Top end work

[Tom M]

I've been trying to resolve a pinging issue since I bought my LeMans nearly 5 years ago. I've messed around with air-fuel mixture via the PCIII and even done partial throttle runs on a dyno to see if I had a lean spot in the 5000rpm ping zone, all to no avail. Since it's winter now and I won't be riding again for a while I decided to pull the heads to measure the squish clearance to see if that's the cause of my pinging as discussed in this thread from a while back: http://www.v11lemans.com/forums/index.php?...quish+clearance I also figured I'd remove the valves and check them since Mike Rich and a number of members here have seen significant wear when they removed them.

 

I found all of my valve stems were at or past the wear limits. The exhaust valves in particular were worn .004". I snagged a set of FBF valves off of ebay from Ferracci a while ago since they were $20 each instead of their normal $72, figuring that I'll install them if needed or stick them on a shelf for later use if mine were OK. Turns out I will be installing them now. I don't have gauge pins so I couldn't measure the valve guides. I'll wait and see what the machine shop says about them.

 

Here's a pic of the new valve next to the old one. Maybe you can see the step in the valve stem.

 

I found no blow-by on my pistons and the cylinders still had a good crosshatch pattern visible, but my ring end gaps were at or a little beyond their wear limits so I'll be replacing them while I'm in there. Also, the anti-friction coating on the piston skirts has worn through. If I reuse the stock pistons I'll send them out first for new skirt coating and have the crowns coated too. A few more pics:

 

As long as I have the barrels off I figured now would be a good time to replace my crankcase breather tube. It's not leaking but it does have some dry rot cracking. I also decided to clean up the 2002 bubbly paint issue on top of the motor. I repainted the bottom of the engine a few years back with very good results and I had some paint left over. Much of the paint on top of the engine blew right off with a blast from an air gun. The rest yielded to a wire brush and screwdrivers. After paint removal:

 

Repaint done and masking materials removed:

 

It's not exactly show quality but nobody can see that part of the engine when the bike is together anyway.

 

Rather than buying a bike lift I decided to build a wooden platform to save my back a bit. I'm glad I did! Here's a pic:

 

 

I haven't done the squish clearance measurement yet because the heads are at the machine shop. I'll post more on that and on my progress once I get the heads back.

 

PS Many thanks to Pete Roper for his excellent tear-down instructions at http://www.thisoldtractor.com/guzzitech.dk/english/index.htm

[raz]

Thanks for sharing this Tom, I'm about to do similar work @ 72,000 kms (45,000 miles). I'm also replacing the pistons with FBF ones I bought unused from Antonio. That was just because I got a good price, my initial plan was to take a millimeter or so from the head to set squish and raise compression. I'll be interested in your progress and I may report some of mine if something interesting comes up.

 

If my memory serves me, your pistons look a lot worse than mine did last time I looked. That was when I broke an exhaust stud at 42,800 kms which is very similar to your mileage. I don't have any pictures of piston sides so I'm not sure.

[GuzziMoto]

When the valves in my wifes V11 were replaced due to wear the guides were toast as well. Hope this work helps your issue. Similar work helped with mine.

[Tom M]

Thanks for sharing this Tom, I'm about to do similar work @ 72,000 kms (45,000 miles). I'm also replacing the pistons with FBF ones I bought unused from Antonio. That was just because I got a good price, my initial plan was to take a millimeter or so from the head to set squish and raise compression. I'll be interested in your progress and I may report some of mine if something interesting comes up.

 

If my memory serves me, your pistons look a lot worse than mine did last time I looked. That was when I broke an exhaust stud at 42,800 kms which is very similar to your mileage. I don't have any pictures of piston sides so I'm not sure.

 

I was surprised to see that amount of wear on the pistons and rings too Raz. I bought the bike with 7k on it and have always used top quality oil. I was hoping for comments from others who have pulled their pistons to comment on the wear that I have. The valve stem wear doesn't surprise me based on what I've heard here and what Mike Rich said when I spoke with him.

 

Be careful with those heads. The Ferracci pistons already raise the compression above stock. I would think that removing a millimeter or so off of the head will really push the compression up there. Once the material is gone it can't be put back, but you could always go to a thicker base gasket I guess.

[Dan M]

Yea, lots of reports of Guzzi guides being made of particularly hard Parmesan. I'd bet yours are bad.

Judging from the pics the cylinders and pistons look pretty good

I thought you were looking into Mike Rich pistons at one time? Better shaped squish - no pinging on my motor.

 

edit- How often do you change your oil?

[Tom M]

Yea, lots of reports of Guzzi guides being made of particularly hard Parmesan. I'd bet yours are bad.

Judging from the pics the cylinders and pistons look pretty good

I thought you were looking into Mike Rich pistons at one time? Better shaped squish - no pinging on my motor.

 

edit- How often do you change your oil?

 

Mike ran out of pistons in the summer of '08 and won't do another run until he has enough buyers. I've been on his list since fall 08 and I'm not going to wait much longer. If he doesn't come through soon I may go with FBF pistons or have my stockers recoated by this outfit: http://www.swaintech.com/store.asp?pid=10298

 

I change my oil every 3-4k miles. I've been using Mobil1 V-Twin for the past 2 years. Before that I used a few different oils but no cheap stuff.

 

How many miles were on your bike when you changed pistons Dan? How did the skirt coating look?

[Slavomir Musilek (R.I.P.)]

left piston after 50.000km

I use 20w-50 oil

change every 5000km

valve clearance is factory standart

 

left piston where oil has been running to the cilinder

 

right piston, also small leak through gasket

 

another view

 

 

and I wonder where did I get the line on the right bottom corner of the piston... no damage to the barrel visible

[Tom M]

Your piston wear looks similar to mine Slavomir, except for that gouge on the skirt. With no corresponding mark in the cylinder I would hope it didn't come from the factory like that.

 

Some anti-friction coatings for pistons are there only for the break in period. I wonder how long the coating that Guzzi used is supposed to last?

 

Here are a couple shots of my other piston in case anyone cares:

[Dan M]

How many miles were on your bike when you changed pistons Dan? How did the skirt coating look?

 

 

I did the pistons with less than 10K so it is not a good yardstick. The skirts looked like new as did the crosshatch.

I asked about the oil intervals because of the wear on the coating. Seems excessive to me for 27K with clean oil. Maybe it is just the way they wear.

[GuzziMoto]

I think the coatings for wear are getting better and better, but they still don't last forever. back in the mid 90's when I first started playing with coatings they would not last 10 hours in our race motors. Nowadays they should last much longer but still not likely the life of the piston, at least not that I've seen. But as I said, they do seem to get better and better. They also ceramic coat the piston domes now which is something else we started playing with way back then. If you are getting the skirts coated I would coat the domes as well.

On the subject of the carbon burnt on the pistons, it can come from a variety of sources but one thing to check are the valves and guides. A few people including myself have had them wear out and cause those kinds of issues. As I recall there is no valve guide seal like a normal motor so valve guide clearance is extra important. Which means if the valve stem and/or the valve guide are worn then oil will make its way down the valve and into the combustion chamber on the intake side and down the stem only to burn into a crusty coating on the exhaust side. It also seems to cause detonation or pinging, at least for me. Just saying it is something to check if you have not done so already.

[luhbo]

You should use 10-W40, a good and especially synthetic car quality, instead this outdated 20-W50 stuff. Then change the oil once a year only, or every second year even, and you'll have a much cleaner and also a better running engine for overall less money.

 

Also I doubt that a bad head gasket will let sip oil into the combustion chamber.

 

Hubert

[Slavomir Musilek (R.I.P.)]

You should use 10-W40, a good and especially synthetic car quality, instead this outdated 20-W50 stuff. Then change the oil once a year only, or every second year even, and you'll have a much cleaner and also a better running engine for overall less money.

 

Also I doubt that a bad head gasket will let sip oil into the combustion chamber.

 

Hubert

 

 

will do next year! it is much better when you see the results (dont wanna open the oil pandora box again) so let's see how the pistons gonna look like after another 20.000km next year

[raz]

This is my right side piston. They actually look pretty good (to me) even now after 72,000 kms. Anyone correct me if I misinterpret what I see but I reckon there's no blow-by and skirts looks wonderful - but it doesn't seem to have had any coating ever.

 

Does anyone know why on both pistons, the amber colour is below second compression ring, but not between first and second?

 

Be careful with those heads. The Ferracci pistons already raise the compression above stock. I would think that removing a millimeter or so off of the head will really push the compression up there. Once the material is gone it can't be put back, but you could always go to a thicker base gasket I guess.

Oh yeah, milling the heads was cancelled from my to-do list as soon as I bought the FBF pistons. I'd rather have MR ones but I got these dirt cheap. I was pleased to see that on my particular bike, the piston tops are level with cylinder tops.

 

Here is my right piston compared to an FBF one. They are 'connected' with a gudeon pin for comparisons.

 

I'll post some other issues in a separate thread (did you check your followers, Tom and Slavomir?)

[Slavomir Musilek (R.I.P.)]

I'll post some other issues in a separate thread (did you check your followers, Tom and Slavomir?)

 

 

sure, cam followers are nice and clear.

[Tom M]

sure, cam followers are nice and clear.

 

Same here. Mine looked great. I can take a pic if you like.

 

I saw your pics in the other thread, those exhaust followers look nasty. I'm surprised your cam is OK. Hopefully Pete or Greg will chime in on your other threads.