Timing belt install

Did you read birdman's guide? If not, then google birdman ferrari 308. Read it.

I've done both a 308 and 456 once.

First, lever the bearing and lock it in loose position.

Then you want to go over the drive gear first, then the cams, then over the tension bearing. This order is based on the lips and clearances. You can't over them one at at time so you need to go over them a little at a time. Get the marks on the long run between the cam and the drive gear lined up first. It's a big fiddly wiggle.

Once in place, release the bearing and tighten via your method choice. I like the rotate method, not the pluck for the 308. 456 is a pluck, but the frequencies are published by Ferrari and you can use and iphone.

Make sure you hands are clean or you will get grease on the belt and you will never go above 4k RPM again.

 

I just recently did a timing belt change on my 3.2 Mondial and had the same thing happen. the cam gears spin due to the valve springs tension. I had marked lines with a ruler on the face of the cams to assure their position was correct. I ended up having to make a wood jig clamp to lock the cams in place so I could pull the belt over the teeth and get the belt back on.
There's a really good YouTube video on Mondial timing belt change from a Ferrarichat member named bell bloke but he doesn't have a problem with his cams spinning. I just about lost my mind when my cams moved. the left side went on perfect then the right side moved. Took me 2 weeks to come up with a solution.

 

I haven’t done my 308 but have done a couple on my Alfa V6’s (same principle) What I do is back off either the crank or the cam enough to engage the belt then turn it back to the mark, it will tighten the belt run between the two in the process. As long as you can get both marks aligned you’re good. Same goes for the second cam so all the slack is on the tensioner side.

 

I assume you cam gears did not move. Did you lock them? Are they aligned with marks? If not you need to solve that problem first. If yes, then you are trying to put the belt on one cam gear at a time. That won't work. You have to put them over the cam gears at the SAME time. You also need to lever the tensioner back and bolt it down. Did you do that? It's fidley wiggle like I said.

 

IIRC (84 QV) We had belt over crank pulley, tensioner adjusted all the way inward and tensioner mounting loosened up, then had to rotate one of the cam gears ever so slightly allowing the belt to be positioned then moved back and the marks lined up. Adjusted tensioner and rotated the crank pulley to full revolutions by hand and marks were again properly aligned.
Would doubt leaving your Cam Belt laying in the yard will provide any benefit other than a chew toy for the dog. Haha.

 

Wish I was there to show you how, but you'll get it. Funny thing is, once you get the first one, the second one will go on in less than a min and you will be wondering what all the trouble was. Just keep after it.

 

Yes, the belt is not going to "stretch" no matter how long you leave it in the sun. The problem is the long run between the crank gear and the cam gear on the non-tensioner side (exhaust on the 1-4 bank and intake on the 5-8 bank) It's difficult to pull all of the slack out by hand but very easy if you just back either the cam or the crank pulley off enough to get the belt engaged then when you turn it back to the mark you have the mechanical advantage of the gear to pull the slack out. You should be able to return completely back to the mark with the belt engaged. Just make sure all your marks are aligned when you're done.

 

One person's opinion: its dangerous to move the crank because the torque required to move the crank will cover up any sense of an obstruction should you turn it enough for a piston to kiss an open valve. This is how valves get bent or cracks in them and subsequently break. Better to move the cam ever so slightly to position the pulley properly for the belt to go on rather than move the crank. Like I said, "one person's opinion". Good luck.

 

Yep. Don't rotate the crank during a cam belt/chain change. Rotate the cams if necessary to realign if they move under valve spring tension. As long as they are properly marked before removing the belt, there is no issue/problem at all. I have never locked a cam on any vehicle to change belts/chains and have never seen a shop do it. I'm NOT saying it's a bad thing but IMO it's extra work that is not necessary.

 

One other thought. Make sure your cam lock is not interfering. When I did my 308 I didn't cam lock. Just did the paint line thing. One cam rotated but it's easy to rotate it back to the marks. The 456 can be locked with vice grips which stay out of the way.

 

(With the tensioner fully compressed) Loosen the three nuts holding the tensioner bearing mount to the engine (this allows the tensioner pulley to move a little outward away from the belt and decreases the path length which makes the belt appear longer).

 

It's common to lock the modern V12 with vice grips. The WSM calls it out. SOP from what I can tell.

 

If you are 1/2 to 1/4 tooth off which way? That's why there are factory assembly marks. Locking cam shafts and unbolting the cogs from the shafts help deal with all the slack issues and trying to wiggle on a new belt and allow the tensioner to fully and properly tension the belt. If the cogs aren't loosened then the tensioner only tensions between the crank and the 1st cog. So people try and compensate for that by turning the motor over with a loose tensioneer to take up the slack. There are 2 reasons to pull the cog pin. Most don't want to believe it. That's fine because the car will run OK. But there are some who take it to the next level which is cam timing. That's a whole new holy war of a discussion.

 

HAVE YOU COMPARED THE NEW BELT WITH THE OLD? DOES IT HAVE THE SAME NUMBER OF TEETH?

 

Im by no means an experienced wrench, and hesitate to even open my mouth, but this is the bullet points on my 1986 328 when I did belts last summer...

1. Had really good marks matching belt to cam and drive cogs..
2. Matched and strung cams first. I too got just short of falling into place on the lower drive cog. Side opposite the tensioner...
3. I understand and appreciate the reasoning for not touching the crank, but I kept the cams locked on both sides of engine, and ever so slightly nudged the crank and belt slipped right in, with marks aligned... Kept binder clips on all the cogs, then installed the tensioner. I figured keeping the belt on one side, with the locks would help keep me from moving the crank too far too easily... If I recall, the movement was so little to get it to fit, it was almost like I only had to take the slack out of the gearing in the system to make it fit. I don't think I moved much of anything in reality... It was so little effort...
4. Once tensioner was in place, rotated 4-5 times and locked when tensioner was pushing inward most. NOTE: I had a piece of tape on the block and a post-it note strip (cut a narrow strip) on the tensioner arm and drew a line across post-it and tape where they overlapped. I bent the post-it like an accordion (Zig-Zag) so the post-it could be flush with tape on the block. This allowed me to see when the line I drew on the post-it moved in relation to line on the fixed tape on the block... Im sure this is confusing and improper, but it worked for me. Tensioner moves so little, naked eye could never track it IMHO.
5. Checking the marks: As the marks on belt VS cogs will move a few teeth along the "circuit" with each revolution, I turned the engine 15-20 revolutions to get the marks back again just as a sanity check and they were all spot on.

Other Comments:
1. I did one belt at a time and kept the opposite side cams locked as well, even when nudging the crank.
2. Because I was nervous, I did leak down after all my revolutions by hand (both belts) just to make sure I got same readings before i started and did not tap / damage any valves in any way...
3. Also bought a tension gauge and compared tension of new belt to the old, also for sanity. Bank 1-4 was slightly tighter on the new belt. The other bank, new belt was about the same as old. Next time I might consider new tensioner springs?

 

Sorry but this is probably the worst piece of advice I have ever read on any car forum.

The reason the new belt wont easily go on is because the old one, when everything was locked, was under tension and the new one is not yet.
As long as the pulleys are marked properly, simply rotate the crank or pulley(s) very slightly to get the untensioned belt on, then when tensioned it will all come back into line as per the old belt.

 

When I did my belts, I counted the notches between the alignment marks I made on the old and new belt to make sure they were the same. Then just install the new belt making sure the marks are aligned. Some wiggling of one cam was needed to seat the belt. Then I used paper clips to hold the belt on each cam while installing the cam tensioner. Worked really well. Once both belts were on, I turned over the engine by hand to set the tension and make sure no valves banged into the pistons. Torque the tensioner and put everything back together. Not a bad job, just take your time and enjoy.

 

Then you also don't believe in cam timing and really don't understand the process. For you we have assembly marks. Your car will run OK.

 

Yes, when we say "turn the crank" we're talking about a little bump like a quarter of a tooth, you're not going to bend any valves and there's no need to unlock your cams.

 

Assembly per Ferrari is the 1st basic. Cam timing is the 2nd. Yes you can get your car to run with nail polish marks and moving the cams or the crank to unknown positions. Just remember every error magnifys itself along the way. So if you are wiggling 1/2 a tooth on the left bank then 1/2 a tooth on the right bank do you really know where you are or what you got? Part of the reason these cars have poor reliability reputations is lack of attention to details. Ferrari gives us these beautiful vernier cam cogs for a reason.