RB26 turbo oil banjo bolts

[sunsetR33]

Hi all.

I need some help buying the correct size banjo bolts for my 2860 turbos. Because whoever installed them tore up the original part, I ordered new ones of this kind, because I just figured these were the most leak-resistant option as I already had trouble with a shitty braided line.

I need to know the thread size of the smaller left hole, that is the turbo oil feed connection. I found out so far that the turbo oil inlet apparently has a 7/16"-24 thread, but I cannot find any listing or description of the thread size on this line. I do not have the original bolts.

I tried using the bolts that were in the turbos (the ones that were mounted with the shitty braided line) but they sit very loosely so they can't be the right thread. Means either these bolts are the wrong ones (how do they fit the turbo then? no clue) or the wraparound-lines have a different thread than the turbo oil feed itself.

Help is appreciated, asking Nissan directly is obviously not going to work.

[GTSBoy]

10 hours ago, sunsetR33 said:

I found out so far that the turbo oil inlet apparently has a 7/16"-24 thread, but I cannot find any listing or description of the thread size on this line.

I'm not sure I follow you. The underlined thread specification is correct. That is exactly the thread called out on the Garrett "flange diagram" of the GT2860R - 0.4376IN-24 - where 0.4376" is close enough to 0.4375" which is 7/16".

It is shown as an inverted flare connection.

A banjo bolt to go into that would want to be that thread size, and I guess not bother about the flare.

Or....are you not talking about on the turbo? Are you talking about the other end of the hard pipe? The supply end?

[sunsetR33]

1 hour ago, GTSBoy said:

Or....are you not talking about on the turbo? Are you talking about the other end of the hard pipe? The supply end?

The hole circled in red. That is where the oil line connects into that is coming from the engine block. I can't find anywhere what thread this is. I'd prefer if I can buy whatever banjo bolt I can get hands on instead of waiting weeks for a Nissan bolt.

[GTSBoy]

OK. So, you will find what you want in this thread. The very post linked.

 

[sunsetR33]

5 minutes ago, GTSBoy said:

OK. So, you will find what you want in this thread. The very post linked.

Thanks for the link, but unfortunately they are only talking about the connections on the block. I need specifically the circled hole on the image. As the turbo is 7/16-24 imperial and the block is M12 I wouldn't be surprised if it was another size entirely.

The bolt I have that was directly screwed into the oil feed hole fit into that very hole but it sat very loosely.

Does an M11x1 bolt fit the 7/16-24 thread perfectly or is it kinda loose? Maybe then I can identify if it is either of these at least.

[MBS206]

19 minutes ago, sunsetR33 said:

Thanks for the link, but unfortunately they are only talking about the connections on the block. I need specifically the circled hole on the image. As the turbo is 7/16-24 imperial and the block is M12 I wouldn't be surprised if it was another size entirely.

The bolt I have that was directly screwed into the oil feed hole fit into that very hole but it sat very loosely.

Does an M11x1 bolt fit the 7/16-24 thread perfectly or is it kinda loose? Maybe then I can identify if it is either of these at least.

What does the circle hole on your image bolt up to in your engine bay?

[GTSBoy]

OK, I'm with you now. The outlet of the tee that is banjo'd into the block.

Dunno what it is, will have a scratch around.

The M11 question is.....messy. The minor diameter of an M11x1.0 male thread is 9.917mm. This is smaller than the minor diameter of a 7/16"-24 UNS (which is 10.08mm).

The M11 major is 11mm. That's smaller than the major on a 7/16"-24 UNS (which is 0.4375" or 11.1mm) so an M11x1 bolt should pass on the major side.

The pitch of a -24 thread is 1.058mm, which is really close to the M11x1, so it should go in at least several turns.

I would expect M11x1 to be loose in a 7/16"-24 UNS, at least until enough thread are engaged to make it stop screwing in, if that can happen. Probably wouldn't happen on such a short bolt as you're looking at on the oil tee.

Keep in mind that 7/16"-24 is NOT a standard/typical 7/16" thread. Standard is 20. That's the UNF or fine thread. -24 is really fine. I imagine that Garrett chose -24 for the turbo housing oil inlet to get the number of threads engaged up.

I would not expect Nissan to have an imperial (UNF, etc) thread on that tee. I would expect it to be metric (if it is a bolt thread) or BSP (actually the Japanese equivalent of BSP) if it is a pipe thread. Given that it's a banjo, it's going to be a bolt thread. If it looks like an 11mm will go in there, then 11mm seems likely.

It is very possible that some clown has stuffed that thread by trying to jam some imperial "near equivalent" into it, perhaps with those hoses of yours. Got verniers? Measure up the threads on the hoses.

[GTSBoy]

2 minutes ago, MBS206 said:

What does the circle hole on your image bolt up to in your engine bay?

See above.

[GTSBoy]

This is the tee

No specs on the page I grabbed it from, out of stock there anyway. But it kinda looks like a 1mm pitch. Would not think it's going to be 0.75mm pitch.

[sunsetR33]

1 minute ago, MBS206 said:

What does the circle hole on your image bolt up to in your engine bay?

Nothing at the moment as previously there was a crappy braided line going from engine block directly to the turbo. I have bought a used OEM hardline for the turbo oil supply, which goes from the engine block to the marked hole.

I don't have any of the OEM banjo bolts for oil except the one at the block.

[sunsetR33]

1 minute ago, GTSBoy said:

This is the tee

No specs on the page I grabbed it from, out of stock there anyway. But it kinda looks like a 1mm pitch. Would not think it's going to be 0.75mm pitch.

No no, sorry I think I made you misunderstand.

I have this Tee as well as the lines that go from there. What I am missing is the banjo bolt that connects this line (OEM turbo oil supply line)

To this hole, this line is mounted on the turbo and reaches around it so you have easy access the oil and water supply being rerouted to this dual banjo port in the front.

like this

[GTSBoy]

Just now, sunsetR33 said:

No no, sorry I think I made you misunderstand.

No, I didn't misunderstand. I showed that tee because that is the threaded hole that you need a banjo bolt to go into yes? Two of them, one either side of the tee. The through hole in the tee is the 12x1.25 into the block.

[GTSBoy]

Oh. I did misunderstand.

[GTSBoy]

I'd suspect it's an M10x1.0 before I'd think it's an M11.

Just go down to the bolt shop and buy a few different sizes?

[sunsetR33]

1 minute ago, GTSBoy said:

Oh. I did misunderstand.

It's alright, working with all these scraps of information from the web is making me question myself as well. It is really easy to find part numbers but never what the specs of these stupid, mostly discontinued parts, is.

Thanks for your effort at least I learned something about threads today

[sunsetR33]

1 minute ago, GTSBoy said:

I'd suspect it's an M10x1.0 before I'd think it's an M11.

Just go down to the bolt shop and buy a few different sizes?

Actually a good idea. But if the bolt I tried before was really a M11x1 as I suspect, and it kinda went in but was really loose, I think it's some imperial thread nonsense as well. But I have no 7/16-24 to try with.

[Duncan]

Did you ever work this out? I've never seen M11 on a skyline, only m10, m12 or BSPT...

[sunsetR33]

1 hour ago, Duncan said:

Did you ever work this out? I've never seen M11 on a skyline, only m10, m12 or BSPT...

I found parts on EFI Solutions webshop that seemed to be the accurate ones. I haven't gotten around to fitting the turbos back on the car yet since I still have to deal with the shitty crack in the engine block. But I'm confident that the bolts I ordered will fit. According to EFI they are also 7-16/24.
The reason M11x1 got involved here is because it is apparently very similar to 7-16/24.