2 questions

[TSuppa]

I am detailing my engine compartment, I just re-installed the cam-cover. It is held on with 6 bolts, when putting it on I noticed 4 bolts had fiber washers and 2 had aluminum washers. Which bolts need fiber and which have aluminum?

Also the VVT solenoid has me a little confused. It appears to push in a plunger type assy in the cam cover, how does this vary cam timing?

Thanks

[Zunige]

The two aluminum washers that are different go closest to the firewall & this is important, so it's good you noticed... There are two types of VVT set-ups: the earlier one is controlled by oil pressure, and the later one by the ECU. There are several threads on cam covers, head gaskets, and the VVT so I would encourage you to do a search. (You may also want to include your Spider model and year in your signature, as this could help with answering questions about your specific car.)

Best regards,

[alfaloco]

I recall the aluminum washers go on the two rear retainer nuts. Others, please correct me on this if I'm having a senior moment online.

There are a number of in-depth Alfa gurus here who can explain the workings of the VVT device, but the short story is the solenoid engages the pin which hydraulically locks a dog device, which in turn advances the intake cam.

[Tifosi]

You can find a bit of info on setting the solinoid type VVT by clicking the link in my signature block

[GraniteAlfa]

Here is a photo of the washers on my car.

[TSuppa]

ok....I installed the bolts with the alu washers on the rear towards the firewall, but I am curious as to why it makes a difference

[rogerspeed]

The aluminum washers at the rear are to give better sealing pressure for the rubber half moon gaskets under the valve cover.

[papajam]

Better sealing pressure is a common misconception for the use of the aluminum washers. Their actual purpose is to electrically ground the cam cover. Alfa published document on the subject is here.

[zentoad]

Hey guys,
I am new to Alfa's and need some clarification...

Jim, you mentioned that the actual reason for the aluminum washers was to ensure electrical continuity, as per the service bulletin, not to seal the half moon washers.

The conventional wisdom seems to be that the aluminum washers be installed on the rear of the valve cover. I don't mean to question you with information that you provided to me (great CD, thanks), but the bulletin on the CD has a picture with the aluminum gaskets at the front... what gives?

Is the picture incorrect?
Is there a later publication with updated info?
Is it a two birds with one stone kind of thing, electrical continuity AND extra sealing pressure on the half moons, since you gotta put em somewhere and the electrons don't care?

I ask because although you clarified the reason for the aluminum washers, you didn't mention the placement issue or post the picture, this would lead me to believe that the rear placement is correct.
Can someone enlighten me as to why we are not installing them as per the bulletin?

Any clarification would be appreciated...

PS the car I am working on is missing them, so I want to know where to install them.

Tony

'67 Duetto

[rogerspeed]

Not to strongly disagree with Jim and a technical service bulletin, but as Guilias around the time of the bulletin were newly fitted with metal bolts and washers fixing the the front tabs of the valve cover to/through the head, the electrical continuity issue of the valve cover became moot, hence my contention the increased sealing pressure through installation at the rear.

[papajam]

Good eye, Tony. Yes, the uncropped TSB shows the aluminum washers at the front. Although the TSB does not indicate a specific location for the aluminum washers, all the parts books of the period show the washers at the rear. My contention is that the TSB drawing is simply to show that two washers go under two cam cover bolts.

rogerspeed,
the sealing pressure on the rear halfmoon seals is limited to the cam cover nut torque spec, not the crushability of the washers. Exceeding the torque spec will bend/crack the cam cover, strip the nut or pull the stud out of the cam journal loooooong before the fiber washer will crush. Just for grins, put a fiber washer in a vise and try to crush it.
Fair point on the front cover bolts presumably providing a ground. However, I see no reason to question the purpose of the washers for anything other than what the TSB indicates; grounding the cam cover through the washers whether or not front cover bolts are fitted.

[zentoad]

Ok, that's enough clarification for me...
whatever the reason is, I'm gonna put them on the rear two bolts.

[Alfacliff]

Odd that they would use aluminum washers to ground the cam cover since there are two bolts holding the cam cover to the head on the front of the engine.
cliff

[Tifosi]

Those two bolts weren't always there though, and later on when they were incorporated, the washers just kinda stuck around.

[zentoad]

the '67 Duetto I'm working on doesn't have the bolts at the front...
and came to me without the aluminum washers