| Author | Message | ||
| Malcolm West (Ferrari_uk_tech)
Junior Member Username: Ferrari_uk_tech Post Number: 92 Registered: 7-2003 |
Byron, I have looked through the old Ferrari Technical information data and can only find the update to the chain pads (dated 10/07/91) which I mentioned previously, unless I'm mistaken the chain - part number 132968 remains the same. I will investigate further and let you know if I find anything else. MW | ||
| Byron (Bmyth)
Intermediate Member Username: Bmyth Post Number: 1219 Registered: 10-2002 |
Malcolm - Thanks for the diagram and the part #'s. I had no idea that it was more of a "conditional" update, where only a slightly larger roller bearing was fitted and not just the latest. My car is an early model 1989 car, Serial 82347. I don't have my engine/assembly number in front of me at moment, but will provide that when I can. This is all VERY good information, guys. However, it is unfortunate that I won't be able to do some careful inspection until 9 days from now when I get back home. Martin, until I can rule out all the other belts, I won't be pulling the engine. However, if the offer still stands and you can get some parts for me, I may need to you up on that in the near future. So just to go back to JRV's question about the oil pump chain... was there an update done to this? (I'm not sure I understood the answer) Should this be done at the same time a cam bearing is replaced? Thanks. | ||
| Malcolm West (Ferrari_uk_tech)
Junior Member Username: Ferrari_uk_tech Post Number: 90 Registered: 7-2003 |
JRV, Thanks for jogging my memory I wrongly assumed that when the "older parts" were ordered that they would altermatically be updated, as they would have been in the UK. On the cars with engine number lower than 24720 (assembley No 4384) the chain pads #138800 and 136059 were replaced with the newer Sthanil material pads #147337 and 147338 and the bearing #136153 to 149241 (which crosses over to #185343. MW  | ||
| Martin - Cavallino Motors (Miami348ts)
Senior Member Username: Miami348ts Post Number: 5904 Registered: 5-2001 |
Byron, my little knowledge is that if the bearings on the belts go bad you do not have a typical visible loosening of the belts or even uneven running of the belt. While you grind down the bearing more and more this will eventually become a problem and then it is too late in most cases. I have heard and seen a bad bearing outside of a car and the wheel still runs but you can clearly hear it is bad it will also spin bad but not wobbly. I would say you have to bite the bullet and pull the engine. Get the waterpump done at the same time. If I can help you with parts in any way let me know. Have you guys checked the waterpump? If the pump goes bad doesn"t that make a noise first too? | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 2375 Registered: 11-2002 |
James, Malcom, what about an Oil Pump Chain Mod/Update on the early cars? | ||
| Malcolm West (Ferrari_uk_tech)
Junior Member Username: Ferrari_uk_tech Post Number: 87 Registered: 7-2003 |
Byron, Assuming that you have eliminated the other components, it would sound like the cam drive bearing has failed - you should be able to detect some play in it to prove the point. The early cars (untill assembley number 4383 or crankcase number 139571) had a "needle" bearing fitted, the bearing was the wrong type and with the tension of the cam-belt it was always going to fail. The later cars had a different cover and also the block was machined differently to accomodate the larger "roller" bearing. There is no way an early car can be updated to the later spec, however when replacing the bearing on an early car you will be supplied with a "roller" bearing slightly larger than the "needle" bearing you are replacing. MW | ||
| J R K (Kenyon)
Member Username: Kenyon Post Number: 657 Registered: 10-2002 |
Sorry Bryon cannot help. I wish I could. I think the later 348's had a modification done. Not sure though.Maybe speak to Ferrari ?? | ||
| Kevin Paul (Klfpaul)
New member Username: Klfpaul Post Number: 23 Registered: 4-2003 |
Oh yes also, The alternator "bolt" that was loose, that Byron refers to, was loose and just went into "space". It did not press on anything when tightened, as evidenced by looking in the slot where the bolt goes on the alternator. should there be something there that it presses on? We tightened the bolt with no change, but this was expected, as described above. -Kevin | ||
| Kevin Paul (Klfpaul)
New member Username: Klfpaul Post Number: 22 Registered: 4-2003 |
Byron, et al Since I am not familiar with what commonly fails on early 348's, I will post what I heard when we tried to diagnose Byron's car last Saturday. We used a stethascope to locate sounds. I hope that the real experts can possibly make some sense of it. What I heard and saw: 1) noise is definately loudest on Alternator side of engine. 2) noise is very loud on engine sump pan nearest the front of engine (getting louder as you approach the front). 3) stethascope (steth) on AC compressor = AC compressor whiring away smooth as glass (belt spins smooth as well), even with AC clutch engaged. 4) noise seems to be AT engine speed, not at camshaft speed. 5) I could see the two idler/tensioner "pulleys" inside the cam cover while looking up from bottom of engine, they appeared to be spinning quite smoothly with no vibration or slop in them or the belt, although one of the "pulleys" appeared to have deep, dark grooves in the surface, unlike the smooth polished appearence of the other one. 6) the noise was quite loud near the water pump on top of engine (noise was loudest near the center of the engine, lessening as you move outward, from the top or bottom of the engine. 7) noise was not coming from the alternator, which was spinning smoothly. 8) noise was apparent, but not overly loud when listening with steth on aluminium cam covers. 9) oil pressure with engine warmed up was 70 on dash gauge. 10) I could not get the noise to lessen in intensity or frequency by loading/unloading the engine (e.g. on American V8's you can get a rod knock to vary in intensity and frequency by quickly varying engine speed and load). 11) If I recall correctly Byron stated to me the noise did not change in sound from when it started at the track to when he got back home, even after a many hours drive, in my experience rod knocks get louder, up to a point. 12) the noise was, in my opinion, a deep (but not American V8 rod knock deep), powerful, unchanging, mechanical "clacking". 13) engine ran smooth the entire time we were "diagnosing". I hope this helps, and if anything else comes to mind, I will surely post it! -Kevin | ||
| Byron (Bmyth)
Intermediate Member Username: Bmyth Post Number: 1216 Registered: 10-2002 |
Jim, The update bulletin specifics would be great - thanks! Verell, I have my fingers crossed that the problem is only at the AC/Alt bearings. Those can be replaced w/o an engine-out, right? I just finished having my gearbox rebuilt... I'm not sure I have the energy (and funds!!  ) to do a full engine out. Plus, I think I'm running out of favors from my friends!!! Ahhh, the joys of ownership. | ||
| Verell Boaen (Verell)
Intermediate Member Username: Verell Post Number: 1101 Registered: 5-2001 |
re:"Does it sound like a constant rattle, like someone poured a bunch of small rocks into your engine?" Yup, typical bearing failure sound. The 'rocks' are the bearings rattling around in the race. | ||
| James J. McGee (Dr_ferrari)
Junior Member Username: Dr_ferrari Post Number: 170 Registered: 7-2002 |
Byron, The cam pulley bearing failure is common if that is your noise (pretty normal part of major service on early 348/mondial t). There is a update to a newer type bearing. I will post tomorrow bulletin specifics when I get in the shop and check my book. Best regards, Jim | ||
| Byron (Bmyth)
Intermediate Member Username: Bmyth Post Number: 1214 Registered: 10-2002 |
No, unfortunately, I didn't get a chance to pull the belts off the alt/ac. Quite frankly, though, I don't even know how this is done! I was only able to crawl underneath with the car on jackstands. I think I need to get it on a lift to see better. Thanks, guys... now I have a bit more direction to do some investigation. (and a pinch of optimism, too!) Any "non-engine-out" repair is a more manageable repair in my book! (for a novice non-mechanic as myself) | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 2367 Registered: 11-2002 |
Byron, pull the two belts (AC & Alt) and start the engine, see if the noise os still there. Sorry I thought you had confirmed all this. | ||
| Byron (Bmyth)
Intermediate Member Username: Bmyth Post Number: 1213 Registered: 10-2002 |
Verell, What does the AC compressor or alternator bearing failure sound like? Does it sound like a constant rattle, like someone poured a bunch of small rocks into your engine? I haven't had a chance to check the cam belts yet, but did notice that my adjustment bolt under the car for the alternator bearing was completely loose... if this is the case, could this mean that my car possibly has an alternator bearing failure versus a cam drive bearing failure? | ||
| Verell Boaen (Verell)
Intermediate Member Username: Verell Post Number: 1100 Registered: 5-2001 |
A cam drive bearing failure is pretty visable on a 308/328. The cam drive pulley noticably vibrates, & quickly gets to the point where it's making the belt jump around 1/8" or more! If you've ever had the front bearing of an alternator or A/C compressor let loose, you'll immediately recognise the sound! When I saw how much my 308's fwd bank belt was jumping around, I nearly killed myself getting to the ignition switch to shut it down. Was terrified that my belt had jumped teeth, or was about to any sec.! | ||
| Byron (Bmyth)
Intermediate Member Username: Bmyth Post Number: 1212 Registered: 10-2002 |
JRV, thanks for your feedback. I'll do my best to rule out all possibilities before going that route. "yanking" the engine is not as easy when you don't have the right facilities! | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 2364 Registered: 11-2002 |
As far as the complete 'chain/bearing' update you'd need to get Malcoms input or call Lee at Algar in parts.. As you are aware by now there is no room in front of the engine to allow any real looking/searching for problems unless they are on the bottom. So if in fact the noise is anything other than the Alt Belt Tensioner Bearing, AC Comp or Alternator there is really nothing that can be seen or done to the engine in car. From the sounds of it, once the engine is out and you have access, you'll likely find the noise without to much trouble. I think if it wasn't something on the bottom, I'd just yank the engine rather than waste time looking around...after being as sure as you can of course . | ||
| Byron (Bmyth)
Intermediate Member Username: Bmyth Post Number: 1211 Registered: 10-2002 |
JRV, Well, if it's the cam drive bearing and the oil pump chain, that might explain the drop in oil pressure since the problem surfaced. We used a stethoscope and listened - the sound is definitely mechanical and not exhaust related. There is rattling in the belt housing covers, and at/near the water pump. Looking underneath, the ac belts look taut and seem to run pretty smoothly - no tensioner issues yet. However, have not looked at the belts from the top - need to check the belt tension to see if the cam bearing has gone bad. anything else I should look at before dropping the engine? | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 2362 Registered: 11-2002 |
I can add that I've seen Cam Drive Gear Bearings fail on 330 GTC's, Boxers and 308's and the noise never sounded like an exhuast leak... If in fact it is the cam drive gear bearing the engine has to come out to effect the repair. | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 2361 Registered: 11-2002 |
Yes I've heard of it and an update...never seen the problem personaly....if memory serves me the oil pump chain update goes along with it. However I followed along with both threads and see no conclusions .. Is the noise in fact the cam drive bearing? | ||
| Byron (Bmyth)
Intermediate Member Username: Bmyth Post Number: 1210 Registered: 10-2002 |
JRV, Mark, Paul, Justin... anyone? | ||
| Byron (Bmyth)
Intermediate Member Username: Bmyth Post Number: 1208 Registered: 10-2002 |
Has anyone here ever experienced a cam drive bearing failure on a 1989 348? If so, what are the symptoms and how was this resolved? As a follow up to the "Engine Noise in a 348" thread (http://www.ferrarichat.com/discus/messages/112/306912.html?1061911830), I suspect that this is the case with my car. I know this was an update for the car, but not sure if this has been done by the previous owner. Also, to my knowledge, this was only apparent on the 1989 year car. Any feedback on this matter is appreciated. Thanks! |