Injection needle for bedplate to block seal

Aaron

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Nov 3, 2016
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Hey guys, in the midst of an N54 rebuild, and have a question.

The factory torques the bedplate to the crankcase/block, and then injects sealant into the groove between the two.

I have the new injection valves, Locktite sealant, the high torque plunger, and the Locktite primer. I ordered what FCP Euro described as the proper needle, bit it is much to small to fit and seal into the injection valves.

Does anyone know which needle is the proper one to use?

Thanks!
 

Bnks334

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Dec 1, 2016
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New York
I just went through this rebuilding my N55.

here is a few tips:

1) Before your do ANYTHING blow compressed air through the block like TIS says to. Ensure air blows out of all 4 holes!
2) Do not put your crank seals in until AFTER you seal the bed plate. This eliminates the chance that you misaligned the seals or didn't push them in enough and they block the sealant exit holes. BMW actually moved to thinner (10mm vs 20mm thick) front crank seal on late model N55s which I am pretty sure was done purely as a convenience thing so that it's easier to see the bedplate sealed properly. Also, sits the seal sits further back it doesn't require as much pressure to push sealant through the tiny slit in the seal.
3) The BMW injection needle WILL NOT work. There is too much back pressure and sealant will blow out of the fill hole instead of pushing out the exits. Don't bother with the neddle!
4) I am not sure if there is a better way, but what I did was I pushed the tube up against the fill hole with A LOT of pressure. Use a towel to keep the tube from hurting your hands. You need to use your body weight to create a seal between the sealant tube and the injection fitting. It takes a lot of effort to keep the seal from breaking. It helps to have a second set of hand to then release sealant into the block per step 5)
5) This take PATIENCE to do right. You need to build up a ton of pressure against the fill hole and then wait for that pressure to slowly push the sealant through the block. Every 3-5 seconds give the tube another turn or two to keep pressure up. Pressure should drop slowly as fluid leaves the tube and goes into the block. It took a good 3-5 minutes of doing this (without letting the seal break) to get fluid to push out the holes. I had to build up so much pressure that the little sealant tube actually blew/pushed itself off the block a few times making a mess.
6) Don't over-do it either... if you turn the knob of the sealant tube too much you risk breaking the seal on the tube plunger (like what happens with a caulk gun).
7) Make sure your local BMW dealer has some sealant in stock. It took me 2 tubes to get this done. Lots of failed attempts.

I don't understand why BMW wouldn't just put a threaded fitting in instead of this stupid needle crap. I guess the reason is because a robotic arm is probably used at the factory which creates a nice airtight seal without needing to be threaded on whereas a human and a stupid little sealant tube can only do so much. An aftermarket fitting with male threads that match the sealant tube would be nice!
 
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Corporal
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Oct 25, 2016
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The Needle is for seal replacements, only. It won't seal on the bedplate valve. It's not designed to.
You need the injection bedplate nozzle, which they do not provide with new tubes any longer.
What's out there, seems to be whats out there. I've not found a separate part number or replacement. Good thing I have a pile of them from previous tubes.
 
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The Convert

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The Needle is for seal replacements, only. It won't seal on the bedplate valve. It's not designed to.
You need the injection bedplate nozzle, which they do not provide with new tubes any longer.
What's out there, seems to be whats out there. I've not found a separate part number or replacement. Good thing I have a pile of them from previous tubes.
Can you post some pictures? I'd bet there's a company out there that makes them and sells them.
 
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JonEQuest

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Nov 7, 2018
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Do you have to do that injection procedure? A BMW mechanic said it was a royal pain and they now recommend just a regular sealant and then put the bed plate back on.
 

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Corporal
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Oct 25, 2016
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Do you have to do that injection procedure? A BMW mechanic said it was a royal pain and they now recommend just a regular sealant and then put the bed plate back on.
This is not only stupid, short sighted, but reckless. good luck if that bedplate doesn't seal correctly. you'll be pulling the engine to fix it- Do it once, do it right.

I can have tips made, if there's a market for them.
 

Aaron

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Nov 3, 2016
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I'm not sure of the numbers, but the correct sealant and primer are manufactured/produced by Locktite. BMW contracted with them to produce it.

I was able to find some needles that worked well from McMaster Carr.
 

Bnks334

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Dec 1, 2016
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Do you have to do that injection procedure? A BMW mechanic said it was a royal pain and they now recommend just a regular sealant and then put the bed plate back on.

Yeah honestly after using the proper method once I would never do it again. I've used anaerobic sealant on bed plates few times now and have not had an issue. Just dont put too much that it oozes out everywhere. They have been sealing engines that way for close to a century lol again just be careful with how thick you lay it in the groove as excess could cause a line bore misalignment.
 
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Bnks334

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I've used the proper method 4-5 times now. Pretty easy to do properly.

Can you link to the injection needle you used? It's a generic tube that all sorts of industrial products are distrivuted in so I am sure the needle is available. Just a matter of finding a supplier.
 

JonEQuest

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Nov 7, 2018
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Kenner Louisiana USA
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2008 335i Convertible
I think I am going with loctite 5970. The reason for injecting the sealant when the engines were built is because robots were building the engines. My BMW mechanic freind said that BMW says to seal with Loctite 5970 in the normal way. From what I have read bmw doesn't inject the sealant in new engines anymore either.
 

Bnks334

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Dec 1, 2016
511
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New York
I think I am going with loctite 5970. The reason for injecting the sealant when the engines were built is because robots were building the engines. My BMW mechanic freind said that BMW says to seal with Loctite 5970 in the normal way. From what I have read bmw doesn't inject the sealant in new engines anymore either.

why use 5970 instead of anaerobic sealant? seems like the complete wrong way to go.

"LOCTITE® SI 5970 is a silicone sealant and cures on exposure to moisture in the air to form a tough rubber gasket." Good for an external seal, like, the oil level sensor which is where 5970 is called for... not so good for a sealed cavity in the bed plate. Even when exposed to moisture and air the 5970 states it has a 21 day full cure time lol
 
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roccos

New Member
Oct 23, 2020
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I just went through this rebuilding my N55.

here is a few tips:

1) Before your do ANYTHING blow compressed air through the block like TIS says to. Ensure air blows out of all 4 holes!
2) Do not put your crank seals in until AFTER you seal the bed plate. This eliminates the chance that you misaligned the seals or didn't push them in enough and they block the sealant exit holes. BMW actually moved to thinner (10mm vs 20mm thick) front crank seal on late model N55s which I am pretty sure was done purely as a convenience thing so that it's easier to see the bedplate sealed properly. Also, sits the seal sits further back it doesn't require as much pressure to push sealant through the tiny slit in the seal.
3) The BMW injection needle WILL NOT work. There is too much back pressure and sealant will blow out of the fill hole instead of pushing out the exits. Don't bother with the neddle!
4) I am not sure if there is a better way, but what I did was I pushed the tube up against the fill hole with A LOT of pressure. Use a towel to keep the tube from hurting your hands. You need to use your body weight to create a seal between the sealant tube and the injection fitting. It takes a lot of effort to keep the seal from breaking. It helps to have a second set of hand to then release sealant into the block per step 5)
5) This take PATIENCE to do right. You need to build up a ton of pressure against the fill hole and then wait for that pressure to slowly push the sealant through the block. Every 3-5 seconds give the tube another turn or two to keep pressure up. Pressure should drop slowly as fluid leaves the tube and goes into the block. It took a good 3-5 minutes of doing this (without letting the seal break) to get fluid to push out the holes. I had to build up so much pressure that the little sealant tube actually blew/pushed itself off the block a few times making a mess.
6) Don't over-do it either... if you turn the knob of the sealant tube too much you risk breaking the seal on the tube plunger (like what happens with a caulk gun).
7) Make sure your local BMW dealer has some sealant in stock. It took me 2 tubes to get this done. Lots of failed attempts.

I don't understand why BMW wouldn't just put a threaded fitting in instead of this stupid needle crap. I guess the reason is because a robotic arm is probably used at the factory which creates a nice airtight seal without needing to be threaded on whereas a human and a stupid little sealant tube can only do so much. An aftermarket fitting with male threads that match the sealant tube would be nice!


i figured out a way to inject the compound with applying any pressure at all.

steps:
1. purchase a a set of stainless dispensing needles, you need the 14 gauge
2. take the 14 gauge needle and cut it with a dremel cutter, cut on angle(very important). you only need about half an inch of needle. if you dont cut it on angle it wont flow.
3. put needle on 193140 compound, screw it on.
4. 14G needle will slip/insert into hole on nozzle it takes about 5-7 turns for each side

be careful you dont let the needle snap, or youll have a problem. have the crank and head facing you while you inject.

this worked perfectly, no waste
 
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