Hydraulic-Valve Engine Issues by Dave Richardson

 

Iíve been biting my tongue for a long time, wanting to write about cam wear problems in the hydraulic-valve (PI) California engines. But while a few rumors could have been dispelled, I didnít see the sense in raising other questions until there were complete answers. Now weíve got íem - well most of them at least.

Initially came a report that some early PIs (EV Tourings and Aluminiums that arrived in late summer, 2002) may have soft (improperly hardened) cams. This could always be believable, at least to an old heat treater like me, as the case hardening process is a bit difficult to perform consistently in production. And sure enough, the first bike we saw with this problem was a very early EV Touring. But then it happened to a Titanium, a fairly late-arriving 2003, so we knew there was more to the story than initially surmised. And that story unfolded gradually, as various service bulletins came out.

Re-torquing

This first-service procedure hadnít been required since the introduction of the 1100s in 1994 but was re-introduced for the PIs sometime after they came out. I think the idea was to keep the top-end height as short as possible so that the hydraulic lifters could operate more in the middle of their range.

First new cam

In December of 2003 Guzzi announced a new cam (0305 3302) - with a 2.5 mm (.097Ē) hole in each of the four lobes. Originals (0305 3300) had a total of two 2 mm (.079Ē) holes between lobes, like all previous two-valve big-twin Guzzi cams. Here are the VINs at which the new cam was first applied.

Models

Titanium

EV, EV Touring

Stone, Stone Touring

World Frame

ZGUKDC1203M133654

ZGUKDC1203M112261

ZGUKDC4203M111687

US Frame

ZGUKDD0074M133659

ZGUKDD0024M112346

ZGUKDD0164M111418

 

Some people understandably put great worth in this cam, but in our experience, it was equally prone to wear as the early version. If looking to buy a bike, I see no reason to favor one with the late cam over one with the early version.

 
Clearance-adjusting shims

Added in February of 2004 was a recommendation to check valve clearances, again as in re-torquing, to keep the hydraulic lifter operating in the middle of its range. Part of the procedure was to drain the hydraulic lifters but thatís now considered part of the problem, as upon start-up the engine runs with excessive valve clearances until pressure builds. This entire procedure is rendered null and void with the introduction of the third-generation cam in 2005.

Other suspicions

Some Guzzisti (me included) have wondered about low oil pressure. There seemed to be good reason to be suspicious. Hereís the background.

All true 2003 big twins (excludes burgundy, light green & silver early 2003 US V11 Sports that to the rest of the world were 2002s) received engine updates. Among those in common: higher-compression pistons, a second exhaust crossover in front of the engine between the headpipes, and oil holes in the connecting rods to squirt cooling oil onto the underside of the pistons. Additionally, the Californias received hydraulic valve tappets. That means that all of these engines have at least two new Ďinternal oil leaksí through the rods, early Cals have six new leaks (rods plus four hydraulic tappets), and later Cals have eight, the last two coming from the December, 2003 cam update.

The supply side of the oiling system hasnít changed: same pump, relief valve setting, and drive ratio. So it seems likely that the pressure isnít as high as before, unless the system had more capacity than necessary to begin with. At our shop, we tested bikes both at idle and at 4000 rpm. We tested bikes both with and without the connecting rod oil holes and both hydraulic and non-hydraulic Californias. Variation at 4000 rpm was minimal while idle speed variations seemed significant. Then again, nothing fell below 30 pounds feet, which I found in automotive references to be perfectly adequate. The connecting rod holes made little difference. Neither did the extra holes of the late PI cam, but the hydraulic lifters themselves seemed to be the biggest contributors to lower idle pressure.

We experimented with other oil issues as well. We substituted the higher-volume Centauro oil pump into one Stone, later hearing that the factory said this wasnít a solution. That bike still runs without problem, but the absence of a subsequent failure doesnít prove this to be a solution. Oh well, it was fun to experiment! We also tested higher-viscosity 20W-50 oil for running pressure. We found a significant increase at idle but we didnít know what problems we might be introducing with the more viscous oil and we didnít know if our Ďimprovementí was useful or not. We finally decided to stick with Guzziís firm recommendation of 5W-40.

Of the PIs weíve seen with problems many repeated, so we wondered if some follower bores were not square with the cam lobes but in the one we checked they were perfect. Itís not directly possible to revert to solid (non-hydraulic) lifters as Guzzi solid lifters are much larger in diameter, therefore requiring case machining (extremely difficult to do accurately) or case replacement (expensive). We wondered about follower length and bearing area, both being less than in non-hydraulic Guzzis, but Iím not an engineer and I donít know whatís sufficient. We also have wondered if repeats are contributed to by remaining debris from an earlier failure. Needless to say, at minimum, cleaning should include the oil pump, oil pressure relief valve, oil filter, oil pan, and non-draining pockets such as those in the cylinder heads for the valve springs.

Remedy!

For unsold, non-registered no-miles bikes, an early 2005 service campaign will update PIs with a third-generation cam and new (less stiff) valve springs, aluminum (in place of steel) upper spring collars, pre-filled lifters, longer (35-mm vs. 32-mm) followers, adjustable rocker arms, and a revised cam thrust retainer. At the same time the shims, if present, are deleted. In the summer of 2005, a similar campaign will be launched to update sold bikes plus unsold bikes with accumulated miles. Details of that program are still being developed but it is expected to be similar although possibly more elaborate than the first campaign.

So why not take care of existing customers first? I donít know for sure but Iíd guess that, quite simply, the no-miles program was first developed because it was the easier to develop, what with fewer variables. And whether they like me saying this or not, I think anyone can understand that after a sustained period of financial problems, an expensive dead-loss service campaign would first be aimed in the direction that might see a return on investment in the form of increased sales. Besides, it seems that cam wear hasnít proven to be a big enough problem for existing customers to be prioritized. And, an existing customer suffering a problem will still get the old fix while waiting for the permanent one. So why not save the time, money, and hassle and give 2005 failures the update right away? Because the program for bikes with accumulated miles hasnít been fully developed yet. Many of us complained about halfway measures in the past, so now apparently Guzzi is going to be sure before acting. How do I feel about all of this? Heck, I got a Titanium with 800 miles on it in December, knowing a fix would soon be announced but not knowing what it would be. So I get to wait like everyone else (probably longer as I get low priority at my dealership!) but Iím certainly not worried about a failure nor am I saving my bike or babying it.

My remaining suspicion

At first Guzzi recommended nothing but 5W-40 for PIs and now more specifically synthetic. Missing, as usual, was any mention of service grade. For spark-ignited engines (non-diesels) these are two-letter codes starting with S for spark (Diesels have a C for compression-ignited). For each new standard the second letter advances. Until recently an advancing letter also meant a Ďbetterí oil but lately it has meant a more specialized oil. You see, the recent SJ and SL are in part designed to help catalytic converters last longer, and so contain less zinc and phosphorous. Motorcycle engines, notably our PIs, really need high-pressure anti-wear elements, so thereís reason to believe that oils not also designated SG arenít good for our motorcycles. Some recent motorcycle engines, such as the Aprilia RSVís 60ļ V-twin, specify SJ, so they donít require an oil also rated as SG. I donít remember Guzzi recommending a specific rating before the MGS/01 Corsa called for SG. Maybe research into a PI solution lead them to finally make this distinction.

Faced with a customerís worn cam and an unusually-specific oil requirement from Guzzi, we sought and found a synthetic 5W-40 but missed on getting one that was SG-rated, so maybe we and other owners/dealers contributed to the problem in this manner. I had thought that cat-friendly car oil was fine for bikes, as one oil engineer told me that they had developed an anti-wear additive package that was more effective in spite of the reduction in phosphorus and zinc. Then I heard from Dr. John Wittner that I needed to pay attention to the service grade. He had recently noticed the dreaded SL rating on automotive Mobil 1 and checked with the manufacturer on its applicability to a Guzzi-built engine. The result was the quick return of the car oil to Mobil and its replacement with SG-rated motorcycle oil. I take this to be significant: if Mobil and Dr. John implore using SG and not SL, thatís all I need to know!

If you investigate oil service grades youíll find plenty of conflicting evidence and information. Again, some say other additives replace phosphorus and zinc. Also, the reduction from SG to SL was a minute percentage and the reduction only applied to thinner oils. And some believe that the motorcycle-specific oils are just a marketing excuse to sell us more expensive oil. I canít be sure about any of that so I choose to pay a few extra bucks for the sure thing: synthetic SG-rated 5W-40. In fact, Iíll be looking for an SG oil to use in my 1990 pickup as well. My local auto parts store knew nothing of service grades and none of their offerings other than Red Line was SG rated. I have noticed that Pennzoil offers an SL/SG-rated oil specifically for automobiles with 75,000-plus miles.

Retrospect

So did Guzzi try to cover up the problem? I have no way of knowing but my suspicion is that it was all fairly innocent. I imagine that testing during development proved the cam system durable, so initial reports of problems would naturally bring focus to production variations and user-induced causes. Itís also natural that when you have a problem and you develop a solution to it that you believe your solution is valid. But sometimes the problemís true causes arenít completely replicated or thereís a time/funding constraint, or marketing is demanding a simple answer to a complex problem. I was set to believe that the eventual solution was delayed by Apriliaís financial problems, but then again, the announcement of a solution came at a time when funding and company morale had to be at their lowest. In conclusion, I find the question unanswerable and largely irrelevant. The fact is, the solution is at hand.