Help needed !! Ferrari 308 1979 carburetor engine noise

Hello all , ( finally I found a way how to upload the video in this forum) may I get your help to listen to the car engine and timing gear noise from the videos below ?

I have just restored the full engine all the bearings are brand new !


Engine noise - seems not common and loud . Pls click the link below

https://youtube.com/shorts/4lDvX3bcCjU?feature=share


timing belt removed , I found the inner timing gears noise .

https://youtube.com/shorts/2o7eHAiOZEw?feature=share

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It seems that part 34 is making this noise . Is this sound common? and this is the factory design with some gaps ? ( sorry for asking as this is the only carb 308 in my country ) Or I am missing some parts that need to tighten timing gear ? Pls help and comment . Thank you !

 

Looking at the diagram that gear meshes with another one the same, the movement would be the clearance between the 2 gears. Is there any movement between the gear output shaft and the timing belt pulley. The pulley looks to be sitting on a woodruff key and these need careful fitting to get the correct tight fit

 

The drive gear is loose or not seated. . Or the bearing is damaged or the bearing may not be seated is my guess
Check to see if the inner drive gear noses are the same length on each sprocket .as in seeing how much thread is showing in the nut in the sprocket . Also do both sprockets stick out the same amount from the cover. Just a starting point. To see if the inner drive gears are fully seated to one another behind the cover.

 

Thank you ! I will check . Btw I forgot to say that BOTH gears have the sound ( loose).

 

just listened to the video of engine running and I didnt hear anything unusual . Listened again exhaust leak?

 

Motor sounds great !! , thats the extent of my ability to answer !!

Than you

 

I am very sorry , I post the wrong video ( the engine sound wasn’t so loud before but it’s now loud) . The video was taken few days apart and the noise get louder . I store the car for a few days on purpose to check on if the car can starts okie then I found this engine noise . The car is not on the road yet I was working on carb tuning and I need to get the rest done before I put on the road .

I no longer can edit the first video link above pls help to listen to THIS engine noise in the link below .

Thanks in advance !

https://youtube.com/shorts/dpKvaqADBXA?feature=share

 

Well I dont think that noise would come from the cam drives gears. I really dont know. Talk to your engine builder. That sux

 

the engine builder suspects the drive gears he listen the location of the noise using a hose. he then removed the belt and use his hand to turn the drive gear shown in second video . The issue we have is that this is the only carb 308 in my country and we don’t know is the drive gear suppose to be like this ( kind of loose fit ?) but we suspect it’s not z

So we will dismantle further on Monday and will check the bearings too ( although they are new when installed )

 

Ok good luck

 

The lower drives have helical gears, there's practically zero backlash. The lower drive pulley should not rock back and forth by hand. If they are, it could be due to a variety of things, however the builder should be able to identify exactly what.

As to the sound, always very hard to identify those. Sounds like it's in time with valve events.

 

Nasty. Can’t tell from vid where noise is. I would guess valve train but if you hear it low there are timing cover bearings that hold those gears

 

The tapping sounds like a loose valve clearance or exhaust leak. The bearing hum could be any of the bearings, use a mechanic’s stethoscope to touch on different parts (timing case, water pump, drop gear housing in the other side etc.) It is probably the cam drive bearings as they are a known weakness (which is why they switched to 44mm bearings on later engines.) Worn bearings would cause the backlash and could cause premature wear on the teeth. I assume you checked the nut on the pulley is still tight and the punched lip is still in the slot. They can come loose if not torqued and locked which then causes the woodruff key to wear.

 

Probably a silly thought but have you checked the oil level? Or what type did you use?


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This car has brand new bearings. I haven't heard of failures of the drive gear outer bearing on 2V motors but I have on QVs.

 

2V and early QV have the smaller 40mm bearing which are weaker and known to fail. There are also a lot of counterfeit bearings out there (many SKFs are fake.)

 

Finally I think I found the problem !! When I overvalued the engine I forgot to replace the inner timing bearing ![emoji2359][emoji2359] what a painful mistake . I have replaced the inner bearing and there’s no more sound ( not loose anymore) when you turn by hand . So I think I found the problem but a painful lesson because the bearing is less than 10 USD but it takes days to open up and replace the inner bearing ! Btw I have to replace both oil seals and both the inner and outer bearings ..

I just received the oil pan gasket ( need to go via oilpan area to remove the timing front cover) , and the front timing cover gasket . Let’s hope all is good after I re install them back and get my engine started again hopefully next week !

 

Did you replace the inner bearings with the engine in situ?

 

Actually Derek, this is partially true. While they both use the same bearing SIZE, the bearings are different. The QVs have no lubrication and no outer seal while the 2vs have an oil feed for the bearing that exits in the grip ring groove therefore lubricating the 2v bearing. The 2V has a seal as well. The QV has a sealed bearing, no lubrication and no seal for the outer bearing - which might explain the higher failure rate in QVs

 

Yes you need to remove the oil Pan and there is a screw needs to be removed from there so that the front timing cover can be removed . Very tedious job .

 

For what it’s worth, MN Exotics (one of the guys here) loaned me the tools needed to enable removing the nuts, sprockets, the bearings (with a small bearing puller) and seals all from the front/outside. It can be done without removing the lower cover.

 

Yes, not a simple job but straightforward. What I don't understand is why someone needed to change the inner bearings.

 

You have to remove the cover to get to the inner bearings. They seldom fail due to the constant oil lubrication and the low loads but I've heard of a few failing on this forum and elsewhere.

 

Okay , I have managed to change the inner bearings . When engine is cold there is no more noise . But when engine is hotter ie after 20 mins there’s slight noise ( no longer like before very noisy even at cold or hot engine ) . What could be the cause ? I was thinking of oil gets thinner when hotter . Or this is common across 308?

 

You have either a bad inner bearing or the hole where the bearing goes in is out of spec. For an engine this old, it is not too surprising. It's just a very difficult thing to change out, as you already know.