Worrying engine noise Mondial T

There are a number of internal engine problems (leaking head gasket and bearing failures come immediately to mind) that can be readily diagnosed via oil analysis, even if you do not have a prior baseline. IMO an oil analysis would be a worthwhile investment unless you can definitively pinpoint the problem without one. It's a very small investment compared to tearing into the engine or having a major internal failure. Take a look at the archives on the Blackstone labs web site for some excellent examples of how oil analysis can help identify specific internal engine problems.

Good luck in your search. I hope it turns out to be something inexpensive.

 

Lots of possibilities, youll have to dig in and investigate if you cant isolate it with a stethoscope. If you possibly need a major done anyway, its a good time for a tear down. Sounds like a clutch/geabox problem to me but i know it doesnt help.

 

Hello

Ok so I tried a few gears with the clutch depressed and the noise is not changing at all so this would eliminate clutch/gearbox.

I have started to disconnect some injectors but haven't done the 8 now.. trying to not make it run too long! Will continue this asap. For now haven't found an injector that removes the noise.

166&456, I can definitely tell you that I won't make stupid tests with it! Will definitely put no revs and no engine load to it since load+low rpm is as bad as revs for big ends.

I now really hate to start it but at the end I still have to! The question to either walk around the issue or just take the engine out is legit. The thing is I would like to know what is OK and not OK before taking the engine out because I don't want to miss a problem or to mess with things that are OK! I would definitely want to do a leak down test for instance before..

I will have a talk with some people regarding oil analysis to decide whether it can be useful for this is no. Have seen a lot of examples for instance regarding the BMW M3 where the copper or lead concentration measured were not matching at all the bearings health (eg: same ppm and a either OK or worn bearings for different people).

 

One thing I'm reasonably certain of is that this is not a lower end issue.
Have you run it yet without the belts? If that noise persists with the belts off I'd be looking at the valvetrain

 

I had a bearing failure in my 328 many years ago.
There were flakes of copper coloured material laying on the bottom in the oil retainer. So this would be my first investigation.
Second: disconnect the waterpump belt for a while. The impeller might have become loose rattling against the waterpump housing.

 

Unfortunately, on the Mondial t, like the 348 (same motor), the engine needs to come out to inspect the water pump. And the single timing belt (for all four cams) runs the water pump as well.
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Sounds like sheet metal rattling. The engine itself seems to be smooth when you rev it. It wouldn't do that if there was an internal engine problem. My guess is something outside the engine.

 

Any progress on your rattle. Please be careful if the problem is in the valve train and it fails the car would probably not be worth fixing. As I indicated in my previous post I just completed my T motor and the camshaft drive in these early cars had many problems. The chain tensioners, and the bearing in the block for the cam belt drive. There is a service update I think 10-32 for this problem. I pulled the front cover and found the tensioners for the chains with groves 1/8 inch deep and the bearing in the block galled and near failure. My car has just over 30k miles. Please check your records to see if these problems have been addressed. These are known issues with the early 3.4 motors

 

Hello

Thanks for the replies. I am afraid I haven't done anything on the Mondial since my last post! I have been quite busy lately and I will soon be out for holidays.. I will update you afterwards.

trainsplanesandautos, when you say "problem in the valve train", you mean the issue with the bearing and chain tensioner? I have indeed read the amazing thread of Ernie "348 engine out major" and I have seen these famous bearing and tensioner.

I don't have many records for this car so I have no idea if it has been solved.

 

I just want you to be careful, yes the updates my car required are well documented. I just restarted my motor after a nine month belt service with many surprises along the way. Upon re-start it was clear my motor was noisy with a rattle like you described. Now all you hear is the wine of the timing belt. I can send photos to the chain tensioners but the Bering in the block came out in pieces. Just because there is a horse'y on the valve covers it does not make them perfect, in fact far less. Please do some investigation, just draining the oil and looking for plastic from the tensioners or maybe oil analysis to look for bearing wear.

 

There is a Service Bulletin for the 3.4 Engines to correct engine timing system noise.
It is a known problem. If you have the aluminum timing belt covers, replace those with the plastic ones too.

 

I hope I'm wrong but maybe it's a busted clutch shaft???

http://www.ferrarichat.com/forum/348-355-sponsored-bradan/280320-steves-gearbox-saga-volume-3-dissasembly.html
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I think from the noise alone - its not an internal engine issue. If it was a bearing you'd also feel the vibration at idle, and as it revs up.

I think you have a cracked header shield. they get worn from heat and cold, crack around the exhaust pipe outlet. the 348 engine has two separate shields on either side. You may also have a rusted out support for the exhaust hangers... that can also rattle like that. the steam is normal on start up.

I hope that helps, I'm not a mechanic, but have had several failures on my Ferrari's and none of them had rattles etc.. usually the noises are belts, and heat shields..... the cars experience a lot of heat sink, and then now in the cold, everything contracts, so you hear rattles much more.

best of luck et Bonne Chance!

 

That's what I was thinking as well. Could it be as simple as loose / broken heat shield slapping against something.

The cadence does not appear to follow engine RPM as closely as something mechanical --- gears, clutch, valve train, engine bearings, con rods, etc. --- would ordinarily.

 

Hello

Still no news since I am currently enjoying fresh snow in the Alps..!

4redude: You are talking about the update of the chain tensioner? Thought it was for reliability? I indeed have aluminium belt covers but why should I go for the plastic ones? (apart from saving a few kgs!)

Ernie; if it was an issue with a shaft it should not do it only at idle?


Spirot; I have only seen heat shields between the backbox and the rear bumper; is it what are you are talking about? I don't think that is the cause. I have the feeling that it comes from the front of the engine and not so far away at the rear..

Finnerty sadly I am not so sure as you but I hope are are right! I have thee feeling from my last tests that the noise was not present just after starting when (very) cold; so either oil viscositt; or lowering idle speed when warming or just something else!

 

If you look at the picture of the 348 engine several posts above, you will see the exhaust pipes have a covering... that is what I'm talking about. that is just a thin metal shield that can over time get brittle and crack... which starts to rattle.

 

Good point, but have a read of post #58 this thread http://www.ferrarichat.com/forum/348-355-sponsored-bradan/277199-well-fun-while-lasted.html. Steve's gearbox was whining with no drivability issues. It was only after we took the gearbox out, and apart that we discovered the destroyed clutch shaft. You may want to change the gearbox oil and check for bits of metal in the oil.

Again I hope I am totally wrong and it is something like an exhaust heat shield.

 

Hello

Well spirot I didn't know that. I had the idea to try holding the exhaust at several places with thermal gloves to see if the noise stops anyway! However I have inspected the manifolds and haven't found anything broken.

Ernie; I have read the referenced post and its symptoms are quite different to mine (and especially the clutch disengaged test). To be honest; due to the poor reliability of the 3.4 gearbox I have planed to have it checked/rebuild as soon as the engine is fine.. I also have a small noise coming from the gear stick and disappearing with clutch depressed which is why I am not confident in the gearbox . Don't know if it is the normal noise as described in the post but I want to check the ring nuts anyway! As I said before; without this risen awareness regarding this rattle; I wanted also to do a gearbox oil change and have a look in the inspection plate. However; my priority is in this rattle for now (or in the engine more generally).

 

Hello

Small update since I resumed working a little on the car today. I initially wanted to finish the injector disconnecting test but I found a stuck throttle preventing to move the car. The axle at the rear of the plenum was completely jammed while it was fine one month ago..! Maybe the strong cold or I don't know. Anyway, this prevented to move the car and I gave up doing this test since I found the car was rattling a lot (maybe placebo effect or not!). Just checked that handling the headers does not remove the noise and only found a small broken piece of a boss on one header not the source of the noise.

I then decided to remove the auxiliary belts. I found a broken alternator tensioner bracket. As soon as I loosened the retaining bolt, the tensioner fall..! According to a picture I made before I think it was already broken and I suspect already welded... I hope this can be welded since the price of this part is quite high..

http://rupp3r.free.fr/mondial/alternatorbracket.jpg

I however doubt it is the source of the noise but who knows. I however found a lot of play in the tensioner bearing by itself, don't know if it is normal?

I haven't started it again since I want to limit the engine running. Next time I start it, I will check if the noise has gone and I will do a leak down test... I am more and more thinking that I will have to take the engine out so I want to do this leak down test before.

 

OH!!!!

Yeah that is not good. Plus it looks as though you have a pretty bad oil leak. I would remove that bracket and either get a new one, or have it welded. Replace that bearing while you are at it, because from the how it looks in the picture it's done.

 

Hello

Ok so finally today was the day where the planets were aligned to perform the leak down test..

I started running the car for roughly 4 minutes in order to heat it a little bit for the leak down test and also to listen to the car without aux belts.

Videos are here (engine was in a garage so maybe weird noise):
https://youtu.be/MCZ3Y4fIshc
https://youtu.be/t65fLh_N3hM

I have never heard it run so smoothly. No rattling at all. However, the idle was up to 1300rpm due to the removed belts and I didn't let it run more since I don't want to empty the battery. Nevertheless, when I started it 2 weeks ago it was rattling from the start and I was still having rattling with higher rpm as we can hear in the previous videos... finger crossed!

Regarding the leak down test, I take benefit from this topic to ask your opinion on the results. It was performed on a almost cold engine since I let it ran only 4 minutes and I lost some time before really starting the test (only the cylinder 5 was done straight after) engine running.



In psi and %:

98/94: 4% | 88/86: 2%
92/85: 8% | 90/89: 1%
93/88: 5.5% | 92/90: 2%
99/93: 6% | 98/96: 2%

Reminder, compression test:

12.5(180) | 13.5(185)
12.5(175) | 13(185)
12.5(175) | 13.5(190)
12.5(180) (counter test at the end: 13(185)) | 14(200)

Your thought? For me it is very good, even if I am little bit suprised by the results at the right bank, very low leakage. The right bank was the one running the richer (very rich) so it must be a little bit clogged and I wanted to do a leak down test in order to be sure that I don't have the weird case where a clogged piston can have better compression than normal..

For the next step, either I weld the alternator bracket and change the tensioner bearing either I run it longer without belts at a lower idle by adjusting the screws to be sure.. will see.

 

Looks good to me for the compression. Averaging out your compression numbers = 181.7 psi for all 8 cylinders. The left side averages out to 177.5 and the right side averages 186.25. Comparing left side to right side average there is a difference of 4.55%. From the lowest compression cylinder (175psi) to the highest (190psi) is a loss of 7.85%. From what I understand so long as the compression is within 10% of each other thats normal.

Your leak down test shows that the left side is leaking a bit more than the right side. Matter of fact the right side, with the 1% & 2% leak down, is solid. The left side seems okay, but you may want to look to see why the cylinder with 8% psi is low, and maybe even the cylinder showing 6%. Is the leak coming from and exhaust valves, intake valves, leaking past the rings, or a leak in the head gasket (but if the head gasket was leaking you would know it pretty fast, the exhaust would be billowing white smoke)? It could be something as simple as carbon build up on the valves and valve seats. You may want to try running a couple of cans of BG 44K ( https://www.bgprod.com/catalog/gasoline-fuel-system/bg-44k-fuel-system-cleaner/ )through a two of tanks of gasoline, give it the old "Italian tune up", then rerun your leak down test to see if the numbers change. You are basically trying to see if you can git rid of some carbon build up on the valves.

That is just my opinion.

 

Hello

Thanks for your reply ernie. Yes I indeed should have paid attention to where it was leaking on the 6 and 8% but I was just happy that all cylinders were having <10% leak.. will see afterwards if I check this.

Anyway, the business right now is on this noise.

Today I have removed the alternator and the broken bracket.
I had to remove the gearbox cable bracket since I wasn't able to remove the lower alternator behind... don't know if it is nominal or a too long bolt?

Here is the broken bracket:
http://rupp3r.free.fr/mondial/brokenbracket.jpg

I have then taken apart the bearing and the pulley.

http://rupp3r.free.fr/mondial/rustytensionerbearing.jpg

You can see that it is quite rusty there. The thing is there is no play in the bearing. All the axial and radial play is between the outer bearing race and the pulley.
The radial play can be seen in this picture:

http://rupp3r.free.fr/mondial/radialplaytensionerbearing.jpg

I don't really understand why. The bearing I have is 62mm OD and 14mm length so should be OK..
I am missing the spacer at the front and instead have two washers but don't think it is changing anything..
http://i.ebayimg.com/images/g/cmUAAOSwWTRWu6lt/s-l300.jpg

Due to the play I am feeling I don't think it is a difference in bearing class/tolerance, maybe my pulley is worn or I am missing something else?

 

Hello

Ok so after looking more in details the pulley, there is a step at the front of the bearing housing. Looks like something happened and the bearing has indeed turned inside the pulley which explains the big play in between.. However, don't know what could have caused this.

There is also a big hit on one side of the pulley.

http://rupp3r.free.fr/mondial/auxpulley.jpg

I have ordered a new pulley bearing and front spacer and will put everything back next week end, together with the now welded alternator bracket.

 

Hello

I have just received all the parts (pulley, bearing and front spacer) and mounted the assembly this morning.

Before rushing to the car, I had a look at this assembly and I can notice that if there is no play between the bearing and the pulley, the bearing can move quite freely between the pulley.
And then reminding the bearings mounting rules, the outer race should be the one fixed and not the inside one.. isn't it?
That should explain why my pulley was shot. I think I need to get some Loctite 638 to fix the outer race..

However, I am quite surprised since I haven't seen this issue anywhere here..?