Technical Awful sound after 500 -> 650 conversion

[Graabein]

Hi all!

I recently did a conversion from 500 cc to 650 cc on my -69 Fiat 500L.

Both engine and transmission was replaced.

At first there was a not to obvious knocking sound when I was driving. But after a while, it got really bad. I have added a link to a movie filmed inside the car when cruising with the engine off.

The sound is related to speed, and not rpm. The sound is there in all gears.

Does anybody have an idea about what this might be?

I cannot replicate the sound with the car jacked up.

Sorry about the english, I'm from Norway

https://dl.dropboxusercontent.com/u/152310/IMG_2178.MOV

 

[p6baseunit]

Think you are in the wrong forum section as this is for the modern Fiat 500

 

[jrkitching]

Think you are in the wrong forum section as this is for the modern Fiat 500

Moved .

You should have more luck with a meaningful response here.

 

[fiat500]

I would check that the 4 hub-flange bolts are tight and think, is the circlip on the end of the driveshafts? Have you possibly got a stone stuck in the area around the alloy coupling?

 

[thepuddlejumper]

Hi, during the conversion did you swap over the 500 drive shafts. The 500 drive shafts are I think 18 mm shorter than the 126 shaft so they must be changed over. This causes a knocking during driving as the gap between the end of the drive shaft and stub axle is almost zero. Another cause could be broken or missing springs between the shaft and stub axle allowing the shaft and axle to make contact.

Ralph