SCREWED! The Tale of my "Rebuild" (long winded, sorry slow day at work)

[Big_D]

Sorry to read about this. I was always worried about these on my car when I owned it...and of course the hormonic balancer pulley.

Which Intake manifold gaskets will need to be replaced? I assume just #5 and #6 ( are #2's are metal so can be reused?)

I do realized some other parts like the EGR / inejectors will be removed and will need new gaskets as well.

Also will red loctite stand up to engine temps or is there a better thread locker for this application? I don't foresee ever wanting to remove the screws/plates.

I would't trust loctite...we don't in the aerospace industry. Red loctite #277 only needs 250 degrees F to become soft enough to allow movement.

Is inspection possible with a borescope?

I believe you could use a borescope and go in through the throttle body and try to snake it through the VVIS plate...but it would be tough.

 

[d.n]

I would't trust loctite...we don't in the aerospace industry. Red loctite #277 only needs 250 degrees F to become soft enough to allow movement.

What would you recommend then? Hopefully something that can be bought in small quantities. How about just plain old JB weld? I'm guessing the IM sees ~300-350ish degrees F?

J-B Weld Properties (psi)
Tensile Strength: 3960
Adhesion: 1800
Flex Strength: 7320
Tensile Lap Shear: 1040
Shrinkage: 0.0%
Resistant to: 500° F

J-B Kwik Properties (psi)
Tensile Strength: 2100
Adhesion: 1800
Flex Strength: 7320
Tensile Lap Shear: 1040
Shrinkage: 0.0%
Resistant to: 300° F

 

[Big_D]

What would you recommend then? Hopefully something that can be bought in small quantities. How about just plain old JB weld? I'm guessing the IM sees ~300-350ish degrees F?

J-B Weld Properties (psi)
Tensile Strength: 3960
Adhesion: 1800
Flex Strength: 7320
Tensile Lap Shear: 1040
Shrinkage: 0.0%
Resistant to: 500° F

J-B Kwik Properties (psi)
Tensile Strength: 2100
Adhesion: 1800
Flex Strength: 7320
Tensile Lap Shear: 1040
Shrinkage: 0.0%
Resistant to: 300° F

Thats a tough call. I think the reason these screws were swaged in the first place was because Honda didn't trust a thread locking compound.

 

[LDominicano]

The two middle plates were loose on mine (cylinder 2 & 5?) i wonder if its the same for everyone??? The other 4 plates were tight and took a decent amount of effort to remove....

....why am i wondering if a disgruntalled honda tech worked on my car @ the factory :tongue: ...x

Thats a tough call. I think the reason these screws were swaged in the first place was because Honda didn't trust a thread locking compound.

What about welding them? I suppose theres a reason honda didnt weld them on either =(

 

[HondaDreamS]

Think tacking the bolts would be suffice?

 

[LDominicano]

Peace of Mind
over
Power

 

[stevieray122854]

Wow. This is not good. I hope Larry B sees this and chimes in on if this is a commonplace occurrence and possibly something that should be brought to the attention of Acura of America although it's probably too late. That's an assembly defect if I ever saw one. Potentially every Honda that has VVIS (G2 Legend, G1 RL?) has this issue---

 

[Big_D]

Think tacking the bolts would be suffice?

That might work if the materials are similar.

 

[CL65 Captain]

....why am i wondering if a disgruntalled honda tech worked on my car @ the factory :tongue: ...x
(

And they're not even Union. :tongue:

 

[latzke]

I would appreciate it if someone would post a high-resolution, in-focus, close-up picture of an intact/undamaged screw from a few different angles. I'm most interested in seeing what the swage looks like.

 

[nsxotic911]

And they're not even Union. :tongue:

Ditto. A bit amazed this didn't come from unions. Oh well.

 

[dirtbag]

I have a low cost borescope I'll play around with tonight. I may need to customize it.

If it's feasible to create a custom borescope tool just for this application I'll do it and let the community pass it around.


Has anyone started compiling a list of VIN's to see who's been effected? Maybe the factory swaging tool became out of tolerance after so many cycles???

 

[TyraNSX]

Used endoscope supplier would probably have one long enough for this. Biospy forceps or retrieval basket could probably grab any loose screws.

I have a low cost borescope I'll play around with tonight. I may need to customize it.

If it's feasible to create a custom borescope tool just for this application I'll do it and let the community pass it around.


Has anyone started compiling a list of VIN's to see who's been effected? Maybe the factory swaging tool became out of tolerance after so many cycles???

 

[pgilliam1]

Has anyone started compiling a list of VIN's to see who's been effected? Maybe the factory swaging tool became out of tolerance after so many cycles???

Excellent idea! People having this problem, list up your VIN's.:smile: Maybe we can identify a finite group of cars?

 

[d.n]

I'll check to see if the screws and plates are magnetic tonight. I think you may not even need to snake the scope all the way to the back to see what's happening. You can see that the plate is off kilter or even completely loose with the engine off and determine if a plate is loose that way. I'll see if you can tap the plates to test them tonight too rather than trying to check visually.

The op's car is a 97. My "spare" IM is from a 95 or a 96. What I'm really wondering is if this is really an epidemic (ie lots of loose plates, just screws haven't been injested yet or have been luckily spit out safely) or if it's just a coincidence that my spare is also a lemon

[edit] I'm also thinking about using RTV/ultra-grey at this point as a thread locker like what is used on the water pump bolts. The temps / vibration resistance look good and use on intake manifolds is actually listed as one of the applications. The copper stuff is good to occasional 700deg so should be okay at 1/2 that temps every day. It also isn't hard enough to cause damage if injested.

 

[Edresh]

Re: What does VVIS stand for and what does it do

What is the purpose of this VVIS unit and what does it stand for?

If I went to the trouble to check this out I would JB weld the threads in place
rest assured it would never come apart, that is providing this VVIS thing didn't need to be serviced or have new plates installed every so many miles

 

[pgilliam1]

The op's car is a 97. My "spare" IM is from a 95 or a 96. What I'm really wondering is if this is really an epidemic (ie lots of loose plates, just screws haven't been injested yet or have been luckily spit out safely) or if it's just a coincidence that my spare is also a lemon

These cars were built to such tight standards that it's reasonable to believe what happens to one will most probably happen to others (IE: main relay and ignition switch problems). I know the engines were assembled by only 2 techs, but were the assemblies, like attaching the VVIS butterflies to the shaft, outsourced to possibly more than 1 machine shop?

 

[LDominicano]

The op's car is a 97. My "spare" IM is from a 95 or a 96. What I'm really wondering is if this is really an epidemic (ie lots of loose plates, just screws haven't been injested yet or have been luckily spit out safely) or if it's just a coincidence that my spare is also a lemon

These cars were built to such tight standards that it's reasonable to believe what happens to one will most probably happen to others (IE: main relay and ignition switch problems). I know the engines were assembled by only 2 techs, but were the assemblies, like attaching the VVIS butterflies to the shaft, outsourced to possibly more than 1 machine shop?

At first i figured that my luck was bad enough that this rare situation would occur to me, but after seeing those other two threads i originally refernced i started to worry thats its not rare... just unknown. I mean how many owners do you here talking about checking out the vvis plate and butterflies?

Any which way I would love to know what people are finding after they get in there and actually check them out if anyone has yet? Not just the spare one in the garage :tongue: that was also loose :frown: ...x

*UPDATE* Also not that i was surprised to hear this, the machine shop let me know that a intake valve was indeed bent as well

 

[latzke]

Has anyone started compiling a list of VIN's to see who's been effected? Maybe the factory swaging tool became out of tolerance after so many cycles???

VIN list is a great idea, along with which screws are impacted. Might be that certain screw locations have a much larger incidence than others and that would be something we'd want to know. Someone want to suggest a naming standard for the screws...and provide a labeled diagram for others to reference?

On degree of swaging being the cause, I'm not ready to jump to / accept that conclusion without more data (why I asked for pics). Swaging is a very-broad term (forging in a certain way) and with screws can mean one of several things. I want to see what is meant here before coming to the conclusion that the screws are indeed swaged for the purpose of keeping them in (i.e. not for some other purpose like reducing insertion torque for self-tapping screws). It is very possible they are not swaged for this purpose but another...and the lack of retention is caused by something else (improper assembly, screw retention overlooked in design, etc).

 

[LDominicano]

VIN list is a great idea, along with which screws are impacted. Might be that certain screw locations have a much larger incidence than others and that would be something we'd want to know. Someone want to suggest a naming standard for the screws...and provide a labeled diagram for others to reference?

On degree of swaging being the cause, I'm not ready to jump to / accept that conclusion without more data (why I asked for pics). Swaging is a very-broad term (forging in a certain way) and with screws can mean one of several things. I want to see what is meant here before coming to the conclusion that the screws are indeed swaged for the purpose of keeping them in (i.e. not for some other purpose like reducing insertion torque for self-tapping screws). It is very possible they are not swaged for this purpose but another...and the lack of retention is caused by something else (improper assembly, screw retention overlooked in design, etc).

Huh? lol joking, i got all the screws i removed and plates in a zip lock at the shop, ill try and swing by on lunch and grab em and post a pic...

 

[d.n]

Okay the butterfly and screws are not magnetic, the axle/rod that the butterflies are screwed to is. The screw looks to be stainless, the butterfly could be coated if it's also stainless. So perhaps welding is an option. Anybody have a good welder/machine shop near San Francisco they can recommend? If so I'll take my spare down there to verify the materials and see if the screw can be welded to the butterfly.

You can definitely push on the butterfly and see if the plate is loose. There is no play at all on the tight ones as there is a spring that keeps the butterflies open when no vacuum is applied is quite strong. I think using a scope will be easier to see for sure though. Perhaps a combination of a scope + a coat hanger / rod to press on the butterly would be the way to go. I'm thinking this can be done without removing the TB.

I also double checked and my 2 loose ones were both of the center butterflies which is what the OP reported as well. We need more data points though.

I don't have a camera capable of taking the high res macro shot. I'll see what I can do tonight though.

 

[pgilliam1]

Okay the butterfly and screws are not magnetic, the axle/rod that the butterflies are screwed to is.

Makes perfect sense. Different metals expand and contract differently when heated and cooled and the engine vibration makes the screws loosen over time as they expand and contract. UHG! So far we have years: 1995, maybe 1996 and 1997. Any others?

 

[robbiedawg]

Re: What does VVIS stand for and what does it do

What is the purpose of this VVIS unit and what does it stand for?

If I went to the trouble to check this out I would JB weld the threads in place
rest assured it would never come apart, that is providing this VVIS thing didn't need to be serviced or have new plates installed every so many miles

variable volume induction system.basically,low end power,seems useful.this honda book describes it:

http://www.nsxprime.com/Gallery/press/tidh/tidh-26.htm

 

[ScienceofSpeed]

That's too bad. We recently observed a similar issue:
http://nsxprime.com/forum/showthread.php?t=154928

This appears to be a critical issue that needs attention during servicing especially on the early / higher mile NSX.

Should you need help with the rebuild, please drop us a line.

-- Chris

 

[EZdoesIt]

One can also simply just remove the butterflies and associated bolts? FastraxTurbo showed the dyno test results and it was not a big difference w/ or w/o the VViS.