Cambelt pulley replacement

Yes, you can remove the center bolt, I just replaced two broken plastic pulleys a few months ago on a 77 308 on the front bank. It's hard to find a good condition plastic pulley as they don't make them anymore but, they do make a metal ones but expen$ive. Make sure when removing the bolt, to secure and lock the pulley then, preferably use an impact wrench.

 

Look closely. The cam pulley is held in place with a 'headed' pin, washer and the big bolt on the end. You may need an impact wrench to loosen the bolt.

Put reference marks on everything including the new cog. The marks on the old and new cog must be in the identical location.

Mark the hole the pin is in in the cam pulley AND cam shaft.

Lock the cam so it cannot move or mark it in a way you can tell if it did and by much.

Remove the bolt. Remove the pin and pull. The cog should come off with a bit of effort. Put the new cog on and put the pin thru the marked holes.

Put the big bolt and washer back on with a new O-ring. Make sure the washer has slipped to its limit properly and torque to spec.

The marks on all cogs and the new belt should line up as before and the cam should not have rotated or 'drifted.'

That is the general idea of this procedure. Somebody else may offer some 'tips & tricks.'

 

If the fence is in tact and not broken you can always glue it back on. This has been done successfully in the past. I think there is a post somewhere about this.

 

My '82 308GTSi has an O ring behind the cam pulley bolt which must be replaced. My cams also have a hex for a large cresent wrench. The bolt is torqued to 80psi.

 

Here's the cam pully bolt that has the O-ring that Mark was talking about.
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You should not have any rotational movement on your pulleys with the index pin inserted. 6 degrees of total movement is unacceptable.

 

Do you mean that you have that much rotational play between the pulley and the cam with the bolt loose (like someone got frustrated and wrongly ground down the alignment pin when they didn't understand how the adjustment works), or

You have that much slop in the belt so that when you rotate the pulley and cam together (with the bolt tight) it has that much rotational movement?

It is important that the tensioner mechanism is properly cleaned/lubed (but it's not a dynamic thing after being locked down -- so it's not rocket-science ).

 

By "Rim" you mean the side flange which prevents the belt from running sideways off the edge of the pulley? Not the actual part the belt runs on (hopefully!).

 

Crikey!

 

Please show us a pic. This makes absolutely no sense what so ever.

 

+1 -- the molded outer shell has separated from the steel inner core. Don't start it again like that

 

WoWzers!!!!!!

Been to three World Fairs and a goat race and I ain't seen noting like that !!!

WHAT HE SAID !!!!!!

 

Welcome to what happens to the plastic sprockets when someone (wrongly) tries to put the timing belt on by just compressing the tensioner -- the fence gets broken off. Each sprocket/pulley on each bank should have one fence IIRC (one inboard and the other outboard) -- see the SPC or OM figures.

 

It's usually just the outboard fences that get broken off -- have you lost the inboard fence on each bank as well?

(Can't help with the replacement sourcing, but I'd, personally, go with a healthy stock set or an aftermarket set just based on better price.)

 

IIRC, there are stock metal ones that will work on our engines with OEM plastic pulleys. I'm fairly noobish, so anyone who knows for sure, please help confirm as I was thinking of swapping my plastics for OEM metal.

Ciao!

Hannibal

 

Oh, and it gets better.

There are aluminum that use the OEM Belt deign(I have anodized red ones) and others that use the modern rounded tooth belt design and are adjustable to advance or retard the cams. Examples of both can be found in threads here.

The thing I Really Like about mine is the cog and fence are all one piece. They cannot be broken off.


Ferrari never made any metal ones for the 3x8 cars IIRC.