I know of a very good mechanic in the UK who has experience with both the 400 and 412. Send me a PM if you want his phone number. He will at least be able to give you a second opinion on if the engine needs to be pulled.
I do not believe the 412's headers will fit a 400i engine. They maybe similar blocks but the 412's engine is larger and I'm assuming this would effect the headers as I don't think the bores would match up.
Does your mechanic have experience working on Ferraris?
Hi , that seems logical that the bores might not match up. Pity though, I sourced a almost new set for $600! My mechanic has experience with another 400i and mine. But really is inexperienced if you know what I mean. He learns on the job, and it costs me. Some bonehead cut off the flanges from the headers and welded straight pipes to them. I replaced the whole exhaust system, and had the shop weld new flanges on the headers. But the welds are not good as he welded them while the headers were still on the car. Sooooo, now I want to have the headers removed and welded properly or replace the headers. Geezz.. Do you know if the headers can be pulled without lifting the engine?
You can definitely remove and refit the headers on a 400 Carburettor with the engine in situ - I have done this. I can't see why a 412i would be really any more difficult. Takes about a day.
You certainly need the correct nuts on a 400. These are copper and are called 'half-nuts' in the UK. Full size nuts won't fit between the bend in the header pipe and the stud on some cylinders (Nos 2 and 11 as I recall). Half-nuts are about half the height of a full size nut.
good info, thank you. My 400i is a 1985 fuel injected model. It should not differ too much than a carbureter model, removing the headers. It is good to know that it can be done in situ. I suppose it is important to replace all the old nuts when replacing headers? if so I will get them. I allready sourced the gaskets at the head, and I probably have to get the gaskets at the exhaust end replaced too?
PS: I just found out that the 412 Headers will fit a 400i. Apparently the head end gaskets and the bore sizes are the same...
You will definitely need new head/exhaust gaskets and also the donuts betwen the headers and the rest of the exhaust, plust the bypass pipe gaskets. The headers come off with the car on a decent set of axle stands, you don't need a lift.
I would definitely sugeest that you recondition the starter whilst the headers are off the car (don't ask!!). I would also suggest that you make sure the battery is disconnected before removing the headers (definitely don't ask!!).
You need a 'special' spanner to remove the starter motor. This is actually a 17/19mm combination spanner which is quite short. A suitable one can be found in the toolkit roll from any Mercedes Benz form the 80's/90's.
My 400 had a starting problem. When it was hot the starter would not work. I thought it was a relay and had just changed the relays and the battery. I had had this problem on and of for two years and the latest changes seemed to have cured it but I still had a nagging feeling setarter was the real culprit. Anyway I had the headers off and made a concious decision not to change starter as it was more money which I could not afford. I fitted the new headers and a week later (yes 7 days) the starter packed up completely. I ended up having to take the headers back off and change the starter. I was rushing to get the headers off and didn't disconnect the battery, dropped a spanner which shorted out the main positive feed to the starter against the block. The connection should have had a rubber sleeve on it but it was missing. Good firework show an no lasting damage fortunatley.
I hate it when I do things like that! having to start all over again, and then some epic mishap happens! Sounds like you were very lucky though, with fireworks but no damage.
After all this brain storming and lining up small parts for the 412 headers, The seller backed out! He had been nagging me over and over, and when I accepted, he raised the price! Then I accepted again, and then he declined again and listing them on Ebay! Still cheap , but I don't have the heart to deal on that type of basis.
Now I 'm thinking back to plan 1. Take the headers off, weld the flanges correctly, repaint the headers, and stick them back on.... :roll:
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