Ok guys, here's the deal...

I got my motordyne 3/8" spacer today and tried to install myself, with help of a friend. I borrowed a torque wrench from another friend and was all set to go.

Got the plenum cover off, cleaned it, aligned the spacers. Then we set the torque wrench to 6 ft/lb. Finger tightened all the screws in place.

We started torquing the first screw (as per the diagram with the bolt positions in this link: http://www.motordyneengineering.com/installHTML.asp).

I kept tightening.... then a small snap. So we thought that was just the wrench clicking.

Moving onto the 2nd screw, kept on tightening, and a loud bang! There was a spark, and we were sure we had snapped the screw. We took the cover off again and realized that the second screw had snapped off. There was no thread showing, so we couldn't get the piece out. So we decided to close up that screw whole with a screw and a nut on the other side (where the spacer is supposed to be... yes, we took that spacer out).

Then after putting it back together (3 hours later). Realized that the first screw had snapped a little also. The screw goes in but does tighten fully.

So what do I do?? The screw in position 1 won't tighten all the way, and there is no spacer in position 2 (the whole is filled with a screw)...

I compared sounds with another G35, and my car sounds a little different, but that might be because of my CAI. When switching off the car, there is a hissing noise. It occurs in both cars, but is longer in mine. I drove the car 2 miles back to my house, and it seemed fine. No check engine light... nothing.

The car drove ok. The sound was better and I drove it a little hard to see what happens. There seemed like there was a little less power, but that might just be in my head.

So can I leave it the way it is? Or do I need to spend a $1000 to get it fixed????

Please help, but no flaming please... I already feel like SH*T.... Thanks.

C

 

show us some pics and we will be better able to help you.

the hissing sound may be a vacuum leak. is your trim around your oil cap stuck between the spacer and gasket? if so, start over and make sure it does not get stuck.

 

if it is a snapped screw.. check out my thread... we all learn from our mistakes..

http://www.my350z.com/forum/showthread.php?t=104750

sorry but u will need to register if u dont already have an account..

 

I don't have a CAI for my G, but in my previous 2 cars Ive had them. Everytime I shut the engine off I would hear a hiss, it was much longer and louder in my Acura and there was no problem with the acura.

 

Could you use a dremel or grinding wheel to cut a slot in the top of the "buried" screw? That way, you might be able to back the broken screws out. I know you'd hate to damage your spacer, but thinking of the bigger picture, it might get you back to your original plenum configuration.

Of course, I might not have a clue but I hope this helps.

 

I've heard several of these snapping bolt stories with the Motordyne plenum spacers. Is this just a case of inferior hardware? You would think if you overtorqued a bolt it would strip the threads of the engine block before it snapped. I have a 3/8" spacer but I'm afraid to install it!

 

excellent guys. I'm going to look into the screw extractor today. See if i can get that screw out!!!

Thanks... Will keep you posted...

 

It will work. Be slow and meticulous with the punch and drilling so you get a good "set" to start with and then slowly turn the extractor and very quickly you'll have a good result.
Good luck.

 

Exactly. And also remove the threaded fastener that has apparently stripped some threads and using the appropriate die and tap see if you can "chase" the threads.

Coming back to the root problem - what size Torque Wrench were you using when you attempted to torque to 6 ft-lbs? It is not good practice to use a Torque Wrench set to the extremes of its range. In other words, if you were using a Torque Wrench with a capacity of say 120 ft-lbs it would not be wise to use it to torque to 6 ft-lbs... better to use a wrench rated at say 10 ft-lbs.

Best of luck with you recoveries.

 

why did you use a torque wrench for something that needs 6ft/lbs ? that number alone should have told you to do it by hand and just do it finger tight.
i snapped a bolt of on my old car and since then learned my lesson.

torque wrenches are not accurate and i only use them on suspension or if working on engine. ANything small like that is not needed.

 

You sort of need an in/lb wrench to get the accuracy required, IMHO. Good luck with the extraction, and heed the other poster's words about chasing the threads.

Cru: If you are worried about the hardware (I wasn't) you could take the set to a parts store and acquire some grade 8's.

 

Yeah, I don't think i need to worry about the threads... the bolts snapped before any of that could happen.

Does anyone know where I can get another spacer however? Can I get them in hardware stores, or am I going to have to contact Tony for another (and i'm pretty sure I can buy the bolts at home depot)? I've sent him an e-mail... just waiting for a response.

Thanks

C

 

I'll send you some new parts Monday.

I was simply untightening one of the "stock" bolts inside my lower plenum last week and it snapped off too... Looks like we both have the same job to do. Nissan probably would have been better off designing the plenum for M8 bolts instead of M6.

With over 450 kits at 18 bolts a piece, that's about 8100 bolts installed. So far, there have been about 5 reports of broken bolts that I know of. That puts the odds of one breaking about 1 in 1620. And approximately all but 2 of didn't have a torque wrench used. Of the two that did, I believe the wrenches were rated to ~60+ pounds capability. Statistically, it doesn't seem as if anything is wrong with the bolt quality.

If Nissan designed it or M8 bolts, the numbers would have been much better. But then again, they probably assemble everything in the factory with calibrated and certified equipment used by experienced techs. They also probably figure the plenum will very rarely need to be opened and didn't figure on an air flow deficiency prompting so many people to install aftermarket plenum mods.

 

The shutoff sounds like CAI, my car did that everytime i turned it off, like a hisss

 

Yes, the turn off hisss is completely normal. Its air equilizing with the vacume in the plenum on shut down.