Technical Bad week for the Bambina

[nzbobc]

I've been troubleshooting what I thought was water in the fuel system and after draining the fuel line and pump, I went for a test ride and now the high beam switch no longer functions properly. The car was still coughing so I drained and cleaned the fuel tank and carb. Took it for another test drive and the speedo light is now on the blink. A couple days later, took a friend for their first ride and the bolts that hold the exhaust onto the engine block fell out! Never even heard that one coming! What a week!!! Geez, the car is falling apart faster than I can fix it! For the month prior to this that we've owned it, it's been just fine. We're thinking that maybe the prior owners haven't used it that much recently.

So, in order to stem the flow, we're gonna just replace all the usual maintenance stuff and give the rest of the car a good looking over.

But, do you know what size the bolts are that connect the exhaust onto the engine block for a 650cc? And, looking at Axel Gerstl's site, there's several different types of exhaust gaskets listed. Some with metal rings, others without. Which one is needed between the block and the exhaust?

Thanks!

 

[Paolo66]

The exhaust goes onto the engine block by way of 4 8mm nuts onto studs in the block. Whenever I've removed gaskets they have always been the metal type with gasket sealant

 

[Damon500]

Sorry to hear you have Bambina bothers! The gaskets between the mainfold and engine have metal flame rings are a different size to the manifold / exhaust gaskets which usually don't have a flame ring. There should be 2x M8x1.25mm bolts with 13mm heads holding the manifold to the head but by now many have been retapped to a variety of different thread sizes so don't be surprised if they are different or the threads are stripped out of the cylinder head.

Usually if the manifold bolts come out it is because the alignment of the exhaust system is incorrect which can be due to incorrect angles of the manifold pipes. The manifold-head bolts should be the last ones tightened and the manifold should touch the head without needing to use the bolts to clamp it towards the head. If the alignment is significantly out the best solution is to heat the downpipes with an oxy torch to red hot the whole way around on the bends when the exhaust is tightened down to relieve the stress.

If your head threads are in good condition and alignment is correct you should have no problems- I used to have lots of Bambina exhausts falling off in early days but since aligning the exhausts properly I haven't had one come off in the last 20 years.

PS. For those of non-New Zealand background a "Bambina" is the NZ name and badging for the Fiat 500F models assembled from Kitset packs in NZ from 1965-71 but it later came to be universally used to describe all Fiat 500 models- there is even a book on the subject called "Bambina" which is a good read!