Anyone changed a cam belt on a 612?

I noticed a strange noise coming from the front of my 612 a few weeks ago. It didn’t sound like a bearing, as it wasn’t constant, rather a “churning” noise with a 2-3 second period. Anyway, it’s cold and miserable here in the north of Scotland, so the car isn’t going to get used much for a few months, so I decided to take it apart to investigate.

When I got the timing covers off, I found two very loose timing belts. The bank where the noise was coming from seemed extremely loose- there was zero tension in the long span, which could be moved back and forth by nearly an inch.

I couldn’t find anything else amiss, and the bearings all seemed fine, so even though it’s not due for a few years, I decided all new belts was in order (and new cam belt bearings).

The problem I’ve got is getting the crank pulley off. Getting a pal to hold the pulley in place with a chain wrench, we were both pulling hard on scaffold tubes to give ridiculous amounts of twist, but to no avail.

I then tried the starter trick, but no joy there either- the starter just doesn’t have enough twist.

Only thing for it is an impact wrench, but there’s very limited space in there to get the tool in. Where I’ve got to is that the steering rack is going to have to come right out to get in there, but I can’t see how it’s going to happen.

Anyone got any clues as to how to get the pulley off or the rack out? What would be amazing is a workshop manual too, so any help there would also be gratefully recieved.

Cheers gents.

 

Is the pulley not having 4 holes around the bolt to block it with a pulley blocker?

 

You need to lock the crankshaft from turning by using a long pry-bar (3-4 ft long) in the opening at the bottom of the bell-housing to keep the pressure plate from turning. The bolt on the crank hub is torqued to 220nm and is secured with medium strength (blue Loctite). You need a breaker bar with a large amount of leverage in order to loosen the bolt. I use a 3ft long breaker bar and then slip a 6ft long jack handle tube over the breaker bar in order to break the bolt loose, and even then it takes a large amount of force on the bar.
The workshop manual is of no help in this regard. It assumes that you know how to work on cars and doesn't tell you how to perform the procedure other than the belt tensioning procedure and crazy cam timing procedure.

 

Ahhh... so there is another way of locking the crank!

Is there a specific locking point, or do you just slip a pry bar into the clutch casing, and resist against the bellhousing?

I thought the manual would be fairly light on the details of doing the cam belt which I’m fine with. The engine ran spot on before, so I’m just planning on using the factory set timing marks (probably should avoid opening this can of worms again though).

I take it there’s enough space to get the pulley off without having the rack fully removed from the car?

Thanks guys, and merry Christmas.

 

It is a common problem for owners and especially sellers to skip replacing the cam belt TENSIONERS with a belt service. Make sure you replace those.

You are very lucky to have caught that.

 

I had to take the front pulley off a 575 crank (same as 612) that was already out of the engine. We locked the crank down on the bench but even a windy gun would not shift the bolt.

As above, a breaker bar with a length of scaffold tube was the only way to break the seal in the end, so good luck trying to do that in situ!

 

The cambelt tensioners on these engines are mechanical, its the bearings on them that get replaced.

 

Sorry for the imprecision.

 

Thanks guys. If it’s possible to upload a video, then I can demonstrate how loose the belts were when I opened her up?

 

The belt tensioners only set the belt tension when the cam belts are replaced and then they are locked down. The belt tension is then checked with a frequency meter to make sure that the tension is correct. The tensioners have no effect on belt tension once they are locked down. As the engine is run the belts get looser over time.

 

My thanks to Motob. His tip with the clutch worked spot on. It’s mildly terrifying how much twist it took to loosen the bastard, but brute force did win in the end.

Yeah, the belt tension should decrease over time as the belt stretches, but it shouldn’t be able to flap about surely? And after 3 years?

I notice that the 550 manual states that you’re allowed to re-tension the belt once during its life within 1500km of fitting it. Is anyone actually going to do that though? It’s a reasonable amount of effort to get to the tensioner, that I guess most people would just replace the belts if they’re in there?

I’ve gone with a replacement Dayco belt rather than OEM based on the performance of the ferrari stamped belt that was put in there last time.

 

No, the belts shouldn't flap about after three years unless you have driven 100,000 Miles. I would not even consider re-tensioning them. If they were flapping around, then they have stretched a bunch. It is also so much work to get in there that it doesn't make sense to not change them .

 

PM me for workshop manual and flywheel locking tool. I can loan you what you need.

 

Update time guys...

Belts all got changed (easy to do once the pulley was off), but when it all went back together, that death noise was back worse than ever. There was a timy bit of play in the water pump pulley, so I changed that too, but still no joy.

I ran the engine without the left hand cowlings today though, and I spotted the issue in about 15 seconds- the left hand timing drive pulley was wobbling about a treat. This explains now why the belt was found so slack initially, and clearly having put a new belt on it and tensioned it back up to about ~150 hz, the load on the pulley bearing is much greater.

So this looks like a bit of a pig to fix, as the space in there looks a lot less than on a 575/550/456. Whats the verdict on just replacing the front bearing too? Asking for trouble? Also, I guess with the play on the bearing, the shaft itself is potentially f$cked, in which case the front engine cover needs to come off anyway. Anyone done this job on a 612 or had it done at a shop?

Certainly something worth checking for anyone doing a timing belt job on one of these V12's. I'm sure a pro would have done, but alas I'm learning the ins and outs of this engine as I go.

 

I'm getting my belts changed in a few weeks (not doing it myself-- way above my ability level) and the recommendation was not to change the tensioners unless they are obviously worn. The car only has about 15,000 miles, and I don't know why age would affect the tensioner bearings-- am I wrong?

This is a Master Ferrari Tech who is doing it, and his advice was to look at them once the belts are off and make the decision then. They weren't changed on the car's previous belt service.

 

The tensioner bearings should be changed, but since the tensioners aren’t active once the tension is set, there’s really no need to change them. The only reason might be if you were unable to achieve the correct tension during setting, but even then the WSM says you can take the tensioner apart and adjust it.

 

If the front bearing has self-destructed to the point where it has been moving around a lot, there may be damage to the gear teeth on the shaft and the bearing in the engine block that supports the rear of the shaft. You could remove the front bearing from the cover and then feel how much play there is in the shaft/rear bearing. The only way to know for sure is to take the front cover off and inspect the gears and all of the bearings. I know that it is a bunch of work, but in the end you will have piece of mind when you are revving the engine at red-line.

 

Cheers motob. I take it this is all do-able with the engine in on a 612?

Also, how tightly is the front bearing pressed in? Is it a bar steward to get it out with the engine cover still on?

 

I don't know if it is possible to do with the engine still in place, as I have never had to do one. Did you remove the front cross-member in order to change the timing belts? This is the normal procedure that the factory recommends, and would possibly give you enough room to remove the cover.

I don't know tightly the front bearing is pressed in, probably normal interference fit. You will need to make/buy a puller in order to get it out, and some light heating of the cover with a torch would probably make things easier. Search the forum for replacement of the same bearing used on the 308-328 series, and you can see some of the methods/tools that people have used in order to remove the outer bearings with the cover still in place.

 

Here is a thread where someone replaced the bearing using a Sykes-Pickavant puller to remove the bearing.https://www.ferrarichat.com/forum/threads/308-cam-drive-bearing-replacement-info.103998/

You remove portions of the bearing cage and insert half-round puller legs into the space between the inner and outer races. I have never used this tool, but if properly sized, It seems like it would be able to generate enough force to remove the bearing. The kit doesn't cost that much. You might give it a go before taking the entire cover off. http://www.sykes-pickavant.com/products/pullers-and-separators/mechanical-pullers-and-kits/874

If it looks like you can remove the entire cover in the car without removing the engine, then that would be my preferred method of repair. The gaskets and replacement bearings for the shaft are not very expensive. It will just take more time. Then you can inspect the gears to see if they have any damage or excessive wear. Knowing that everything is perfect lets me feel ok about driving the car like it should be driven, full throttle to red-line.

You were smart to run the engine with the covers off and find the source of the noise. I shudder to think what would have happened to the engine if someone had just kept on driving it until something failed.

 

Thanks again Brian, especially for looking out that page for me. From what I can see, removing this bearing is going to be enough of a faf that the time saved in not taking the engine cover off is probably outweighed by how much more awkward it will be to remove and install the bearings in-situ. With the cover plate on the bench, it's a straightforward job- though one that I might just hand over to a local machine shop to save me buying the puller kit.

Is removal of the cover plate as simple as just undoing all the bolts around its circumference, breaking the gasket seal and sliding it off? I take it the remnant oil in the dry sump needs to be drained first, but is there anything else to remove before the cover will come off- the smaller access plate on the cover for example?

Lastly, any advice on a workaround for the ring nut without buying the tool from Hill?

Thanks as always guys.

 

Don't try to fudge the ring nut socket, unless you have a CNC mill/lathe and can make one yourself, just buy the correct tool. The small cover is for access for the oil pump drive. I have never had the main timing cover off on a 612, so there may be a hidden bolt under this cover. I would remove it and inspect inside before attempting to remove the main cover. The hardest part besides getting the harmonic damper off and the two belt sprockets off, is going to be getting the bearings in the cover to slide off of the shafts for the cam drive sprockets. I don't know how tight the fit is, but there is no puller that can be used to get the cover off. It may require some heat on the inner races of the bearings in order to get the cover off. My guess is it is going to be a little bit of a challenge.

 

I thought the drive gears and all the gubbins for the oil pump drive come off with the cover? The only thing staying put being the rear bearings for the drive gears?

Thinking about it then, the small acces cover has to come off to allow the oil pump drive sprocket to be undone from the pump.

 

I don't know, as I have not had that cover off before. It looks like all of the oil pump drive system stays mounted to the engine block, and I would assume that the drive gears for the cam sprockets would stay on the motor as well. You would remove the cam sprockets. Then as you pull the timing cover off, you would lightly tap on the ends of the gear shafts with a brass hammer to drive them out of the front bearings, so the gears would stay in place.

 

Cheers Brian. I'll have a crack at it later this week when I get the ring nut socket.