another VVIS engine damage! C32B

austrian type-R

austrian type-R

Experienced Member
Joined
27 February 2004
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645
Location
AUSTRIA (Europe)
Some month ago I bought this C32B engine with some damage, the former owner told me the shop his NSX got inspected did an 0W70 oil in it and after 70km there was some noise coming out of the engine so he shut off and the car got back by trailer to the shop. IMO I think a ow70 (Lotus oil) would not cause an engine damage?!

Now I had time to put off the IM and after that I heard some rattling noise come out of it when I shaked the IM. look the pics. It was a 1997 or 1998 CB32B engine. I think it was pure coincidence that after the shops visit the engine goes bad?! How long has this engined runned w/o damage while 2 plates fall off? All 4 screws was remain in the IM as well a part from an broken valve guide. :( .....I hope the cylinder walls are still good and the head can be repaired.

110520131253.jpg 110520131254.jpg 110520131255.jpg
 
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should we be opening this up and tightening the screws regularly???
If so, how should this be done - is it an easy DIY?
 
when it comes to throttle valves there are two ways to retain them. one is a thread locking compound (loctite) the other is to stake the end of the screw .most carbs are staked . In photo #two the screw appears not to be staked but i'am not sure .Check the end of the screw if it was staked you will see what appears to be an X. Does Honda use a thread compound ? I looked in the manual but it made no reference .
 
Hey Ralph,

If you look close that are staked, just no very well. I think I would do both, re-stake and loctite.

I am thinking I may need to make this a routine service. With the age of the cars now, especially the early ones. mmm....think I will open mine up:)

JMO,

Regards,
LarryB
 
Same here. Although I scoped mine awhile back, it could be a worthy, piece of mind weekend project.
 
Larry Bastanza said:
Hey Ralph,

If you look close that are staked, just no very well. I think I would do both, re-stake and loctite.

I am thinking I may need to make this a routine service. With the age of the cars now, especially the early ones. mmm....think I will open mine up:)

JMO,

Regards,
LarryB
Click to expand...

Hey Larry ,
Yea, on my pc I can see the middle screw is staked . A drop of penetrating threadlocker can't hurt (for this I use permatex green ) . Larry do you know if this has ever happened to a stock motor that has never been opened up before. It is very rare to see these screws back out
Regards Ralph
 
Hard to say, I have seen this rarely, but considering the age of many NSX's and the catastrophic nature of the failure, time to start checking them.

Regards,
LarryB
 
Larry, Since we discussed this last year we have now made this part of our major services ( TB/WP ) to inspect and verify these are ok. In probably 15+ jobs we have yet to run across one with an issue. Confusing as to why some are ok and some are not..
 
This problem only seems to affect certain years. Considering it can cause total engine destruction, perhaps we should bring this to Honda's attention for a recall or TSB? It would be nice if they would at least have dealers inspect the plates.
 
I had this problem, mine had come off so count 95 in those years... But I bet it's all of them. I retained it for now but put locktite in there. Very disappointed at the catastrophic potential for damage that Honda could have easily avoided.
 
Larry Bastanza said:
Hard to say, I have seen this rarely, but considering the age of many NSX's and the catastrophic nature of the failure, time to start checking them.

Regards,
LarryB
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Hey Larry ,
Totally agree with inspection , people must be aware of the proper procedure how to deal with these screws. you cannot just unscrew these fasteners , you have to file down the staked end of the screw .As you back out the screw if there is any resistance you must stop ,retighten and clean up the staked end .If you dont you will bore out the shaft rendering it useless .If i found a screw loose I would retightened and then add loctite , there are very few techs (mechanics ) that have dealt with these properly . As far as re-staking them ,the shaft must be supported at the screw head and staked with the proper tooling and i Dont mean hitting with a hammer and chisel.
regards
Ralph
 
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People were fancy about the VVIS at its reveal time. Some People Report no power loss accross the whole range. I'd like to see a before/after dyno of someone who cancelled it. It cannot believe Honda did engineer it just for fun.
 
goldNSX said:
People were fancy about the VVIS at its reveal time. Some People Report no power loss accross the whole range. I'd like to see a before/after dyno of someone who cancelled it. It cannot believe Honda did engineer it just for fun.
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No they didnt , VVIS works excellant in real world driving , Toyota and other manu. use this system . It maintains intake velocity at low rpms, dont get hung up on dyno numbers ,they dont always reflect real driving .
 
ralph cerbone said:
No they didnt , VVIS works excellant in real world driving , Toyota and other manu. use this system . It maintains intake velocity at low rpms, dont get hung up on dyno numbers ,they dont always reflect real driving .
Click to expand...

+1. i cant find it now, but i remember seeing a dyno chart of an NA engine with and without vvis. it lost torque everywhere in the rpm range without vvis. now on FI its a different story though....

edit: found it: post 12 here http://www.nsxprime.com/forum/showt...uild-quot-(long-winded-sorry-slow-day-at-work)
 
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Based on the dyno test by FaxtraxTurbo linked to above, deleting the VVIS system will not only banish the possibility of the screws getting sucked into the combustion chambers, it will also increase your top-end power by about 3 hp at 7800 rpm.

However, deleting the VVIS will reduce your mid-range power by up to 8% from 3200 to 4900 rpm. I’m just going to keep checking the screws to make sure none are backing out.


Edit: I forget where I found this, but this is the effect that Honda says the VVIS has:



If you compare that with the effect that FastraxTurbo measured on a dyno, you can see Honda was right. The VVIS boosts midrange power and torque. Unfortunately, since it has moving parts, things can go wrong over time if left unchecked.
 
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regarding that 0w70 oil, that will cause issues by it self, I've seen NSX's ruin there heads on 10W60.
Stick with 5w30.

We always recommend inspection on the VISS when ever there is the opportunity, for example tb/wp and when upgrading intake manifold.
I haven't been able to track the year range down for the issue, I do know the C32A and C35A engines are not effected by the issues at all.
 
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Honcho said:
Seems to be mid-late 90's. I have not seen any early cars or any 2000 or newer with this problem.
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Correlates with my observation that there have been no failures in Europe so far (except austrian's C32B) but most of our cars are 91/92. In Switzerland are only 14 out of about 260 (about 5%) 97+. I think you've a much higher percentage of 95+ cars in the US. Not sure if the younger cars (2000+) don't have the mileage (usage) on average to show this failure too.
For this Kind of Problem I'd expect a Service Bulletin from Honda but there haven't been one released, no? I can't imagine Honda is not Aware of this Problem.

Just wondering: how long does it take until a screw breaks free and if it's loose in there how long does it take until it falls completely off (could be really fast if it's staked uneffectively). I can imagine that this could happen within less than 3k miles.
 
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