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Old 03-05-2010, 01:04 PM   #1
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Default Injector disassembly

Hey guys I just got a set of injectors the 326cc's and have an issue with them.

If the guy that sold them to me off e-bay doesn't replace refund I might need to fix these.

Looks like they clamped down on the injector before it fully inserted into the manifold. Basically a nice C shaped gouge through the tip, the hole is offset and oval shaped now....

Don't think that will do well for a spray pattern...

Anyways is there anyway of disassembling the injector or replacing the plastic tip???

Also the plastic tips themselves are loose, I don't remember mine being loose at all. They will basically rotate and pull on off about 1/16th of an inch or more...

advise???
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Old 03-05-2010, 01:31 PM   #2
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send it to witch hunter on injector rehab and they will fully rebuild it for alot cheaper than you can.
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Old 03-05-2010, 01:37 PM   #3
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Also deschutesworks and rc engineering. All are roughly $20 an injector, and no, you shouldn't just send one. If they're used, you should send them off no matter what, damage or not.
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Old 03-05-2010, 03:38 PM   #4
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Deatchwerks is a sponsor here and will give you an upgrade in service if you mention miataturbo.net

Do get any injector you plan to use with a turbo cleaned/tested so you don't risk blowing your motor over some easily avoidable problem.
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Old 03-05-2010, 04:09 PM   #5
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guys I only paid 30 bucks for all 4...
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Old 03-05-2010, 05:34 PM   #6
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Oh in that case go blow up your engine with diy repaired injectors. I promise you, we won't care.
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Old 03-05-2010, 07:02 PM   #7
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Oops my mistake guys sorry, I thought I posted on miataturbo.net not miata.net. Forgot that miata.net is just full of a bunch of buy here people.

--------------

I taked with a friend of mine that's running a superstock car. He commented that the plastic cap is simple to protect the "???pendlue???" if the center pin is not damage and the cap doesn't interfer with the spray pattern it will be fine.

He actually said if you think it will simply cut some of the plastic back.

Now he did say that I may have a problem if they are loose. If they are loose I will probably bleed boost, and potentially fuel, past the injector to atmosphere. All I have to do is pressure test the intake system once installed to see if this is a possibility.


Anyone have any success poping the plastic tip off... he said they crack half the time.
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Old 03-05-2010, 07:17 PM   #8
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Quote:
Originally Posted by jhouston View Post
Oops my mistake guys sorry, I thought I posted on miataturbo.net not miata.net. Forgot that miata.net is just full of a bunch of buy here people.

--------------

Cute attempt at sarcasm.

Pintle cap.

You should send these out to be cleaned and completely rebuilt. If you don't and they happen to be horribly mismatched, you will end up blowing your motor due to an uneven fueling condition. For 80 bucks, why risk it?
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Old 03-05-2010, 07:20 PM   #9
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Its not worth blowing a engine over injectors that where 30 buck. spend the money and save your self in the long run better off that way.
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Old 03-05-2010, 08:17 PM   #10
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But guys! They have 100s of thousands of miles on them, they're covered in grime, they've been crushed, and they were only $30! Why would I have them rebuilt?!?

Serious answer OP: It is indeed only $80-$95, both deschutesworks and RC engineering have a discount for us, and even my "recently rebuilt" injectors had one off 5% and dripping. Two were randomly switching off. $94 later they came back crystal clean and perfectly balanced within 1cc.
https://www.miataturbo.net/forum/t43637/
Miata.net would never advise you on replacing injectors at all btw, it'd ruin the British heritage of the car to make it more powerful. We're only trying to advise you on how to save your engine, make more power, get better mileage, and have a smoother power band. If you don't want this, we'll stop talking.
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Old 03-05-2010, 10:56 PM   #11
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are you saying for 20 dollars they will rebuilt the entire injector and replace the pintle cap...

The reason why I was sarcastic was I posted on injectors, then get 3 posts in a row for sending them off to be cleaned.


That's like buying a motor that has a rod sticking out the side. Commenting that theres a rod sticking out the side and 3 people say you should send that off to get compress checked its only 50 bucks a cylinder... guess what I know 1 will be bad...

I will probably end up getting a set balanced, but 3 ballance and 1 broken doesn't give you much...
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Old 03-06-2010, 02:16 AM   #12
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You will need too pay for any new parts on top of rebuild. So $80 to 95 + 30 for injectors + parts . A good deal is not so good. Why waste 30 on junk in the first place. What are your plans for your car.
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Old 03-06-2010, 04:29 AM   #13
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Thats a horrible analogy. You obviously cannot comprehend what we are trying to tell you so just forget it and don't send them out and blow your car up, please.


Quote:
Originally Posted by jhouston View Post
are you saying for 20 dollars they will rebuilt the entire injector and replace the pintle cap...

The reason why I was sarcastic was I posted on injectors, then get 3 posts in a row for sending them off to be cleaned.


That's like buying a motor that has a rod sticking out the side. Commenting that theres a rod sticking out the side and 3 people say you should send that off to get compress checked its only 50 bucks a cylinder... guess what I know 1 will be bad...

I will probably end up getting a set balanced, but 3 ballance and 1 broken doesn't give you much...
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Old 03-06-2010, 09:13 AM   #14
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b/c you can buy used cheaper than you can buy new at times.

Your not going to blow-up a motor on used injectors, you'll blow up a motor on bad injectors. used doesn't equal bad.

Also there are so many ways of checking for injector unbalance... reading plugs, (a lost art), shooting your exhaust runners with a IR gun. listening for knock and ping...

I would love to have a balanced set of brand new RC injectors for 250 bucks.

But if I were going to do that I wouldn't buy 326cc's I'd get 440's or larger and a megasquirt or something.

Shoot even going with a set of peak and hold and a driver box...

My idea is make the car on a budget. Currently I'm running about 6 psi on stock injectors, and that's pretty lean the car really runs better around 4-5psi. The thought is get a decent set of used 305's to 326's run them at 38psi (if i can I've found the practical limit to be around 36psi anything less than that and you don't get good atomization) idle. Then keep upping the boost to lean at 95-100 psi on a stock computer. Using a SFMU BTW.
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Old 03-06-2010, 09:48 AM   #15
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Quote:
Originally Posted by jhouston View Post
b/c you can buy used cheaper than you can buy new at times.

Your not going to blow-up a motor on used injectors, you'll blow up a motor on bad injectors. used doesn't equal bad.
I've got a set of "good"/"recently cleaned" used injectors and a blown motor (and a new one experiencing knock) that may say otherwise.

I think I just figured out why I'm getting knock. Was thinking about this on the way in this morning, and had to share since you hit it exactly.

I just swapped out a motor 2 weekends ago, not something I want to do again soon. The old motor was burning oil, which was why it came out, but it had also developed some pretty good high load detonation. No reason too, as I run a conservative spark table, and use water injection. I also datalog at least monthly.

I blamed it on poor rings causing high cylinder pressure in order to maintain the same load.

Then when my CAS died on the new motor, I blamed it on that, assuming it was "floating" timing as it was on it's way out.

Now I have a new motor, new CAS, and still have knock.



My point is, sure there are ways to check for a bad injector, but how often will you do this. I read my plugs, and change them monthly (just didn't bother when old motor was burning oil).

Now compare the frequency of even the most avid plug reader (since the only IR gun I have access to they will fire me for taking home), to exactly how long a 220whp/12psi Miata motor is going to stand up to some serious det in one cylinder. One of those is measured in days and weeks, the other is measured in milliseconds.


I DO NOT want to swap another motor again anytime soon. I would happily pay the money to get my injectors cleaned, checked, and fitted with some new parts, and I'm crazy on my budget. I've maybe got $2500 into my whole car. Also, that's easy to do now, and much harder to do when they're installed and you're driving it.


You're basically saying you're going to wait until you know you've got a problem to fix it, instead of doing some easy prevention WITH proven power and dependability benefits. It's not often you see a preventative item that is smart, and going to allow you to tune for a little extra as well, especially at that price point.


I won't let another set of injectors hit my car without being either RCs or cleaned by a pro...even if I find out this isn't my current problem. It's easy to say it doesn't matter when your car is running fine...like saying it's okay to carry $500 in your wallet the 99.9% of the time you're not getting mugged.


I'm going to have to do some of those checks you mentioned above, and hopefully not too late.
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Old 03-06-2010, 10:05 AM   #16
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Quote:
Originally Posted by jhouston View Post
Oops my mistake guys sorry, I thought I posted on miataturbo.net not miata.net. Forgot that miata.net is just full of a bunch of buy here people.

--------------

I taked with a friend of mine that's running a superstock car. He commented that the plastic cap is simple to protect the "???pendlue???" if the center pin is not damage and the cap doesn't interfer with the spray pattern it will be fine.

He actually said if you think it will simply cut some of the plastic back.

Now he did say that I may have a problem if they are loose. If they are loose I will probably bleed boost, and potentially fuel, past the injector to atmosphere. All I have to do is pressure test the intake system once installed to see if this is a possibility.


Anyone have any success poping the plastic tip off... he said they crack half the time.
i sent in my 550's of unknown condition and for 70 bucks totall i got back 4 injectors with new caps pintels and verified flow that included shipping both ways. one injector was totally stuck and the others where well under par it is cheap insurance.
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Old 03-06-2010, 10:14 AM   #17
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Well everyone comments about getting the fuel injectors matched to within 5% or even saying wow those are out blah blah blah...

Anyone ever flow balance their head and intake????

You can get more than 5% airflow difference between the cylinders depending on intake design and porting.

Also do you index you plugs? That's important to... not only gap.

I also run non plats for tuning. This way you can check the timing mark and if your getting detonation (even slight) you'll get little silver specks or ***** up in the plug.

O.K. let me hustle you....

DUDE YOU DON"T HAVE AN IR GUN!!!! LIKE OH MY GOD!!! how do you live with yourself your going to break everything and your cats going to pee in your soup and your neighbour going to run off with your dog if you don't get one... it could happen just watch...

Seriously an IR gun is 1/2 the price of a wideband, set of balanced injectors, about 3 cases of mobile 1.

go to grainger.com

Also another $0.30 tool, a piece of rubber tubing that fits in your ear... the other attach it to a piece of copper pipe 3/8" or so. You can diagnose everything from, valve lash, busted water pump, which clyinder is missing, bearing noise (a/c, p/s, clutch throw out), probably even a faultly fuel injector...

Hey if it's good enough for a medical diagnosis it's good enough for a car, and cars are easier...
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Old 03-06-2010, 10:17 AM   #18
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Originally Posted by magnamx-5 View Post
i sent in my 550's of unknown condition and for 70 bucks totall i got back 4 injectors with new caps pintels and verified flow that included shipping both ways. one injector was totally stuck and the others where well under par it is cheap insurance.
that sounds pretty cheap, who did you use... I'll get a quote from them.

sorry checked your previous post I'll give them a shout!
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Old 03-06-2010, 10:18 AM   #19
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Quote:
Originally Posted by jhouston View Post
Well everyone comments about getting the fuel injectors matched to within 5% or even saying wow those are out blah blah blah...

Anyone ever flow balance their head and intake????

You can get more than 5% airflow difference between the cylinders depending on intake design and porting.

Also do you index you plugs? That's important to... not only gap.

I also run non plats for tuning. This way you can check the timing mark and if your getting detonation (even slight) you'll get little silver specks or ***** up in the plug.

O.K. let me hustle you....

DUDE YOU DON"T HAVE AN IR GUN!!!! LIKE OH MY GOD!!! how do you live with yourself your going to break everything and your cats going to pee in your soup and your neighbour going to run off with your dog if you don't get one... it could happen just watch...

Seriously an IR gun is 1/2 the price of a wideband, set of balanced injectors, about 3 cases of mobile 1.

go to grainger.com

Also another $0.30 tool, a piece of rubber tubing that fits in your ear... the other attach it to a piece of copper pipe 3/8" or so. You can diagnose everything from, valve lash, busted water pump, which clyinder is missing, bearing noise (a/c, p/s, clutch throw out), probably even a faultly fuel injector...

Hey if it's good enough for a medical diagnosis it's good enough for a car, and cars are easier...


A few months ago I said all the same ****, and have been an advocate of cheap used injectors. I changed my mind recently.


Just trying to help...have fun.


EDIT:

Indexing plugs has shown very small gains on four strokes...but is a good old trick for 2-stroke motors.

I never run platinums regardless, as I change my cheapie NGKs monthly, and they're good enough for me. The one time I tried Plats I was still n/a, and I hated them.

What's the deal with an IR gun? I was just pointing out that's not a common garage-hold tool. I'm kinda surprised you think it's necessary Mr. Budget. I was admitting to liking your tips on checking for injector problems...my point is that you shouldn't have to. I wouldn't go to grainger.com anyhow, I go into the store every third day for work...I used to use one daily at my last position here, but still don't consider it a tool I need in my home garage.

Much easier for most of us to have a flow sheet on a set of injectors instead of blindly installing them and then trying to tell if they're right. Like I said, I've done this for over a year, and told everyone else the same was ok...until now. Had my brother not returned my motor to me burning oil a few months ago, I probably would have noticed the problem coming on, but that's only because I pay attention. Kudos to you for being the same way, but my wife gives me minimal garage time and time is money too. For what I get paid at work the time un-installing and installing another set of cheap injectors when a set does eventually give me problems would pay for half the cost of cleaning them in the first place.


Moral of the story...det kills motors. Besides stupid tuning of timing, the quickest way to get det is with a poorly flowing, or unbalanced injectors. Used sets are worth about as much as 4 lottery tickets. What are the chances something could go wrong? I've bought, sold, or traded 4 sets of used injectors...and there's a reason I sold the last two sets for half what they normally go for (about what you paid)...because I recommended the buyers use that money to get them cleaned, and I knew I had no business asking the kind of money a refurbished set should go for like everybody else does.

Get over yourself with the all-caps and ****. I don't think I was being sarcastic or made any personal attacks in my post up there, but was instead trying to give some solid advice from experience. You're arguing that you're saving yourself money, but my time is valuable to me. Any time spent fixing a problem I could have avoided is time I could have spent with my family, or working on another part of the car.


EDIT 2:

And yes, I'm currently working on a better flow-matched intake tuned more for high rpm flow and with a larger plenum, instead of our mid-range torque designed 1.6L POS.

I'm also doing my own port and polish on the built motor, and am matching compression chamber and runner volumes/profiles.

Last edited by gospeed81; 03-06-2010 at 11:07 AM.
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Old 03-06-2010, 11:37 AM   #20
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Didn't mean any offense with the whole IR gun discussion, it was suppose to be a joke and point out an opionion of what's useful and not. It's a good tool not needed just like everything else... not needed but certainly useful.

I've used it for may other things as well around the house. Check out house thermal surveys, that will and can save you enough money to buy two sets of injectors.

Totally agree with the NGK's and thats pretty much what I do. I don't like the plats, for anything modified but have used them with nitrous. Plat plugs seem to work well with MSD's and nos.

Yeah I'll probably get them cleaned and balanced, still in negotiation with the seller. I'm most pissed off that they were not advertised as damaged.

If your going to do all the work on the heads and you sound more than capable have you considered making your own flow tester???

I am considering it. all one really needs is a stock fuel pump, regulator, solvents, a power source, and some beakers, most of those parts i have lying around.
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