wrong injectors?

2005 CHEVROLET 1500
1 MILES • 6.0L • V8 • 2WD • AUTOMATIC
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BILLSBLUE68
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Ryan,

I need some help please. I am trying to install DeatschWerks Fuel Injectors 35U-01-0044-8 into a Summit manifold SUM-226125B and I'm having a great deal of difficulty getting the injectors installed. I have ruined almost all of the O-rings on the end of the injector that goes into the manifold despite using the supplied lube. I can't even get them into the manifold by trying to install them individually. This is the manifold/injector set that was featured on your 2Car Pros YouTube channel that Summit sponsored, so I know the manifold and injectors are correctly paired. I am not a beginner at engine building so something seems off. Please help. Between the manifold and the injectors, this is a big investment for me. I have attached some pictures. The manifold injector bores are .540" and the o rings are about .575". That sounds like a lot of interference to me. I saw in the comment section when you installed the injectors that someone else was having the exact same issue and you recommended some kind of generic Amazon o ring kit, not the kind of response I hoped for. Did the issue ever get resolved? Please help!
Thanks,
Bill Curtis
Jan 30, 2023 at 10:46 AM
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RYAN L
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Hello Bill!

Thank you so much for watching the series!

So, ours fit perfectly well and had no drama at all. It was a perfectly snug fit, and we did not have to use different O-rings or anything like that. It kind of sounds like the problem lies with the manifold. I would exchange it for a new one and see if the problem persists. Summit is super good about replacing defective parts. If there is a problem with the production line that arose after I did my build, they need to know about it.

Really hope that helps! If you have any other questions, please let me know!

Best,
Ryan
Jan 30, 2023 at 2:37 PM
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BILLSBLUE68
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Ryan,

Thanks for the reply. I have been communicating with Summit and DeatschWerks all day and Summit is no help. If you go back to episode 10 and look at Andrew Smith's comment, he experienced the same thing I'm going through, so it sounds like a problem that was not resolved. I bought my parts September 2021, when did you get yours? I just now got the engine all together, so parts have been sitting on the shelf for a while. I need an advocate to help me at Summit. I'm currently watching your install into the 55. Would it be possible to inspect and measure 1 of your injector bores in your manifold? I don't mean to be a pain but I'm 72 and can't just throw the money I've tied up out the window. Mine measure about .540 which is correct for the small series truck injectors.
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Jan 30, 2023 at 3:13 PM
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RYAN L
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Bill,

Not a problem! That is surprising to me. Every time I have called in, they have been super helpful.

I believe we got ours in May or so of 2020. It is difficult to remember an exact date. Maybe the slightly too big O-rings got shipped in your box by mistake?

Yeah, I can measure that later this week. I am a little busy, but I should have time around Friday.

Best,
Ryan
Jan 30, 2023 at 4:24 PM
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BILLSBLUE68
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Ryan,

The injector o-rings are correctly sized per spec by DeatschWerks. They have been helpful. I've ruined all the injector o-rings trying to install them. DeatschWerks has confirmed that the 35U injectors are not suitable for the small-bore Summit intake and have spec'd out a different injector set for $500.00 which I can't afford right now.
I'm looking forward to that injector bore measurement on your intake. Thanks,

Bill
Jan 30, 2023 at 4:58 PM
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RYAN L
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Bill,

Have you looked into getting different sized O-Rings? It would be much cheaper than getting new injectors. Because I measured mine just now, I found a gap in my schedule, and they are at 0.05465 which is perfect. I did not get different O-rings and I can confirm they sent me 35U-01-0044-8 see pictures below. I even confirmed the injector hole size my Summit intake is right on the money and so are my injectors. Maybe they put the wrong injectors in your box or maybe my box?

I am sorry you are having difficulty. I made this series to make building an LS as easy as possible. Hope this helps!

Best,
Ryan
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Jan 31, 2023 at 11:56 AM
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BILLSBLUE68
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Ryan,

This is very helpful information. It appears that there is no issue with the manifold as mine measures the same as yours. The o-ring you have measures .025 smaller than mine. That is the issue. I will now follow up with the injector company and Summit and I will let you know what I find out. You have been very helpful, thanks!

Bill
Jan 31, 2023 at 1:02 PM
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RYAN L
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Bill,

No problem! Hope you get the issue resolved soon!

Best,
Ryan
Jan 31, 2023 at 1:23 PM
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BILLSBLUE68
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Ryan,

Well, that didn't go well. I forwarded all the info and pictures you sent me on to Levi Graham at DeatschWerks and he basically accused you of fudging the measurement on the o-ring to get what you wanted. He emphatically stated that the 35U injector in question has never been shipped with anything but a .571 diameter o-ring and that "somebody" put a mongrel o-ring on there to make it work and they are absolved of any responsibility. So, I know it's not your problem but with you being in the repair business, is there any way you can determine what o-ring you actually have on your injector and a source for it? I'm thinking if you order a replacement set of those 35U injectors today, they won't fit your manifold. I appreciate all that you've done to help me, but I'm still stuck.

Bill Curtis
Feb 1, 2023 at 11:26 AM
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RYAN L
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Bill,

Well, I would think twice about using DeatschWerks injectors again if they are accusing me of that. I have no reason to lie. If it did not work, I would say it and point you in the right direction. I took the injectors out of the box and put them on engine, you can even see me taking them out of the bag on video. They worked great for me. Maybe someone put the wrong O-rings in my box. Mistakes do happen. Strange they would not just admit to it though and send you a box of O-rings. They cost like fifty cents to them.

For a "mongrel" O-ring they sure do fit nice. I had no problems with it.

I would try something like this that has a bunch of different sizes.

https://www.summitracing.com/parts/fel-es73217/make/chevrolet

Best,
Ryan
Feb 1, 2023 at 12:04 PM
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BILLSBLUE68
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Here is the last email I got from Deatschwerks, they are done responding to me:

Hi Bill Curtis,

I appreciate your do diligence but those injectors are built by us "Deatschwerks" specifically for stock manifold 00-06 GM truck ONLY. It states that on our website and Summits. If it can work in a different application that is great but we spec all of our injector builds off of stock manifolds ONLY. Most of our injectors can have O-ring changes for different options for custom builds but 35U's we do not offer any other O-ring options to. Measuring O-rings can be fudged any way you look at it. I can squeeze harder on the measurement of the O-ring and get it to the measurement that the 2 car pros did. I measured everything with the digital gauge loosely contacting each side.

Thanks

Levi Graham
Technical Product Specialist


DeatschWerks
415 E. Hill St.
Oklahoma City, OK 73105
T: 405-217-0215
E: [email protected]
Feb 1, 2023 at 3:48 PM
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RYAN L
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Bill,

If all I did was squeeze the O-ring, which I did not, how does it fit in my Summit intake manifold perfectly? I just put mine back in yesterday and it fit great.

I'm so sorry you have had to deal with them and this. I will definitely think twice before using them in the future.

By the way, on a different note. Which rocker arms did you use?

Best,
Ryan
Feb 1, 2023 at 4:09 PM
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BILLSBLUE68
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https://www.jegs.com/i/JEGS/555/20957/10002/-1?_br_psugg_q=ls+rocker+arm+kit

I bought a lot of parts for my build from Summit because they were the parts you were using and I didn't want any issues. But i deal more with Jegs because they are more racer oriented, and I have a direct contact there. If you can play it, I have a break in video of my engine with carburetor but obviously it will be fuel injected in the car. It's long so fast forward through it. That wisp of smoke was from a valve cover leak.
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Feb 1, 2023 at 6:11 PM
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RYAN L
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Bill,

Okay great! I was just asking because it looked like you followed my build really close. We noticed when we put mine together the valve covers were just a touch too close to the rocker arms so I put the taller valve cover link in the description but not in the video. I changed it off screen. But since you used those, you are good either way!

Sounds great by the way! I am so happy you sent that video. That really made my day!

Best,
Ryan
Feb 1, 2023 at 6:15 PM
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BILLSBLUE68
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Glad you enjoyed it. I ran it through 4 heat cycles and then changed the oil and filter. It's going in a 1959 English Ford with a custom chassis I made. BTW, it's a 408. Also, a pic of my 1958 drag car. And video here if it works and you are on Facebook. It was a licensing pass. I was only supposed to go 1/8 but did the quarter.

https://www.facebook.com/brett.curtis.50/videos/10214485509437695
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Feb 1, 2023 at 7:01 PM
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RYAN L
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Bill,

Thanks for posting the pictures! Those are some seriously cool cars you have built! I am so glad I could be a small part of it!

Best,
Ryan
Feb 2, 2023 at 11:18 AM
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CHARTWIG1980
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Did anyone determine the correct o-ring for the DW injectors and the Summit intake? Im having the exact same issue right now. I have the same parts and the injectors won't go into the manifold. Any help is greatly appreciated.
Dec 23, 2025 at 2:50 PM
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CHARTWIG1980
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Was this o-ring issue resolved? I have the same setup and the same issue. Injectors won't go in the intake.
Dec 23, 2025 at 2:53 PM
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RYAN L
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I would just buy a bunch of different size o-rings and use good ole trial and error. I wish I had a better answer or just a link to click and buy but DW is really difficult to get an answer out of. Thank you for using 2CarPros!
Jan 8, 2026 at 10:30 AM
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BILLSBLUE68
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The injector issue was resolved. Even though I bought the injectors from Summit, they would not help me. I had several emails and phone calls with Deatschwerks and they resolved the issue. I sent them my 35U-01-0044-8 injectors which were not compatible for the Summit intake and they exchanged them for 18U-01-0042-8. The replacements fit fine.
Jan 8, 2026 at 4:48 PM
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RYAN L
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Thank you so much for coming back to post that!
Jan 9, 2026 at 3:31 PM
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CHARTWIG1980
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BILLSBLUE68
Thanks for getting back to me on this issue. I have also worked with DW to swap to the 18U-01-0042-8 injectors. I just sent back the 35U-01-0044-8 on RMA yesterday. I worked with Summit Racing quite a bit. They sent me photos today showing that they were able to cram one 35U into their intake. I was told it took a lot of effort, but they got one to fit. "Now try it with all 4 injectors in the fuel rail" was my response. If it took all your effort to force one down, shouldn't that tell you something Summit Racing???
I'm excited to get these 18U injectors so I can continue on with the LM7 build. One last question I have for you. Did you have to get any spacers to fit the 18U injectors or did they work with the intake and fuel rail without additional modifications?
Jan 13, 2026 at 11:13 AM
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RYAN L
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I did not use anything additional whether spacers or otherwise to get everything to fit and work. It did not even take a lot of effort to get the injectors in the intake in the video. Everything went together super normal. I am not sure why everyone else is having this difficulty. Sorry you had to deal with this but I am glad it is resolved. Thanks for using 2CarPros!
Jan 15, 2026 at 11:05 AM
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BILLSBLUE68
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I did not need any additional parts or pieces either. Pretty sure I installed all the injectors in the manifold and then lined them up and installed the rail.
Jan 15, 2026 at 11:13 AM