8V cam Pt 2: follow-up

[Greg Field]

It's probably not a problem of the engine design or even of an improper material pairing. I wonder where such informations come from.

Instead it's again quite certainly just an issue of bad supplier quality as so very often with Guzzi.

 

Hubert

 

 

I believe that everyone's blaming this on a vendor that under-hardened the tappets when the real explanation is just bad engineering on Aprilia's part.

 

What do I have for evidence to support this claim? Well, as the parts lists describe, the first-series 8V tappets were made of cast iron, whereas the new ones are hardened steel. Cast iron is not conventionally "hardenable," so how could a vendor have under-hardened them? Here's what most likely happened: Somebody at Aprilia specified cast iron tappets when they should have specified hardened steel tappets. Also, the new steel tappets appear to have more of a radius on their underside than the early, iron tappets did.

[Greg Field]

Well said. That's one reason why some say it would be only good for Guzzi, for the brand, if it would leave Mandello as soon and quick as possible. On the other hand, there are big suppliers situated there like Lafranconi which deliver good quality to BMW for instance. So it's not too much to do with the climate down there.

 

Hubert

 

 

Really? This engine was not designed in Mandello. It is the design that was faulty. How, then, could leaving Mandello prevent this type of problem.

 

I'm going to have to cal Dr. John. He once talked about a friend of his who was on this engine project warned of a problem with the cam system and was transfered out or fired for his trouble. I'll see if my memory serves or not . . .

[gstallons]

A proper way to settle this would be to send a worn cam/lifters to a racing camshaft company for an opinion.

Moving the assembly plant out of Mandello would not cure the camshaft problem.

[luhbo]

......when the real explanation is just bad engineering on Aprilia's part.....

Your word on that?

 

..... Cast iron is not conventionally "hardenable," so how could a vendor have under-hardened them....

That's new to me. Wikipedia or a local Guzzi-Guru?

 

.....Also, the new steel tappets appear to have more of a radius on their underside than the early, iron tappets did.

Really, do they? What does it mean, "(they) appear to have more..."? You've seen a picture on the web or what? A 1248x1024 highres shot?

 

....

I'm going to have to cal Dr. John. ...

Let me know when you'll call him, so I can stand upright as long as you two talk to each other. Or how about a conference for three? (Not me, no worries.)

 

Hubert

[Greg Field]

Your word on that?

 

My opinion. I gave you the facts upon which it is based. I've examines and held the parts. I stand by my opinion 'til someone can offer something more substantial.

 

That's new to me. Wikipedia or a local Guzzi-Guru?

 

As I said, the Piaggio parts diagrams clearly say that the early tappets are cast iron and that the later ones are steel. No guesswork involved.

 

Really, do they? What does it mean, "(they) appear to have more..."? You've seen a picture on the web or what? A 1248x1024 highres shot?

 

It means I've held both sets of tappets in my hand and compared them. The steel ones appear to have clearly more crown on the underside. Your experience is what?

 

Let me know when you'll call him, so I can stand upright as long as you two talk to each other. Or how about a conference for three? (Not me, no worries.)

 

Hubert

 

I'll let your know.

[luhbo]

Mr Field, sit down, you're childish. You're giving answers to questions I haven't asked.

Did you stamp your foot while you wrote them down?

[GuzziMoto]

WTF?

[luhbo]

A good question, indeed!

 

Edit: I have to apologize I think, maybe at least. Could be I used the "quote" function the wrong way. It should have been read like this:

 

------------------------------

Greg: ......when the real explanation is just bad engineering on Aprilia's part.....

 

Me: .....Your word on that?

 

Greg: ....My opinion.....

------------------------------

 

or:

 

---------------------

Greg: ..... Cast iron is not conventionally "hardenable," so how could a vendor have under-hardened them....

 

Me: ....That's new to me. Wikipedia or a local Guzzi-Guru?

 

Greg: ....As I said, the Piaggio parts diagrams clearly say that the early tappets are cast iron and that the later ones are steel. No guesswork involved.

---------------------------------

 

HTH.

[mike wilson]

Here's what most likely happened: Somebody at Aprilia specified cast iron tappets when they should have specified hardened steel tappets.

 

That's interesting. It's not possible to (or, at least, I didn't) pick that up from any of the picture published so far. High-quality chilled cast-iron might be a suitable material for the tappets but I would have thought steel finished products would be easier (and therefore cheaper) to produce. Makes me wonder what Piaggio is going to do when the milk-cow of disposable scooters comes to an end.

[Greg Field]

Again, it is Piaggio's parts diagrams that say the first-series lifters were cast iron. It's not something I made up. Since no one believes it, let's see if I can post a screen shot to prove it.

 

I guess that's not possible, now. The parts diagram has, within the last week, been modified to omit any mention of the earlier tappet. I might have a printout at the shop, though. The part number for the cast-iron tappet and mention of it and its being cast-iron are in the lastest Guzziology, so at least I will have that information. One must document stuff quickly today before Piaggio sanitizes its records. They remind me of H-D in this respect.

[luhbo]

....One must document stuff quickly today before Piaggio sanitizes its records. .....

 

You're ill, sorry. That's paranoid. There can be written [EDIT:] in those charts [:EDIT] what the translation programm wants. [EDIT:] What would it proove?[:EDIT]

Have you ever looked at the "drawings" they supply in these manuals? Wonder why no one mentioned that so far. Look at these drawings, do you believe an engine with parts like this would last longer than 5 minutes?

 

Hubert

Edited May 28, 2009 by luhbo

[Greg Field]

First, I am childish and stamping my feet and now I'm paranoid? Would you like to hear what I am beginning to think of you?

 

I work with Piaggio every day. I have seen and held and compared the parts in question here. I have absolutely no idea if you've ever seen the parts or ever worked with Piaggio, so I'll take my own counsel on matters Piaggio, rather than yours. Last week the online parts diagrams listed part numbers for the early cast-iron tappets and the later steel tappets. Today they do not. They were "sanitized" within the past week. These are facts that exist despite your opinion on the matter.

[chris a]

Thank God there are some sane and proficiant people like Greg around here . Thanks for all of your posts and long may you keep them up.

chris

[GuzziMoto]

It's not something I made up. Since no one believes it, let's see if I can post a screen shot to prove it.

I believe you Greg.

You are an excellent source of information to me, and while we may differ on matters of opinion I see this as a statement of fact from you, not opinion.

[pete roper]

Last week the online parts diagrams listed part numbers for the early cast-iron tappets and the later steel tappets. Today they do not. They were "sanitized" within the past week. These are facts that exist despite your opinion on the matter.

 

Yup. I can confirm that.

 

Hubert? Both Greg and I, maybe a few others too, have access to the on-line parts and service sites. Why? Because we are service agents or work at dealers. Why would we BOTHER making stuff up?

 

Pete