Noisy lost motion assemblies

[thouchin]

There isn't much info on these things in the manual. I'm pretty sure the valve noise I have is coming from them. When I push them down they dont come back immediately.
before I replace them I was thinking about dousing them with brake clean.

Question: do they get gunked up with old oil or is it actully hard nasty carbon that I would be cussing to remove even if they were off the car and in my hand.

T.J.

 

[RON98]

what is this ... lost motion assemblies

is it like the qantum hyper drive in the Voyager? :smile:

you have a page number in the nsx manual?

 

[DutchBlackNsx]

There isn't much info on these things in the manual. I'm pretty sure the valve noise I have is coming from them. When I push them down they dont come back immediately.
before I replace them I was thinking about dousing them with brake clean.

Question: do they get gunked up with old oil or is it actully hard nasty carbon that I would be cussing to remove even if they were off the car and in my hand.

T.J.

I cleaned one with just good dishwashingsoap, which cured the sticking.
If i would have puled them for the ticking (mine where realy bad), i would put new ones in from SOS, they seem to be a much better design, its expensive, but replacing them is quiet a job with risk involved.

I also took one apart, and it was realy hard to see any dirt build-up, so i cleaned it, tried it again, and the sticking was gone.

Always wanted to try a realy,REALY strong engine cleaner before i was going to pull them, but since me engine has gone south, i'm not soon going to find out.


hth

 

[4AU4LIFE]

what is this ... lost motion assemblies

is it like the qantum hyper drive in the Voyager? :smile:

you have a page number in the nsx manual?

you're kidding right?

 

[thouchin]

I also took one apart, and it was realy hard to see any dirt build-up, so i cleaned it, tried it again, and the sticking was gone.

This is good news. I'm hoping that spraying brake clean on them while they are in the car and then pushing them up and down might do the trick. Even if I have to do this every few years it might be better than having to pull the cams.

Thanks hth

T.j.

 

[DutchBlackNsx]

This is good news. I'm hoping that spraying brake clean on them while they are in the car and then pushing them up and down might do the trick. Even if I have to do this every few years it might be better than having to pull the cams.

Thanks hth

T.j.

I'm not sure you want all that stuff in your engine.
Also please notice that you realy need to soak them to clean them, there's much more then to one of those things then you might think.

 

[Larry Bastanza]

Interesting idea about blasting them with the heads assembled. I would recommend an oil change immediately following this procedure, after you have taken the car out to get the oil up to full temp. I would not recommend running around at red line or close until you have changed the oil.

This may be a little over precautious, but will not hurt, for sure.

Please keep us posted as to the result.

Regards,
LarryB

 

[thouchin]

I'm not sure you want all that stuff in your engine.
Also please notice that you realy need to soak them to clean them, there's much more then to one of those things then you might think.

From your first post it sounded like they were not difficult to clean. If it was just sticky oil then what "stuff" are you saying would get into the engine? This is why I asked if the gunk was carbon buildup, which would be chunks and generally requires wirebrushing.

If dishwashing soap did it, then I'm thinking brake clean would be a no brainer. And its vapor pressure is very high so its gone very quickly. Changing the oil afterward is a good precaution anyway.

Does anyone have an exploded picture of them? I really dont know what Im working with.

T.J.

 

[RON98]

you're kidding right?

lol :wink:

 

[DutchBlackNsx]

From your first post it sounded like they were not difficult to clean.

Correct, when you have them in youre hands, you can get in from the back and get any cleaning fluid in, from the front its much more difficult.

If it was just sticky oil then what "stuff" are you saying would get into the engine?

The brake cleaner. I have no idea how seals and such would react to that.

This is why I asked if the gunk was carbon buildup, which would be chunks and generally requires wirebrushing.

I have not seen any chunks.

If i remember correctly the device consists out of 6 different parts: bottom part, top, snapring, small spring, large spring, small dish.
I might forget one, dunno, been a long time.

 

[DutchBlackNsx]

Had a quick look around me ol' garage and found the one i took apart (destructive action, notice the cut in the side of the bottom part).

The snapring can not be found in this picture, since it prolly went into bits when i took it apart. It sists on the inside of the top of the bottom part, where i cut it. Cant get it out normally.

 

[ScienceofSpeed]

Keep in mind that once they start sticking, the piston bores are likely scratched and some amount of noise will probably still be there. We offer an LMA kit that is a fraction of the cost of the LMAs for the 91-99 cars. This is the same style that Honda switched to, likely due to the noise issues.

http://www.scienceofspeed.com/products/engine_performance_products/NSX/ScienceofSpeed/LMA/

-- Chris

 

[MvM]

Keep in mind that once they start sticking, the piston bores are likely scratched and some amount of noise will probably still be there. We offer an LMA kit that is a fraction of the cost of the LMAs for the 91-99 cars. This is the same style that Honda switched to, likely due to the noise issues.

http://www.scienceofspeed.com/products/engine_performance_products/NSX/ScienceofSpeed/LMA/

-- Chris

Ok, now my questions in all of this are:
- HOW to I detect if I have a problem nor not with the Lost Most Assembly?
- And IF I have a problem with them, just how SERIOUS is this or how serious can/could it be?
- And also, of course, how do you correct that problem and
- is it something you can do yourself or is it best left to a/your qualified mechanic?

 

[britlude]

1 adjust the tappet gaps to honda spec.
2 is it still ticking?
3 can you live with it?

 

[thouchin]

OK, luckily my noisy LMAs are the easy ones to get to. I took a video of the stickiness...

I push down then let go... the LMA sticks, then pops against the cam.
http://home.insightbb.com/~tjhjunk/MVI_1177.avi

So I tried for about 10 min to clean it. I started by pushing on the rocker which pushed the LMA down and sprayed it with some generic brake clean. Then I oscilated it for maybe 2 minutes and it didn't change noticably. I then used a syringe to suck up some acetone and drip it on the LMA. Same oscilation for a few minutes. No change.

To be sure it was the LMA that was sticking, and not the VTECH rocker (I wasn't sure whether is could stick against one of the regular rockers), I pushed down and also pulled up on the rocker. Every time I did this I heard the LMS ping against the follower. Its definately the LMA that is sticking.

I'm letting it soak now but I'm not very optimistic. Ill prob mess with it a bit more after Thanksgiving. However, if it takes this long to clean this easy one, I'm thinking it might be just as easy to replace them.

QUESTION: when I pull the cams, can I rotate the VTECH rocker up enough to get the LMA out? If not, I have to pull the rocker shaft and I think that means pulling the engine.

T.J.

 

[HYPERTUNE]

Keep in mind that once they start sticking, the piston bores are likely scratched and some amount of noise will probably still be there. We offer an LMA kit that is a fraction of the cost of the LMAs for the 91-99 cars. This is the same style that Honda switched to, likely due to the noise issues.

http://www.scienceofspeed.com/products/engine_performance_products/NSX/ScienceofSpeed/LMA/

-- Chris

Are you guys using a Honda part for this kit? If it is an aftermarket part, the only question is how reliable is it?

I can only assume that you have fitted quite a few by now, and are not having any problems. In that case, the SOS LMA kit is the only way to go. It seems quite cheap to me (considering the alternative) and will definately be part of my upcoming engine build.

 

[DutchBlackNsx]

OK, luckily my noisy LMAs are the easy ones to get to. I took a video of the stickiness...

I push down then let go... the LMA sticks, then pops against the cam.
http://home.insightbb.com/~tjhjunk/MVI_1177.avi

So I tried for about 10 min to clean it. I started by pushing on the rocker which pushed the LMA down and sprayed it with some generic brake clean. Then I oscilated it for maybe 2 minutes and it didn't change noticably. I then used a syringe to suck up some acetone and drip it on the LMA. Same oscilation for a few minutes. No change.

To be sure it was the LMA that was sticking, and not the VTECH rocker (I wasn't sure whether is could stick against one of the regular rockers), I pushed down and also pulled up on the rocker. Every time I did this I heard the LMS ping against the follower. Its definately the LMA that is sticking.

I'm letting it soak now but I'm not very optimistic. Ill prob mess with it a bit more after Thanksgiving. However, if it takes this long to clean this easy one, I'm thinking it might be just as easy to replace them.

QUESTION: when I pull the cams, can I rotate the VTECH rocker up enough to get the LMA out? If not, I have to pull the rocker shaft and I think that means pulling the engine.

T.J.

I have problems opening your avi, so maybe later at home it works.

Anyway, i made a drawing (MS-paint, so forgive me), which show how the internals are situated, and also, how the oil channels are layed out. As you can see, dripping cleaner on top of the LMA is not going to do much, but using a fine nozle to get it in from the open ended top should do the trick.
Will be though, but worth the try.
Looking at how the thing is supposed to work makes you wonder what more may lead to this malfunctioning. How is oil-pressure used in this device, and is it because it is sticking, the LMA becomes a problem, or is it because the top small spring looses its strength.
In my opinion the sticking surface is the surface on top of the dish, which binds to the bottom flat surface of the top piece...god forgive my english....

 

[Cees-Jan]

OK, luckily my noisy LMAs are the easy ones to get to. I took a video of the stickiness...

I push down then let go... the LMA sticks, then pops against the cam.
http://home.insightbb.com/~tjhjunk/MVI_1177.avi

So I tried for about 10 min to clean it. I started by pushing on the rocker which pushed the LMA down and sprayed it with some generic brake clean. Then I oscilated it for maybe 2 minutes and it didn't change noticably. I then used a syringe to suck up some acetone and drip it on the LMA. Same oscilation for a few minutes. No change.

To be sure it was the LMA that was sticking, and not the VTECH rocker (I wasn't sure whether is could stick against one of the regular rockers), I pushed down and also pulled up on the rocker. Every time I did this I heard the LMS ping against the follower. Its definately the LMA that is sticking.

I'm letting it soak now but I'm not very optimistic. Ill prob mess with it a bit more after Thanksgiving. However, if it takes this long to clean this easy one, I'm thinking it might be just as easy to replace them.

QUESTION: when I pull the cams, can I rotate the VTECH rocker up enough to get the LMA out? If not, I have to pull the rocker shaft and I think that means pulling the engine.

T.J.

You can take out the rocker shaft in the car...remove the end cap at the side of the cilinder head and pull it out with a small bolt.

 

[NSX-Appeal]

Always wanted to try a realy,REALY strong engine cleaner before i was going to pull them, but since me engine has gone south, i'm not soon going to find out.

I'm wondering if any owners here have been brave enough to use an internal engine cleaner product before an oil change. I've used the stuff in the past with some of my old V8 iron, but wasn't brave enough to try it with my NSX. I seem to have a slight "ticking" sound also when the engine is cold, and thought about using some. It silenced a sticky lifter once on an El Camino I had. Can't remember the brand offhand, but it might have been made by Rislone or Gumout -- something like that.

 

[Supercar]

Are you guys using a Honda part for this kit? If it is an aftermarket part, the only question is how reliable is it?

I can only assume that you have fitted quite a few by now, and are not having any problems. In that case, the SOS LMA kit is the only way to go. It seems quite cheap to me (considering the alternative) and will definately be part of my upcoming engine build.

Chris, can you confirm this. I also have this problem (ticking sound from the engine). But my mechanic said that this is due to a part called 'valve lifters'. He also mentioned that the movement of this valve lifter is controlled by oil presssure. And it looks like a bullet. Could this be the LMAs? If so, then I will try out SOS's LMAs. Can somebody please confirm.

 

[angus]

anybody use ac delco eos? engine oil supplement,made to free up sticking lifters? I am generally against any type or oil supplements but this was recommended to me by several engine shops.

 

[greenberet]

Are you guys using a Honda part for this kit? If it is an aftermarket part, the only question is how reliable is it?

I can only assume that you have fitted quite a few by now, and are not having any problems. In that case, the SOS LMA kit is the only way to go. It seems quite cheap to me (considering the alternative) and will definately be part of my upcoming engine build.

Looking at the OEM parts catalog, the lost motion assemblies seem to have changed with the model year 2000. From 1991-1999, they looked like #15 in the attached picture and from 2000-2005 they switched over to #18. The rocker arms that the lost motion assemblies damp have the same part number for all model years.

Maybe the later lost motion assemblies fit into earlier NSXs as well. The Science of Speed LMA's look just like the drawings of the OEM newer ones. The newer OEM lost motion assemblies have a list price of $121.56 for a set of 12 before any discounts are applied and the SoS set costs $133.89. I should have looked into this when a few of my lost motion assemblies were sticking instead of just having them all replaced with OEM assemblies of the older design.

 

[NSX-Appeal]

Anyone have an idea about how many man hours we're talking about, to replace these LMA's?

 

[ScienceofSpeed]

The rocker arms are the same, however, the cylinder heads are different. The later model LMA will not work in a pre-2000 cylinder head as the depth of the counterbore is different. Precision shims are made to set the height of the new LMA. These are included in our kits.

Cheers,
-- Chris

Looking at the OEM parts catalog, the lost motion assemblies seem to have changed with the model year 2000. From 1991-1999, they looked like #15 in the attached picture and from 2000-2005 they switched over to #18. The rocker arms that the lost motion assemblies damp have the same part number for all model years.

Maybe the later lost motion assemblies fit into earlier NSXs as well. The Science of Speed LMA's look just like the drawings of the OEM newer ones. The newer OEM lost motion assemblies have a list price of $121.56 for a set of 12 before any discounts are applied and the SoS set costs $133.89. I should have looked into this when a few of my lost motion assemblies were sticking instead of just having them all replaced with OEM assemblies of the older design.

 

[ScienceofSpeed]

It sounds like two different systems are being confused. The VTEC rocker arm is engaged by oil pressure. The LMA is not engaged by oil pressure, only lubricated by oil. Assuming no cylinder head damage is present, the only abnormal noise the NSX head will make is if the valve - rocker clearance is off (which can be adjusted into spec) or the LMA's are sticking. That being said, the NSX head is somewhat noisey, so it may be best to compare to another car as well.

-- Chris

Chris, can you confirm this. I also have this problem (ticking sound from the engine). But my mechanic said that this is due to a part called 'valve lifters'. He also mentioned that the movement of this valve lifter is controlled by oil presssure. And it looks like a bullet. Could this be the LMAs? If so, then I will try out SOS's LMAs. Can somebody please confirm.