Top end work, 1100 Sport

[luhbo]

That's a lot? Please elaborate.

...

 

Some tenths of a mm, that's a lot. Let's say 3/10 or 4/10, that's a huge bit of material. You probably thought of 2 or 3/100 of a mm.

 

The other thing is: what will he take for guiding his grinding machine? The lobe itself?

 

And: usually a modern lobe profile means less wear. Hotter or not. It seems as if the V11 cam is a very good one actually. Maybe better than the older aftermarket versions even.

 

Hubert

[luhbo]

Phil Irving.

 

Nothing more needs to be said.

 

Great. You're refering to this one, aren't you? What does he say? Get things right? That's beyond discussion. Getting things right is ok. The question is: what does it cost and what would be the tradeoffs.

 

Hubert

[raz]

Some tenths of a mm, that's a lot. Let's say 3/10 or 4/10, that's a huge bit of material. You probably thought of 2 or 3/100 of a mm.

 

The other thing is: what will he take for guiding his grinding machine? The lobe itself?

Sorry, I was thinking in terms of "pushrod lowered 0.2 mm" which was what he and I were discussing. That is negligable. An aftermarket head gasket of 1.75 mm will lower it more than twice of that, compared to an 1.2 mm one and last time I ordered two head gaskets from SD I got one of each thickness <_>

 

I understand your concern about not having a fresh master. I was concerned too. But this is a reputable pro and after looking at it for a while he said there is enough unworn profile at the very edges for him to make a proper master. If I wouldn't trust him I should not leave my cam there in the first place.

[luhbo]

If that's the case I could borrow you a V11 camshaft, a strip of 4 mm on each lobe still unworn. Interested? -> PM

 

Hubert

[motoguzznix]

Based on what? Experience? Gossip? Academic studies? Come over with some numbers. How much out of balance would the system become if the pushrod was 1mm too short or too long?

You have milled your heads down. How did you address the mentioned problem? Did you shorten the pushrods?

Hubert

I did no comparison runs on a test rig.

But I have had a lot of valve train parts in my hands and have seen deep grooves of wear in them. An I have seen home tuned engines wearing fast the valve train parts out of this reason. When the angles described above get tighter the forces involved increase dramatically. This can be calculated easily. I can't back up by figures how much longer/shorter the parts last if everything is is right/wrong, but the influence is not negliable. I learned this the hard way doing things wrong myself when I was beginning to work on my Guzzi engine.

Concerning my own V11 I was milling 1+0,45 mm off head/cyilinders and I use a reground cam with the same lift and slightly shorter timing to overcome the difference in pushrod length.

 

Sorry, I was thinking in terms of "pushrod lowered 0.2 mm" which was what he and I were discussing. That is negligable. An aftermarket head gasket of 1.75 mm will lower it more than twice of that, compared to an 1.2 mm one and last time I ordered two head gaskets from SD I got one of each thickness <_>

I understand your concern about not having a fresh master. I was concerned too. But this is a reputable pro and after looking at it for a while he said there is enough unworn profile at the very edges for him to make a proper master. If I wouldn't trust him I should not leave my cam there in the first place.

A new Guzzi cam starts with a base circle diameter of ~ 28 mm. A reground cam has a base circle of approx 25-26 mm. This difference compensates for a pushrod length of 1 - 1.5 mm which is exactly what is needed for the V11 engine after everything is machined.

The stock V11 cam profile is a good one and it is hard to find a better one without sacrifieing power in the higher/lower rpm range. It is a good compromise for a sporty Guzzi engine and is very similar to the ancient Guzzi Sport cams available by tuners, p ex Dynotec 7906 and others. With the now 1064 cc engine the engine character gets less cammy allowing a wide power band. So reworking the cam to the original spec is not the worst idea.

[raz]

I just noticed Guzziology mentions that Guzzi introduced a new cam in 2003 for bikes using hydraulic lifters, with a 2.5 mm oil gallery in each lobe instead of two 2 mm holes between lobes. I wonder if the "Breva cam" available for us has this same mod, or was that only for the PI bikes?

 

All HMB-Guzzi's cams are modified the same way. I suppose any cam shop can do a similar modification when regrinding, for very little added cost. Are there downsides?

[gstallons]

I just noticed Guzziology mentions that Guzzi introduced a new cam in 2003 for bikes using hydraulic lifters, with a 2.5 mm oil gallery in each lobe instead of two 2 mm holes between lobes. I wonder if the "Breva cam" available for us has this same mod, or was that only for the PI bikes?

 

All HMB-Guzzi's cams are modified the same way. I suppose any cam shop can do a similar modification when regrinding, for very little added cost. Are there downsides?

 

I don't know how the oil circulates through to feed the (hydraulic) lifters to keep them "pumped" up. I don't know what these holes (in the cam lobes)do? I do not have a manual here to give an oil feed circuit.

Anyone else want to comment?

It only has to last til 2012 any way. The world is coming to an end then.

[Greg Field]

The holes ooze oil oil directly onto the lobe. I can't remember for sure if the late V11 cam had them or not.

[gstallons]

Was there not enough oil spray (from the crank,etc.) to lube the cam lobes?

[Greg Field]

Was there not enough oil spray (from the crank,etc.) to lube the cam lobes?

 

There never is too much. Traditionally, the RH exhaust lobe wears fastest on Guzzis. Why? Being in a lubrication shadow is one theory. Usually, the RH exhaust lobe is the one that wore out on the hydro EV cams that were failing. Guzzi tried three different cams before it was fixed. Part of the fix was the oiling holes.

[luhbo]

I don't know how the oil circulates through to feed the (hydraulic) lifters to keep them "pumped" up. I don't know what these holes (in the cam lobes)do? ...

 

Hydro followers are installed to run the valvetrain "lashless". That's the reason why they are working so quietly, and that's the reason why a very good lubrication between lobes and followers is a must. The oil enters the followers lateraly, by the way.

 

I assume that the Hydro engines used a special camshaft. Is that true?

 

Hubert

[Greg Field]

Hydros have a unique camshaft. Oil to fill the hydraulic lifters is supplied through the block, not through the cam.

[raz]

Does anyone know if 30022060 (head gasket, Cal.1100/1100 Sport/V11) is supposed to be 1.75 mm? Is there some other part number for 1.2 mm ones? Are there any other sizes available than those two?

[motoguzznix]

Does anyone know if 30022060 (head gasket, Cal.1100/1100 Sport/V11) is supposed to be 1.75 mm? Is there some other part number for 1.2 mm ones? Are there any other sizes available than those two?

Stock gaskets are always 1.2 mm.

The aftermarket offers 1.7 mm too. These are on the upper limit for a working squish clearence.

[raz]

Stock gaskets are always 1.2 mm.

The aftermarket offers 1.7 mm too. These are on the upper limit for a working squish clearence.

I just got confirmation from Stein-Dinse that they only supply 1.75 mm ones. And he called it "that normal 1.75 version". Who would ever want that thickness? On a stock bike the compression would drop below 9:1 if I got the numbers right.

 

I'll try to get OEM ones over the counter somewhere so I can check them.