850 Sport Coupe series 2 track car.

This is the 2023 Fiat Nationals Sprints at Broadford circuit, Victoria, Australia. This is just a photo shoot before the start. It's a great little circuit with a lot of hills! I never had a great day and finished just the first session and had to retire with a blown main rear crankshaft seal. I knew I had a problem when the sintered clutch slipped! I probably topped up about half a cup of oil. The engine was hot and that synthetic oil leaks well. So the gearbox is coming out again! I'm not sure how the sintered clutch will fare with all the oil. The interweb says brake cleaner will clean it up. I will try it and see.
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Stripping all the stuff down so I can drop the gearbox tomorrow. Grandkids to do the heavy lifting! I pulled
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the clutch cover off and I expected to find oil everywhere! The thrust bearing and the spring have some oil on them but the sintered clutch and the flywheel are spotless. Some oil on the bottom of the flywheel as you would expect and I'm guessing while driving the oil was flung everywhere inside the bell housing.
 
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I changed the rear main crankshaft seal yesterday. The seal had failed due to my stupidity above. It had been leaking previously but just the odd drop, the engine oil must have been a lot hotter than normal this time. The old seal was a genetic one that was probably installed by the mechanic who owned my car in the seventies when I did not own it for a period. The new seal is for CCW engines and the rubber inner lip was impossible to fit before I made up a tube for it to slide off. The pipe is a bit of an exhaust pipe with an outer diameter of 63mm. I machined a slight bevel on the inside edge. I slopped oil over it and just pushed it hard up against the end of the crankshaft. Gave the seal a bit if a twist and tapped the seal straight in. Worked a treat. Now the bit of pipe with the old seal on it will live in my drawer!
 
On Monday I had my last trackday for 2023 at Sydney Motorsport Park on the Druitt circuit. The car ran well all day with the only niggle being a fast idle after the last session. I suspect there is an air leak on the throttle body manifold. It was a fairly hot day and my lap times got longer as the day wore on. An interesting group of cars included two 240zs, two Alfa
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s, a Purvis Eureka 2L, a Ginetta and several MGBs Sprites and MG Midgets. I could overtake one of the 240zs and a couple of MGBs and Sprites but most of the day I was watching in my mirror as the faster cars blasted past! The Druitt circuit is a fast flowing circuit with corner one being the fastest corner in Australia. My car handles well but on this circuit, the tyre rubber has got too much grip and the car sort of jumps sideways in the rear. The rubber forms lumps around the circumference and makes the ride rough till it wears off. I have a small amount of toe in on the rear and will have to do some research in this area.
 
String line wheel alignment for the toe is now done. I have settled for 0 at the front and the rear is 2mm in per side. The right rear was about 3mm out! The left rear was in so doing an alignment using a centreline is fraught with problems. The car is aligned with 86 kg in the driver's seat.
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The string line in my case was thin SS wire. I started by setting up a perfect rectangle from the centre of each wheel. The track is different from the rear to the front. I used a pressure pack lid which conveniently had a centre and set up the rear first with the distance the same on both sides. Then the front but you have to just keep going back and forward to the gaps are right.
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Next week I have a trackday followed by a hillclimb. It's a short circuit with fairly slow corners so won't know how much difference the new settings make.
Then it's on to the next mod. Air/water intercooler. Unfortunately, this means a heat exchanger on the front of the car which will spoil the looks a bit!
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I had a successful track day on Wednesday, and the car came home in one piece! First outing after correcting the wheel alignment. First couple of laps were interesting. The steering was initially quite different with zero toe in. The build up of rubber on the rear wheels took a couple of laps to smooth out but then it was brilliant. This was a short circuit so the speed was down compared to Sydney's main circuit. Car felt very safe.
 
Reminds me of when I was racing. It was usually something but that feeling when it all comes together can’t be described.
 
I had the plugs out and I decided to check the tappets. I have had to modify the rocker cover oil filler so the intercooler fits over so I took this opportunity to do it as it will be a big job once it's installed to get the cover off. I was alarmed by how slack the 4 ribbed belt for the supercharger was. I could easily slide the belt around by hand! When I looked at a few recent data logs it was obvious it had been slipping for a while! These flat belts are difficult to get right and after one breakage I was over cautious on setting the tension. This obviously was the cause of my poor performance at the last hillclimb where I was beaten [only just] by a 1050 cc twin side draft Weber car!
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ramona300 said:
I had the plugs out and I decided to check the tappets. I have had to modify the rocker cover oil filler so the intercooler fits over so I took this opportunity to do it as it will be a big job once it's installed to get the cover off. I was alarmed by how slack the 4 ribbed belt for the supercharger was. I could easily slide the belt around by hand! When I looked at a few recent data logs it was obvious it had been slipping for a while! These flat belts are difficult to get right and after one breakage I was over cautious on setting the tension. This obviously was the cause of my poor performance at the last hillclimb where I was beaten [only just] by a 1050 cc twin side draft Weber car!View attachment 81977
Click to expand...
I'm not sure but the only recognizable Fiat 850 part I see is the alloy motor mount.....Oh! there's the oil filler cap also!
 
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