8V Failure info.

[DanPez]

They are still researching the possibility of fitting them to the A8 NTX.

To get back on course..
Pete, I said the new engines had the prefix A10, I was wrong, the two Stelvios I saw yesterday were both stamped AC.
Hope to get pics of the roller followers next weekend.

Brian,
If you have any info ..... please let us know if there is still the chance you can fit the rollers on the A8 or A4 (edit: A5 engine )

and thanks for getting back on course.

 

[Brian UK]

This is being researched as I type. As soon as I hear anything I will pass it on.
One problem is that in the new parts list, Guzzi don't provide a part number for the bare head, only a complete one. While everyone involved is fairly sure the head casting hasn't changed, it's proving difficult to be certain.
Guzzi declined the request to upgrade the 2010 NTX in the workshop at the moment.

 

[pauldaytona]

Brian,

Heads have same numbers in 04-2011 and 09-2011 parts catalog. So must be the same for both versions. But having the rollers isn't enough, the alu Rocker arm support is different too. I don't think parts are still avaialble. Looking more at that parts list, I see they changed the shimming of the cam, with a Belleville spring between two shims, no individual shimming anymore. But will have to wait until a next generation or won't come because they weren't happy with it.

 

[Brian UK]

Well it's good news if the heads can be confirmed as the same. This means that "all" that has to be changed is the rocker gear, camshafts, followers, valve springs and spacers, plus no doubt a few more bits and pieces.

 

[Phang]

That’s a good news indeed. It opens up the possibility of upgrading to the roller tappets. I hope the fueling part is as simple as a MAP update in order for the bucket follower bike to run the roller tappet valve train.

Phang

 

[pauldaytona]

Well if you change all, it's a pretty sum, if you pay it yourself. The cams have new partno, but the timing could be the same, so no new map needed. Anyway, the map belonging to these new cams isn't available. Or the cams have same profile and the you don't need other map.

 

[Mi_ka]

Any room available for a possible DIY roller ad-on?

 

[pauldaytona]

That will be a very DIY solution for the better machinst. I found a nice writing about roller versus fixed tapets, read also the comments
http://www.myrideisme.com/Blog/camshaft ... vs-roller/

something like these might fit, but I think are all to high:
Tappet including pushrod is almost 50mm high, cam contact is 22.3mm, that should go with the 0.842 inch diameter.
http://www.compcams.com/v002/Products/C ... %27-0.aspx

With some reading, I see that some aditive(zinc) isn't in oil anymore, what gives problems with the tappets, modern american cars use rollers instead

http://www.cpgnation.com/forum/new-tech ... ft-10.html

 

[Brian UK]

Interesting quote from your last link Paul.
Recent market trends and misinformation have led to a new and adverse side effect known as “Overloading on ZDDP”. When overloading on ZDDP, the additive can actually cause blocking of other important additives, such as friction modifiers or detergent agents. It is imperative that the ZDDP level is carefully specified and blended to correct concentrations.
:twisted:

 

[pauldaytona]

question stays why bmw that has the same construction does not have these problems, it can work.

 

[john zibell]

question stays why bmw that has the same construction does not have these problems, it can work.

Paul,

Good question. possible answers:

Metallurgy? Running lighter (BMW oil is a 10W-40) oil for faster flow rates thus better cooling?

 

[Mi_ka]

It could have to do with the BMW's over square combustion chamber dimensions leading to smaller valve lift and less abrupt cam profiles, so less stress on tappets. Also, the flat cylinder placement may promote added thick oil fume lubing or so.
In general, I believe the Italians know about manufacturing proper alloys.

 

[john zibell]

In general, I believe the Italians know about manufacturing proper alloys.

They have had that problem in the past. For example, the pre-mature wearing of clutch hubs in the 80s (2mm hubs) due to insufficient heat treatment, thus the redesign to the 4mm splines and new heat treatment specification. Again only trying to reference possibilities.

 

[Penis Rotor]

I'm spending way too much of my life over-thinking about this :roll: :lol:

The thing is I can't see any consistency in the failures. Is it perhaps related to how the bikes are used and where? Certainly most of my customers don't use their 8V's for commuting in traffic or short hops. Could that be a factor? Are the bikes in Spain and the UK that have failed only being ridden a few miles at a time and never getting warm? Or do theyy spend hours idling in traffic??? Who knows? (Shrug..)

Pete

 

[youcanrunnaked]

With some reading, I see that some aditive(zinc) isn't in oil anymore, what gives problems with the tappets, modern american cars use rollers instead

/quote]

I have already been cautioned to not turn this into an oil thread. However, with all due respect to our host, I do not see how one can seperate the 8V failure issue from certain oil issues, such as the one you have raised. Therefore, with respect to just that issue....

Zinc is an oil additive, in the form of zinc dialkyldithiophosphate (ZDDP). It is still present in motor oil. However, because the EPA has been specifying increasingly longer warranty requirements for catalytic converters, and ZDDP reduces the effectiveness of catalytic converters, the latest API-rated automotive oils for gas engines have specified 600 ppm ZDDP. This has been documented as causing excessive wear in flat-tappet car engines (e.g., '60's and '70's muscle cars). Motorcycle (and diesel) -specific oils that meet the older SG (and diesel-equivalent) rating, have 1200 ppm ZDDP, which is considered the minimum acceptable for flat tappet engines. While too much ZDDP can cause a build-up that can block oil passages, according to an engineer in this field with whom I have corresponded, you can safely increase the amount of ZDDP in the oil of dry clutch motorcycles to 1800 ppm, using a ZDDP additive. See my prior post regarding this.

 

[pauldaytona]

SInce until now most failures are in warranty, we get no idea about how often it happens, in what percentage of bikes.

 

[youcanrunnaked]

question stays why bmw that has the same construction does not have these problems, it can work.

I think I can explain this.

At any mass-producer of vehicles, they are going to employ a large number of engineers. Some of their engineers will be superstars; some will be average; and some will be dullards.

At BMW, they assign their superstars to the valvetrain, and their dullards to the final drive; at Moto Guzzi, they do the opposite.

 

[draidt]

With some reading, I see that some aditive(zinc) isn't in oil anymore, what gives problems with the tappets, modern american cars use rollers instead

/quote]

I have already been cautioned to not turn this into an oil thread. However, with all due respect to our host, I do not see how one can seperate the 8V failure issue from certain oil issues, such as the one you have raised. Therefore, with respect to just that issue....

Zinc is an oil additive, in the form of zinc dialkyldithiophosphate (ZDDP). It is still present in motor oil. However, because the EPA has been specifying increasingly longer warranty requirements for catalytic converters, and ZDDP reduces the effectiveness of catalytic converters, the latest API-rated automotive oils for gas engines have specified 600 ppm ZDDP. This has been documented as causing excessive wear in flat-tappet car engines (e.g., '60's and '70's muscle cars). Motorcycle (and diesel) -specific oils that meet the older SG (and diesel-equivalent) rating, have 1200 ppm ZDDP, which is considered the minimum acceptable for flat tappet engines. While too much ZDDP can cause a build-up that can block oil passages, according to an engineer in this field with whom I have corresponded, you can safely increase the amount of ZDDP in the oil of dry clutch motorcycles to 1800 ppm, using a ZDDP additive. See my prior post regarding this.

Craig

I am having trouble finding were you posted the recommended amount of ZDDP Plus additive per volume of oil , I am a believer but do not want to over due it.

 

[Mi_ka]

Certainly most of my customers don't use their 8V's for commuting in traffic or short hops. Could that be a factor? Are the bikes in Spain and the UK that have failed only being ridden a few miles at a time and never getting warm? Or do theyy spend hours idling in traffic??? Who knows? (Shrug..)

Seems you are right on the spot on that:
I have been living at village near a town in central Greece for 5 months now.Today I met a young fella with a Breva 11 there and chatted about differences with the Griso 850 he formerly had.He mentioned of how much more tiring the Griso is in the city and how much hotter it got without the oil cooler.The Breva on the other hand is also a bigger bike not well suited for city riding.
TIP: This 100 thousand people town is about 10-15 minutes from side to side on a bicycle! Not more than 40 minutes walk! I myself feel uncomfortable moving downtown on my DR650 and prefer to use the portable bicycle when I get there for business.The DR is too big to be practical - the town is so small! This nice fella seemed to be using only the accessory laden Breva to move around. Er, this "around" can't be much... (Shrug many times...)

So maybe conditions for damage can incubate in cold oil conditions and develop on first heavy thermal load or so...

 

[youcanrunnaked]

Craig

I am having trouble finding were you posted the recommended amount of ZDDP Plus additive per volume of oil , I am a believer but do not want to over due it.

No problem, Dan. I forwarded my correspondence with Mr. Hoyt to your email address, so you'll have the whole story.

Briefly, the dosing instructions he gave me were as follows:

Dosing for your example:

3.5qts of 1200ppm P oil


Added ZDDPlus to get:

1400ppm = 0.5oz

1600ppm = 1.0oz

1800ppm = 1.5oz

I would not suggest that you exceed 1800ppm of P in your engine.


You're right about not wanting to over-do it. Too much ZDDP causes other problems, apparently. As I understand it, the "sweet spot" is 1200 - 1800 ppm.