there (at least that was my idea).

You can open the CIS injectors if you carefully pry open the pintle valve on the business end and wrap some turns of copper wire around the projecting tip. One strand of one copper of the insulated wires in an extension cord is what I am talking about, maybe 24 gauge.

Then soak the injectors in a jar of Berryman's B12 or Seafoam, or your favorite solvent, maybe even lacquer thinner. I put three of mine at a time in a jar with a tight fitting lid and shook the heck out of the jar for 5-10 minutes. The amount of fine dust that came out of the injector filters was amazing.

Mark

So there not just your run of the mill CIS injectors. Well, is anything cheap on a 930? And if not, 134.25 is indeed cheap for a turbo. Also, if rebuilding the engine, That would be a good time to put new ones in.

The main thing you want to know is about the spray pattern. Go to a diesel shop and use their diesel injection tester with kero or a cleaner and you can see the spray pattern and at what pressure or if the injector leaks.
Bruce

I did the same thing with my old 930 injectors, soaking them upside down or pintle end up in a glass jar of techron for a few weeks occasionally shaking the jar gently to turbulate or move the naphtha/alcohol techron solvent around.
I did see some small particles of dirt show up on the bottom of the glass jar after a few days of soaking and gentle shaking the 6 injectors.

After 3 weeks or so I removed them leaving the fine strand of copper wire holding the pintel open and put a short piece of 8mm fuel line over the pintle end of each injector with a hose clamp, filled the hose with techron and blasted 120psi air and techron through them backwards - backflushing them.
Techron mist shot out the injector line end about 15 feet.

Doesn't seem to have hurt anything and probably cleaned any dirt off the tiny cone shaped fine screen fuel filter thats inside the injector body if it had dirt on it because the motor runs smooth and perfect at all times.

Could an ultrasonic cleaner (ah-hem..."the Wifes jewellery cleaner"...shhh) be used once the injectors are held open (as described above?)

The solvents we are talking about will melt the plastic basket or top and sides of the unit in short order. Water based cleaners may not be as effective in breaking up the solidified crud in the filter or insides of the injector. But hey it might work...

Just don't put the injectors on the bottom of the unit and turn it on, it may fry the ultrasonic transducer.

Mark

CIS injectors are all metal with no plastic that i've seen in any of them and the 930 ones have metal threads and no oring for screwing them into the injector blocks.

Techron is naphtha and seafoam is naphtha with isopropyl alcohol mixed in for absorbing any water that may be in the fuel system. Neither of these solvents will do anything to most automotive plastics.
Naptha won't even hurt any type of automotive paint and is the ingrediant in prepsol and pre-kleano which are industrial solvents made for the final wipedown in on automotive paints after washing to remove any wax, tar, or silicones possibly on the painted surface before sanding and priming so fisheye doesn't become an issue when spraying on the paint.

J,
No more eggnog for you. I was talking about the plastic on the cheap Chinese ultrasound units...

Mark

oh sorry, i thought you might be thinking of efi injectors that usually have some type of high temp plastic or molded phenolic resin in the body.

havn't had any eggnog, just hanging out alone and bored on christmas eve reading the message boards and felt like being sort of social..

merry christmas, happy holidays, and have a happy new year!

Sure, do that right after baking your powder-coating in the oven, nickel-plating in the sink and blue-printing the transmission in the bedroom, shouldn't cause any issues... :D

I've got several sets of 930 injectors, and was intending to soak them in solvent and then use an ultrasonic cleaner to try to clean them further.

My reading on ultrasonic cleaners is that they can work very well, so long as you use an agent to reduce the surface tension of the water, which increases the cavitation due to the ultrasound (which is more pronounced the higher the frequency). Apparently dish soap works some large fraction as well as the more specialized and expensive formulations, but the very best results are probably obtained with a specialized wetting agent/cleaning solutions (e.g. probably non water-based, targeted at the specific cleaning task).

The cleaning effect is also apparently greatly enhanced both by heating/warming, and the power and frequency of the ultrasonic transducer.

I thought this one looked ideal for an experiment to see what results could be obtained - Amazon has it for about $73: KENDAL PRO 160 WATTS 2.5 LITERS DIGITAL HEATED ULTRASONIC CLEANER

I had three injectors that didn't have a good spray pattern. Soaking in Techron did not fix them. I bought 3 new ones when they were $100 each. Figured it was cheaper than holing a piston....