850 Sport Coupe series 2 track car.

A new alternator is now installed. I had to make a pulley out of an old power steering pulley. I machined up the original V pulley for the centre and bolted and glued the outer section. The old pulley was 50mm. The new one is 110mm. Rpm range is now 2000 to 11,000 rpm. The engine idles at 1500 and that gives 13.8v. The load on the engine is noticeably less so I should pick up some power!
New alternator.jpg
 
Brief trackday today. Couple of laps in on the practice session and the gearbox failed. Hopefully I have it all on video. I have three spare boxes at home and a new final drive to go in so this sounds like the ideal time.
 
Talk about a crappy day, I have just found out that I failed to start my camera!
Yesterday just after I was towed back to the pits there was this Finnish bloke waiting for me. I had talked to him previously and he owns a Lombardi with a 903cc engine and gearbox. He asked me to start the engine and select reverse and first. The car bucked dramatically. Jacked up the rear and rotated the wheels and they were OK but there was an occasional click on one side. He tells me that when he lived in Finland he built a lot of these gearboxes for ice racers and that the factory did a particularly poor job setting up the ring and pinion gear and this was a regular failure with this gearbox. He also said that using hypoid gear oil was absolutely critical. For the last few months I have been using Redline MTL and I just read the label. Not for use for hypoid gears!
 
ramona300 said:
I should add that when the Finnish gentleman was looking at my car he reckoned I should have an oil cooler and 12v pump for the gearbox.
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I am enjoying this thread, but I noticed all the earlier pics are gone. Any chance we might get you to reload them? Thank you!
 
Well, that Finnish gentleman was spot on. The ring and pinion look particularly secondhand! The gearbox itself seems OK.
crown and pinion 28-4-23.jpg
 
I have decided not to change the ring and pinion gear in one of my spare gearboxes myself.
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I took the gearbox to a local shop that does manual gearbox repairs. Their main business is wheel alignments and I have had my 3 cars there at various times. They were very happy to be working on the little red Fiats gearbox! The job is not all that difficult but I was concerned about setting up the diff correctly and finding the right size shim behind the pinion. I'm fairly sure the problem I had was probably when I installed the drive shafts many years ago and did not have the adjusters locked in place. As I was poking about getting the shafts in I probably loosened off the adjusters. There is too much noise inside the car to hear diff noises! The wrong oil probably finished the job!
 
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ramona300 said:
I have decided not to change the ring and pinion gear in one of my spare gearboxes myself. View attachment 73013 I took the gearbox to a local shop that does manual gearbox repairs. Their main business is wheel alignments and I have had my 3 cars there at various times. They were very happy to be working on the little red Fiats gearbox! The job is not all that difficult but I was concerned about setting up the diff correctly and finding the right size shim behind the pinion. I'm fairly sure the problem I had was probably when I installed the drive shafts many years ago and did not have the adjusters locked in place. As I was poking about getting the shafts in I probably loosened off the adjusters. There is too much noise inside the car to here diff noises! The wrong oil probably finished the job!
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That pinion looks absolutely gnarly. I have seen them (not a 850) nearly rounded off with both gears completely destroyed.
 
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