The car is a 1999 360 Modena, 18,000 miles. I have owned it over 2 years, and it always ran strong, pulling like a race horse in all 6 gears. I have an invoice from a well-regarded Ferrari dealership that states that the variators and the left hydraulic tensioner, along with a major service, were done in 2005 at 8,000 miles, under warranty. I also know that the car was in storage for most or the time since then, so I knew the timing belts were on borrowed time, to say the least. So, I am in the process of doing a major service. What I found has me stumped. At TDC for number 1 cylinder (front-most on the left bank), the timing marks on all 4 cams are off by, I would guess, 30 degrees. If this is true, how did it run so well? Could someone look at the attached photos and comment? There is a photo of the timing marks with #1 at TDC, or within a very few degrees. The other photo is of the left cylinder head, looking toward the front. The intake cam is above, or to the right of, the spark plug hole. Image Unavailable, Please Login Image Unavailable, Please Login
Well - Like a girl once told me: You’re in the wrong hole... Nr1 cyl is in the right bank closest to the passenger (if you drive on the right side of the road ). After I did the timing on mine I did a comp test (wet cylinders). Picture is showing the results and cylinder numbers. Oh - How it went with the girl? I told her: I’m sure it’s correct and kept on planting potatoes. Image Unavailable, Please Login
"Well - Like a girl once told me: You’re in the wrong hole..." Better in wrong hole than in no hole at all!
Well, I replaced the right bank hydraulic tensioner. I replaced the belts and set the tension by the frequency method. With the right bank tension set within specs, the gap at the top of the tensioner is below spec (about 1.2 mm). The left tensioner gap is zero. So, some more questions: 1. What can be done if I cannot get both the gap and the frequency in spec at the same time? Which one governs? 2. Since the left tensioner gap is zero, should I replace the tensioner on that side too? 3. OK, this isn't a question. I owned a Mondial; for 11 years. On that car, you changed the belts, rotated the crank two times, and locked down the spring-loaded tensioner. All done. Also, it had clear TDC marks on the flywheel. Just saying.
To me it's a bit 'tai-chi'... if the tensioner and belt are all good, both the gap and the frequency will be within spec - It's not one or the other, but largely controlled by the tensioner pulley . I found it took 2 turns for things to settle after each adjustment and in the end even the pin would slide in and out. If the other tensioner is at zero - then it's buggered or you did something wrong. I'll admit in public to my secret mistake - this will make the experts laugh. The 1st time i did it, i rotated the belt tensioner pulley in the wrong direction (didn't look at the photo of how it was before i took the belt off). All seemed fine, but the gap would not come right even though the freq was spot on. Took hours for me to figure it out. I feel much better now for sharing that dark secret.
1. I would say gap overrides frequency for the simple matter that if the belts are too tight and they cause the tensioner pulley arm to bottom out on the body of the tensioner assy. you run the risk of jumping time. HOWEVER....notice the caps....both will come into align, as I had both L&R gapped and tensioned correctly when I sent it out...I was just off a few teeth (as long as we are telling on ourselves!). This only happened after I replaced both tensioners with OEM NIB parts and a lot of contorted positions and words. Be sure to use the proper tool or a suitable one to both hold the tensioner bolt and torque it at the same time. 2. Set the tension on the left side the same way you did on the right, If the tensioner bottoms out after sitting for several hours, I'd say change the tensioner assy. 3. DOHC Ferrari's are a special beast and are the most finnicky engines I've dealt with and I've played with some real winners before!
If you've never heard the term tolerance stacking....this is what you are dealing with. Both the tensioner gap and the frequency have a range. Get either one too high, too low within that range and it could and will throw off the overall...It takes time and a whole lot of patience....beer helps but only if your not prone to throwing tools....
Flying Haggis Racing: Thanks for admitting to a mistake. Makes us mere mortals feel better. Both idler pulleys are rotated CW to increase tension, correct? Ghostdiver: Thanks for all of your help. I am familiar with tolerance stacking. I'm an old guy with plenty of time, so I'll keep playing until I get it right.Or what I think is right.
if you rotate the bearing it in the wrong direction, can it still "hold" and run correctly? , assuming the frequency is right.
When i did this, it seemed to hold just fine, but the tensioner gap wouldn't fall in spec. It was close but i could not get the pin hole to align as everyone talks about. As to what would happen if the engine ran that way - who can tell, but it wouldn't surprise me if it would run perfectly fine.
i might got mine rong. ah!!! i might have to do it again! my gap is around 4mm, and the frequency is right! new tensioner, new tensioner bearing, new everything
Dennis, what are you using to do this....the WSM alone or do you have the edited version Black360 wrote up some time ago?
I am using every single word I can find on the subject! WSM, Aldous Voice, this site, other Ferrari sites.
Not sure if you have these but I put them up last night for someone else.... https://www.dropbox.com/sh/bo3zuh565bfz1fp/AABbg_CYOTNTocbHyOtfdAXNa?dl=0
Well, now I have another question (after taking time off to go to Watkins Glen for the SVRA weekend). For bolt torque setting, my WSM says "Tightening of belt tensioner bracket", and "Tightening of belt tensioner to bracket" both "M10 x 1.25, torque 49 Nm. That's what I did, using new bolts. Then, I thought about it. Those bolts aren't M10, they're M8. The torque should be half that. So, are the bolts going to snap in service? Also, I can't find any data on the idler pulley bolts. Anyone know the torque for those?
Thank you. My WSM , Section A 3.04, says Generator-Water Pump: 100 Hz; AC Compressor: 145 Hz; Steering Pump: 100 Hz. It's a wonder these cars ever get fixed right. Not only that, my trusty Craftsman torque wrench died Saturday, and the local store won't have a replacement until Monday. If it ain't one thing,........