F355 - Clicking noise from pumpkin

Sorry Jeff. There are lots of inconsistencies here. If I got the jist of your entire post you started with a foreign noise. You diagnosed the issue as somewhere in clutch. You replaced part of clutch and still have the noise. So you looked into the gearbox and think the noise is now normal. This make no sense. It seems to me that you need someone with more experience listening to the noise. You cannot just look at gears and deem them ok. You can sort of check the gear mesh with prusian blue. Sometimes under load the mesh is different than turning by hand. You can have very small discrepancy in gear mesh and have noise and ultimate gear destruction. If you guess wrong you will destroy your box. A noise, if lucky, can be a warning shot over your bow. These boxes can be saved if you don't let them go to far astray.

 

I know, this thread is not very clean, sorry. What I meant was the gearbox noise seems normal IFF you twist the clutch shaft back and forth in opposite directions, which would simulate a 'spikey' load from maybe a cylinder not performing like the others. The noise shouldn't be happening but it's not the gearbox's fault, it's just a downstream symptom. I realize the job of the damper is to smooth out power from the engine but maybe there are certain conditions that it can't handle very well.

Summary:
1) Strange noise thought to come from flywheel, vibration felt in vehicle in at low rpms.
2) Repacked flywheel, replaced all bearings (3), no change to noise and vibration.
3) Re-diagnose noise as radiating from clutch shaft, can repro by twisting by hand.
3) Visual inspection of gears and gear oil, no metal, nothing strange looking.
4) Diagnose noise as clicking between the main drive gears.
5) Proceed to wait on new spark plug wires and gearbox mounts.

 

If three is true why not remove the clutch shaft and inspect the lock ring? This is a common gearbox failure that simulates t/o bearing clutch noises.

 

Does the whole gearbox have to come out and apart to do this? I can't find much info on just removing the clutch shaft. And, is the lock ring pictured in the parts diagram above, like item 17 in the lower right?

 

No
Yes

 

I found a good picture of the clutch removal tool here, thanks TheItalianJob!

http://www.ferrarichat.com/forum/348-355/234915-348-ratio.html

And I found FBB's instructions from way back in 2002 about using a torch for sure with the slide hammer, thanks FBB! Here's my gismo in the picture.

So anyway, I got it loose, yet as it comes out so does the inner shaft, is it supposed to? I quit removing and pushed it back in for now.

Thanks
Image Unavailable, Please Login

 

it is ok keep tugging. It is quite tight in there. You can do it cold with more force or with some heat and less force. Going back in is a breeze. You can now rule out a loose gear here which is a common failure. I hope you are ok here otherwise it is a complete box teardown if the gears are buggered.

 

Got the clutch shaft out, the prop shaft came out with it, hope that's normal. And .. I do believe I've found the little noise maker and I bet it's not pretty .. my main shaft! Is a gearbox tear down coming on? I made another video of it.

https://www.youtube.com/watch?v=yIP7KB3DGC4&feature=youtu.be
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

Jeff,

I've been following your thread with interest. Sorry for your problem and hope it's not to painful to fix. The pictures are a little hard to follow. Can you describe what you're seeing that is of concern.

Thanks,

Brewman

 

Thanks Brewman, it's not what i'm seeing, it's what i'm hearing, and I doubt it's normal. It started out as a clicking noise that I thought was the flywheel, but have now tracked it down to the gear shown in the bottom picture above. I can wiggle it back and forth and it makes quite a noise, check out my short youtube video. The noise occurs in neutral and while on the lift in gear, but only at low rpms. Part number 168047 (bevel set) is apart of the gear i'm talking about.

 

It's funny because now every gear I can put my hands on makes a similar noise, I think i'll just put it back together and ... drive it like I stole it.

 

Too bad there is no one near you who knows what these boxes are supposed to be like. If you can't figure it out it is time for a pro. If you allow gears to slap they will blow up especially on track. You can eat a box very fast. Maybe do a search on 348 gearbox issues. The 355 box is very much the same with probably some assembly improvements and more splines for the clutch shaft that make up for dumb assembly. You will learn about clutch shaft ring nut issues and side case bearings. There is a lot that can cause loss of cohesion of the box. 355's are relatively immune from box issues unless maybe your box has had more stress applied. 348's have known issues we know how to fix preventatively.

 

I really appreciate all your help FBB, and others who've viewed and replied (even non-replies tells me I have peoples heads scratching!) I will be sure to post my end results, may be a while. Thanks!!

 

Worst case scenario, what will it cost for a complete gearbox teardown and rebuild vs. a new gearbox?

 

Well the plot thickens for me. My #6 cylinder only gives me 20 psi on a compression test. #3 is at 70, all the others are 150+. I guess this answers my rough idle issue and probably causes so much 'bounce' that it causes the tranny to make some noise.

Regarding the low compressions, what would be a good next move for me? help.

 

Repeat the test, do a cylinder leakdown test.

If the results are similar,

Engine out, heads off.

Bring money.

 

Jeff,

From the start of all this your diagnosis seems like it has been way off. To go from swearing the noise was over the pumpkin to 2 wiped out cylinders is huge. You go from a couple thousand dollar potential mis-diagnosis potential to a $25K diagnosis issue. I say go a head and learn and take Tim's advice and then have a pro look at your car and see what he comes up with. You know you have learned something if his diagnosis jives with yours. If not you need some lessons at the local trade school or hire a Ferrari mechanic to work side by side with you. I did that during my beginning. That's just the cost of learning and not breaking things. If you need heads off so be it. The worst thing that can happen is heads off and still have the original problem. If you do decide to do this yourself do it with coaching from a buddy who has been down this road before. If your diagnosis is right there are many places to accidentally make a big job bigger. Good luck! I feel for you.

 

It seems so because of all my panic posts. Let me give a good recap just to tidy up the thread.

Went to track event, last session of day I swapped ends and ended up in the grass with no apparent damage. Made a couple more laps and called it a weekend and came home. Took it out the next day for a test drive and began to notice a low rpm vibration, especially in high gear low rpm acceleration. Pulled into my garage, noticed the rougher than usual idle and also heard the clicking noise. My thought: Do I have two problems or one? The consensus on this board was the clicking noise was the cause of the low rpm vibration, fix that first. I misdiagnosed it to be the flywheel damper (repacked, replaced bearings no change), then decided it was gear noise. Pulled cover and no apparent metal or damage noticed, and can only repro the noise when I move the gears back and forth. Now that movement is not normal, they should be under a consistent load and therefore not make the noise. So my thoughts were then, "what could be causing a non-consistent load to make these gears sound like that?". Replaced tranny mounts, new kingsbourne wires, no change. Decided to do my first compression test ever and, well, it was very obvious that #6 especially is doa. So my new theory is I've been chasing symptoms, root cause=engine. Do I get any credit?

 

It's worth reiterating that you should repeat the test including a leakdown to try an isolate the cause of the compression loss before taking anything apart. There are a few likely scenarios (discussed ad-nauseum here) but a detailed diagnosis (by someone who knows what to look for) might save more than a few dollars.

 

Are these good? (just kidding)

cyl------compression------leakdown
1----------150---------------60/100
2----------070---------------11/100
3----------170---------------78/100
4----------175---------------89/100
5----------160---------------69/100
6----------020---------------08/100 (92% leakage)
7----------150---------------11/100
8----------145---------------26/100

Compression was done on medium hot engine, at least twice per cylinder, more on #2. Leakdown was done on cold engine. Car runs great except for the low rpm shudder/ rough idle (I'll stop talking about the gear noise).

 

Those are very typical numbers to find on a 355. Cylinders 2 and either 5 or 6 are the most common to see fail a compression and leak down. I would love to know a reason why those cylinders are always the first to go. There is something inherently wrong with the 355 engine that they seem to kill those cylinders first.

If anybody has any ideas as to why, I would love to hear them.

To add, cylinder #2 is almost always the first tube on the exhaust manifolds to burn through.

 

Air flow and or ECU tuning could do it. Ferrari never admits mistakes by the way nor spends money to fix problems. The 458 is here and black plastic parts are still getting sticky! Jeff if your numbers are correct that engine is toast. I would take that engine down to the block not just heads off or at a minimum leak down the block. How many miles? What an amazing powerplant to make an owner with numbers that bad say that the engine runs great. Many of us just have untuned seat of the pants. Can you imagine all the 355's that have had early failure of just 1 tube saying the car runs great. Wait until your engine is perfect. On the first drive with throttle mashed the first 2 words out of your mouth are going to be, "Oh *****.' It will be painful getting there but when you do...355 Nirvana!

 

FBB, for my education and probably other forum lurkers how can air flow and ECU tuning cause low compression/high leak down values ?

Thanks,

Brewman

 

Got the engine out, throttle bodies off, exhaust manifolds off, getting ready to pop the heads. I played more with my leak down tester and of course with the exhaust manifolds and throttle bodies off you can really tell where the leak comes from. Heck i can stick my finger on the valves and really know. Question: What would make most of my exhaust valves leak? My intake valves are silent. My bypass valve has been wired open since before I bought it 12k miles ago. Would this contribute?
Image Unavailable, Please Login

 

Bad valve guides, running too lean, exhaust leaks, among others.