OEM Fuel Injector Spray Pattern

[Martin]

Due to a sooty exhaust and backfiring on over run I decided to check my injectors. Using my home made rig, I found all the injector patterns were terrible. So after multiple runs in the ultrasonic bath with Valvoline injector cleaner and flowing and back flowing and upping the pressure to 65 psi with a 50-50 mixture of cleaner and petrol. I finally ended up with two distinct patterns at 35 psi. Two injectors have a single stream and one has a cone shaped pattern. I looked up online what sort of pattern I should be looking for and found two different theories. The first theory says that it should be a single stream that atomizes on hitting the back of the inlet valve. The other theory says that the pattern should be cone shaped. I'm leaning towards the cone shaped pattern.

I was running out of time so I threw the Brick together and went for a ride. The backfiring on over run was more prevalent after you got up it. So I gave it a bit of stick and found it no longer backfired on overrun, even if I tried by not fully closing the throttle. I got home and used a digital temperature gage on the header pipes, two showed a lot cooler. Unfortunately in my haste to reassemble I had not noted where I had put the cone pattered injector. I assume it must be the hotter cylinder. Further tests will happen this weekend with more cleaning with lacquer thinners.

A mates son who is an auto electrician is building a better rig with graduated vessels and auto pulsing. He is also using a stronger cleaner potassium hydroxide. He is away at the moment for a week, and I don't know if he has finished it. I didn't know about it until I mentioned mine. I have a question while I do believe I should be aiming for a cone shaped even spray, do any inmates no what the correct spray pattern is. This is for OEM injectors on a 2V K75 1992.

Regards Martin.

[K1300S]

there are no injector cleaning services in AUS?  think you have already exceeded the amount it would have cost to just send them out for professional rehab, with pattern testing...  :-)

of course, that is not nearly as much fun as playing with flammable carcinogenic chemicals...;-)

[jakgieger]

Ways to do things...

1. The easy way,
2.  The hard way,
3.  The way that makes the hard way look easy .

Martin, just cut loose and buy a four hole set.  If you are concerned on the price, just check w/the wreckers :hehehe .

[Martin]

I  finally got hold of the local BMW wrecker, and I got quoted $110.00 ea for cleaned and tested injectors. I might have got hold of some old K100 injectors to play with. I actually enjoy trying to find a way of doing things without having to sacrifice an arm or a kidney.
Regards Martin.

[alexis291]

Interesting stuff, good to see a bit of proper R&D going on! In my experience injectors with a solid jet are quite rare but used in some applications, e.g. the Aston Martin DB7. Whether they are better than cones is engine/cylinder head/throttle position specific but the biggest improvements are likely to be at maximum power/full throttle. Cone shaped sprays will generally give better atomisation and are better at part throttle conditions, where most road engines spend most of their time. That's not to say that your engine won't be better with solid jets, the inlet tract layout may be such that it works better - but I would be surprised if BMW didn't do some experimentation when they designed the engine.


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[alexis291]

Interesting stuff, good to see a bit of proper R&D going on! In my experience injectors with a solid jet are quite rare but used in some applications, e.g. the Aston Martin DB7. Whether they are better than cones is engine/cylinder head/throttle position specific but the biggest improvements are likely to be at maximum power/full throttle. Cone shaped sprays will generally give better atomisation and are better at part throttle conditions, where most road engines spend most of their time. That's not to say that your engine won't be better with solid jets, the inlet tract layout may be such that it works better - but I would be surprised if BMW didn't do some experimentation when they designed the engine.


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[alexis291]

PS - that should say R&D - damm you AutoCorrect!


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[alexis291]

Aargh!


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[jakgieger]

  Yeah, just kidding you Martin.  As I farmer I understand the challenge/reward involved in creating your own solution as opposed to "buying" a solution.  In my situation, I have to ask myself can I afford the time to make a solution!  But seriously, with my 4 hole injectors, I have NO backfire and instant throttle response.  If your single holes are in such bad condition, perhaps your gas is of lower quality and the smaller 4 hole orifice would be even worse???

[wally.fisher]

Just my view, there isn't any benefit using a 4 hole injector on a K100/75 other than to empty your wallet, it has been tried and reported on by many, rather buy a injector service kit from Alibaba for a tenner use brake cleaner inside the injector to break the scale build up. Backfiring is mostly TPS related if continued after injector service.


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[Laitch]

Aargh!

alexis291 seems in distress. Doesn't anybody care?  :sip:

[Martin]

 :dunno 

[Martin]

I decided to remove the belly pan in order to get better shots at the header with the laser temperature gun. I took it for a hard run and I am now showing all header temperatures pretty well equal. Pulled the spark plugs and all showing the same grey tan colour. Went over to a mates place in order to have a look at an old K75 engine he has got. I wanted to see what colour pintle caps it had, they are yellow, and I do believe my original ones were yellow. The one I have just removed were green and they have been replaced with blue ones. When I tried to get some the other day I tried to get yellow ones but he didn't have any so I am using the blue ones. The green ones are not counter sunk at the orifice the yellow and the blue are. I am not sure what the differences are beside the obvious ones such as length and the counter sinking. What are the correct pintle caps opinions very welcome.

At the moment I still have not had any backfiring just the normal rumble gurgle on overrun even with a partially open throttle which previously invoked large back fires. My brick has always had a slight supposedly normal backfiring problem. The problem has been minimized by keeping the mixture, and TPS adjusted. I have used Caltex Techron once or twice a year and cleaned my injectors with the ultrasonic cleaner, every few years. It was not until I built the test rig that I became clear the ultrasonic cleaner while it will clean them you don't know when they are clean unless you test them. And it seems that you may be able to cure K75's backfiring in some cases.

I decided to buy a sequencer I found one on EBay cheapish $37.00, I could of got one cheaper same brand from China but impatience set in.  As Repco has a 30% off sale on Sunday I'll buy some carby cleaner tomorrow apparently better  than injector cleaner. I'm going to keep chasing a local source of pintle caps, "O" rings and filters so far no luck. I will continue testing when the sequencer arrives.
Regards Martin.

[Martin]

The OEM spray pattern for 2v Bricks is 13 deg which is very narrow and accounts for it appearing as a straight jet. From what I could find out the OEM pintle cap colour should be yellow although some Bricks are now running blue or green. I am unsure what the effects are from running different caps are. The yellow and blue appear similar with counter sunk orifices, and I found a reference to the blue caps as Bosch universal. The green caps are not counter sunk and they were put on my Brick about 17 years ago when I had them cleaned by a guy who did BMW European cars non dealer. If any inmates can ad to or correct what I have posted please feel free to do so.
Regards Martin.

[Martin]

I've recently  been playing with injectors, and cleaning them. I decided to try three different cleaning solutions and the outcome on totally blocked injectors. These injectors were showing 15 ohms on three Bosch 3.9 Falcon and 12 ohms on three OEM k75 the second type. All these injectors were totally seized no clicking. First solution was a mixture of Valvoline injector cleaner and petrol 50-50. This is what I had used on my partially clogged injectors on my Brick using my test rig and ultrasonic. It cleaned two and partially cleaned one which came good, but not sure until I retest. Multiple runs cleared the blockage eventually on one Falcon injector. Straight injector cleaner failed to clean any after multiple baths and soaking for 24hrs. Repco carby cleaner sprayed into the injectors and left to soak for 24 hrs no change. Repco cleaner followed by the Valvoline mix in the ultrasonic 6 cycles and soaking failed. Acrylic thinners cleared the three OEM injectors after 4 ultrasonic cycles and one Falcon. It took six cycles to clear the next and eight to clear the last. Each cycle was three minutes long set on high. Although the injector solenoids are now functioning it might take either more cycles or flushing and back flushing to get correct patterns. All cleaning was done with the internal filter baskets in place, and thinners will make the "O" rings swell. Further testing will be done when I get the sequencer.
Regards Martin

[Martin]

Received the sequencer pulsar on Wednesday, came home from dump day and decided to have a play. Two of the borrowed K75 injectors just dribbled on the tester, one totally blocked. So back in the thinners filled ultrasonic bath with the sequencer attached, two came good after one bath. The last one came good with three baths sequencer attached, patterns on all three look good. Until I know what the pattern is on the Ford ones are I will leave them alone.

So the total cost of setting this up MAP bottle and hose and some of the fittings I already had $20.00 for the ones I didn't have. Three bottles of injector cleaner I've had in stock for a year bought for $2.00 Au a bottle, one can carby cleaner $7.50 Au, 600ml of thinners $10.00 Au, sequencer was $37.00 Au. "O" rings, filters, pintle caps $15.00 Au. I would not use injector cleaner carby cleaner again, on totally frozen injectors. The thinners was the only thing that cleared them quickly. With more time maybe the cleaners might have worked. I'm still chasing a source of yellow pintle caps, mates son is back and he's going to question him about a source for injector parts. The total cost for the rig and cleaning six injectors has been $75.50 Au. And I'm not including the three Falcon ones which are partially done. Even with the parts I already had I wouldn't have exceeded $100.00 Au. The fuel filter is one I removed from my Brick on the last service and kept for use in the rig.

Even though the Brick is running better than it has ever run, and no matter what I try I can't induce a backfire. On Monday for the sake of thorough testing I will remove my previously cleaned injectors,  and put them on the rig with the sequencer. Due to the way it's running I'm expecting to see good patterns. The mate who has lent me his spare injectors is highly sceptical of my Brick no longer backfiring after cleaning the injectors. He had his injectors cleaned and tested by his son when his son worked for another company. And after cleaning, his brick still backfired on overrun. Maybe I have just been lucky, anyway I will post the results when I do the next test.
Regards Martin.

[Laitch]

Received the sequencer pulsar on Wednesday, came home from dump day and decided to have a play. Two of the borrowed K75 injectors just dribbled on the tester, one totally blocked. So back in the thinners filled ultrasonic bath with the sequencer attached, two came good after one bath. The last one came good with three baths sequencer attached, patterns on all three look good. . . .

Even though the Brick is running better than it has ever run, and no matter what I try I can't induce a backfire. . . .

Thursday I rode in beautiful fair weather to the Button Box in Sunderland, Massachusetts and sampled a selection of Irish button accordions and concertinas for an hour.

I used focused backfiring on the trip home to keep the deer and woodchucks out of the road. :giggles

[The Mighty Gryphon]

Thursday I rode in beautiful fair weather to the Button Box in Sunderland, Massachusetts and sampled a selection of Irish button accordions and concertinas for an hour.

I used focused backfiring on the trip home to keep the deer and woodchucks out of the road. :giggles

I just learned that another member here is a concertina aficionado when I smuggled an old Italian one into the Great White North for Bocutter Ed.

Re focused backfiring, is it effective?  Anything I can do to deter the damn bambi's getting close to the raods I travel at night would be welcome even if it will be waking the neighbors.

[Laitch]

Re focused backfiring, is it effective?

My route home leads along a gravel road traveling through a mix of hayfields, wetland and ledge. A moment of deceleration a hundred yards or so from most likely crossings seems to stimulate prompt decision-making among the local whitetails. Could be the note of a stock K75 exhaust is repellent or it might be luck. I'm sticking with the program no matter which it is. :giggles

[Martin]

Backfiring might work with Deer but nothing works on Roo's, they are just too dumb. The only good thing about them is they can't jump backwards. Which is why I am still here and haven't left this mortal coil, in a flurry of blood guts and tortured metal.
Regards a now stealthily Martin.

[Martin]

Just finished putting the Brick back together after testing, all injectors displaying an excellent pattern. And the flow rates with what testing equipment I've got are the same. I used a 250 ml graduated vessel sourced from a home brew shop. I have found out something that should have been obvious don't spill thinners on a cheap Aldi ultrasonic cleaner. Still trying to find a local source of yellow pintle caps and "O" rings and filters. I will post if and when I find a source.

As far as the test rig and the injector pulsar sequencer goes I am extremely happy. I have however changed the way I attach the hose to the injector, for speed I have done away with the machined up part with the bolts. I now use a hose reducer and attach the hose directly using a hose clip you can also reverse the connection to back flow the injectors.
Regards Martin.

[Martin]

The Brick has definitely got more grunt and is quite noticeable after cleaning the injectors. I have now got a source of "O" rings, filters and caps not sure of the cap colour but the yellow and blue are apparently interchangeable. The mate rang tonight and told me I can get them though his sons company. He told me to work out what I want and he'll get me a price, so I'm going to put an initial order in to cover twelve injectors. I'll get back with the prices when I get them.
Regards Martin.